Good news: U.S. air pollution deaths nearly halved between 1990 and 2010

From the University of North Carolina, Gillings School of Global Public Health. This should limit the urgency that the EPA had over implementing new air pollution laws where they make claims of increasing death tolls.

Los Angeles Smog

Air pollution in the U.S. has decreased since about 1990, and a new study conducted at the University of North Carolina at Chapel Hill now shows that this air quality improvement has brought substantial public health benefits. The study, published Oct 19 in the journal Atmospheric Chemistry and Physics, found that deaths related to air pollution were nearly halved between 1990 and 2010.

The team’s analyses showed that deaths related to air pollution exposure in the U.S. decreased by about 47 percent, dropping from about 135,000 deaths in 1990 to 71,000 in 2010.

These improvements in air quality and public health in the U.S. coincided with increased federal air quality regulations, and have taken place despite increases in population, energy and electricity use, and vehicle miles traveled between 1990 and 2010.

“We’ve invested a lot of resources as a society to clean up our air,” said Jason West, PhD, professor of environmental sciences and engineering at the UNC Gillings School of Global Public Health and study co-author. “This study demonstrates that those changes have had a real impact with fewer people dying each year due to exposure to outdoor air pollution.”

The study was led by Yuqiang Zhang, PhD, former postdoctoral researcher at the UNC Gillings School and at the Environmental Protection Agency and current research scientist at the Duke University Nicholas School of the Environment, and in collaboration with West and several scientists at the EPA.

This study supports results from a small number of other recent studies that also showed similar and marked reductions in air pollution-related deaths, but this study is unique in its use of a 21-year computer simulation and ability to estimate air pollution deaths each year.

Zhang, West and colleagues analyzed concentrations of two pollutants, known as PM2.5 and ozone, from a 21-year computer simulation of air pollution across the U.S. PM2.5 are very small particles suspended in the air that come from power plants, motor vehicles, industries, and some commercial and residential sources. The diameter of such small particles is less than 2.5 micrometers, which is about 3 percent of the diameter of a human hair.

They then related the declining concentrations of PM2.5 and ozone to the geographical areas in which people live and the causes of death in those areas, using data from the Centers for Disease Control and Prevention, to estimate deaths from air pollution during the period. They estimated deaths from ischemic heart disease, chronic obstructive pulmonary disease, lung cancer and stroke related to PM2.5, and from respiratory disease for ozone.

Because other factors also influence the overall rates of these causes of death, the drop in deaths was not solely the result of improved air quality. Still, the authors found that improved air quality likely reduced deaths by about 40,000 in 2010, compared to the number that would have resulted if air pollution had stayed the same from 1990 to 2010.

“These health improvements likely have continued beyond 2010 as we observe that air pollutant concentrations have continued to decrease,” said Zhang.

The team plans to use other datasets to analyze air pollution deaths since 2010.

Still, despite clear improvements, air pollution remains an important public health issue in the U.S. The estimated 71,000 deaths in 2010 translates to 1 of every 35 deaths in the U.S. – that’s as many deaths as we see from all traffic accidents and all gun shootings combined.

“Even though we’ve seen some tangible success, there are still people dying, and a public health challenge remains going forward,” West said. “New federal policies curtailing air pollution regulations likely will slow the improvement in air quality or possibly make air quality worse.”

The study was funded by NASA through its Health and Air Quality Applied Sciences Team, of which Dr. West is a member, and by the EPA.



The paper: (open access)

Long-term trends in the ambient PM2.5– and O3-related mortality burdens in the United States under emission reductions from 1990 to 2010

