Characteristics and Sources of Organic Aerosol Markers in PM2.5

Zheng Li,Li Yan,Ruiwen Zhou,Tonglin Huang,Yuanyuan Li,Jingjing Meng,Min Chen,Yanan Yi,Yachen Wang,Zhanfang Hou

doi:10.4209/aaqr.210180

Abstract

ABSTRACT To investigate the molecular compositions, sources, and evolution processes of organic aerosols (OAs), PM2.5 samples in wintertime were collected in Jinan, a typically polluted city in the North China Plain (NCP). The concentrations of PM2.5, carbonaceous species, and organic components (e.g., sugars, fatty acids, polycyclic aromatic hydrocarbons (PAHs) and oxygenated-PAHs (OPAHs)) in haze episodes were 1.8–2.7 times higher than those in clean episodes. Levoglucosan was the most abundant saccharide, which exhibited significant correlations with carbonaceous species during the whole sampling period, demonstrating that biomass burning has an important effect on the concentrations of carbonaceous species in PM2.5 of Jinan during wintertime. The higher ratios of both secondary OC/OC (SOC/OC) and C18:1/C18:0 was observed during the clean days than those during haze days, implying that OAs during clean periods were more aged. The higher ratio of OPAHs/PAHs in the daytime reflected the more photochemical formation of OPAHs in the daytime. Positive matrix factorization (PMF) model proved that biomass burning was the major source of OAs during the whole sampling period. Potential source contribution function (PSCF) and concentration-weight trajectory (CWT) results indicating that Shandong Province and Beijing-Tianjing-Hebei (BTH) region made important contribution to the levels of PM2.5 in Jinan during the winter. Moreover, the CWT results showed that OAs during haze periods were largely originated from local and surrounding regions. These results confirmed that biomass burning can significantly influence the concentrations and chemical compositions of OAs, thereby they can affect human health and atmospheric chemistry.

Highlights

Haze, a weather phenomenon that causes the atmosphere visibility < 10 km because of the mixed state of vapor, smoke, and suspended particles in the atmosphere (Lee et al, 2014)
The temporal variations of PM2.5, Organic carbon (OC) and elemental carbon (EC) are presented in Fig. 1 along with the temperature (T), relative humidity (RH), and wind speed (WS)
To investigate the characteristic of PM2.5 pollution and the potential formation processes, PM2.5 samples were collected in Jinan, which is a typical polluted city in North China Plain (NCP)

Summary

Introduction

A weather phenomenon that causes the atmosphere visibility < 10 km because of the mixed state of vapor, smoke, and suspended particles in the atmosphere (Lee et al, 2014). Previous researches have illustrated that organic components play a significant role in the haze occurrence in the NCP, especially the secondary aerosols (SOA) (Huang et al, 2014; Zhou et al, 2017). OAs typically account for as much as 75% of PM2.5 mass in urban atmosphere and attract much public attention because of their important influence on human health, visibility, and climate change (Huang et al, 2014; An et al, 2019; Li et al, 2019a; Ari et al, 2020; Meng et al, 2020). OAs can change the aerosols hygroscopic properties, because most of OAs (up to 80%)

Methods

Results

Conclusion