The Social Costs of Air Pollution from Cars in the UK

By Neil Lock

August 2017

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Back in April the mayor of London, Sadiq Khan, introduced from the coming October a £10 a day “toxicity charge” for pre 2006 cars, both petrol and diesel, entering the current London congestion charge zone. He also set out plans for a London “Ultra Low Emissions Zone” (ULEZ) [[1]]. From April 2019 (brought forward from September 2020), it will cost £12.50 per day to drive in this zone a diesel car first registered before September 2015, or a petrol car built before 2006. Furthermore, he plans to extend this zone to the area inside the North and South Circular roads by 2021.

It was also mooted that drivers of diesel cars first registered before September 2015 should be charged to enter any of up to 35 cities around the UK. In some cases, there would also be bans on diesel cars driving into cities at certain times of day. This raised the spectre of greedy, activist, anti-car councils all over the UK imposing arbitrary bans and heavy charges on diesel drivers who enter, or drive within, their areas.

More recently, as reported by the Daily Mail [[2]], the government has said such measures are intended only as a last resort, only for the dirtiest cars and only when they are actually using the few dozen roads which have been identified as the worst polluted. However, it still isn’t clear what other punitive taxes they are planning in an effort to force people out of diesel cars.

I myself drive a 2011 diesel car. When my previous (petrol) car failed in early 2014, I was looking for a car to keep running at least until 2023 (when I will be 70), and hopefully many years longer. I didn’t intend to or want to buy a diesel. But I couldn’t find a petrol example of the model I wanted. I later found out this was because the manufacturer had made 40 diesel cars of that model for every petrol one. So, as I approach retirement, I’m likely to be stuck with a car I can’t afford to replace, and taxes and charges I can’t afford to pay.

Social cost

My immediate reaction to the proposed schemes was that the charges seemed outrageously high. So, having long ago been trained as a mathematician, I decided to try to calculate the “social cost” of the pollution from cars in the UK, so I could compare it with the proposed charges.

Social cost is the total expense, to all those affected, of the effects of an activity. In the context of pollution, the term is used to mean the total cost of the “externalities” (that is, secondary or unintended consequences) caused by the pollution, and specifically by its effects on health.

In making these calculations, I uncovered some interesting backstory on the issue, some of which may be new to many people. So, my purpose today is twofold. One, to tell the backstory as best I can. And two, to come up with some rough figures of how much people ought to have to pay for the health effects on others of driving their diesel or petrol cars. So, what I’m going to do is work out this social cost, as best I can, as a number of pounds per car per year. And then I’m going to break it down among cars of various ages, according to the emissions standards which were in force at the time they were built.

The players

As in almost any governmental activity, there’s an alphabet soup of agencies involved. Here is a list of the major players in the case.

· WHO (World Health Organization). This is a United Nations agency, concerned with public health on an international level. It issues “guidelines” which, in matters of air quality, offer global guidance on thresholds and limits for key air pollutants that pose health risks.

· COMEAP (Committee on the Medical Effects of Air Pollution). It provides independent advice to UK government departments and agencies on how air pollution impacts on health.

· DEFRA (Department for Energy, Food and Rural Affairs). Its involvement in the case includes: Reporting on emissions of air pollutants in the UK as a whole. Making calculations on the social costs of pollutants as an input to policy, on the basis of guidelines provided by COMEAP. Providing information to the public on air pollution, limits and targets, and air quality policy.

· HPA (Health Protection Agency). It produced a significant 2010 report on COMEAP’s behalf.

· RCP (Royal College of Physicians). Together with the RCPCH (Royal College of Paediatrics and Child Health), it produced a 2016 report on the long term effects of air pollution in the UK.

· LAQN (London Air Quality Network). It reports, since 1993 and normally yearly, on air quality at various sites in inner and outer London, including kerbside, roadside and urban background sites. These reports indicate how well the air quality meets (or not) the limits and targets it is supposed to.

The pollutants

For cars, two pollutants are of interest: particulate matter (PM) and nitrogen oxides (NOx).

Adverse health effects from PM come mainly from one kind of PM, called PM2.5. These are particles smaller than 2.5 micrometres. The calculations made by COMEAP and the HPA regarding the health effects of PM have all concentrated on PM2.5.

As to nitrogen oxides, the generic term NOx means a combination of two oxides of nitrogen, nitric oxide (NO) and nitrogen dioxide (NO2). Since NO rapidly oxidizes to NO2, measuring it is done, in effect, by measuring NO2. Hence, in the context of air pollution, the terms NOx and NO2 are often used interchangeably.

Air quality limits and targets

In the UK, air quality standards are the province of DEFRA [[3]]. According to DEFRA, “Action to manage and improve air quality is largely driven by European (EU) legislation. The 2008 ambient air quality directive… sets legally binding limits for concentrations in outdoor air of major air pollutants that impact public health.” The 2008 directive was incorporated into English law in 2010, around the time of the change of government from Labour to the Coalition.

The standards are supposed to be “acceptable in terms of what is scientifically known about the effects of each pollutant on health and the environment.” Broadly, there are Limits and Targets. Limits are “legally binding EU parameters that must not be exceeded.” Targets are “to be attained where possible by taking all necessary measures not entailing disproportionate costs.” For the pollutants of interest, they are specified as annual concentration means, or as the mean over a period of time within a day, with an allowed number of exceedences.

Emissions standards

The EU sets emissions standards for vehicles for both PM and NOx [[4]]. UK standards have generally been kept in line with EU ones.

Every five years or so, the EU makes new, tighter standards. The vast majority of cars now on the road in the UK were required to be built to one of four standards: Euro 3 (applies to cars built since 2001), Euro 4 (since 2006), Euro 5 (since September 2010) and Euro 6 (since September 2015).

For PM, the limits to be met by diesel cars have been successively reduced. Thus, Euro 5 and 6 diesels produce only a tenth as much PM as Euro 3 ones. For petrol cars, no limit was set until Euro 5, and this only applies to cars with direct injection engines (and is the same as the limit for diesels of the same year).

For NOx, the standards for both petrol and diesel cars have also been tightened between Euro 3 and Euro 6. Of course, for diesels this is somewhat moot, since it’s now clear that most diesel cars don’t actually meet, in the real world, the NOx limits they were supposedly designed for.

Half a century of progress

DEFRA produce each year a statistics release on emissions of air pollutants in the UK over that period. This covers pollution from all sources, not just cars. The latest report [[5]], published in December 2016, covers the period up to 2015.

As the graph on page 2 of the report shows, progress in reducing air pollution in the UK over the period of almost half a century since 1970 has been most impressive. Levels of PM2.5 in 2015 were less than a quarter of what they had been in 1970, and levels of NOx less than a third. And I don’t remember the air being badly polluted back in 1970, at least not where I lived. Haven’t we done well? Which prompts the question: having done so well, why should we be expected to make any more sacrifices?

Reports, Reports, Reports

There are five UK reports, on which I’ve based my calculations. I’ve put them in chronological order. If you’re not interested in the gory detail, you can skip to the next section, as I’ve included brief summaries and some headline quotes from the documents below.

· COMEAP, “Long-Term Exposure to Air Pollution: Effect on Mortality,” 2009 [[6]].

· HPA (on behalf of COMEAP), “The Mortality Effects of Long-Term Exposure to Particulate Air Pollution in the United Kingdom,” 2010 [[7]].

· DEFRA, “Valuing impacts on air quality: Updates in valuing changes in emissions of Oxides of Nitrogen (NOX) and concentrations of Nitrogen Dioxide (NO2),” September 2015 [[8]].

· COMEAP, “Interim Statement on Quantifying the Association of Long-Term Average Concentrations of Nitrogen Dioxide and Mortality,” December 2015 [[9]]. This included a copy of the recommendations COMEAP previously made to DEFRA in July 2015.

· RCP and RCPCH, “Every breath we take: the lifelong impact of air pollution,” February 2016 [[10]].

Early Deaths and Mortality Costs

Most people will have heard sound bites like “23,500 early deaths a year” caused by the “toxic fumes” of nitrogen oxides. Or even 40,000. But this doesn’t mean at all that each year there are 40,000, or even 23,500, corpses with death certificates that say “Killed by pollution from diesel cars”. Rather, calculations suggest that of the people who died in a given year (in this case 2013), about 23,500 had lost a certain fraction of their lives due to NOx pollution from all sources. That fraction turns out to be about 11.7 years on average. This can equally well be put as a loss of life expectancy from birth, for everyone, of a little less than five months.

To match that 23,500 figure, DEFRA give a social cost figure of £13.3 billion. Big scary number, heh? Dividing out, I get £566,000 per death caused by pollution.

I haven’t found any document justifying this number of £13.3 billion. Some seem to think it only includes the effects of the pollution on those who die of it, not on everyone. (In technical terms, only “mortality,” not “morbidity”). But looking at reports from as far back as 2004, it seems that DEFRA do aim to include both lethal and non-lethal health effects in their calculations. And they use the term “social cost” without qualifying it to say that it includes some costs but not others.

The backstory on PM

I’ll deal with PM first. Not only because it was the first of the two pollutants to be investigated in terms of health effects, but also because the backstory is less controversial, and the calculation less convoluted, than for NOx.

Following the 1992 Rio summit, attention was directed for the first time at trying to quantify the health effects of long term exposure to air pollution. A major study on PM2.5 was carried out in the USA on behalf of the American Cancer Society in about 1995, and updated in 2002.

The 2009 COMEAP report

The first UK specific report on the matter was produced in 2009 by COMEAP [6]. Broadly, they agreed that the approach used in the 2002 US study was applicable in the UK too. They set out to estimate the value of the “risk coefficient” which should be used. (The risk coefficient is the percentage chance of death from a pollutant for a given unit of change of concentration. In this case, the unit of concentration was 10 micrograms per cubic metre). They agreed that the risk coefficient suggested by the US study, 6 per cent (also sometimes stated as a “relative risk” of 1.06) would also be appropriate as the best estimate of the risk in the UK.

