Ambient Precursor Gaseous Pollutants and Meteorological Conditions Controlling Variations of Particulate Matter Concentrations

In many areas of China, rapid industrialization, urbanization, and transportation development have resulted in PM2.5 concentrations higher than the WHO-recommended level. The precursor gaseous pollutants, which will befinally transformed to PM2.5, should be identified and controlled in the early stage. Dynamic factor analysis (DFA) was performed to investigate how precursor gaseous pollutants and meteorological factors associate with the temporal dynamics offine particulate matter (PM2.5) in Wuhan in 2013. The optimal DFA model satisfactorily accounted for the fluctuations in PM2.5 (coefficient of efficiency was 0.88). The results showed that the temporal dynamics of PM2.5 in Wuhan were primarily associated with sulfur oxides, nitrogen oxides (NOx), carbon monoxide (CO), relative humidity, temperature, and wind speed. PM2.5 concentrations were also slightly affected by three common trends mainly representing soil dust and urbanization process. Temperature contributed more to the long-term dynamics of PM2.5 than wind speed and relative humidity did. High temperature favors the formation of PM2.5. However, relative humidity was negatively contributed to PM2.5. NO2 and CO were the two major precursor gaseous pollutants contributing to the compositions of PM2.5. In Wuhan, NO2 and CO mainly emitted from motor vehicles and industrial processes should be restricted, because these precursor emissions will finally format particulate matter.