Abstract. Concentrations of both fine particulate matter (PM2.5) and ozone (O3) in the United States (US) have decreased significantly since 1990, mainly because of air quality regulations. Exposure to these air pollutants is associated with premature death. Here we quantify the annual mortality burdens from PM2.5 and O3 in the US from 1990 to 2010, estimate trends and inter-annual variability, and evaluate the contributions to those trends from changes in pollutant concentrations, population, and baseline mortality rates. We use a fine-resolution (36km) self-consistent 21-year simulation of air pollutant concentrations in the US from 1990 to 2010, a health impact function, and annual county-level population and baseline mortality rate estimates. From 1990 to 2010, the modeled population-weighted annual PM2.5 decreased by 39%, and summertime (April to September) 1h average daily maximum O3 decreased by 9% from 1990 to 2010. The PM2.5-related mortality burden from ischemic heart disease, chronic obstructive pulmonary disease, lung cancer, and stroke steadily decreased by 54% from 123700deathsyear−1 (95% confidence interval, 70800–178100) in 1990 to 58600deathsyear−1 (24900–98500) in 2010. The PM2.5-related mortality burden would have decreased by only 24% from 1990 to 2010 if the PM2.5 concentrations had stayed at the 1990 level, due to decreases in baseline mortality rates for major diseases affected by PM2.5. The mortality burden associated with O3 from chronic respiratory disease increased by 13% from 10900deathsyear−1 (3700–17500) in 1990 to 12300deathsyear−1 (4100–19800) in 2010, mainly caused by increases in the baseline mortality rates and population, despite decreases in O3 concentration. The O3-related mortality burden would have increased by 55% from 1990 to 2010 if the O3 concentrations had stayed at the 1990 level. The detrended annual O3 mortality burden has larger inter-annual variability (coefficient of variation of 12%) than the PM2.5-related burden (4%), mainly from the inter-annual variation of O3 concentration. We conclude that air quality improvements have significantly decreased the mortality burden, avoiding roughly 35800 (38%) PM2.5-related deaths and 4600 (27%) O3-related deaths in 2010, compared to the case if air quality had stayed at 1990 levels (at 2010 baseline mortality rates and population).


46 thoughts on “Good news: U.S. air pollution deaths nearly halved between 1990 and 2010

  1. I doubt both figures, as the attribution of “deaths” is models all the way down.
    NASA and the EPA are very likely using a LNT (linear-no threshold) model, which is relatively simple to use and will very likely produce the scariest numbers. However, testing the model is something the regulators are quite resistant to, with the usual reliance on a claim there is nothing else to use, and they have to use something.

      • It’s total hogwash…..they tell the computer this much air pollution causes this much death
        ..with absolutely no way to verify that

        Someone a long time ago made that up..and it’s still going around

        • Latitude

          I can’t help but wonder where these studies are conducted. Air pollution and ‘consequent’ deaths are hardly a feature of rural areas so I guess they are measured in city areas, as the photograph would suggest (and yes, I know it’s a convenient shot for WUWT).

          However, In the London area for example, that bounded by the M25 motorway which encircles the general area (London as such is a one square mile section in the centre of the conurbation which generally referred to as London) there is not a single electricity generating power station. They have all been farmed out to the surrounding rural areas.

          Therefore, London doesn’t suffer the consequences of it’s own profligate energy consumption. But, like many other countries, air quality is routinely judged on that of city centres and the results imposed on the the countryside which invariably forms the vast majority of any nation.

          The UK’s drive (forgive the pun) to impose electric cars on the nation is an almost exclusively London centric initiative. I daresay there’s not a rural inhabitant or a farmer who gives a toss about EV’s or air pollution.

        • Those death numbers have very little credibility. In the region of Paris (France), it is claimed by environmental associations, that 6600 persons die each year of particulate pollution (source: Crit’Air). But that pollution is now 11 micro-gram per cubic metre of air, when it was 185 micro-grams at the end of the 1950’s (official source: Airparif web site). So in 1957, with a linear model with no threshold, more than 110,000 persons should have died from particulate pollution. That is more than the total number of deaths that year in the region. Something must be wrong in those estimates.

    • As several others have noted below – most of the gains are due to the reduction in cigarette smoking.

      • Got my vote .
        No need to read any further.
        ” In 1988, the International Agency for Research on Cancer designated radon as a known cause of lung cancer, based on studies of underground miners exposed to high levels of the gas prior to the adequate ventilation of mines [1]. Radon further decays into a series of radon daughters, some of which emit α-particles capable of damaging cellular DNA [2]. Radon, formed during the radioactive decay of uranium-238, is present in air, soil and water. Upon release from the Earth’s crust, radon enters homes through cracks in the foundations and accumulates primarily in the basement and lower living areas [3]. Combined analyses of case–control studies conducted in North America and Europe have also implicated residential exposure to radon as a risk factor for lung cancer”

    • Agree. They are publishing a hypothesis not a finding. The hyposthesis is at the center of their models, and they appear to be applying the linear-no-threshold model as you state which is not physiologically sound. They are also basing this on correlation studies that have never been validated by cause and effect observations.