However, they were unsure about the level of confidence that ought to be placed on this estimate, as it appeared that standard statistical methods could not be used. They therefore used a novel method they called “expert elicitation.” Seven experts each made judgements on how likely they thought the risk coefficient was to be above each number from zero to 17 per cent. The results were pooled, and they concluded that the uncertainty in the risk estimate was so high that the true value of the coefficient could be anywhere between 1 per cent and 12 per cent. And even the chance of it being inside that range was only three-quarters.

As you can see from the numbers on page 157 of the report, the experts came up with wildly different ideas. One, expert A, gave almost every percentage the same chance. In other words, he was saying “I have no idea at all what the true risk value may be”. At the opposite extreme, expert D reckoned there was a 50 per cent chance of the value being less than 1 per cent. That’s an order of magnitude lower than the “consensus” estimate of 6 per cent.

So, there is very little certainty in this report’s central estimate. There is a factor of 12 between the upper and lower bounds! Imagine if a businessman asked one of his staff to estimate the cost of a project so he could work out whether to go ahead with it or not, and got the answer “between £1 million and £12 million.” Or if an engineer wanted to know how big a plug he needed to stop a particular gap, and was told “between an inch and a foot.” And yet numbers with such wide error bounds, it seems, are considered good enough for social engineering. They are seen as good enough for making political policies which will severely affect, and if got wrong will unjustly hurt, millions of people. They’re “good enough for government work.”

The 2010 HPA report

The next report was produced in 2010, on COMEAP’s behalf, by the HPA [7]. This used the figures from the earlier COMEAP report to derive specific estimates of mortality rates due to PM2.5. The headline conclusion was:

“An effect on mortality in 2008 of nearly 29,000 deaths in the UK at typical ages and an associated loss of total population life of 340,000 life-years. The burden can also be represented as a loss of life expectancy from birth of approximately six months.”

To their credit, the HPA went out of their way to make it clear that this did not mean 29,000 death certificates with “PM2.5” as cause of death. At one extreme, it meant that 29,000 people who died in 2008 could be considered to have lost on average 11.7 years of their lifespan due to the effects of PM2.5. At the other, it meant that everyone in the population would on average have their life expectancy lowered by about six months due to these effects.

The HPA were also careful to stress the huge uncertainty in COMEAP’s risk estimate. They said:

“Using the 75% plausibility interval suggested by the expert elicitation in COMEAP (2009) this means a range of effects on mortality equivalent to 4,700–51,000 deaths with a loss of 55,000–597,000 years of life in 2008, or effects on average life expectancy of between 1 month and one year, for England and Wales.”

The formula they used

I reverse engineered the calculation the HPA did for 2008 mortality due to PM2.5 in the UK as a whole, using the data on pages 61 and 65-67 of their report. This is the formula I think they used:

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Here, clip_image006 is the total deaths in the population aged 30 and over (568,680). clip_image008 is the risk coefficient (6% or 0.06). clip_image010 is the actual concentration of the pollutant (8.97 micrograms per cubic metre), and clip_image012 is the unit of concentration for which the risk coefficient is estimated (10 micrograms per cubic metre). When I plug these numbers into the equation, I get a figure for clip_image014 of 28,874, against the HPA’s 28,861. The difference, I think, is explained by the HPA having used in their calculation a more accurate value of the concentration (8.966 rather than 8.97) than the rounded one they gave in the report.

It struck me that there is a less sensationalist, and perhaps more informative, way to express this number than in deaths per year. The fraction

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represents the proportion of all deaths in the year, of those who died aged 30 or older, which can be attributed to this specific cause. Using the HPA’s figures for UK wide PM2.5 in 2008, this comes out as just over 5 per cent (to three significant figures, 5.08%). So it’s possible to re-state the “29,000 deaths” meme as: “Among people who died aged 30 or older in 2008, just over 5 per cent died as a result of long term exposure to air pollution by particulate matter.”

It’s also worthy of note that the equation is linear in the concentration, clip_image010[1]. As I understand from the HPA report, this is OK for small values of the concentration, where clip_image010[2] is smaller than, or not much greater than, the unit clip_image012[1]. But it wouldn’t be correct, for example, to calculate the figure for 1970, when PM2.5 levels were four times those in 2008, as four times the above, and so to say “over 20 per cent of deaths over age 30 in 1970 were due to particulate matter pollution.” I’d be interested to know what COMEAP and HPA think was the percentage of deaths attributable to PM back in 1970.

A sanity check

I always like to sanity check my results by comparing with figures calculated in different ways from different sources. So, I looked at a WHO fact sheet [[11]]: “Ambient air quality and health.”

It gives an estimate of 3 million premature deaths world-wide caused by air pollution of all types in 2012. It also says that 92 per cent of the world population live in places where the WHO’s air quality guidelines are not met. Now the UK’s population in 2012 was 0.9 per cent of the world population. So if the UK was average in pollution among all countries, we would expect about 27,000 of these deaths to be in the UK. But we know that the UK does meet the guidelines for all pollutants except NOx; it’s in the least polluted 8 per cent of the world. So either the WHO’s number is low, or the HPA’s 29,000 for 2008 – and that’s for PM2.5 on its own! – is over the top.

The per-car social cost of PM from diesels

To work out the social cost of PM pollution per diesel car per year as at 2008, I needed to find out some more numbers.

· The fraction of PM2.5 emissions attributable to road transport in 2008 – 24 per cent, from [[12]].

· The fraction of these emissions attributable to diesel cars as opposed to other diesel forms of transport. (I assumed that PM emissions from petrol engines were negligible compared to diesels). In a National Statistics fact sheet on fuel consumption [[13]], I found a graph of fuel consumption by vehicle types for a number of years, including 2008. This shows that diesel car fuel usage, and so presumably emissions, were one third of the total for diesels.

· The number of diesel cars on UK roads in 2008 – 7.16 million, from spreadsheet VEH0203 at [[14]].

I was now ready to calculate the social cost per car for emissions of PM from diesel cars as at 2008. It came out to £183 per car per year. So, if the numbers going in to my calculation are accurate, the problem of PM pollution from diesel cars was real back in 2008.

Apportioning PM costs from diesels between Euro standards

Next, I needed to apportion this cost of £183 between cars of different ages. In 2008, Euro 4 was the newest standard, having been in force since January 2006. I used spreadsheet VEH0207 at [14] to calculate how many of the cars on the UK roads were less than three years old in 2008. I assumed that the proportions for diesel cars were roughly the same as for all cars. I also assumed that the cars older than Euro 4 were, on average, meeting the Euro 3 standard. Dividing the social cost between these in proportion to the PM levels allowed by the standards, gave a social cost per car per year of £207 for Euro 3 and £103 for Euro 4 cars. And, as Euro 5 marked a five-fold decrease in the PM limit, with no further decrease for Euro 6, the social cost per car per year came out to £21 for both Euro 5 and Euro 6.

Note that these social cost figures don’t depend on which year the data came from. As long as it keeps to the same standards it was originally built to, the contribution of any individual car to the social cost, ignoring inflation, will remain the same from one year to the next.

The backstory on NOx

Now, it’s time to look at NOx. The history is chequered. It begins in 2001, when prime minister Tony Blair, chancellor Gordon Brown and chief science adviser David King decided to offer incentives to drivers to buy diesel cars. They did this, supposedly, because diesel engines emit less carbon dioxide (CO2) per mile than petrol ones, and so were expected to cause less putative “global warming!”

By early 2006, a problem was becoming apparent. Insiders at the European Federation for Transport and Environment [[15]] had found out that, in the “real world” as opposed to laboratory testing, emissions of NOx from diesel engines were much higher than the emissions limits the cars were supposedly built to meet.

And this had effects on measured air quality, too. The LAQN’s report for 2006 and 2007 [[16]] – which, curiously, wasn’t published until 2009 – stated that the EU limit value for NO2 was being “consistently exceeded at background sites in inner London and at roadside sites throughout London.” And that the increases: “are thought to be due to changes in diesel vehicle technologies … and an increase in the proportion of diesel vehicles on London’s roads.”

More curiously still, the LAQN report for 2008 wasn’t published until November 2012. In contrast to earlier reports, it was slim. It had no management summary, had only raw data with very little accompanying text, and drew no conclusions. The 2009 and 2010 reports followed during the next month. It’s hard to avoid the suspicion that Gordon Brown, the prime minister in 2009/10 and one of the architects of the diesel scheme, had the original 2008 report suppressed. And that the Coalition either didn’t find out about it, or continued to suppress it, until 2012.

In early 2014, the NOx problem became “official,” with a court case brought against the UK by the European Commission [[17]].

In July 2015, COMEAP issued guidelines to DEFRA on how to estimate the mortality associated with NOx pollution. These are attached to reference [9]. They suggested a risk coefficient of 2.5 per cent, with a range of uncertainty from 1 per cent to 4 per cent. I haven’t found any document justifying these numbers, so I can’t assess how good or bad they might be.

COMEAP also suggested that this coefficient should be reduced by up to 33 per cent when calculating NOx health effects in conjunction with PM, to avoid double counting. They also made a caveat: “there is uncertainty in the extent to which the association between long-term average concentrations of NO2 and mortality is causal.” So, the science is not “settled” at all!

In September 2015, DEFRA issued their report on NOx [8]. The bottom line, for NOx alone and based on 2013 data, was a central estimate of 23,500 deaths and a £13.3 billion social cost. This is the source of the 23,500 deaths figure you hear in the media. The ranges were from 9,500 deaths to 38,000.

