Underestimation of biomass burning contribution to PM2.5 due to its chemical degradation based on hourly measurements of organic tracers: A case study in the Yangtze River Delta (YRD) region, China

Li Q 1 , Zhang K 1 , Li R 1 , Yang L 1 , Yi Y 1 , Liu Z 2 Show all authors , Zhang X 2 , Feng J 1 , Wang Q 3 , Wang W 1 , Huang L 1 , Wang Y 1 , Wang S 1 , Chen H 1 , Chan A 4 , Latif MT 5 , Ooi MCG 6 , Manomaiphiboon K 7 , Yu J 8 , Li L 9

Affiliations 

  • 1 School of Environmental and Chemical Engineering, Shanghai University, Shanghai, China; Key Laboratory of Organic Compound Pollution Control Engineering (MOE), Shanghai University, Shanghai, China
  • 2 School of Environmental and Chemical Engineering, Shanghai University, Shanghai, China; Key Laboratory of Organic Compound Pollution Control Engineering (MOE), Shanghai University, Shanghai, China; Jiangsu Changhuan Environment Technology Co., Ltd., Changzhou, Jiangsu, China
  • 3 Department of Chemistry, Hong Kong University of Science & Technology, Hong Kong, China
  • 4 Department of Civil Engineering, University of Nottingham Malaysia, Semenyih, Selangor, Malaysia
  • 5 Department of Earth Science and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
  • 6 Institute of Climate Change, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
  • 7 The Joint Graduate School of Energy and Environment, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
  • 8 Department of Chemistry, Hong Kong University of Science & Technology, Hong Kong, China; Division of Environment & Sustainability, Hong Kong University of Science & Technology, Hong Kong, China
  • 9 School of Environmental and Chemical Engineering, Shanghai University, Shanghai, China; Key Laboratory of Organic Compound Pollution Control Engineering (MOE), Shanghai University, Shanghai, China. Electronic address: Lily@shu.edu.cn
Sci Total Environ, 2023 May 10;872:162071.
PMID: 36775179 DOI: 10.1016/j.scitotenv.2023.162071

Abstract

Biomass burning (BB) has significant impacts on air quality and climate change, especially during harvest seasons. In previous studies, levoglucosan was frequently used for the calculation of BB contribution to PM2.5, however, the degradation of levoglucosan (Lev) could lead to large uncertainties. To quantify the influence of the degradation of Lev on the contribution of BB to PM2.5, PM2.5-bound biomass burning-derived markers were measured in Changzhou from November 2020 to March 2021 using the thermal desorption aerosol gas chromatography-mass spectrometry (TAG-GC/MS) system. Temporal variations of three anhydro-sugar BB tracers (e.g., levoglucosan, mannosan (Man), and galactosan (Gal)) were obtained. During the sampling period, the degradation level of air mass (x) was 0.13, indicating that ~87 % of levoglucosan had degraded before sampling in Changzhou. Without considering the degradation of levoglucosan in the atmosphere, the contribution of BB to OC were 7.8 %, 10.2 %, and 9.3 % in the clean period, BB period, and whole period, respectively, which were 2.4-2.6 times lower than those (20.8 %-25.9 %) considered levoglucosan degradation. This illustrated that the relative contribution of BB to OC could be underestimated (~14.9 %) without considering degradation of levoglucosan. Compared to the traditional method (i.e., only using K+ as BB tracer), organic tracers (Lev, Man, Gal) were put into the Positive Matrix Factorization (PMF) model in this study. With the addition of BB organic tracers and replaced K+ with K+BB (the water-soluble potassium produced by biomass burning), the overall contribution of BB to PM2.5 was enhanced by 3.2 % after accounting for levoglucosan degradation based on the PMF analysis. This study provides useful information to better understand the effect of biomass burning on the air quality in the Yangtze River Delta region.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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