Laws on pollution in Toronto – failing? Pollution levels haven’t changed despite efforts as indicated by this University of Toronto study.
Looking over the last decade, there has been no overall reduction in smog in the GTA, despite best efforts to control some of the contributing factors,
However, claims of health impacts due to pollution in Toronto and other Canadian cities are up according to some other studies. Ross McKitrick says in a new peer reviewed study that the models and claims don’t add up.
Study Questions Link Between Air Pollution, Serious Health Effects
University of Guelph News Release
Challenging accepted wisdom, a University of Guelph professor says claims about the health effects of air pollution are not supported by data from Canadian cities.
Guelph economist Ross McKitrick, along with Gary Koop of the University of Strathclyde in Glasgow and Lise Tole of the University of Edinburgh, analyzed a new database from 11 Canadian cities over a 20-year period. Unlike most earlier studies, this one included controls for effects of smoking and income.
They found no evidence that air pollution affected either hospital admission rates or time spent in hospitals. However, they did determine that both smoking and income levels directly affect respiratory health. Their findings appear this week in the journal Environmental Modelling and Software.
The researchers compared monthly hospital admission rates between 1974 and 1994 for all lung ailments to ambient levels of five common air contaminants. “We were looking for predictable, common physical effects from standardized exposure levels,” McKitrick said, adding the researchers examined data over a longer time span than most previous studies, and used advanced econometric methods called Bayesian Model Averaging to ensure they considered all possible combinations of effects.
“Our examination of data back to the early 1970s was motivated in part by the fact that air pollution was much higher compared to today,” he said. “If today’s air pollution levels are causing thousands of hospitalizations, the effects should have been even stronger in the 1970s when air quality was much worse.”
“But the data showed no evidence of changing health effects at the pollution levels observed in Canada over recent decades.”
The findings contradict hundreds of studies that have connected urban air pollution levels and respiratory health problems. Such studies have resulted in calls for tighter air pollution regulations and more stringent emission standards.
McKitrick said the discrepancies between this study and earlier research stem from the common practice of not examining long enough data sets and not controlling for model uncertainty, smoking rates and socioeconomic variables. He added that their study drew data samples from the 1970s, when many Canadian cities had high pollution levels, through the 1980s, when steady reductions began, and into the 1990s, when pollution levels were historically low.
“It’s important to get accurate measures of the potential benefits of air pollution regulations, namely improved quality of life and reduced health-care costs, in order to guide regulatory decision-making,” McKitrick said.
“We did find consistent evidence that lower smoking rates lead to fewer hospital admissions and shorter stays,” he said. The researchers also found evidence that, all else being equal, regions with larger economies tend to have higher hospital admission rates. This may indicate more hospitals and longer patient treatment regimens, McKitrick said.
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See the paper and supporting data here in Dr. McKitricks web page.
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Models that predict thousands of smog-related hospitalizations in Toronto don’t hold up
By Ross McKitrick
For many years we have heard that air pollution in Canada is responsible for thousands of annual deaths and hospitalizations. In 2004 Toronto Public Health claimed that 1,700 premature deaths and 6,000 hospitalizations occur each year in Toronto alone, due to air pollution. The Ontario Medical Association, provincial and federal governments, lung associations and other groups regularly cite these kinds of figures in support of calls for new regulatory initiatives. These death and hospitalization rates are astonishing. It is like suffering a 9/11-sized terrorist attack every 10 months.
But is it really true? The estimates are derived by taking correlations in the epidemiological literature between observed pollution levels and health indicators, like hospital admission rates, and then extrapolating across populations to estimate how many deaths and illness diagnoses can, in theory, be attributed to pollution. In other words, the numbers come from statistical models, not from direct observations. That means we need to pay close attention to how the statistical modeling is done.
Together with my coauthors Gary Koop of Strathclyde University and Lise Tole of the University of Edinburgh, I have just published a peer-reviewed study in the journal Environmental Modelling and Software that does just that. What we found gives us reason to believe that the kind of statistical modeling behind common claims about air pollution may need a careful second look.
There are hundreds of studies in the epidemiological literature that have reported correlations between air pollution and health measures. But there are some common weaknesses to this literature. First, the results are not consistent across studies. Some studies find particulate matter (PM) affects health, but not sulphur dioxide (SO2) or carbon monoxide (CO). Others reported SO2 has an effect, but not PM. Another reports CO has an effect but not ozone (O3), while another finds O3 matters in some cities but not others. One large U.S. study found PM increased mortality risk a little bit across the U.S., except in 20 out of 88 cities in which it actually reduced mortality risk. These kinds of inconsistencies should not occur if the health effect is based on a real physiological response. This is a second puzzling aspect of the literature: Despite decades of testing, clinical investigations have not found experimental support for the idea that current ambient air pollution levels cause lung disease or mortality.
