Association of exposure to metallic components in fine particles and respiratory mortality

Abstract

TPS 761: Health effects of pollution sources and components, Johan Friso Foyer, Floor 1, August 28, 2019, 3:00 PM - 4:30 PM Background/Aim: Epidemiological studies suggested that the association between short-term exposure to fine particulate matter (PM2.5) and mortality or morbidity was possibly due to some chemical components of PM2.5. However, findings were inconsistent for the responsible PM2.5 components. This study aimed to examine the city-specific association of short-term exposure to PM2.5 metallic components with daily respiratory mortality in 6 major South Korean cities for 2011-2015. Methods: We obtained daily 24-hour concentrations of PM2.5 mass and chemical components measured every day or every third day for 2011-2015 at single monitoring sites located in residential areas of six major South Korean cities: Seoul, Busan, Daegu, Gwangju, Daejeon, and Ulsan. We focused on lead, nickel, silicon, vanadium, copper, and zinc that showed the associations with mortality in previous epidemiological studies. We also computed daily respiratory death counts for the same study period and area from death certificate data. Using Generalized Addictive Models, we estimated relative risks (RRs) of daily respiratory mortality for interquartile range increases in daily PM2.5 and metallic component concentrations for 0 to 7 previous days, while controlling for a long-term time trend and meteorology. Results: PM2.5 was marginally or significantly associated with respiratory mortality in 3 out of the 6 major South Korean cities (RR=1.073-1.107). The associations for metallic components varied across the 6 cities. However, in the second largest city with large major ports, Busan, there was strong positive associations with vanadium (RR=1.102, 95% confidence interval=1.033-1.175) and nickel (1.138, 1.061-1.221). RRs for vanadium and nickel tended to be higher in the cities with higher daily concentrations. Conclusion: Our findings showed that metallic components responsible for PM2.5-associated respiratory mortality differed across major South Korean cities depending on dominant pollution sources, suggesting large health effects of oil combustion-related PM2.5 components in major port cities.