  2. By 1990, the start of their period, tremendous strides had already been made in reducing particle concentrations. If the authors had extended their model back to the time of the Clean Air Act of 1970, or to the time in 1975 when all states were working toward achieving the standards set by EPA, they would have found even larger gains in public health. Cities were cleaned up from their black Satanic mills. Smog in Los Angeles was largely reduced. This is an amazing success story that deserves to be celebrated.

    • As several others have noted below – most of the gains are due to the reduction in cigarette smoking.

      • Repace and Ott (2012) compared the reductions in U.S. population exposure from 1990 to 2010 from outdoor fine particulate matter in the 50 States due to EPA regulations, to the reduction in fine particle exposure from secondhand smoke made possible by state and local clean indoor air
        laws. We found that over this 20-year period, the annual average PM2.5 ambient air concentrations nationwide, according to EPA’s network of outdoor air pollution monitoring
        stations, had decreased by 38%, from ~16 μg/m3 to 10 μg/m3, as a result of EPA regulations
        governing mobile and stationary source emissions. On the other hand, over the same 20-year period from 1990 to 2010, we estimated that the U.S. population’s personal exposures to PM2.5 from SHS had decreased by 76%, from ~16 μg/m3 to 4 μg/m3, due to smoke-free laws and smoking restrictions. [ESTIMATED REDUCTIONS IN POPULATION PM2.5 EXPOSURE FROM AMBIENT AIR POLLUTION AND SECONDHAND SMOKE, 1990 TO 2010. J.L. REPACE & W.R. OTT, PAPER TUE2, 22ND ANNUAL MEETING OF THE INTERNATIONAL SOCIETY OF EXPOSURE SCIENCE, SEATTLE WASHINGTON, OCT. 28-NOV.1, 2012]. In 1990, the population exposure from outdoor PM2.5 and indoors from secondhand smoke PM2.5 were the same. Smoke-free laws were more effective in reducing secondhand smoke PM2.5 than outdoor air laws. However, they were much cheaper to enforce than outdoor air laws. Moreover, coal-burning power plants were much harder to control given the effective opposition by the industry.

  3. Are these models based on the same studies that EPA refuses to release to the public because they are “proprietary?” If some, the “good news” is just as suspect as the “bad news.”

  4. I don’t see any note that they corrected for the large reduction of cigarette smoking during the same period

      • Thinking about the cigarette effect you’d have to go back well before 1990 to account for it’s impact.

    • Some topics are just too obvious to be put in the abstract. If they have not corrected for cigarette smoking, which undoubtedly is the largest cause for exactly the same diseases as those caused by air pollution, they would have failed even in a high school project.

      This is research carried out by university professors and published in a scientific journal. Asking whether they have remembered to corrected for cigarette smoking is about as naive as asking whether climatologists have remembered to move the thermometers outdoors when they are measuring global temperatures.

      • And yet we have seen many submitted, approved, and published studies that have done just that, or worse made an adjustment with the wrong sign to make their case look better, or simply made up all the data for the purpose of supporting a cherished idea.

        Peer review mostly seems to be a good way to keep inconvenient ideas out of publication.

        • In both the Journals Science and Nature the talk is of a reproducibility crisis with published papers. There are lots of retractions and outright fraud.

      • I downloaded the full paper. There is no reference to smoking, tobacco, cigarettes etc. On page 15005 they detail the origin of mortality data and cause of death. Death certificates which I’m very familiar only give the technical cause copd etc. I see no credible way to separate tobacco use as a variable.

          • Estimates, estimates…….. the paper is built on a house cards. If tobacco/capita use was constant you could make a case. With tobacco falling precipitously during the same period makes the papers assertion void.

          • Jan

            I have a couple of issues with this paper. First is the claim that air pollution ‘kills more people than car accidents and shootings combined’. Those are two ’causes of death’ in the medical sense. The attribution of air pollution as having caused premature death is from public health statistics, not coroner’s reports.

            No one has ‘air pollution’ posted as a cause of death.

            “Still, the authors found that improved air quality likely reduced deaths by about 40,000 in 2010,…”

            And there you have it: ‘likely’. Because something was attributed as a cause doesn’t mean there is a causal relationship.

            As most readers know, the ‘premature deaths’ are based on the EPA’s guess that there is no safe exposure limit.

            There is no one death with ‘only air pollution’ as the sole contributing factor. And you can’t ‘half die’ from one of multiple causes (which includes everyone).

          • Crispin says:

            the ‘premature deaths’ are based on the EPA’s guess that there is no safe exposure limit.