…
We found, not surprisingly, that smoking is bad for lung health. We found that regions with higher Gross Domestic Product (GDP) tend to have higher hospital admission rates, depending on the model specification, which may indicate that those regions have more hospital services. And we found evidence that hot days with high air pressure tend to produce more hospital admissions.
What we did not find was any evidence that increases in air pollution levels are associated with increased rates of hospital admissions. We looked at the data every which way imaginable. If we were to cherry pick, by looking only at a sub-sample of the time or by picking just the right form of the model, we could find evidence that CO or nitrogen dioxide (NO2) have positive effects on lung disease, but those results do not get strong support in the data. The models that get consistent support either show no pollution effects or — paradoxically — negative effects. In other words, in some cases as air pollution rises, hospital admissions go down. As odd as that sounds, we are by no means the first to report negative coefficients in the literature. Nobody is trying to argue that air pollution is good for you: this is either just noise in the data, or it might be an effect from “averting” behaviour, where people who are susceptible to lung problems stay indoors on days with bad air quality.
Based on our analysis, we could estimate what the effect on hospital admissions would be if all the pollution currently observed in Toronto air were to disappear. Toronto Public Health claims about 6,000 fewer hospitalizations would occur. But this claim gets no support in the data. We found that there would be no reduction in lung-related hospitalizations. If anything there might be somewhere between 20 and 200 more admissions, if we apply the statistical results in a mechanical fashion.
Very few studies over the past decade have controlled for socioeconomic covariates (including smoking), fewer still have looked at long data panels back to the 1970s and fewer still have dealt with model uncertainty. Those that have addressed one or more of these issues typically find the effect of air pollution shrinks or disappears outright. Thus our results are actually quite consistent with the relevant group of previous studies. The popular idea that current ambient air pollution has a powerful effect on lung health might look like it is based on a large empirical foundation, but on closer inspection the pile contains a lot of weak results.
So the bottom line is that, for the purpose of assessing the link between air pollution levels and hospital admissions, one needs to look closely at the kinds of studies being done and how they did the statistical modeling. More studies need to be done using long time series that go back to the 1970s or earlier, more studies need to control for socioeconomic covariates and more studies need to take account of model uncertainty. Based on evidence to date, as these things begin to happen, we should not be surprised if current estimates of the health effects of air pollution turn out to be in need of major revision.
Ross McKitrick is a professor of economics at the University of Guelph.
Read complete article: http://network.nationalpost.com/NP/blogs/fpcomment/archive/2010/03/17/where-are-the-bodies.aspx#ixzz0in3quaUy
I notice in passing that they don’t include CO2 among the pollutants in their grid. Quite right too, but tell that to the EPA.
Having lived through the pea-soupers of the English West Midlands in the 1950’s, my idea of smog is not quite the same as what they seem to referring to here. I imagine that if I visited China I would once more run into my old “friend” the pea-souper. What they’re referring to here seems to be more what I would call pollution haze that tends to hang over big cities, especially in the Summer. We often see that when driving into Paris which lies in a hollow and does not get much wind. It often stinks too.
One of my pet mad ideas would link be to link it to a boundary layer (or Coanda) effect that would cause stagnant air to cling to the large surface area afforded by tall buildings close together. But then I’m no scientist – nor statistician: and statistics which are the main concern of this article (yawn).
But speaking of China, it might be an idea to do a comparative study of a Western city like Toronto with say, Shang Hai or Beijing, looking at all aspects including chemical composition of the smog as well as its effects on the population.
pft (00:52:54) :
Coughs:
Shanghai and HK may not have been good for you for some reason but can you be sure it was air quality alone? Also note that the articles were assessing 20 years of selected Canadian cities not industrialised China. That said they came to the same conclusion as you, which was what the exercise was all about. Models are not to be trusted without complete investigation.
Denying health effects:
That was not what the study was setting out to do. I thought that was clear from the text. In fact you are saying pretty much what the study says – ot at least what McKittrick says in his opinion piece.
