Source Estimation of PM_2.5 Observed from 2016 to 2017 in Niigata City Using Organic Marker Components

Abstract

Continuous monitoring of PM_2.5 was conducted at two sites in Niigata city from 2016 to 2017. Mass concentration and chemical components including organic marker of the PM_2.5 were measured. The highest concentration of Levoglucosan which reported as biomass burning marker was observed in autumn (81.8 ng/m³). The higher ratio of Levoglucosan and Mannosan (L/M) was observed in autumn, which may be affected by both rice straw burning in Japan and open burning in northeast China. In winter, a good correlation was observed between Levoglucosan and As. This result suggests that Niigata city may be affected by transboundary air pollution from northeast China in winter because both coal and biomass fuel are mainly used for household heating in that region. PM_2.5 source apportionment was conducted by PMF (Positive Matrix Factorization) model and 11 sources were identified. As the results of the estimation of each source contributions, PM_2.5 in Niigata city was clarified to be more affected by secondary aerosols than primary aerosols.