Improvements in real air pollution problems

From the Harvard School of Public Health  some good news. Unlike the claim thatb Co2 is a pollutant, real air pollution problems and real related health issues continue to improve.

Declining air pollution levels continue to improve life expectancy in US

Boston, MA — A new study led by researchers at Harvard School of Public Health (HSPH) has found an association between reductions in fine particulate matter and improved life expectancy in 545 counties in the U.S. from 2000 to 2007. It is the largest study to date to find beneficial effects to public health of continuing to reduce air pollution levels in the U.S.

The study appears in the December 3, 2012 online edition of the journal Epidemiology.

“Despite the fact that the U.S. population as a whole is exposed to much lower levels of air pollution than 30 years ago—because of great strides made to reduce people’s exposure—it appears that further reductions in air pollution levels would continue to benefit public health,” said lead author Andrew Correia, a PhD candidate in the Department of Biostatistics at HSPH.

The study looked at the effects on health of fine particulate matter, small particles of 2.5 micrometers or less in diameter—referred to as PM2.5. Numerous studies have shown associations between acute and chronic exposure to fine particle air pollution and cardiopulmonary disease and mortality. Studies have also shown that reductions in air pollution are associated with reductions in adverse health effects and improved life expectancy. Air pollution has been declining steadily in the U.S. since 1980, but the rate has slowed in the years since 2000. The HSPH researchers wanted to know whether the relatively smaller decreases in PM2.5 levels since 2000 are still improving life expectancy.

Controlling for socioeconomic status, smoking prevalence, and demographic characteristics, the results showed that a decrease of 10 micrograms per cubic meter (10 μg/m3 ) in the concentration of PM2.5 during the period 2000 to 2007 was associated with an average increase in life expectancy of 0.35 years in 545 U.S. counties.

The research expanded on a 2009 study published in the New England Journal of Medicine by some of the same authors (Pope, Ezzati, and Dockery) that found that reduced air pollution was associated with increased life expectancy in 211 urban counties. This new study looked at more recent data, more than two-and-a-half times as many counties, and included both rural and urban areas. The findings showed that there’s a stronger association between declining air pollution and increased life expectancy in more urban, densely populated areas than in rural areas. The results also suggested that reduced levels of air pollution may be more beneficial to women than to men.

As to why there was a stronger association between reductions in fine particulate matter and improvements in life expectancy in urban areas, the researchers speculated that the composition of the particulates there may be different from that in rural areas.

“Since the 1970s, enactment of increasingly stringent air quality controls has led to improvements in ambient air quality in the United States at costs that the U.S. Environ¬mental Protection Agency has estimated as high as $25 billion per year. However, the extent to which more recent regulatory actions have benefited public health remains in question. This study provides strong and compelling evidence that continuing to reduce ambient levels of PM2.5 prolongs life,” said senior author Francesca Dominici, professor of biostatistics at HSPH.


Other HSPH authors included Douglas Dockery, professor of environmental epidemiology and chair, Department of Environmental Health; and Yun Wang, senior research scientist, Department of Biostatistics.

Funding was provided by the U.S. Environmental Protection Agency (R-834894, RD-83479801), National Institutes of Health (ES019560 and ES012054), Harvard-NIEHS Center for Environmental Health (ES000002), NIEHS (T32ES007142), MRC Strategic Grant, and the Health Effects Institute.