I think your concluding thought again misses the point. Interestingly there have been articles in the UK press recently about the burdens on our doctor services from ‘the worried well’. Those who think they may be unwell or demand testing on a ‘just in cae’ basis when there is nothing wrong with them. These may be a function of the ‘private’ services, available for those who can afford to pay, creeping into the National Health Service. Higher GDP offers an opportunity for more people to pay for the service or carry the cost (lost work time and earnings potential for example) when other, poorer, areas may not feel they have the opportunity. (Just a theory of course, I doubt there is enough level of detail in the ‘data’ across the UK to make such a call.)
I’m not sure where your rural comparison come in to this – the study was based in data for 11 Canadian Cities. I note the word Cities. No doubt some of them have more rural tendencies than others but I would need to accept the authors’ assertion that they were dealing with City data.
Anyway, our opinions matter little here. The paper is out there and others in the field can choose to take pot shots at it if they wish. Let’s see what happens.
BTW, I have known a number of people, from time to me including me, who have decveloped broadly ‘respiratory’ health effects, like mild but persistent coughs, when working in new environments – say moving from a typical UK office block environment of 20 or 30 years ago into a more modern ‘air conditioned’ facility. But then, as you say, correlation is not causation.
They should go back to Victorian times and see how health was suffering compared to now. Michael Crichton put it best when he said activists jump on things such as smog and decarbonisation that have been improving for decades, centuries even, and then claim that their activism made things better. They do it to take credit for things they have not achieved and to swell their membership and coffers while expanding political influence.
“..Denying the health effects of smog is crossing the line of believability….”
“But the data showed no evidence of changing health effects at the pollution levels observed in Canada over recent decades.”
The second sentence clairifes the first. At the levels of pollution in Canada over the last few decades, no effects were found, not that pollution can have no effect. The question really becomes once you reach a certain level of pollution is it worth it to keep pouring more and more money into more reduction for smaller or no additional benefit.
McCitrick doesn’t “deny” a possible health effect of air pollution. What he does find astonishing though are the alleged effects in Toronto: “In 2004 Toronto Public Health claimed that 1,700 premature deaths and 6,000 hospitalizations occur each year in Toronto alone, due to air pollution.”
These are incredibly high numbers. The city has 2.5 Million inhabitants. So that’s on the order of 30K naturally occuring deaths per year given Canadas high life expectancy. So what they’re saying is more than 5% of all deaths are caused by outdoor pollution.
The immediate conclusion would be that there must be a huge aluminium smeltering operation without any filters right in the middle of Toronto.
This reminds me of the pesticide debate. If you have a small group of people that have severe reactions the data may not show up as significant but it can severely impair the health of some. We know pesticide exposire can kill and we know exposure to fine particulates is detrimental for human health.
On the wealth issue, obesity is the third biggest killer in North america, there just might be a link there with affluence. Here in Montreal they found some of the worst air quality was in westmount, an affluent neighbourhood where they drive gas guzzlers.
Ref – Dodgy Geezer (03:28:59) :
@pft “..Denying the health effects of smog is crossing the line of believability….”
Umm…pft, are you saying that one should BELIEVE, rather than examine the data?
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Two excellent points! The truth can get complicated. It is also very time consuming for each of us to examine ALL the data and make our own determinations. I dare say, as the Brits like to say, life would be a might boreing if we had to examine ALL the data for everything, every day.
Perhaps the “truth” for the moment goes something like this:
SMOG causes breathing problems and can be the “cause” of eventual death, AND McKitrick says in a new peer reviewed study that the models and claims about Toronto SMOG don’t add up.
I would like to see a similar analysis applied to another phony health scare: lawn pesticides. Municipalities are banning these heavily tested products based on what I believe are imaginary problems. The weeds and bugs are winning. Again, where are the bodies?
pft, You seem to be missing what the study really says;
pft – “If you have never lived in Shanghai or Hong Kong maybe you will believe this story. I developed a chronic cough that did not leave until I left the area after 5 years, who knows what will happen in 10 years.”
study – “Nobody is trying to argue that air pollution is good for you: this is either just noise in the data, or it might be an effect from “averting” behaviour, where people who are susceptible to lung problems stay indoors on days with bad air quality.” AND, “Very few studies over the past decade have controlled for socioeconomic covariates (including smoking), fewer still have looked at long data panels back to the 1970s and fewer still have dealt with model uncertainty. Those that have addressed one or more of these issues typically find the effect of air pollution shrinks or disappears outright. Thus our results are actually quite consistent with the relevant group of previous studies. The popular idea that current ambient air pollution has a powerful effect on lung health might look like it is based on a large empirical foundation, but on closer inspection the pile contains a lot of weak results.”