            Sorry, but it seems like you are wrong here Crispin.

            See formulae 2 and 3 on page 15005
            Th C0 is the threshold concentration (5.8–8.0 µg m−3 ), below which no additional risk is assumed

  5. Since we do not have air pollution listed as cause of death, or cause of disease these are estimated based on assumptions. The good news is that the estimates are significantly decreased using the assumptions that told us air pollution was going to kill all of us. The vas news is that this analysis could have been done for years and was not when someone needed to justify new environmental regulations.

  6. Well, that’s a real set-back for the Gaea types – I mean, aren’t we supposed to be being culled as a species – you know, to save the planet?

    We’re a ‘pestilence’, after all.

  7. The foundation for studies like this is the claim the pm2.5 actually causes death. And if you drill down through the citations and references you end up finding that this claim is based on a study from the EPA here:

    The claim is based on the previous EPA’s secret science where those skeptical of the claim could not get hold of the data or methodology. This makes it impossible to replicate but very easy to cite regardless. Other studies bash the EPA claim like this recent one looking at California:

    “The daily death variability was mostly explained by time of year or weather variables; Neither PM2.5 nor ozone added appreciably to the prediction of daily deaths. These results call into question the widespread belief that association between air quality and acute deaths is causal/near-universal.”

    Note that California is a state with outstanding air quality data.

  8. Are these premature deaths or real deaths? Prof Frew was interviewed by Andrew Neil who corrected the media humbug about air pollution. Prof Frew said 40,000 people in the UK do not die from air pollution there might be 40,000 premature deaths. A premature death is someone already ill with multiple complaints that might die 30 days earlier than would otherwise be the case because of current levels of air pollution. Prof Frew also said that if we removed all vehicles from our roads it would reduce air pollution by 2 micrograms/metre cubed almost nothing. Their are 3 times more pm2.5s in homes from voc’s in cleaning products and London tube tunnels are five times more polluted than above ground basically steel wheels grinding steel tracks and brake residue.

    Then we have all of the pm2.5s from gas office heating and wood burning stoves which are “really” fashionable because they burn renewables. Like Drax which consumes imported from America the wood pellet equivalent of 36,000 tons of coal every single day.

    We also know from MOT testing stations that emissions testing on white vans with 250k miles on the clock emissions are so low as to be not measurable. Just like the farce about Co2 which is also viewed as a vehicle pollutant that needs to be eradicated air pollution in the UK is near to the Gothenburg protocol but no mention is made of this fact it is all doom gloom and hysteria, we are all going to die bunkum.

    Jim Skea IPCC says that we need to burn more wood because it gets re absorbed but it takes 200 years. We import pellets from NCarolina which have 2/3rds of the calorific value of thermal coal and emit 12% more Co2 but 68% of the 2/3rds is consumed in chopping, shredding pelletising transport shipping 3500 miles across the Atlantic and 14 trains a day from port to Drax, more diesel. But because burning trees is cited as renewable by the EU it doesn’t seem to matter how much Co2 you emit if the EU legislation says its OK but if we elect to do it then that’s destroying the planet.

    We now have 20GW’s of wind capacity in the UK which today is generating 2.14GW a snip at £400 billion and Renewables UK say its getting cheap, cheaper than what??

    Our remaining 10GW’s of coal fired generation will be retired in 2025 with our 8GW’s of nuclear coming off line at more or less the same time. The only nuclear under construction is Hinkley at 2.8GW’s but the same reactor in France has already been under construction for a decade and they have just found more welding faults in the containment vessel costing another £400 million to repair. Now Claire Perry BEIS wants to go zero carbon and all electric cars from 2040. Recent report said a Nissan Leaf using a super charger for 30 minutes consumes enough electricity for 10 homes. We have 32 million cars then charging 32 million electric cars for 30 minutes at day equates to enough electricity for 320 million homes.

    Where Perry thinks all of this electricity is going to come from I really don’t know.

  9. Excerpted from above commentary:

    The team’s analyses showed that deaths related to air pollution exposure in the U.S. decreased by about 47 percent, dropping from about 135,000 deaths in 1990 to 71,000 in 2010.

    Given the fact that autopsies are NOT performed on ALL deaths in the US, just who in hell is it that decides how many people die each year from “air pollution exposure”?

