Since 1990, air pollution in the U.S. has reduced considerably. Now, according to a recent study performed at the University of North Carolina at Chapel Hill, this improvement in air quality has brought significant health benefits to the public.
Reported in the journal Atmospheric Chemistry and Physics, the study found that deaths caused by air pollution were almost reduced by 50% between 1990 and 2010.
The researchers’ analyses revealed that deaths caused by exposure to air pollution in the U.S. reduced by approximately 47% — that is, decreasing from around 135,000 deaths in 1990 to 71,000 in 2010.
Such improvements in air quality and public health in the U.S. happened simultaneously with improved federal air quality regulations, and have occurred regardless of increases in population, electricity, and energy use, and vehicle miles that were traveled between 1990 and 2010.
We’ve invested a lot of resources as a society to clean up our air. This study demonstrates that those changes have had a real impact with fewer people dying each year due to exposure to outdoor air pollution.
Jason West, PhD, study co-author and professor, environmental sciences and engineering, The UNC Gillings School of Global Public Health
Yuqiang Zhang, PhD, former postdoctoral researcher at the UNC Gillings School and at the Environmental Protection Agency, headed the study in association with West and several EPA scientists. Zhang is now a research scientist at the Duke University Nicholas School of the Environment.
This study backs up results from several other recent studies, which also demonstrated analogous and considerable reductions in deaths caused by air pollution. However, what is unique in this study is the ability to estimate air pollution-related deaths every year and the application of a 21 year computer simulation.
West, Zhang, and co-workers examined concentrations of two pollutants, called ozone and PM2.5, from a 21-year computer simulation of air pollution throughout the U.S. PM2.5 are very tiny particles that are suspended in the air and come from industries, motor vehicles, power plants, and certain residential and commercial sources. These tiny particles have a diameter that is less than 2.5 micrometers, which is approximately 3% of a human hair diameter.
In order to estimate air pollution-related deaths during that period, the researchers subsequently related the reducing concentrations of ozone and PM2.5 to the geographical locations where people live and the occurrences of death in those regions by using data from the Centers for Disease Control and Prevention. The team estimated deaths from respiratory disease related to ozone, and from stroke, lung cancer, chronic obstructive pulmonary disease, and ischemic heart disease related to PM2.5.
Since the overall rates of these causes of death are also affected by other factors, the reduction in deaths was not exclusively the result of better air quality. Nevertheless, the authors discovered that improved air quality could have reduced the deaths by roughly 40,000 in 2010, as opposed to the number of deaths that would have occurred if air pollution had remained the same between 1990 and 2010.
These health improvements likely have continued beyond 2010 as we observe that air pollutant concentrations have continued to decrease.
Yuqiang Zhang, PhD, former postdoctoral researcher, The UNC Gillings School and The Environmental Protection Agency
The researchers intend to apply other datasets to study deaths caused by air pollution since 2010.
However, air pollution continues to be a major public health issue in the U.S, despite robust improvements. In 2010 alone, there were an estimated number of 71,000 deaths that translates to 1 of every 35 deaths in the U.S. – that is as many deaths as one sees from all gun shootings and all traffic accidents combined.
“Even though we’ve seen some tangible success, there are still people dying, and a public health challenge remains going forward,” said West. “New federal policies curtailing air pollution regulations likely will slow the improvement in air quality or possibly make air quality worse.”
The study was supported by the EPA and by NASA through its Health and Air Quality Applied Sciences Team, of which West is a member.