Study – “The estimates are derived by taking correlations in the epidemiological literature between observed pollution levels and health indicators, like hospital admission rates, and then extrapolating across populations to estimate how many deaths and illness diagnoses can, in theory, be attributed to pollution.
My manufacturing engineering group is not allowed to use linear or surface response mathematical models for extrapolation of any type (far too risky), only interpolation within actually measured factor levels.
Points are: Hong Kong ain’t Toronto. And, if you are going to use statisitical modeling as the foundation of your “scientific-study”, you better slice all reliable, publically available data in all possible combinations and permutations before publishing, or guys like Mckitrick you going to show you as a fool.
@pft
..Denying the health effects of smog is crossing the line of believability….”
There we go again, dismissing any findings that don’t fit Green prejudices as “denial.” Perhaps, pft, you would find it beneficial to put your fingers in your ears, shut your eyes, and shout “La la la la la la,” lest something comes along to burst your bubble.
Al Gore’s Holy Hologram: “They have what can only be called post-industrial paranoia and delusions of pre-industrial utopias.”
I heard a suggestion on the radio that the rise in allergies could be a result of the lack of dirt in our present lives. The theory is that the body’s immune system expects a certain level of activity, and in the absence of any pathogens to fight, it ups the sensitivity in a kind of self-correcting control.
The problem therefore with removing all the dirt in our lives, is that in the absence of infection, the immune system automatically increases its sensitivity expecting a “normal” level of infection and in doing so can have its sensitivity turned up so high that it no longer just attacks pathogens, but ends up attacking perfectly benign substances we come into contact with.
Whether or not that is true, I personally think society can have a similar auto-immune type disease. Our level of anxiety was designed for a life where there were literally wolves at the door, where every stranger could and would steal, rape, abduct, so we are naturally designed for a high risk environment.
Take away all that risk, put us in a cosy middle-class life-style, with nothing more to worry about than whether the world could heat a fraction of a degree, or whether a small amount of smoke from a car might be bad (our ancestors lived in huts full of wood-smoke) and because we are naturally designed to be anxious – because risk was the ordinary way of things until recently – in a world without real risks, we transfer our anxiety to items of minuscule risk but deal with them as if they were real risks like the cave-man wolf at the door.
When there is a pack of wolves coming down to your cave to pick off the odd homo-erectus, the precautionary approach worked to select those who were precautionary. These days, the precautionary approach is the symptom of a community sickness of a society whose sensitivity to risk has been hyper stimulated trying to make sense of an environment which is largely risk free.
OT
Volcano erupts in Iceland
The EPA rules kill. The EPA is a killer.
We can research deaths in car accidents. We can look up the weights of the cars from Manufacturing records. We can plot the EPA fuel mileage stats.
We can see there are 40,000 more killed by reason of driving lighter more fuel efficient cars as opposed to lower death rates from accidents in heavier cars.
The EPA gives deadly advice.
This is not some coincidental claim by me.
I wonder if pft moved to Toronto?
The major issue in air pollution health research is: which types of particles are harmful?
Older studies examined effects of only a few types of particles, ignoring emissions from vehicles (!).
New studies which include many types of particles, including those from vehicles such as black carbon from diesel engines, almost always find statistical associations with black carbon, but few associations with other types of tiny particles.
Toxicology studies confirm that diesel emissions and black carbon cause a number of effects in animals, people, and lung cells which variously lead to atherosclerosis and to hospital admissions for cardiovascular and all cause mortality.
Studies which examine effects of other types of small particles, in studies which also include black carbon, generally find no or few statistical associations with these other pollutants, which include sulfates and secondary carbonaceous aerosols and airborne dust particles (which are marked by silicon), the largest components of particulates in the air on days with high pollution levels (in the US). One exception is tiny nickel particles, which are biologically very active, but there are very few places with high levels of nickel in ambient air.
I would avoid living near major roads or walking extensively near them, or spending much time near off road diesel equipment. Unless you live near a particular industrial source such as a steel mill or a nickel smelter, I don’t think any other source of small particles in the air causes much harm.
I’ve just realised that my suggestion that global warming is a social “autoimmune” type sickness is testable. Because if it is an over-sensivity to risk due to the absence of real risk in modern society, then this would predict that those individuals and society who experience risk directly, would be least likely to believe the rubbish on global warming.
That suggest: soldiers, those in high-crime areas, and countries with histories of civil unrest would be least ready to go along. Whilst countries with low-crime, low-disease, low risk of invasion, low social depravation, welfare systems and a general PC culture against risk taking, would be those most likely to be susceptable to the global warming sociasickness.
