Saccharides in summer and winter PM2.5 over Xi'an, Northwestern China: Sources, and yearly variations of biomass burning contribution to PM2.5
2018
Wang, Xin | Shen, Zhenxing | Liu, Fobang | Lu, Di | Tao, Jun | Lei, Yali | Zhang, Qian | Zeng, Yaling | Xu, Hongmei | Wu, Yunfei | Zhang, Renjian | Cao, Junji
Saccharides are important constituents in atmospheric aerosols but studies in northwestern China are still very limited. Here, we have measured anhydrosugars (levoglucosan, mannosan and galactosan), primary sugars (glucose, fructose, sucrose and trehalose), and sugar alcohols (arabitol, mannitol, sorbitol and inositol) in ambient PM₂.₅ samples during summer and winter in Xi'an city, northwestern China. The abundance of total saccharides showed no clear seasonal variation, but apparent distinctions on the levels of the three categories and individual saccharide compounds were found. Primary sugars and particularly sucrose were dominant in summer. In contrast, levoglucosan was the predominant species in winter, contributing 60% of total saccharides. Source apportionment by positive matrix factorization revealed that airborne pollen was a major source of PM₂.₅ associated-saccharides in summer, accounting for 35% of total saccharides; while biomass burning activities contributed to 60% of the winter saccharides. Furthermore, an increasing trend of biomass/biofuel burning contribution to winter PM₂.₅ was observed in comparison with previous studies in Xi'an, suggesting a change in emission sources may be underway in northwestern China.
显示更多 [+] 显示较少 [-]