Effects of Meteorological Factors and Anthropogenic Precursors on PM 2.5 Concentrations in Cities in China

Fine particulate matter smaller than 2.5 μm (PM 2.5 ) in size can significantly affect human health, atmospheric visibility, climate, and ecosystems. PM 2.5 has become the major air pollutant in most cities of China. However, influencing factors and their interactive effects on PM 2.5 concentrations remain unclear. This study used a geographic detector method to quantify the effects of anthropogenic precursors (AP) and meteorological factors on PM 2.5 concentrations in cities of China. Results showed that impacts of meteorological conditions and AP on PM 2.5 have significant spatio-temporal disparities. Temperature was the main influencing factor throughout the whole year, which can explain 27% of PM 2.5 concentrations. Precipitation and temperature were primary impacting factors in southern and northern China, respectively, at the annual time scale. In winter, AP had stronger impacts on PM 2.5 in northern China than in other seasons. Ammonia had stronger impacts on PM 2.5 than other anthropogenic precursors in winter. The interaction between all factors enhanced the formation of PM 2.5 concentrations. The interaction between ammonia and temperature had strongest impacts at the national scale, explaining 46% ( q = 0.46) of PM 2.5 concentrations. The findings comprehensively elucidated the relative importance of driving factors in PM 2.5 formation, which can provide basic foundations for understanding the meteorological and anthropogenic influences on the concentration patterns of PM 2.5 .