Around the same time, September 2015, the Volkswagen diesel scandal erupted in the USA. The fact that many diesels failed to meet the emissions standards they were supposed to have been built to – known to insiders as early as 2006 – became public knowledge for the first time.

In December 2015, COMEAP issued revised guidelines [9]. They said that the combined effects of PM2.5 and NOx together might not be any greater than the effects of PM2.5 or NOx calculated individually. Meaning, that the overlap factor by which one result should be reduced, before it can be added to the other, would be higher than the 33 per cent they had previously reported, and might be as high as 100 per cent. They also admitted that their previous figures of mortality effects of PM2.5 were probably over-estimated.

The RCP report

In February 2016, the RCP and RCPCH published their report [10]. The chair of the RCP’s working group, Stephen Holgate of Southampton University, was also on the panel that produced the COMEAP report back in 2009. (I wonder which of the seven experts he was?) And the vice chair, Jonathan Grigg, was quoted in the mayor of London’s press release [1]: “To maximise the effectiveness of this initiative, the Government must now act to remove the current toxic fleet of diesel cars, vans and buses from all our roads.”

Even the title of this report is alarmist. It has a general tone of rampant greenism and nanny-statism. And it includes the phrase “climate change” more than 70 times. This is zealotry, not science.

The bottom line paragraph in this report goes as follows:

“When quantifying the total impact associated with exposure to both NO2 and PM2.5, it is therefore necessary to account for this overlap in the response functions. Defra estimates that the annual equivalent number of attributable deaths associated with the two pollutants combined is 44,750–52,500, with an associated annual social cost of £25.3 billion – £29.7 billion. However, a subsequent paper issued by COMEAP in December 2015 indicates that the level of overlap in estimates between pollutants may be greater than originally thought. On this basis, while recognising that COMEAP’s research on this issue is continuing, this report adopts a combined estimate of effect of around 40,000 deaths annually with an associated annual social cost of £22.6 billion (both with a range for a central estimate of ±25%).”

That’s where the headline-grabbing figure of 40,000 deaths came from. For the overlap factor, they have reduced the NOx deaths figure, before adding the two together, by a little more than half. And the reduction in the risk coefficient is also a little more than half. This is plausible, given COMEAP’s advice. But the range given, ±25%, is way less than the error bounds in the numbers we started with – a factor of 12 for PM and a factor of 4 for NOx. That can’t be right.

The per-car social cost of NOx

The calculation for NOx is made harder than the one for PM by three things. First, DEFRA’s deaths figure is based on 2013 data, not 2008. As I don’t have numbers for 2013 on emissions from different types of transport, I’ll have to move my window to a different year. So I’ll use a year, 2015, for which I do have the data I need to complete the calculation. Second, petrol cars emit a significant amount of NOx. So their share has to be taken into account. And third, I want to estimate the cost of the manufacturers’ failure to build their diesel cars to the standards they were supposed to meet. So I’ll need to do the diesel calculations twice over: once with real world emission levels, and once with the values from the standards.

The first step is to move DEFRA’s deaths figure of 23,500 from 2013 to its equivalent in 2015. NOx levels in 2015 were roughly 11 per cent lower than they had been in 2013. But the total number of deaths of people aged 30 or older increased from 2013 to 2015 by about 4.6 per cent [[18]]. So the equivalent deaths figure for 2015 comes out to 21,883, to the nearest individual.

Now, the other numbers I need:

· The fraction of all NOx emissions attributable to road transport in 2015 – 34 per cent, from [5].

· The fraction of road transport NOx emissions attributable to diesel cars in 2015. In the recent air quality plan [[19]], produced jointly by DEFRA and the Department of Transport, I found a pie chart of emissions from different sources in 2015 (Figure 3a). Eyeball and protractor measured the sector for diesel cars as 34.4 per cent of all NOx emitted by road traffic.

· The fraction of road transport NOx emissions attributable to petrol cars in 2015. This is shown in the same pie chart as the diesel emissions. It’s 8.1 per cent.

· The number of diesel and petrol cars on UK roads in 2015 – VEH0203 at [14] gives 11.4 million and 18.5 million respectively.

Cranking the handle of the calculator, I get £127 per car per year as the social cost of NOx emissions from all diesel cars, and £18 for all petrol cars.

Apportioning NOx costs from diesel cars between Euro standards

Next, I need the numbers of diesel cars on the roads in 2015 that were (supposedly) built to each of the Euro standards. I found these in a working paper produced by the RAC [[20]]. Happily, the same table also shows estimates of actual NOx emissions for each category. Happier yet, they match the numbers shown in the air quality plan [19].

I calculated the following social costs of NOx from diesel cars, per car per year, broken down by Euro standard:

Standard Social cost of real world emissions Social cost if cars met their standards Social cost due to manufacturer fault %age due to manufacturer fault
Euro 3 £158 £79 £79 50.0%
Euro 4 £127 £40 £87 68.7%
Euro 5 £127 £29 £98 77.5%
Euro 6 £95 £13 £82 86.7%

Apportioning NOx costs from petrol cars between Euro standards

For petrol cars, I don’t have figures on the distribution of the cars among Euro standards. So I’ll have to assume that the proportions are roughly similar to diesels. The calculated social costs, per car per year, are: Euro 3 £33, Euro 4 £18, Euro 5 and Euro 6 £13.

Putting PM and NOx figures together

Here, I hit a problem. COMEAP recommend that the risk coefficient (and thus, approximately, the deaths figure and so the social cost) from one pollutant should be reduced by an overlap factor before adding it to the other. But it makes a difference whether you calculate PM first and then adjust the NOx figure (as COMEAP initially recommended) or calculate NOx first and then adjust the PM, or use coefficients each adjusted for the other pollutant. With a range of figures like mine, I think the third method would be the most appropriate. But I don’t know the values of those coefficients. So, I decided to take a simple approach, and to apply the same overlap factor to the estimates for both pollutants. That is, I’ll simply add up the two figures and then multiply by 40,000/52,500 (approximately 76.2 per cent) as suggested by the deaths figures quoted in the RCP report.

The results are as follows:

Standard Social cost of real world emissions Excess over 2017 car of same type Social cost if cars met their standards Driver excess over 2017 petrol Social cost due to manufacturer fault %age of total due to manufacturer fault
Euro 3 diesel £278 £190 £218 £205 £60 21.6%
Euro 4 diesel £175 £87 £109 £96 £66 37.7%
Euro 5 diesel £113 £25 £38 £25 £75 66.4%
Euro 6 diesel £88 N/A £26 £13 £62 70.5%
Euro 3 petrol £33 £20 £20
Euro 4 petrol £18 £5 £5
Euro 5 petrol £13 £0 £0
Euro 6 petrol £13 N/A N/A

The “excess over 2017 car of same type” column shows the difference in the social cost of real world emissions between a car built to one standard and a new car of the same type. The “driver excess over 2017 petrol” column (bolded) shows the difference in social cost between a diesel or petrol car built to one standard and a new petrol car, if the diesel cars had met the standards they were supposed to.

What do my figures imply?

To return to where I came in, the over the top level of proposed entry charges to London.

If I can believe the central estimates for both pollutants, there is a case to be made for charging drivers of Euro 3, and perhaps Euro 4, diesels a fee to drive in areas that are especially badly affected by air pollution. But there is no case, on social cost grounds, for such charges on Euro 5 diesels or on any petrol cars. For all these cars, the excess of the social cost of the pollution they emit, compared to a new (Euro 6) car of the same type, is £25 a year or less. Two entry fees to the London ULEZ would cover the social cost of this pollution for a whole year. To levy such outrageous charges on drivers of these cars (including me) is unreasonable.

Further, since new diesel cars have a higher social cost of pollution than Euro 3 petrol cars, the question must be asked why Euro 3 petrol cars are to be charged, and Euro 6 diesels not. If the aim was, as claimed, to reduce NOx levels quickly and so meet the EU limit, then drivers of even brand new diesel cars should have been charged. It’s hard to avoid the thought that the decision on who to charge for entry to the ULEZ, and who not, was arbitrary and political.

On a longer term basis, there is a case to be made for some kind of pollution charge for diesels; and perhaps for Euro 3 petrol cars. But it should not be more than the difference between the social costs per year of these cars and of a new Euro 6 petrol car. Furthermore, diesel drivers should not be penalized for the part of the cost which is down to the manufacturers’ fault; and most of all for Euro 5 and 6 diesels, where the manufacturers’ component is more than two-thirds of the total social cost. So, on social cost grounds, no-one should be charged more than the figures in the “Driver excess over 2017 petrol” column in my table above. If the new taxes, when they are announced, are any bigger than this, we’ll know we’ve been had. Again.

And let’s not forget the uncertainty in the figures. The true impacts of the pollution might easily be a quarter, or even less, of the figures I used. What if that turns out to have been the case? Millions of drivers will have suffered huge, unnecessary costs, and the unlucky will have lost their personal mobility entirely. And some of them may have lost their livelihoods as a result. If that happens, who will pay for the fiasco?

Life Expectancy

It’s interesting to follow up on the HPA’s estimates of life expectancy. Their worst case is 203 days of life expectancy lost due to all forms of PM pollution in 2008. This equates to about 16 days of loss caused by PM from diesel cars. However, I want to work with the year I did the NOx calculations for, 2015. So I need to adjust this to take account of the generally cleaner vehicle fleet in 2015 compared with 2008. This brings it down to 11 days.

The loss of life expectancy due to NOx alone will be in proportion to the number of deaths figure from NOx. Thus the loss of life expectancy due to NOx emissions from diesel and petrol cars combined is 22 days. Adding the numbers together and multiplying by the overlap factor gives an average loss of life expectancy due to air pollution from cars, at 2015 levels, of 25 days.

