Acute effects of air pollution on all-cause mortality

Abstract

PDS 68: Outdoor air pollution, mortality and morbidity, Exhibition Hall (PDS), Ground floor, August 26, 2019, 10:30 AM - 12:00 PM Haze episodes causing by forest fire and agriculture waste burning during dry season have been widespread in Chiang Mai Province for more than a decade. The local governmental agencies have been proactive in taking comprehensive measures to control the haze and its impacts on health of the population since early 2008. This study assessed acute effects of ambient air pollutants on all-cause mortality before and after the haze control interventions. We obtained daily mortality counts and data on mass concentrations of particulate matter (PM)<10 micron in aerodynamic diameter (PM10), gaseous pollutants, and meteorology in Chiang Mai Province between Jan 2002 and Dec 2016. We analyzed the data using case-crossover design adjusting humidity, day-of-week and seasons for each three periods: Jan 2002-Dec 2007 (Period 1, before intervention), Jan 2008 to 2011 (Period 2, after intervention), Jan 2012 to Dec 2016 (Period 3, after intervention). Air pollution concentrations decreased over the study period. We found an increased risk of all-cause mortality for one IQR increase in PM10 of lag0 and mean of lag0-1; and O3 for lag0, lag1, and mean of lag0-1 before the intervention (Period 1), but no significant effects after the intervention (Period 2 and Period 3). In Period 1, the effects of PM10 and O3 are stronger for age 65 and older than those of all ages. In Period 3, we found significant effects of NO2 for lag0, lag1, and lag2 and O3 for lag2 for age 65 and older, but after the intervention no significant effects were observed for PM10 and gaseous pollutants for all ages. The findings suggest a reduction in risk of acute effects of all-cause mortality for PM10 and O3 after haze control measures are in force in Chiang-Mai Province.