Fine Particulate Matter in Beijing: Sources and Health Impacts

Abstract

Introduction: High concentration of atmospheric fine particulate matter (PM2.5) could deteriorate air quality, reduce visibility, influence climate change, and affect human health. PM2.5 has attracted increasing attention in Beijing, China, as there are frequent haze episodes in recent years. Health impact of PM2.5 is still a great concern of the public. To better understand the health effects of PM2.5 and develop effective policies to control fine particulate pollutants, research on sources of particulate matter and its associated health effects are in urgent need. Methods: PM2.5 was collected on filters at a representative urban site in Beijing in different seasons, including haze and non-haze days. Detailed chemical composition including carbonaceous components, ions, and metals in fine particles was measured. Receptor-model based source apportionment of PM2.5 was performed to determine source contributions. The production of reactive oxygen species by fine particles was determined based on the cell-free surrogated lung fluid solution method. Results: Sources of fine particle in Beijing exhibited seasonal variations, with higher biomass burning contribution in summer and fall, and higher coal combustion contribution in winter. Secondary sources played a dominant role in most of the haze episodes. However, reactive oxygen species produced by per PM2.5 mass was much higher in clean days compared to haze days, and was found to be well correlated with trace metals such as Fe, Mn and Cu. Conclusions: Chemical characteristics and sources of PM2.5 in Beijing have clear difference between haze and non-haze days and between seasons. Correlations between chemical compositions and sources with health effects have been investigated through reactive oxygen species. The study of sources and health impacts of fine particles during severe haze episodes in Beijing is very important, which requires more research in the future.