“The Effect of Air Pollution Control on Life Expectancy in the United States: An Analysis of 545 US Counties for the Period 2000 to 2007,” Andrew W. Correia, C. Arden Pope III, Douglas W. Dockery, Yun Wang, Majid Ezzati, Francesca Dominici, Epidemiology, December 3, 2012 online edition

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Crispin in Maseru
December 4, 2012 6:52 am

These conclusions will also support the continuation of programs that promote cleaner cooking solutions in the developing world where biomass combustion dominates indoor air quality problems. There is a popular rule-of-thumb saying that a reduction of 90% in PM2.5 is required before a substantial improvement in family health can be detected by conventional survey methods. At a low change level, the investment may be unjustifiably large if the benefit is small. How much per human ‘death’ (or significant negative health impact.
An improvement of 10 micrograms per cubic metre is very small. If this small change can make a detectable change in health I will be impressed on two counts: first that they managed to detect a difference, and second, that the confidence interval is such that the signal is larger than the noise. If the evaluation method holds up to scrutiny, this is a significant advance in the field of PM’s effect on human health.
The much more conservative approach taken on the opposite Coast can be studied on the Berkely website where the collected works of Dr Kirk Smith are posted, along with his recommended methods and the precision needed to quantify human health impacts. Read, compare and decide for yourself.

December 4, 2012 6:54 am

Back in the 1970’s when I lived in Denver area, there were days when the soot was lowering the visibility to a distance of less than a block. If nothing else, today’s clearer smog has improved the visibility and I would say has improved the health of those who survived those times. Logically, the cumulative affect would diminish one’s health and lead to shorter life spans in general. A comparison would be similar to the black London fog still stuck to some of the stone structures.

December 4, 2012 7:13 am

Watch out people , they will be trying to deny you the use of your wood burning stove next . They have got to have you paying that electric and gas bill so they can suck up the taxes involved , and enrich their buddies in the utility supply business .

December 4, 2012 7:30 am

The problem with pollution controls is that the EPA and many environmentalists take a “d@mn the costs” approach to it. If a decrease in pollution is good for us, then we should do it, no matter how much it costs.
The problem is that diverting money from other uses to pollution control also has health costs. A wealthier society has more time to spend taking care of itself and more money to spend on improving health and inventing new health care technologies.
For every pollutant, there comes a time when the increasing costs of a cleaner environment result in more deaths than the amount of pollution that was removed did.
I suspect that for many pollutants in the US, the cross-over point was reached years ago.

December 4, 2012 7:30 am

To be absolutely clear on this, what we’re talking about is increasing regulations on large diesel engines:
Trucks, trains, buses – these are the primary sources of urban pm2.5.
We could repower all of them with CNG or LNG tomorrow and see real health improvements. The exact same kind of real health improvements that shutting every coal plant in the country wouldn’t achieve.

December 4, 2012 7:41 am

It looks like the CARB, and the local Air Pollution Districts in CA, will have another study in support of their efforts to minimize particulate matter.
The use of biomass (i.e. wood) as a source of energy to heat homes in CA is likely going to be less of an option in the future.
The Air Pollution Districts in the state have goals (a high priority) to reduce particulate levels in their districts. If the particulate matter goal is given priority over the carbon neutral heating goal, then the consequence of meeting the particulate goal is going to make it harder to use biomass as a direct heating option for homeowners in many areas of the state.
What happens to the CO2 mitigation plans if burning wood is no longer allowed?

December 4, 2012 7:42 am

If this study used simply “life expectancy” rather than reduction in mortality due to reduction in those ailments associated with particulates, then the study is totally invalid. General “life expectancy” has been increasing thruout the ages, due to an enormous number of variables, not simply particulate matter rates. And even if they did show an association, the real issue is “how much.” The danger from large studies is that they can often show a “statistically significant, non-zero effect,” which is, in fact, trivial. Uncontrolled, natural experiments like these are also highly prone to all kinds of unknown biases and errors. Control variables,” such as smoking, etc. are not anything more than educated guesses as to what other factors need to be taken into account
and their comprehensiveness and effectiveness is always open to question. These types of “experiments” need to be be examined and replicated even more so than controlled lab experiments. I wouldn’t put much faith in these claimed results, which were financed by an agency with a desire to find such effects and justify its continued existence and influence.

December 4, 2012 7:44 am

Reblogged this on Climate Ponderings.

