The Impact of Chronic Ambient Exposure to PM2.5 and Ozone on Asthma Prevalence and COPD Mortality Rates in the Southeastern United States

Abstract

Respiratory diseases affect millions of people across the United States annually. Two of the most common respiratory diseases are chronic obstructive pulmonary disease (COPD) and asthma. Mortality rates due to COPD have increased by an estimated 30% between 1980 and 2014, with significant variances among geographic regions. Both acute and chronic ambient exposures to fine particulate matter (PM2.5) and ozone have been associated with exacerbations of respiratory diseases in numerous studies, and exposure to air pollutants are considered as the largest health risk factor globally. This study adds to the current literature by reporting the results of a time series analysis of the impact of PM2.5 and ozone on prevalence rates of asthma and mortality rates for COPD at regional and county levels across the southeastern United States for the years 2005–2014. While general reductions in levels of PM2.5 and ozone were demonstrated across all years, a distributed lag model showed continued strong associations between PM2.5 and prevalence of asthma and mortality due to COPD, even at relatively small increases in ambient exposure (<1 μg/m3) across the southeastern United States. The results of the study support the need for additional research that considers factors such as patient demographics, medical histories, and health disparities in combination with ambient exposures to known pollutants.