In order to better understand the molecular composition and sources of organic aerosols in Tianjin, a coastal megacity in North China, ambient fine aerosol (PM2.5) samples were collected on a day/night basis during November – December 2016 and May – June 2017. Organic molecular compositions in PM2.5, including aliphatic lipids (n-alkanes, fatty acids and fatty alcohols), sugar compounds and photooxidation products from isoprene, monoterpene, β-caryophyllene, naphthalene and toluene, were analyzed using gas chromatography-mass spectrometry.
Fatty acids, fatty alcohols and saccharides were identified as the most abundant organic compound classes among all the tracers detected in this study during both seasons. High concentrations of most organics at night in winter may be attributed to intensive residential activities such as house heating and the low boundary layer height. Based on the tracer methods, POC derived from fungal spores, plant debris, and biomass burning accounted for 2.78–31.6% of OC in the daytime versus 4.72–45.9% at night in winter, and 1.28–9.89% versus 2.08–47.2% in summer. Biogenic SOC from isoprene, α/β-pinene and β-caryophyllene exhibited obvious seasonal and diurnal variations, contributing 2.23±1.27% and 8.60±4.02% to OC in winter and summer, respectively. Anthropogenic SOC from toluene and naphthalene oxidation contributed higher to OC in summer (21.0±18.5%) than in winter (9.58±3.68%).
This work from researchers at the Institute of Surface-Earth System Science (ISESS) of Tianjin University and collaborators from Chinese Academy of Sciences, Chubu University and University of Birmingham, has been recently published on Atmospheric Chemistry and Physics. The first author is Yanbing Fan, a master student from ISESS; the corresponding authors are Prof. Cong-Qiang Liu and Prof. Pingqing Fu from ISESS.
Yanbing Fan, Cong-Qiang Liu*, Linjie Li, Lujie Ren, Hong Ren, Zhimin Zhang, Qinkai Li, Shuang Wang, Wei Hu, Junjun Deng, Libin Wu, Shujun Zhong, Yue Zhao, Chandra Mouli Pavuluri, Xiaodong Li, Xiaole Pan, Yele Sun, Zifa Wang, Kimitaka Kawamura, Zongbo Shi, and Pingqing Fu*, 2020. Large contributions of biogenic and anthropogenic sources to fine organic aerosols in Tianjin, North China. Atmospheric Chemistry and Physics, 20: 117–137. https://doi.org/10.5194/acp-20-117-2020