Which would you prefer? To travel where you want, when you want, in the comfort and privacy of a fast, smooth, quiet, spacious car? Or to be granted an extra 25 days at the end of your life, and in exchange to be forced to spend your travelling life waiting at bus stops in the pouring rain or standing on freezing station platforms, and when you finally do get moving it’s noisy, rattling, uncomfortable, crowded and often slow? I know which I’d pick. Moreover, wouldn’t you spend a lot more than 25 days of your life at those bus stops and on those platforms? (Exercise for the reader: how many days is 5 minutes a day over a lifetime?)

The political backstory

To grasp how this sad and sorry situation came about, it’s necessary first to understand two things. One, that the United Nations, of which the WHO is an agency, is the force behind the world-wide environmentalist agenda, which is the cause of so much pain to ordinary people in the Western world. And two, that the UN has been pushing this agenda for more than 30 years. For those interested in the backstory behind the backstory, I myself have documented [[21]] the history of the 1987 UN report that set the green juggernaut rolling, and led to the 1992 Rio summit and all that has happened since.

If you read further into the WHO fact sheet [11] I referenced earlier, you will find a list of policies they recommend to reduce air pollution. Such as: Making us walk, cycle or use public transport instead of cars. Cramming us into compact cities and high-rises. Recycling as a religion. Dismantling our affordable, reliable energy infrastructure, and replacing it by energy that is expensive, intermittent and requires gigantic solar arrays or ugly, noisy wind farms. That’s the deep green agenda. It’s not designed for our benefit, is it?

And if you think that “fixing” the immediate problem of NOx emissions from diesel cars will get the so called “green blob” off our backs, think again. For example, for PM2.5 the EU (and so UK) limit today is two and a half times the WHO guideline set back in 2006. There will surely be pressure to drive that limit down. But as reported by the LAQN, in 2015 no sites in London, which could reliably make the measurement, actually met this guideline limit.

This is not about solving a problem and then getting on with our lives. It’s about an agenda. Something I noticed about the HPA report is that much of it is concerned, not with the burden of PM pollution as it was at the time, but with the effects of changes to, and especially reductions of, the concentration. This is, in my opinion, cart before horse. Rationally, the first question to ask should be, “How big is the problem?” And only when you have a good handle on that can you sensibly ask, “What might we do to fix it?” It’s as if the agenda was already predetermined, and the HPA were simply told to fit in with it.

That agenda was hammered out in the late 1980s, and agreed by politicians from most countries, including the UK, at the 1992 Rio summit. John Major was prime minister at the time. They were setting out to transform Western societies, and the world as a whole, into a utopian model of so called “sustainable development.” The narcissistic politicians and their cronies wanted the fame and glory of “saving the planet.” And it didn’t matter how much the little people suffered. So, in came Guidelines and Directives and Limits and Targets, and all the paraphernalia of the system under which we suffer today. And bad laws were made, which should never have even been contemplated. Bad laws which, as Edmund Burke told us, are the worst sort of tyranny.

The whole idea of setting hard, inflexible, ever tightening collective limits on what people may do is madness. As is the idea, that such limits should be set without any concern for cost-effectiveness. Most of all, it is madness even to try to set such limits when the underlying science isn’t fully understood. If COMEAP, who are supposed to be the experts, can’t accurately calculate the toxicity of the mixtures of pollutants that exist in the real world, and can’t even estimate the toxicity of PM2.5 on its own to better than a factor of 12, how can someone at the WHO, or at the EU, or at DEFRA possibly claim a right to set hard limits for concentrations?

Perhaps, in the heady atmosphere of the build up to Rio, Major and his cohorts failed to detect the zealotry of those pushing the deep green agenda. Or perhaps they may have, at least in part, bought into the agenda themselves. Or perhaps going along with it just seemed like a good idea at the time. But they were wrong, I think, to sign up to the Rio agreements. And that is the root cause of all these problems. Furthermore, to sign up to the idea of hard EU or WHO limits on air pollution was wrong too. If nothing else, allowing UK policies to be set by third parties – and third parties with agendas, to boot – is a denial of democracy.

Blair, Brown and King were wrong to encourage diesels, too. Not so much because of the pollution aspect, but because their push to reduce CO2 emissions was (and still is) based, as anyone who has looked hard and objectively at the facts will know, on no more than bad “science,” hype and skullduggery. If Brown or others had LAQN reports suppressed, that was wrong as well. The car manufacturers were wrong to hide for so long their failure to meet diesel emissions standards in the real world. If, as I suspect is possible, they were pressured into that position by the EU, that was wrong too. And we drivers are to be expected to make enormous sacrifices, both financially and in convenience, for the sake of bailing out those that have done these things to us? That’s about as wrong, wrong, wrong as you can get.

How pollution might be dealt with in a sane world

I’ll make it clear at this point that I’m not at all advocating that people should be allowed to pollute air, water or other common resources exactly as they want to. In fact, I entirely agree with the principle of “polluter pays.” Those responsible for the pollution – and that includes politicians like Blair and Brown, and their advisers – should pay for its consequences to those who are harmed by it. This is a particular case of the general idea of personal responsibility; that people, who unjustly cause damage to others, have a responsibility to compensate those affected.

The problem of pollution is an example of a case where one group of people – I’ll call them A – wants to do an activity X, which brings great benefits to them. However, it has side-effects which have negative consequences for another group of people, B. Here’s an idea for how I think such problems might be dealt with in a world saner than today’s.

First, you must get an objective, accurate estimate of the social cost of X. Plus or minus 10 per cent would be reasonable. If the cost of X to group B is so big that it outweighs the benefits to A, there may be a case for prohibiting X entirely. (That’s not the case here, of course). Otherwise, you apportion the social cost of X according to how much of the problem each individual is responsible for. That’s what I’ve been aiming to do here, by calculating costs per car per year.

Then you need to apportion the costs borne by group B among the members of B. In the case of air pollution from cars, this might be based on where an individual lives, and how close to badly polluted main roads. Then you simply require each individual in A to pay the relevant fraction of the cost, and pass the relevant fraction to each member of B.

In such a scheme, once the costs and compensations have been assigned, government acts as no more than a router. All it does is make sure the right amounts are collected from the right people, and the right amounts are distributed to the right people. There are no political policies in such a scheme, no arbitrary limits which must not be exceeded, and no infringements of freedom.

In conclusion

If my figures are right, then on the specific issue of air pollution from cars in the UK, there may be a case for charging drivers of Euro 3 and perhaps Euro 4 diesel cars to enter certain very limited areas like central London. There is no social cost case for any such charges for Euro 5 or 6 diesels, or for any petrol cars. There is a case for charging drivers of diesels, and of petrol cars which do not meet the latest standard, an amount equivalent to the social cost of the pollution they cause (excluding the part of the pollution from diesels which is the manufacturer’s fault). There is no case for charging any more than this.

But there’s a much wider issue behind all this. Car drivers today, and diesel drivers in particular, are victims of a sequence of collusions and wrongdoings, which stretches back more than 30 years. All this comes, ultimately, from an agenda that was hatched, and has been pushed forward, by the United Nations. And which most politicians and too many others in government, egged on by extremist cheerleaders like Greenpeace and their fellow travellers in academe and the media, have been all too happy to lend their weight to. Without any regard for the negative consequences on the people they are supposed to serve.

It is high time, I think, for the good people of the UK and of the world to wake up. To see the deep green agenda for what it is. To reject it and its proponents. And to seek to set up in its place just measures based on good science, honesty and common sense.


Links:

[[1]] https://www.london.gov.uk/press-releases/mayoral/mayor-plans-to-introduce-ulez-in-april-2019

[[2]] http://www.dailymail.co.uk/news/article-4730134/All-petrol-diesel-cars-banned-2040.html

[[3]] https://uk-air.defra.gov.uk/air-pollution/uk-eu-limits

[[4]] https://en.wikipedia.org/wiki/European_emission_standards

[[5]] https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/579200/Emissions_airpollutants_statisticalrelease_2016_final.pdf

[[6]] https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/304667/COMEAP_long_term_exposure_to_air_pollution.pdf

[[7]] https://www.gov.uk/government/publications/comeap-mortality-effects-of-long-term-exposure-to-particulate-air-pollution-in-the-uk

[[8]] https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/460401/air-quality-econanalysis-nitrogen-interim-guidance.pdf

[[9]] https://www.gov.uk/government/publications/nitrogen-dioxide-interim-view-on-long-term-average-concentrations-and-mortality

[[10]] https://www.rcplondon.ac.uk/projects/outputs/every-breath-we-take-lifelong-impact-air-pollution

[[11]] http://www.who.int/mediacentre/factsheets/fs313/en/

[[12]] https://uk-air.defra.gov.uk/assets/documents/reports/cat07/1009030925_2008_Report_final270805.pdf

[[13]] https://www.gov.uk/government/statistics/sub-national-road-transport-fuel-consumption-2011-factsheet

[[14]] https://www.gov.uk/government/statistical-data-sets/veh02-licensed-cars

[[15]] https://www.transportenvironment.org/docs/Bulletin/2006/2006-02_bulletin146_web.pdf

[[16]] https://www.londonair.org.uk/london/asp/reportdetail.asp?ReportID=lar2006&ReportType=All

[[17]] http://europa.eu/rapid/press-release_IP-14-154_en.htm

[[18]] https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/deaths/datasets/the21stcenturymortalityfilesdeathsdataset

[[19]] https://consult.defra.gov.uk/airquality/air-quality-plan-for-tackling-nitrogen-dioxide/supporting_documents/Draft%20Revised%20AQ%20Plan.pdf

[[20]] http://www.racfoundation.org/assets/rac_foundation/content/downloadables/Diesel_scrappage_scheme_calculation_Al_PG_Final_March_11_2016.pdf

[[21]] https://wattsupwiththat.com/2017/04/20/our-common-future-revisited-how-did-the-roadmap-for-the-green-juggernaut-fare-over-30-years/

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109 thoughts on “The Social Costs of Air Pollution from Cars in the UK

  1. The Mayor of London is a shameful creature like the Mayor of New York. Both are garish warning posts that mindless ideology has a feverish grip on automatonic swaths of the population. Pay them no mind.

