气候变化领域集成服务门户(CCPortal): Insights into atmospheric oxidation capacity and its impact on PM2.5 in megacity Beijing via volatile organic compounds measurements

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DOI	10.1016/j.atmosres.2021.105632
	Insights into atmospheric oxidation capacity and its impact on PM2.5 in megacity Beijing via volatile organic compounds measurements
	Wei W.; Wang Y.; Bai H.; Wang X.; Cheng S.; Wang L.
发表日期	2021
ISSN	0169-8095
卷号	258
英文摘要	This study conducted a VOCs monitoring campaign in Jul and Oct of 2018, Jan and Apr of 2019 in Beijing urban area, to explore the atmospheric oxidation capacity and its impact on PM2.5 there through investigating the chemical behaviors of VOCs at a 1-h time resolution. We totally detected 53 VOCs in the atmosphere over Beijing, sum of them (TVOCs) reaching 29.0 ± 12.9, 47.6 ± 29.4, 45.7 ± 56.4 and 35.8 ± 19.3 ppb (mol/mol) in Jul, Oct, Jan and Apr respectively. The gap between VOCs and CO diurnal amplitudes presented the trend of Jul > Oct and Apr > Jan, which implies the more chemical loss of VOCs in non-winter seasons compared to winter. Then, according to the notable difference in OH- and O3- reactivity of various VOCs, hourly OH exposure ([OH]Δt), O3 exposure ([O3]Δt) and OH concentration were estimated. In result, in Jul, Oct, Jan and Apr, the daily [OH]Δt was 10.39 ± 4.95, 11.10 ± 6.01, 6.39 ± 3.74 and 8.96 ± 5.05 × 1010 molecules·s·cm−3, the nighttime [O3]Δt was 9.43 ± 2.83, 5.22 ± 3.62, 5.79 ± 3.65 and 8.60 ± 4.74 × 1015 molecules·s·cm−3, and the daily OH was 9.76 ± 5.17, 5.11 ± 2.98, 2.95 ± 2.18 and 6.26 ± 3.18 × 106 molecules·cm−3, in respective. The OH peak magnitudes agreed well with the OH measured in-site, which indicates the reliability of our estimates on the oxidation capacity of atmosphere over Beijing. During our studied periods, [OH]Δt, OH and atmospheric oxidability combining OH and O3 (ACO) were all positively related to PM2.5 in Jul and Apr; only [OH]Δt was positively related to PM2.5 in Oct; while [OH]Δt, OH and ACO were all negatively related to PM2.5 in Jan. The proportion of SO2 and VOCs oxidized through gaseous OH reactions was found to increase with PM2.5 increasing in non-winter seasons, but decrease with PM2.5 increasing in winter. It means that high PM2.5 concentrations are attributed more to gas-phase oxidations in non-winter seasons and potentially boosted by photochemistry in summer and spring. But, in winter high PM2.5 concentrations effectively inhibit photolysis reactions and weaken atmospheric oxidation capacity, which makes high PM2.5 less dependent on the gas-phase oxidations. © 2021 Elsevier B.V.
英文关键词	Atmospheric oxidation capacity; Gaseous oxidations; OH radical; PM2.5; Volatile organic compounds
来源期刊	Atmospheric Research
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/236727
作者单位	Department of Environmental Science and Engineering, Beijing University of Technology, Beijing, 100124, China; Key Laboratory of Beijing on Regional Air Pollution Control, Beijing, 100124, China; Department of Environmental Engineering, School of City Construction, Hebei University of Engineering, Handan, Hebei 056038, China
推荐引用方式 GB/T 7714	Wei W.,Wang Y.,Bai H.,et al. Insights into atmospheric oxidation capacity and its impact on PM2.5 in megacity Beijing via volatile organic compounds measurements[J],2021,258.
APA	Wei W.,Wang Y.,Bai H.,Wang X.,Cheng S.,&Wang L..(2021).Insights into atmospheric oxidation capacity and its impact on PM2.5 in megacity Beijing via volatile organic compounds measurements.Atmospheric Research,258.
MLA	Wei W.,et al."Insights into atmospheric oxidation capacity and its impact on PM2.5 in megacity Beijing via volatile organic compounds measurements".Atmospheric Research 258(2021).