    Is it the same person that decides how many people die from “cigarette smoke” each year, to wit:

    Cigarette smoking causes about one of every five deaths in the United States each year. Cigarette smoking is estimated to cause the following:

    •More than 480,000 deaths annually (including deaths from secondhand smoke)


    “HA”, and those wackos are so smart and clever that even without an autopsy or seeing the corpses that they can easily tell the difference between the yearly deaths caused by “air pollution” (135,000) and the yearly deaths caused by “cigarette smoke” (480,000).

  10. What kind of error bars are drawn? The way it seems it seems to be meant, they can’t draw any conclusion at all. Even an increase would be consistent with the data!

  11. The target here is clearly automobiles and thermal power stations, both produced by those nasty corporations, but many substances enter the lungs by other means, such as cigarette smoke, biomass burning smoke (normally associated with purer-than-driven-snow “greens”) and simply walking/working in dusty air.

    I don’t believe any correlation unless it has several wiggle cycles, which this one doesn’t.

  12. I too don’t buy into the confidence level that these many people per year are directly dying of air pollution. Especially in the first world now that we have really cleaned up our act. Undoubtedly, it contributes to the general malaise in health, but how do you really differentiate between the two on any consistent level? Setting a number of deaths by air pollution, probably is as mistaken as is the premise that CO2 causes dangerous climate change. Actually, come to think of it, probably the air pollution has more credibility than the CAGW aspect of fossil fuels.

    What I am more convinced of is that heavily densified cities like Bangkok, Manila, Mexico City or Beijing suffer from a signifiant loss of IQ where so many millions of peoples are subject to carbon monoxide poisoning where they live and work in very close proximity to the filthy air of exhaust fumes. I was just in 3 of those cities, and just walking around, I felt very sick and could barely breath and was fairly physically sick from just walking around in that extremely polluted air. Many were wearing masks, but that doesn’t help with very fine particulates or CO poisoning, so this is real issue in high density cities. It became very apparent to me why in Manila, Philippines, so many poor people would support and vote for a nutbar President that was sending out death squads to kill them because of illegal drugs like pot and meth. They obviously not so intelligent, so a lowered IQ must be the only answer.

    • And yet chinese score consistently higher than europeans on IQ tests (and the people in Hong Kong and Singapore, not exactly low density cities, score highest of all).

      • “chinese score consistently higher than europeans on IQ tests”

        And they all have to memorize thousands of characters at a young age. I wonder if there is a correlation?

        • Having gone to school in Northern California in the 1960’s and 1970’s, North East Asians value education highly, and their families expect them to work hard at school. It wasn’t that the Sansei or ABCs were that bright, at least the ones I knew, they just worked hard at it.

          • I concur…with a fiery TigerMom breathing down your neck, and threatening to beat with you a broom if you get a B+, the incentive to score near perfect for many Asians is exceedingly high. Very high family expectations. The Asians seem to have a much higher personal discipline level, and we even see it at the state level, were they surrender individuality for the good of the collective and work themselves to death.

            We could learn a lot from that mindset, except they still have to resort to stealing all the West’s secrets, because they lack a lot of original thought and/or innovation. Very good at imitating/copying things and same for knowledge, but on a per capita basis, they still are very much behind matching intelligence and brilliance in creating something from scratch as compared to the results of a ‘free’ society. This is in IMHO, the reason why Eurocentric populations have dominated the world up to now.

  13. The difficulty with this study is that while it is well established that ozone is unhealthy (indeed it is highly poisonous) the health effects of PM2.5 is very largely hypothetical.

  14. After having read the paper I can inform you that it is entirely model-based and completely unsullied by any actual data, either on air pollution or mortality.

  15. Real air pollutants have dropped 40~99% (depending on pollutant) just since 1980:

    Most clueless Leftists think air quality is getting worse and worse because of the propaganda they’re taught in school, and see and read in the MSM…

    Aggressive Leftist ignorance and Socialism kill far more people around the world than air pollution ever has or will..

  16. Total garbage – they estimate one number based on what they would like it to be and then compare it to another estimated number.

    US (and UK) causes of death are in any event utterly unreliable. Nobody in either country dies of old age according to the statistics.

  17. Ask them for the name of one of the 71,000 in 2010. Watch them squirm.

    The numbers are completely made up. Fake news from UNC.

  18. West said. “New federal policies curtailing air pollution regulations likely will slow the improvement in air quality or possibly make air quality worse.”

    ‘Likely” “possibly” Dr. West couldn’t resist suggesting that President Trump wants to kill us all. Of course, if he can’t keep the scare going, he loses his livelihood.

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