      • Make no mistake, all this PM2.5 hype is just a backhanded way of attacking “fossil fuelled” transport as a means to force us all into electric cars.

        No one wants to sit behind an old bus belching clouds of stinking black fumes but that has nothing to do with modern diesel cars. ( By modern, I mean post Y2K ).

        Every year they introduce mew, more stringent regulations and force millions of perfectly good functioning vehicles on to the scrap heap and owners who are already struggling find they need a new bank loan to buy another car just to get to work to pay the bank back for the last one.

        And there we get to what all this is about: boosting consumer credit and “saving the banks”. Nothing to do with saving the planet.

      • Greg,
        Many of the PM2.5 particles are not from engines/exhausts. They are fr4om tyres and brakes.
        I imagine that electric cars will include tyres and brakes – and so will produce some PM2.5 emissions.

        And the watermelons would then deny the populace such cars too.
        Their target, remember, is a population – globally – of no more than 750 million [<10% of current population], and 'ideally'500 million.
        And most of those will be peons or concubines [of either/any sex] for the 'Elite'.

        Auto

    • The social cost of the fracking ban in NY was the $350 million payout for the Tesla mega factory in Buffalo and associated $400 million for equipment costs.

    • Government gets bigger. They run out of money. They invent new taxes. People ask for yet more government.

      Socialism at work. However, its our sons and daughters who work in the government who are now the problem. Its easy there. Great working conditions, not much to do. try having a rational discussion with anyone about this. It is always someone else who is scamming the system.

      If you work for the government its YOU.

      • “They run out of money. They invent new taxes. People ask for yet more government.”
        Bingo, we have a winner. In the beginning Govs to have a new tax system instead of rising other taxes so in the end all taxes get raised. Once more people depend on an government funding than work in the private sector and paying paying taxes the government structure fails.

    • There’s a also the forgotten problem with “brake dust and tyre rubber” that has not be addressed. It could be up to 50% of the total particle pollution problem!

      • There are also particulates coming from heating systems. It is true that in the UK government fairyland there will be no gas heating in the future but back in the real world it is used for heating the vast majority of buildings. Once vehicles have been removed from the streets of London – don’t think that there aren’t those who want to achieve this – they will then find not much has changed.

      • I see no evidence yet that PM2.5 is actualy a problem at all…..

        And life expectancy continues to increase, opioids excepted.

  2. Well, by raising fee income they can import more wood pellets from clear cutting to burn in boilers. I thought diesel cars were popular with consumers in the UK and Europe in response to sky high fuel taxes. Maybe it’s the kingdom of unintended consequences.

      • Don’t give them any ideas. But then direct approaches like that are much too simplistic and do not involve enough administration to be practical from a lobbyist and advocacy funding point of view. Make it complicated and expense and it has a chance.

      • Yep, had those before. Go to any large motor museum and you will find a wood gas powered car from the Second World War usually in response to petrol rationing. That they are not still with us gives you a clue as to how good an idea they are.

    • “Resourceguy August 11, 2017 at 12:10 pm

      Well, by raising fee income they can import more wood pellets from clear cutting to burn in boilers. I thought diesel cars were popular with consumers in the UK…”

      Not in the UK as diesel is more expensive than petrol and mostly offsets any increase in mileage/gallon.

  3. With the horrible air pollution in China you would think people would be dropping like flies……but they are not. You would also think China should be in the midst of another ice age since aerosols are said to cause cooling (i.e. 1970s global cooling scare).

      • If you want others to be concerned about actual pollution, you need to denounce, renounce, and repudiate the designation of the Base of the Food Chain (CO2) as pollution.

        Carbon Based Life Forms need Carbon.

      • Chris

        From your link.

        “Visibility in the city reduced to no more than a few hundred yards on Thursday, officials said, as pollution particle readings jumped to more than 20 times the safe limit recommended by the World Health Organisation (WHO).”

        If you care to live in a city, you take the risk of pollution to earn your big bucks.

        There are alternatives, like, don’t live in a city.

        Which would be socially, as well as environmentally responsible as rural areas are crying out for talent.

        You can’t have it both ways. If you live in a city and want fresh air, the only way to achieve it is to displace your pollution to power stations outside the city.

        And that’s the reason people voted Brexit, because the minority London elite is dictating to the rest of the country that we should all live by their rules.

      • Hot Scot,

        Wrong. I live in Singapore, which has clean air and a very robust economy, including a large manufacturing industry and petrochemical industry. But they have invested heavily in mass transit, and the utilities have natural gas fired turbines, not coal fired plants.

      • US has reduced the six primary air pollutants by 64% since 1980 according to the EPA. US life span averages 79.3, China a developing nation 76.1. Hardly a 15 year difference.

      • I think you’re missing the point. There is NO WAY to prove your life is reduced by fifteen years. That’s all completely made up based on assumptions.

        In fact I can say pretty confidently that it WON’T reduce lifespan by 15 years. And that’s because 1) China is already working to clean it up 2) the tech, developed by the West, already exists and is deployable with little cost to them and will be deployed more in years to come 3) the human body has a remarkable ability to heal after being exposed to toxins like smoke. Those already damaged will heal and live even longer than was predicted for them at birth.

        This can all be seen by looking at what happened in LA and other cities in the 60s. The air was bad. It was cleaned, and now stays clean.

        It’s not rocket surgery.

      • Geoff,

        China lifespan data is for a country of 1.5B, not for a city of 20M known for it’s severe pollution problems.

      • Chris- “scientists say…”

        2015 life expectancies differ by about 4 years:
        U.S.- 79.7 years
        China- 75.4 years

        But a big contributor to this difference is cigarette consumption.
        Year 2014 data for 15+ year old people-

        U.S.- 1083 cigarettes/person/year
        China- 2250 cigarettes/person/year

      • chris y, interesting, when folks post wikipedia links on WUWT, they are called out on it. inaccurate, unscientific, left leaning rubbish. but when it serves your purpose it’s rock solid, eh?

        I’ll go with the research scientists, who, if anything would be inclined to understate the severity of the problem. The Chinese government does not like to be shown to be harming their people – for example, for years they tried to get the US Embassy to stop reporting pollution levels, which the Chinese govt always underreported.

      • Chris,
        this quote from your link,
        “The BMJ explained that “the year of life lost varied depending on age, sex and other factors”. It told The Independent: “Some people had their lives shortened by many, many years, others not at all, and it varied by group. The average years of life lost came out to be (around) 15.””
        So it seems to me total B.S. “others not at all” “other factors”,
        Remember the old saying,”Bullshit baffles Brains”.
        Don’t get sucked in.

      • “Chris August 11, 2017 at 12:47 pm

        Perhaps you don’t think having your lifespan reduced by 15 years is a big deal. I do. http://www.independent.co.uk/news/world/asia/beijing-issues-smog-warning-as-scientists-say-pollution-cuts-life-expectancy-by-15-years-9065204.html

        Your claims are bogus, Chrissy.
        Personal health concerns? Based on non-existent data and specious claims?

        Above article author Neil Lock identifies the London total impact to life expectancy as two to three weeks.
        Two to three weeks reduction to life expectancy, before addressing the false science used to drive PM standards and alleged health effects.

        Whether you personally believe your health is in danger is immaterial.
        Unproven fears are your personal problem. Your fears are not ours’ or the world’s concern at any level.
        Hypochondriasis and your other personal prejudices are yours, and solely yours, for as long as you believe fake science and specious claims.

        We owe you nothing. Enjoy your echo bubble, trollop.

      • ATheOK,

        Just to clarify, my figure of 25 days of life expectancy lost applied only to pollution (PM and NOx) specifically caused by cars. It’s substantially more than this for all kinds of pollution. If you believe the government’s figures in the first place, of course.

    • Geof Pohanks: again, it is difficult to be sure whether the figures have been inflated by alarmists or swept under the carpet by the Chinese government, but some estimates suggest an extra 350k to 500k extra deaths per year

  4. I’d like to see a summary table for expected annual charges versus the social cost as estimated. Most climate believers have very short attention spans and need simple tables to better understand.
    The fact that the EU forced people to buy diesel autos based on faulty science in the first place is bad enough. Penalizing them now for being compliant should be the basis for a class action lawsuit of epic proportions?

    • Brad,

      The difficulty with that is that they haven’t yet announced how big the new “toxin taxes” (over and above the ULEZ entry charges) will be. Of course, government being what it is, they are almost certain to be orders of magnitude bigger than my numbers.

  5. Well, why don’t we all just stay home, watch TV, and suck off the government teet. Because we won’t be making or buying anything we won’t need cars to get us there. Watermelons like that kind of thing so they can put flowers in their hair and sing kumbaya.

  6. The problem of pollution is an example of a case where one group of people – I’ll call them A – wants to do an activity X, which brings great benefits to them. However, it has side-effects which have negative consequences for another group of people, B

    “Negative consequences” is the wrong (opposite) assumption. People traveling into city centers are doing commerce, transporting goods, using medical services, shopping, sightseeing, etc., they are benefiting people in those cities. A city like London, with its extensive public transport, I would suggest people are driving as a last resort anyway. A plumber is not carrying tools on the Metro as example. If you want to see the negative consequences of people NOT using the city center – just go to Detroit USA.

    • That’s a classic misunderstanding of externalities. The benefits are accrued, and so do not have to be accounted for – you have them and you pay for them. What are not accounted for are the negative benefits.

      In effect, you are overpaying for the benefits, since they come with small negarptive effects.

