A new study led by researchers at the University of North Carolina at Chapel Hill has found that deaths related to air pollution in the US were nearly halved between 1990 and 2010. The open-access study is published in the journal Atmospheric Chemistry and Physics.

The team’s analyses showed that deaths related to air pollution exposure in the US decreased by about 47%, dropping from about 135,000 deaths in 1990 to 71,000 in 2010. Improvements in air quality and public health in the US 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.

Trends in the total mortality burden (black) for PM_2.5 (a, as a total of ischemic heart (STROKE) + chronic obstructive (COPD) + lung cancer (LC)) and O₃ (b, chronic respiratory disease (RESP)), and mortality burdens considering the air quality change only (blue), and with air quality changes excluded (red). Units are deaths year⁻¹. The error bars are the 95 % CI for the total mortality burden (black). Zhang et al.

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, study co-author

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 Dr. Jason West, professor of environmental sciences and engineering at the UNC Gillings School of Global Public Health, 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 PM_2.5 and ozone from a 21-year computer simulation of air pollution across the US. They then related the declining concentrations of PM_2.5 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 PM_2.5, 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.

—Yuqiang Zhang

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

Air pollution remains a public health issue in the US; the estimated 71,000 deaths in 2010 translates to 1 of every 35 deaths in the US—as many deaths as from all traffic accidents and all gun shootings combined.

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.

Resources

• Zhang, Y., West, J. J., Mathur, R., Xing, J., Hogrefe, C., Roselle, S. J., Bash, J. O., Pleim, J. E., Gan, C.-M., and Wong, D. C. (2018) “Long-term trends in the ambient PM_2.5- and O₃-related mortality burdens in the United States under emission reductions from 1990 to 2010,” Atmos. Chem. Phys., 18, 15003-15016 doi: 10.5194/acp-18-15003-2018