December 4, 2012 7:50 am

This study was funded by the EPA! what does that do the the creditability of these “scientists” and their study? This study is being sighted for the justification of greater regulation, more control over all activities and greater funding. Sounds like more “Post Normal Science” to me. pg

December 4, 2012 8:10 am

At this point, it may be germane to ask, what are the sources of the small particulates? What proportion is man-made and what proportions are from nature?

john robertson
December 4, 2012 8:37 am

EPA finds desert dust in violation, threatens to sue state.

December 4, 2012 8:52 am

johnmcguire says:
December 4, 2012 at 7:13 am
Watch out people , they will be trying to deny you the use of your wood burning stove next
That’s already a reality in Washington State. We have ‘burn bans’. Fireplaces l and wood stoves are prohibited on such days unless it can demonstrated that it is the ‘only possible source of heat’.

December 4, 2012 8:58 am

It will be interesting to see how the results of this study meld with the lawsuit to stop illegal human experimentation by the EPA. ( see )
Notice that this PM2.5 was described by Lisa Jackson to Congress as lethal at any concentration.

December 4, 2012 9:58 am

P.G. Sharrow says:
December 4, 2012 at 7:50 am
This study was funded by the EPA! what does that do the the creditability of these “scientists” and their study?
The research may well have gone through all the normal procedures but the outcome would have been predetermined which would have affected the types of the various tests carried out.
Is that credible? It’s life in the 21st century.
If you read any study about anything, in 9 out of 10 (the probability may be higher) cases you will know about the direction of the findings by first getting to know who funded it.
I know that living longer appears to be the utopia for some, (companies involved in care for the aged for instance) but there is a difference between keeping people alive with no quality of life at all costs versus a slightly shorter life with good mobility and then being allowed to pass on.
I don’t really care if my life may be extended by 3 months or 2 years if it is bed ridden but good for the statistics ( the latter being good for the politicians).
Dignity for the aged is something we appear to have lost in our madness to extend life expectancy statistics.

December 4, 2012 10:44 am

Please note the following:
“a decrease of 10 micrograms per cubic meter (10 μg/m3 ) in the concentration of PM2.5 during the period 2000 to 2007 was associated with an average increase in life expectancy of 0.35 years ”
Not having all the numbers, I’m still very puzzled. The average life expectancy of the entire population was increased by four months in seven years? Remember – air pollution would only affect a fraction of the population – many die of cancer, and air pollution would hardly be involved there. So the actual increase in life expectancy for those affected by air pollution was much larger than four months. And this is for a relatively small change over a short period. If this is true, what was the change between 1980 and 2000, when larger changes were made? And what was the total change in life expectancy between 1980 and 2000, that 0.35 was a part of? Surely all that money we spend on new treatments has been doing something. This number just doesn’t ring true to me. It could be correct, but someone has a lot of ‘splanin’ to do before I buy it.

Donald Mitchell
December 4, 2012 11:00 am

I notice that while an association was claimed, there was no mention of causation. In this article there was also no mention of what levels were declining from, what the actual declines were, or what the prior exposure to the population had been. I spent part of an hour looking for current PM2.5 levels in the US, but most of them were below 20 uG/m^3. If he was looking at changes on the order of 2 or 3 uG/m^3, he was talking about an increase in lifespan of about 1 month. I would really need to see what data the study was based on before I would give it any serious consideration.
Not all correlations are obvious. Reducing PM2.5 by replacing all internal combustion vehicles with electric vehicles might reduce average life expectancy due to increased pedestrian deaths.