  7. As a result of increasing energy poverty (or in this context – not wanting to pay for enough electricity) in the UK, that around 100 000 new wood heaters are being installed each year.

    Those extra 100 000 wood heaters emit more pollution (PM2.5) each year, than the 28 million vehicles used.

    It is farcical that anyone would limit vehicle emissions and not limit wood heaters.

    • Yes this was shown in London recently.
      A cold weekend had less cars and more log burning stoves.
      Result …….. the NO2 fraction and particulates increased well above average

  8. Every five years or so, the EU makes new, tighter standards.

    So, it is not that the air is more polluted, the perception of what is polluted and what is not is being adjusted.

  9. London’s mayor , Vancouver’s mayor , Chicago’s mayor are absolutely wrecking their cities but they got voted in so if you don’t like it move out or don’t visit them .
    Detroit and Baltimore are just a little further down the ghetto path . Vancouver is kept afloat by
    laundered Chinese and Persian money propping up a real-estate Ponzi scheme aided and abetted by
    government addicted to the property purchase tax .

  10. Is there any way we can convince the American Democrat Party to run on this platform…
    …for, say, the next 10-12 election cycles?

    :)

  11. Why stop at GBP12(??) per day? Why not 120???
    And how about CO2 tax on all people entering the City to account for the supposedly toxic load of their respiratory effusions? Collect it thro a tax on train..tickets??

  12. Well researched and well explained Neil: thank you. I think there are a couple of shaky parts of the whole issue (not just you – all the reports you cite too). Firstly the actual impact of these pollutants is clearly not understood – and there may be others. For example, I wonder about the effect of several hours exposure to low concentrations of carbon monoxide. One study I’m acquainted with found differences in children’s brain development depending on proximity to a busy highway. So the impact of these pollutants is a big unknown. It may be hugely worse than currently believed, or it may in fact be trivial.

    The second shaky area is the thorny question of how you put a price on early death. An actuary would probably reckon that digging more wells in Africa for clean water would be better use of money than spending billions on pollution control to avoid killing off a few Londoners.

    I agree with you that encouraging diesel cars in the first place to reduce CO2 was most unwise.

  13. In America and Canada after WW2 they encouraged women to leave the workforce to make room for the returning men. Folks were encouraged to buy a car and move to the suburbs. The economy boomed as people bought durable goods and established families. What a contrast with the 1930s. It really was the workers paradise.

    So, what happens when we encourage people to live in tiny highrise boxes and give up their cars? We stand a real chance of invoking the Paradox of Thrift. The vast majority of us would be worse off. That would cause tens of millions of premature deaths because prosperous people live a lot longer than poor people. link

    The increase in premature deaths caused by a rather small amount of pollution is three orders of magnitude smaller than the number of premature deaths caused when greenie alarmist policies bork the economy.

  14. Thoughtful, well reasoned analysis of available information. My issue is the shakiness of the available information. To say it is tenuous at best is a compliment. Same is true with the EPA studies on NOx and PM2.5. Steve Milloy’s book Scare Pollution covers the EPA part in some detail.
    Fact is diesel was strongly encouraged in Europe and UK because of CO2 nonsense, and is now being punished for what may well be mostly NOx and PM2.5 nonsense. The statistical links to actual medical problems are very weak, and there are major confounding factors like asthma cardivascular disease, and lifestyle (fitness, foods). Indoor PM2.5 is produced by cooking (frying, roasting, broiling), candles, and wood burning fireplaces. We don’t worry about them causing health hazards and shortened lifespans. There are other real air pollutants in cities from other sources, like brake and tire dust. And other real health hazards like carcinogenic nitrosamines from cooked cured meats . But we dont penalize brakes, tires, or bacon.

    • Shhhh…..Don’t give them any idea’s. Although I like the idea of “No Brake Zones” in California, that would be interesting.

    • Ristvan – I absolutely agree that we have a cocktail of pollutants all round us, any of which (or any combination of which) may be exacerbating anything from autism to Alzheimers, and that sorting out one from the other is complex and messy. Just as a matter of passing interest as you mention it, EVs reduce brake dust because of regenerative braking: they put momentum back into the battery.

    • Rud,

      You’re right, the available information is shaky; that was one of the points I was trying to get over when I set out to write this essay.

      It’s interesting to compare this issue with the climate change one. From what I’ve seen, there doesn’t seem to be as much bad “science” and nonscience in toxicology as in climate. But the level of objective knowledge seems similar; low to very low. And it does look rather as if politicized agenda setters have infiltrated the scientists, and told them what to do.

  15. John Hardy

    “It may be hugely worse than currently believed, or it may in fact be trivial.”

    Why not just say you’re hedging your bets.

    “An actuary would probably reckon that digging more wells in Africa for clean water would be better use of money than spending billions on pollution control to avoid killing off a few Londoners.”

    And the actuary would probably be right.

    “I agree with you that encouraging diesel cars in the first place to reduce CO2 was most unwise.”

    Despite diesel being 25% more efficient than petrol, the refinement process being less energy intensive and the distribution, use and storage of diesel being 25% more efficient than petrol.

    Essentially 25% less vehicular activity on the roads with diesel. We have had 30 or 40 years of environmental and government pressure to clean up petrols act. Diesel rocks up, is given 10 or 15 years, then it’s kicked into touch. Despite it being the most important means of motive power ever invented by man.

    Given the headway, car manufacturers would be extracting 100MPG from clean diesel engines within the next 10 years.

    But no, big lefty government stepped in and told us we will all be driving EV’s by 2040, so 81 roads in the UK would benefit.

    Talk about the tail wagging the dog. We are cotowing to minority rule in the UK.

    • The difficulty being that all the major parties are engaged in this virtue-signalling drivel. The intellectual calibre of politicians generally has never been so low. Which makes it difficult to see how good sense can ever be restored.

    • Diesel is 10percent denser than petrol which accounts for around half the efficiency gain. Crude oil naturally contains different hydrocarbons which are seperated by distillation. To increase the diesel fraction would likely increase the energy costs in refineries, and further reduce any efficiency advantage. The world runs on Diesel, Kerosene, Jet1, petrol is a waste product which is put to good use, mainly in North America.
      Long chain hydrocarbons of course emit more CO2 per joule than short chain, this is of course more than offset by the increased thermodynamic efficiency of compression ignition, but reduces the CO2 advantage of diesel.
      Diesel cars are on average much larger than petrol, and large SUVs in Europe are almost exclusively diesel, upshot is that drivers use diesel efficiency to burn more fuel, not to save money.
      I think that overall the move to Diesel has had a fairly insignificant effect on carbon emissions, and government would have been directing its effort elsewhere.

      • Colin

        So what you’re saying is that diesel engines are more thermally efficient that petrol engines, but there are reasons for it. I can’t disagree with that.

        “Diesel cars are on average much larger than petrol, and large SUVs in Europe are almost exclusively diesel, upshot is that drivers use diesel efficiency to burn more fuel, not to save money.”

        Anecdotally, I have been running a Euro 6 compliant, 2014 Mercedes 220D estate for the last 3 years. On my trips from Kent to Scotland, I could maintain a 95 mph cruising speed and return 40+mpg. At a more sedate pace, 75 mph, it was returning around 50 mpg.

        My wife has a 2016, 1200cc turbocharged, petrol Skoda Yeti. On the same trip, at around 75mph, it barely returns 30mpg.

        Cars similar to my Mercedes, and larger (e.g. Range Rovers, M5’s, G Wagons, S class and 7 series BMW’s) were being run on petrol engines long before we were all convinced to change to DERV’s by a government who already knew of the supposed dangers of diesel particulates, but pursued the clamour for CO2 reduction.

  16. The real killer is cigarette smoking……if govt wanted to save people’s lives they would ban tobacco….but the tax money and political fallout is just too big.

  17. The paradox is that, based on actual mortality statistics, life expectancy in heavily polluted London is greater than in less polluted parts of the UK. Perhaps air pollution isn’t that important!

  18. You’ve got this all wrong. Government bureaucrats created a bad policy and someone has to pay. Turns out it’s you and anyone that drives. In the US there are few places where politicians would get away with this. Perhaps you ought to be looking for a new mayor or simply leave the city to the iealogues. Politics today seems to be about taking care of your “needs” for free then turning your everyday activities into a vice that they can tack a fee into. You end up with a massively regressive taxing structure. That’s progressivism.

    • Hey, buying votes and locking in special interest groups requires lots of money. There is a constant hunt for new sources because what was raised before in a prior scheme is already spoken for.

  19. Airhead Central: ICCT. Here we have a snapshot from two years ago when diesel cars were the answer to everything. Maybe Margo Oge will send Neil her volt in recompense.

  20. The official and manufacturer malfeasance, zealotry and heavy-handedness in Europe and in UK is colossal. I see no way to live in such places. The control in people’s lives designed by misanthropist iдеолоguеs of иеомагхбrотнеrs stripe is virtually beyond rehabilitation.

    In the Caribbean, I’ve met German, British and other expats who have carved new lives out for themselves, no longer feeling any affection or identity with their abandoned homelands. They’ve begun small service and manufacturing companies and created quality schools, etc. I believe this type of emigre is becoming huge and is the real “climate” change immigration numbers to watch.

    I believe if Trump can shake the Liliputians in Washington and the Dems across the country off his back, the US will become the premier destination for an exodus of the best from Europe and, sadly UK (Brexit appears to be too late, the antiBrexit bureaucrats, the same type of illness that Trump is dealing with, but absent the character of leadership necessary in UK.

    Ironically, Eastern Europe and Russia, yes Russia, is becoming the the repository for European values. The recalcitrance of Russia and its determination to not succumb to the UN/EU and US Dem fеllош тгаveleгеrs, is the prime reason Russia is vilified (and China admired). Steven Segal became a Russian citizen recently and French and Germans have also made the move. Whatever one thinks of this idea, this post on UK ацтноriтагуанisм and cultural sцiciде tips the balance away from Europe.

