The Different Impacts of Emissions and Meteorology on PM2.5 Changes in Various Regions in China: A Case Study

Wenjie Zhang,Yaqiang Wang,Huizheng Che,Yue Peng,Zhaodong Liu,Hong Wang,Yifan Zhao,Xiaoye Zhang,Junting Zhong

doi:10.3390/atmos13020222

Wenjie Zhang, Yaqiang Wang + Show 7 more

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https://doi.org/10.3390/atmos13020222

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Abstract

Emissions and meteorology are significant factors affecting aerosol pollution, but it is not sufficient to understand their relative contributions to aerosol pollution changes. In this study, the observational data and the chemical model (GRAPES_CUACE) are combined to estimate the drivers of PM2.5 changes in various regions (the Beijing–Tianjin–Hebei (BTH), the Central China (CC), the Yangtze River Delta (YRD), and the Pearl River Delta (PRD)) between the first month after COVID-19 (FMC_2020) (i.e., from 23 January to 23 February 2020) and the corresponding period in 2019 (FMC_2019). The results show that PM2.5 mass concentration increased by 26% (from 61 to 77 µg m−3) in the BTH, while it decreased by 26% (from 94 to 70 µg m−3) in the CC, 29% (from 52 to 37 µg m−3) in the YRD, and 32% (from 34 to 23 µg m−3) in the PRD in FMC_2020 comparing with FMC_2019, respectively. In the BTH, although emissions reductions partly improved PM2.5 pollution (−5%, i.e., PM2.5 mass concentration decreased by 5% due to emissions) in FMC_2020 compared with that of FMC_2019, the total increase in PM2.5 mass concentration was dominated by more unfavorable meteorological conditions (+31%, i.e., PM2.5 mass concentration increased by 31% due to meteorology). In the CC and the YRD, emissions reductions (−33 and −36%) played a dominating role in the total decrease in PM2.5 in FMC_2020, while the changed meteorological conditions partly worsened PM2.5 pollution (+7 and +7%). In the PRD, emissions reductions (−23%) and more favorable meteorological conditions (−9%) led to a total decrease in PM2.5 mass concentration. This study reminds us that the uncertainties of relative contributions of meteorological conditions and emissions on PM2.5 changes in various regions are large, which is conducive to policymaking scientifically in China.

Highlights

IntroductionPM2.5 pollution in China is closely related to anthropogenic emissions [6,7,8,9]
PM2.5 pollution has serious impacts on human daily life and health by affecting radiation, visibility, the ecological environment, etc. [1,2,3,4,5], which has attracted widespread attention in China.PM2.5 pollution in China is closely related to anthropogenic emissions [6,7,8,9]
PM2.5 mass concentration in the BTH unexpectedly increases to 77 μg m−3 (26% more than Atmosphere 2022t,h13e, 2P2M2 2.5 mass concentration in FMC_2019) (Figure 2b–d)

Summary

Introduction

PM2.5 pollution in China is closely related to anthropogenic emissions [6,7,8,9]. Combustion sources (coal combustion, traffic emissions, industrial emissions, biomass burning, etc.) have made significant contributions to aerosol pollution over the past several years [10,11,12,13]. Coal combustion contributed to more than 50% of PM2.5 emissions during the winter in Northern China [14,15]. Traffic emissions have increasingly become the largest source of PM2.5 emissions and account for 40 to 60% [11,12,16]. Secondary aerosol formation can contribute significantly to elevated PM2.5 mass concentration, accounting for 50 to 70% of the aerosol components during the heavy aerosol pollution episodes (HPEs) [17,18,19,20]

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