Lance Wallace
December 4, 2012 11:09 am

This study and its predecessor on the mostly urban communities will be most likely the central studies in the next round of regulatory considerations of the Federal PM2.5 standard. The present standard is 15 micrograms per cubic meter, not to be exceeded more than 3 times in 3 years, as I recall. Also as I recall that number was selected by a previous Administrator although it was the highest number in the range (12-15?) offered by his own staff, an unusual action, although later emulated by another Administrator who disregarded his/her own staff on the ozone standard. So these studies will be used as the main arguments for lowering the present standard, perhaps all the way down to 12. CARB will also probably use it in considering restrictions on wood burning.
There is a paradox here in that if the dose-response curve found for these low exposures to fine particles is linearly extended to cigarette smokers, they would all die almost immediately. Clearly there is something else at work here. Doesn’t seem to be differing toxicity (suggested as the reason for the lower effect in rural counties) since diesel exhaust and cigarette smoke are similar.
Another consideration, as raised by the first commenter, is the truly enormous effect of biomass burning for cooking and heat indoors in developing countries, as first shown by Kirk Smith now of Cal Berkeley and confirmed by WHO to be responsible for about 1.4 million deaths per year. This has led China for example to provide 800,000 new stoves with chimneys to their rural residents. Their exposures are enormous, in the range of milligrams per cubic meter. If the HSPH study is right, then lowering their exposures by a factor of two or even 10 might not provide the benefit that one might expect.

December 4, 2012 11:38 am

MarkB says:
December 4, 2012 at 10:44 am
…. many die of cancer, and air pollution would hardly be involved there. …

And there you would be profoundly mistaken. It depends on the type of cancer and the type and degree of irritation triggered by the particulate material. Some particulates are relatively inert, others, such as fine glass, silica, metallic dust and hydrocarbon impregnated dust are far more problematic.

December 4, 2012 12:27 pm

Drives me NUTS! Lying cretins don’t want to TOUCH the history of URBAN AIR QUALITY going back to the COAL HEATING ERA (post Civil War to about 1955). What the HECK do they think living in that was like? Just the shift to Natural Gas for home heating must have dropped the “cancer rate” dramatically? (OR DID IT? If one removes infant mortality, the general length of life on the average, say from 1950 to now (60 years later) has moved up about 4 to 6 years, and much of that is in “intercepting” things that would kill you in your last 15 years of life…
Again, more bogus out of the “bogus crisis” industry!

December 4, 2012 1:14 pm

“Declining air pollution levels continue to improve life expectancy in US”

And the irony is that fossil fuel use at the start of the industrial revolution (along with other factors) helped to improve life expectancy in the US by providing energy.

December 4, 2012 2:56 pm

While this is nice for those living in the US, the pollution has simply been outsourced to Asia.

December 4, 2012 4:30 pm

The downtown Toronto air monitoring station shows that the average 2011 PM2.5 reading was 6.2 μg/m3, and the daily average was above 10 μg/m3 for only 59 days in the year. Environment Canada says the Canada average PM2.5 is 6.621 μg/m3. By shutting down coal fired electrical generating plants, Environment Canada estimate the average PM2.5 will be reduced to 6.607 μg/m3, or by -0.21%, as shown here;
They estimate the health benefit of reduced PM2.5 is $123 million (63% of $195 million/yr of total health benefits) for our 35 million population at a cost of $8.2 billion. (1 $Canadian = 1 $US)
Obviously, reducing PM2.5 by shutting down coal fired power plants is very uneconomic. Does anyone has a cost estimate to reduce PM2.5 concentrations by a more effective scheme than shutting down coal fired power plants?

john robertson
December 4, 2012 5:14 pm

The logic being used is the same as , If nobody moves nobody will get hurt logic , coming from our safety regulators.

December 4, 2012 6:40 pm

This paper wouldn’t have passed a high school science fair back in the day. Air pollution has declined. Life expectancy has increased. However, do they mention any diagnoses attributable to PM2.5? No. This is just a random “correlation.” It is not good news, Anthony. It is propaganda. It is junkscience.

December 4, 2012 8:00 pm

Already the case in some (urban at least) parts of California. No NEW fireplaces can be built and we have “no burn days” with fireplace police that drive around with IR scanners looking for hot chimneys…. don’t know if it’s city or county or State or…

Brian H
December 7, 2012 11:51 am

Beyond the Law of Diminishing Returns lies the swamp of Unintended Consequences. Costs have costs…

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