  21. How about I sponsor you for a visa and you retire to the US, you buy a used car of whatever type you want, and you teach math part time at our local schools?

    I’ll even buy you a gun.

  22. A thoughtful and detailed analysis. However two issues arise.

    We live in South West UK. On occasional (approx monthly) visits around London it is utterly evident that air quality degrades massively as London is approached. Quite simply on major roads the air smells. Pollution levels measured are far in excess of recommended levels and damaging to health.

    In the SW there are a few larger towns which suffer localised high levels of pollution usually during rush hour, but in rural and semi rural areas any pollutants disperse quickly and are largely undetectable.

    This impacts on costing – only those vehicles using low emission zones should pay, not shared as a charge amongst the total car population. This would make a material difference to what constitutes a fair charge.

    The charging regime is also intended to reduce the use of the most polluting vehicles and ultimately encourage electric only with genuinely zero local emissions. This will not happen in the immediate future until battery life, recharging, initial cost issues etc are resolved.

    • I agree with what you wrote about the difference in air quality between the south west and London. My current car is a diesel that was registered in 2014, and so is on the wrong side, by a few months, of the proposed limit for punitive taxation. Yet, despite being bigger than my old petrol car it is far more fuel efficient. On long journeys I often get over 60 miles to the gallon. My old car rarely got more that 40 miles to the gallon.

      Diesel is not so good for short journeys but most of my milage is accounted for by medium and long journeys. Why should I, as the owner of a fuel efficient car who was encouraged to switch to diesel by previous governments, now be penalised because of a problem with air quality in places like London which I rarely visit?

  23. This is all invented assumptions to allow the enforcement of a social policy to ban ordinary people from freedom to travel – the same reason is behind electric car mandates. PM2.5 are common but it is only PM2.5 from certain car engines that is taxed. If physicians really think these particulates are so dangerous should they not ban face powders and talcum powders, including baby powder, which have a large proportion of PM2.5 and which are inhaled in large quantities? Instead what we are seeing is ‘scientific’ groups with particular axes to grind (sic) who make wild unjustifiable assumptions that politicians with the same biases then use for their preferred social engineering under the pretext of ‘scientific’ evidence.

    • Spot on Ian.
      Its just the same as the ‘Smart’ electricity meters that seemingly are going to be imposed on everyone.

      Control Of The Individual.
      Not business because, ‘business’ is where many of these regulators and law-makers go (as consultants, advisers, board members) after they’ve been de-selected.
      Cosy and very lucrative positions that involve minimal to zero actual work.

      Which word? Choose from: Selfish. Mendacious/hypocritical. Greedy.
      Or any of your own

  24. Neil Lock

    There is nothing real behind the early American study you refer to. The explanation is complicated and is being detailed as I write.

    “Adverse health effects from PM come mainly from one kind of PM, called PM2.5.”

    It is not a ‘kind’ it is a size. The assumption of ‘equitoxicity’ for all PM is one of the heroic assumptions that forms the fluid basis of these ‘social cost’ and ‘premature death’ and ‘relative risk’ calculations. It is far less defensible than anyone’s worst misunderestimations. It is hocus pocus health.

    Please email me and I will connect you to people working on the missing section of your excellent review above. The analysis you make is fine, but unfortunately there is much less ‘there’ there when one tracks down the root claims. The additional alphabet includes GBD, IHME, RR, IER, DALY and that most creative of all, the aDALY: the avoided disability adjusted life year and its $ value. The claim is that it is possible to ‘avoid’ a DALY, even though the DALY itself is based on vapourware.

    It is akin to the Kyoto Agreement: they signed and did nothing, and the temperatures stalled. It must have been the ink, right? Cause-effect, right? “Let’s all agree to say from now on, ‘it was the ink.'”

    • Crispin,

      I had a quick look at the abstract of what I believe to be the original study (Pope et al. 1995). The relative risk number quoted by COMEAP (1.06) certainly didn’t jump out of the page at me. I’m interested to know what your friends have unearthed regarding this study. ~CTM has my e-mail address.

      When I used the words I did about PM2.5, I wasn’t meaning at all to imply that all PM is equally toxic. In fact, one of the confounding issues in this case seems to be, just how toxic is the secondary PM which results from the reactions of NO2 with other components of the atmosphere?

      • I realise that you did not intent to imply that all PM2.5 is equally toxic. Obviously it isn’t, but underlying all those claims about premature deaths is the assumption that it is. I can provide the chain of papers that lead, one to another, from a sorry set of unsupported assertions to a silly set of assumptions to a data-free set of relative risk assessments and population-based (not individual risk) assessments of the relative contribution of all causes to the shortening of all lives lives of those who died before the age of 86.

        Such calculations are useful for directing health policy. They are not useful for making claims about deaths caused by [fill in contributor] which is a medical question. Public health and medicine are quite separate fields of endeavour.

  25. Costs based on pollution “externalities” are much loved by the green blob because they are often effectively impossible to calculate in any meaningful way….Which means they can, and do, get away with using any number they like. Just as the climate-model alarmists use aerosol forcing as the magic number you adjust to get the desired result, so too can their ‘green economist’ consorts adjust aerosol pollution costs to argue for the desired policy out come.

    The varnish of respectability afforded by quantitative numerical estimates of ‘money’ is an improvement on environmentalists’ previous tactics which relied mainly on outrageous verbal claims using words designed to inflame the emotions, coupled with equally suspect photographs. (The BBC again today had pictures of white steam photographed to make it look like black smoke)

    Of course the number they never like to calculate, is the one that really matters: The benefit, not cost, of the industrial revolution and our modern civilization built on the foundation of fossil fuel energy. It is the benefit which trumps all of the costs, by a large margin. China understands this. That is why they tolerate their current pollution problems, knowing that they can fix them fairly quickly once they have first achieved the more important goal of raising themselves out of poverty. How they must laugh at Western governments trying to travel in the opposite direction.

  26. So many questions and things to think more about, here’s some of mine.

    1. If road transport makes 34% of the NOx and diesels make ~34% of that, why is the resulting ~11% such a problem?

    2. Petrol cars are all fitted with catalytic converters which are tested annually after the car gets past 3 years old. So why are they making so much (8%) of the NOx?

    3. Is it *really* impossible to design/build a cat for a diesel engine?

    4. Yes there things that effectively work as ‘scrubbers’ for cities. They are called “Parks”
    4.1 Otherwise just blow the polluted air through a water-soluble. NOx are *very* water soluble and you get valuable plant fertiliser – otherwise made using large amounts of fossil fuel. Nat Gas as it ‘appens.

    5. Just how much NOx comes from burning natural gas?
    5.1 What would be the NOx level in a typical household kitchen while dinner is being prepared using a gas cooker?
    5.2 How much NOx comes from domestic and industrial heaters. Domestic heating boilers now have to be ‘condenser’ boilers. This they are for the first 5 minutes of being switched on. That condensate goers through concrete like adding vinegar to baking soda and is patently nitric acid from dissolving NOx into water. Carbonic acid would not be so strong.
    Where does the NOx go when the condenser boiler warms up and ceases condensing?

    6. Why are the big red ‘London Buses’ given a free pass to create so much smut?
    Surely not because they are a ‘tourist attraction’ And what are ‘tourists’ if not Cash Cows. Just like the typical private motorist.
    Smacks of the buying of indulgences does it not?

    7. As a concentrated ‘point source’ that could be making a lot of people ill, what are the NOx levels on a typical platform on the London Underground? Surely as everyone knows (please tell me they do know), electrical sparking is a very effective way of oxidising atmospheric nitrogen.
    So just how much NOx do those big DC motors that push underground trains along actually make, in places where there is quite effectively no escape. And listen to the electrified rail fizzing and crackling. That is corona discharge, promoted by carbon dust coming out of the train’s motors and that electrical discharge is creating yet more NOx.
    You want a gas-chamber? There you are, use public-transport and visit London Underground, as becoming increasingly enforced by Government.
    Is that not one *horrible* irony?

    Will let you do-your-own-homework on #8/9/10 etc.
    As is usual for me, I say “Don’t post links, let ’em think”

    • Peta, I can take a crack at it:

      1. If road transport makes 34% of the NOx and diesels make ~34% of that, why is the resulting ~11% such a problem?

      It isn’t. However it is not a problem for diesel per se, it is a problem for diesels running at ‘full power’. The infamous VW engine passes the test if it is not allowed to develop it famous high power.

      2. Petrol cars are all fitted with catalytic converters which are tested annually after the car gets past 3 years old. So why are they making so much (8%) of the NOx?

      I don’t think cat-convs are targeting NOx. They are supposed to burn particles and gases of incomplete combustion.

      3. Is it *really* impossible to design/build a cat for a diesel engine?

      Don’t bark up that tree. It is not the solution. The creation of the gases should be avoided in the first place. There are all sorts of ways to do that.

      4. Yes there things that effectively work as ‘scrubbers’ for cities. They are called “Parks”

      Not a question.

      4.1 Otherwise just blow the polluted air through a water-soluble. NOx are *very* water soluble and you get valuable plant fertiliser – otherwise made using large amounts of fossil fuel. Nat Gas as it ‘appens.

      Correct. Remediation is possible. It is still better to avoid making it.

      5. Just how much NOx comes from burning natural gas?

      Burning fuel without pressurizing the process greatly reduces NOx. NO forms above 700 C with very little NO2. I am simplifying but the main culprit is pressure as in an engine, and very high temperatures. Cooking with natural gas produced very little.

      5.1 What would be the NOx level in a typical household kitchen while dinner is being prepared using a gas cooker?

      Very low.