Hospitals kill. Hospital patients have much higher death rate than people that are not in the hospital. This has been confirmed bu tracking identical twins.
Obesity is life shortening. However very few break it down. Many obese people that exercise more do better in for example recovery after a surgery. The lack of exercise is detrimental and can be behind obesity.
Medical research is far superior to climate research. Climate research had pressumed only one variable and that is CO2. Medical research uses longitudinal studies and blind control groups.
I suspect no one wants to claim India and China life expectancy rates are climbing but the 75% of the Indians and Chinese still use coal, stover, wood and charcoal in open fires in their homes for heating and cooking.
(Statisticians & modelers) + computers ≊ a room full of kids armed with loaded AK-47’s, playing a game of cops & robbers.
After reading this piece, go back and reread:
http://wattsupwiththat.com/2010/03/20/science%e2%80%99s-dirtiest-secret-the-%e2%80%9cscientific-method%e2%80%9d-of-testing-hypotheses-by-statistical-analysis-stands-on-a-flimsy-foundation/
Especially, go back to the main article at:
http://www.sciencenews.org/view/feature/id/57091/title/Odds_Are,_Its_Wrong
These articles remind me of another blog, Junkfood Science, which would often hit these type of reports — seemingly serious “studies” based not on real hard data, but on surveys and then massaged to produce great PR scare stories.
A much more interesting study region for effects of air pollution on population health under different conditions through two decades (1990-2010) would be the Brown Coal Region near Most in North Bohemia (Czech Republic), esp. around the plant concentrations in Litvinov (the Old Hermann Goering Works, still run to produce petrol from sulfur-rich coal!). Here the smoking habit continues in the population free of social controls typical in North America, the actual air pollution in Late Warsaw Pact times was actually much higher than anything seen recently (post WW2) in the West, and effective constraints post-1990 on actual regional pollution (not CO2) much more effective. Thermal inversions from the Ore Mountains (Krushne Horze “dead tree zone” ) also amplify the regional impact and make relations between specific emmisions and population effects quite direct.
London Ontario has not had one single smog warning in over 2 years although the fear mongering local health unit and the fear mongering local media always like to issue plenty of smog alerts, just in case.
I suggest that this is another case where the government believes in the Linear No Threshold (LNT) law without proof. There is increasing evidence that hormesis exists for many things. Just because something is bad for you at high doses doesn’t mean it is bad for you, in a measurable way, at low doses.
This appears to be true for Radon and most remarkably for radiation exposure shown by Chen. Here the cancer death rate of many thousands of people was reduced to only 3% of the general population!
See Figure 1 in http://www.jpands.org/vol9no1/chen.pdf
The powers of Nature and the cosmos would have to be alterd by us human monkeys in order for pollution to be a real danger considering 5 billion years of volcanoes, comet hits and environmental chaos.
Ths cave man thinking of environmentalism is laughs for the history books.
If these environMENTALists are so worried about pollution in cities on the OTHER side of the world, why don’t you all go and tax volcanoes and worry about them too? Nature is NOT weak, fragile and tender and in danger from a harmeless gas that human monkeys say both provides life for the planet and destsorys it at the same time. Insanity I say, pure insanity.
Voters have real consensus, not lab coat consultants called “scientists” by the church of environMENATLism.
I just watched a documentary about the town of Stuttgard in Germany where officials are forced to close the city limits for 4/5 of the current traffic to meet the latest EU air quality standards.
Such a measure would simply kill the town!
Until now the towns relied on the emission rules for vehicles only closing down the odd shopping street.
But the Greens started legal procedures forcing the town to act.
The rules are crazy, especially since we know that 1/3 of the “pollution” is imported and 60% of the fine dust is natural (Sahara dust and other natural sources a.o from agricultural activity from the fields bordering the town.
IMO the emission rules serve the same sick agenda as the entire AGW doctrine!
We should get rid of them asap, perform a review as suggested in this excellent article.
Interesting paper Dr. McKitrick et al. As with seemingly all reviewed science announcements these days, when one looks closely at the methods supposedly good enough for some reviewers rubber stamp, one finds dubious work and speculative results prepared by some advocacy group.
Anyone else see the CTV piece this am about the endangered bunny? They ran a story in which they show a woman purported to be a scientist but give no name or affiliation. They frequently refer to “scientific” studies but never mention by whom or for what group.
So much of what we are told is sound science turns out to be papers so full of errors that they couldn’t even be relied upon to line the bottom of your birdcage!