Study Shows Low Levels of Air Pollution Pose Risk for Older Adults

Published January 12, 2018

The Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS) for pollutants considered harmful to public health and the environment. These standards also protect the health of "sensitive" populations such as asthmatics, children, and the elderly. EPA sets NAAQS for six principal pollutants, which are periodically reviewed and may be revised. The six principal pollutants are carbon monoxide, lead, nitrogen dioxide, ozone, particle pollution (PM) and sulfur dioxide.

Previous studies have shown that long-term exposure to air pollution decreases life expectancy; however, there haven’t been many studies that looked at the effects of long-term exposure to air pollution levels below the NAAQS. To fill this gap, EPA grantee Francesca Dominici and colleagues conducted a nationwide study to examine the link between mortality and long-term exposure to ozone and PM2.5 at levels lower than the current annual NAAQS.

The researchers analyzed health records of more than 60 million Medicare beneficiaries together with satellite-based estimates of the pollutant concentrations at individual zip codes. The results show that even low levels of air pollution raise mortality risk for older adults. For locations where annual-mean PM2.5 concentrations were lower than the level of the NAAQS, an increase of 10 micrograms per cubic meter in PM2.5 was associated with increases in mortality of 13.6%. The effect was most pronounced among African Americans, men, and people with low income. An additional, smaller, effect was also observed for ozone exposures below the NAAQS. The study was designated as one of the ten most meaningful studies of 2017 by the New England Journal of Medicine.