      5.2 How much NOx comes from domestic and industrial heaters. Domestic heating boilers now have to be ‘condenser’ boilers. This they are for the first 5 minutes of being switched on. That condensate goers through concrete like adding vinegar to baking soda and is patently nitric acid from dissolving NOx into water. Carbonic acid would not be so strong.
      Where does the NOx go when the condenser boiler warms up and ceases condensing?

      Condensing boilers do not stop condensing. They condense water vapour formed by burning Hydrogen. The latent heat of evaporation is recovered. There is a continuous output of warm water which is drained away.

      6. Why are the big red ‘London Buses’ given a free pass to create so much smut?
      Surely not because they are a ‘tourist attraction’ And what are ‘tourists’ if not Cash Cows. Just like the typical private motorist.
      Smacks of the buying of indulgences does it not?

      Lack of viable alternatives.

      7. As a concentrated ‘point source’ that could be making a lot of people ill, what are the NOx levels on a typical platform on the London Underground? Surely as everyone knows (please tell me they do know), electrical sparking is a very effective way of oxidising atmospheric nitrogen.:

      Those DC motors produce ozone. Sparks like lightning precipitate nitrogen fertilizer.

      The idea of point sources is not like a distributed source like train motors. The platform is more appropriately called an indoor air quality problem. The solution is dilution by air.

  27. The author might wish to spend some time exploring the significance of a relative risk of 1.06. Years ago, Richard Doll (smoking and lung cancer fame) used to regard an RR of less than 3 as only of passing interest without repeat studies. Times have moved on a bit, but 1.06 is really negligible. Puffing up a small RR of this kind by prorating over a large population is now a standard trick. For comparison, various combinations of smoking and cancer/CVD yield RRs between 5 and 25.

  28. We live in an age that depends on technology and science. It is a big worry that in these areas the majority of UK politicians and senior civil servants are “pig thick”.

  29. And who drives pre-2006 cars. Here’s a clue:

    It’s not the rich.

    Typical left wing idiocy – steal from the poor, give to the rich.

    h/t Monty Python: Dennis Moore

  30. Externalities offer all sorts of avenues for abuse based on selective misinformation and misunderstanding. The avenues are most promising whenever you can stand on your government pulpit and proclaim “people will die.” Speaking of selectivity, I wonder what the social costs are for government induced poverty and diminished choice and utility. Or turning people into automatons controlled by government designed fear stimuli.

  31. By far the quickest, cheapest and most efficient way of dealing with current air pollution problems would be for an immediate start to a programme of replacing at least all diesel driven vehicles, if not also petrol driven vehicles, by Liquified Natural Gas (methane) fuelled vehicles. Effectively LNG vehicle emissions contain only water vapour and CO2.
    Such motors have been around for 40-50 years or so and been used and demonstrated to massively reduce urban pollution levels. Just ignore the Greenies who still insist CO2 is a pollutant!

    • First, you mean either LPG (Liquified Propane Gas), or CNG (Compressed Natural Gas) not LNG. LNG boils at -162°C (-260°F); you cannot keep it liquid without continually compressing and re-liquifying the boil off. Not a good property for a transportation fuel which might keep unused in vehicle tanks for several days. Many city buses in Atlanta use CNG (Compressed Natural Gas). CNG requires very strong, cylindrical tanks (The Honda Civic GX tank will take 3600 psi — about 250 atmospheres). The tank restrictions limit usable volume and therefore range. Not a problem for the buses as they have a fixed daily route and refueling availble at the depot at the end of the service day.

      Details on the Honda Civic GX are here. There is a CNG booster site here. According to their station locator there are 13 CNG fueling stations in the metro Atlanta area. CNG fueling stations have to sit on an existing gas pipeline; I don’t see supplies being trucked in. So CNG refueling will not be available in the middle of the Mojave Desert. There will be many opportunities for pipeline protesters to get triggered before CNG refueling is widely available outside urban centers.

      I’m not sure just how “cheap” and “quick” this solution is. If you mandated say 50% CNG vehicle sales by 2030 (extremely aggressive) and assuming the industry could comply, you are still looking at 15 more years or so before 50% of the vehicles on the road were CNG. Depending on the price premium maybe longer. Current conversion kits only cover a limited number of car models and void the manufacturer’s warranty. Adoption will be resisted by both industry and consumers. Remember Obama’s energy plan for “1 million EVs by 2015”?

      CNG is not a solution for long-haul trucks or railroad locomotives.

      And to what end? If it’s the particulates you’re worried about, even if you eliminate them from vehicle exhaust the battle will simply move on to brake and tire dust. NOx is an unavoidable result of combustion in an atmosphere containing 79% nitrogen. We have sufficient oil to refine gasoline. What precisely would be accomplished by mass conversion to CNG that would justify the cost?

      This is yet another scheme that only makes sense if you cast it as a way to fight the infinite cost “catastrophic climate change” bogeyman. But compared to Armageddon, anything looks reasonable, right?

  32. Life expectancy in Scotland is 2years lower than England although air pollution is much less. Go figure!
    The most plausible explanation I’ve seen for our reduced lifespan is vitamin D deficiency, not helped by official Government advice to stay out of the sun, in this rather rainswept corner of the Atlantic fringe.

  33. The sad fact is that diesels are a disaster in cities. It was a dreadful mistake to promote them, as a sop to the green mania about CO2. But the right thing to do now is to admit it and to get rid of them.

    The second thing we have to accept is that cars are a disaster in cities. We have set up a system in which large numbers of people are always on the move, driving through each other’s residential work or play areas, and making them unsafe and unpleasant, in the effort to get to someplace else.

    Getting cities liveable and usable involved getting the cars out of them. It means treating places as important in themselves, not as passageways which inconveniently have people living in them and getting in the way. Makes some difference if they are diesels (terrible), gasoline (bad) or electric (fairly bad). The main problem is fast vehicles moving through streets in which people live work and play. This is what we have to stop. Electrics are better, but not all that much better.

    This is not a green point. Its very simple: no-one likes to breathe exhaust fumes, and no-one likes the noise and dirt that cars cause.

    The author of this piece wants to drive his diesel engined car in cities where he does not live. He should go live on the Edgeware Rd, or on the A12 entering London. This is total insanity, and future generations will wonder what possessed us to allow it. Just as now we look back on Londoner discharging raw sewage into the streets and into the Thames in the 19c, and wonder what on earth they were thinking of.

    It is wrong and it is stupid, and we have to stop it. And yes, to the author of this piece, if you want to come into London that is going to mean the train or the tube. Get used to it. Those of us who live here don’t care if you can’t afford the fines (which is what they are) for polluting our air. In fact, we are delighted, and want them set still higher!

    • “if you want to come into London that is going to mean the train or the tube”

      What do you suggest they do when the railwaymen are on strike – not an uncommon event?

    • Michel,

      I didn’t say I wanted to drive my diesel car in London. As it happens, I haven’t had reason to drive into central London for more than 20 years. I am simply asking, if for whatever reason I need to do that again, why should I be charged more, or even far more, than the actual cost of the pollution I cause?

      As it happens, when I lived in London (first half of the 1980s) I used to bicycle up the Edgware Road on my way home from work. The pollution was far worse than it is now, and the worst polluters by far were buses. The cars were far less of a problem, because they were going faster than I was, and so soon got past me.

      You claim that cars are a disaster in cities. Maybe you only feel that because the journeys you need to make happen to fit within the public transport paradigm. If you often had to travel “across the grain” of the public transport system (which in London is essentially radial), or even out of London entirely on some days, would you find it easy to live without a car? As is typical among the politically active, you seem to have no consideration for anyone whose needs and desires are not the same as yours.

  34. Pretty obvious that the London Mayor has never run any business or organisation that involves
    using his own money!!

  35. The author did a great job and explained well the approach to investigating this topic. While I do not agree with the conclusions, given the following discussion, I do appreciate the good honest effort. I find diesel vehicles with diesel particulate filters (DPF), to be a greater part of the solution to lowering urban PM levels and not contributing to the problem.

    A significant error is being made (not by the author) but in the present characterizing vehicle PM (and hydrocarbon (HC) and carbon monoxide (CO)) emissions from modern vehicles leading to errored conclusions. Most current emission estimates are based on laboratory tailpipe emission tests using filtered -air. These are perfectly valid for regulatory purposes quantifying laboratory-tailpipe emissions to hold vehicle and engine manufacturers’ accountable to an emission standard. However, when characterizing On-Road emissions current methods over estimate on-road PM emission rates roughly 100 – 500 percent and HC and CO 20-80 percent.

    When operating a vehicle on-road, all internal combustion powered vehicles consume air (with varying levels of entrained air pollution) in proportion to the fuel burned. This consumed ambient air pollution is reduced by the vehicle’s pollution control devices 95-99% and emitted along with the tailpipe emissions, resulting in net-emissions. On-road ambient air pollution is 3-5 times higher than ambient monitoring stations measurements, further enhancing on-road vehicle emission reductions. Overall these are still small values –but in urban areas there is enough ambient air pollution coupled with today’s extremely low tailpipe emissions to frequently result in negative PM emissions. HC and CO are also estimated to be 20-80 percent lower than laboratory-tailpipe only estimates suggest. All present on-road emission estimates, do not account for the ambient air pollution reduction –which is relevant for today’s cleanest gasoline and diesel engines.

    California’s Emission Inventory estimates on-road diesel makes up less than 5% of the PM inventory even with the present method not accounting for the ambient air pollution reduction. Also in California, and perhaps the nation as well, heavy duty diesels equipped with DPFs, introduced since 2007, make up 70% of the vehicle miles travelled today growing 5% annually. I suspect that in 6-10 more years diesel vehicle’s direct PM’s contribution will be effectively eliminated and the urban PM issue will still be as prevalent, because of the other remaining non-vehicle tailpipe exhaust related contributors.

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