Nitroaromatic compounds in six major Chinese cities: Influence of different formation mechanisms on light absorption properties

Huang，Shasha1; Shen，Zhenxing1; Yang，Xueting1; Bai，Gezi1; Zhang，Leiming2; Zeng，Yaling3; Sun，Jian1; Xu，Hongmei1; Ho，Steven Sai Hang4; Zhang，Ying5; Cao，Junji6

2024-06-20

10.1016/j.scitotenv.2024.172672

Science of the Total Environment   影响因子和分区

0048-9697

1879-1026

Nitroaromatic compounds (NACs) are important nitrogen organics in aerosol with strong light-absorbing and chemically reactive properties. In this study, NACs in six Chinese megacities, including Harbin (HB), Beijing (BJ), Xi'an (XA), Wuhan (WH), Chengdu (CD), and Guangzhou (GZ), were investigated for understanding their sources, gas-particle partitioning, and impact on BrC absorption properties. The concentrations of ΣNACs in PM in the six cities ranged from 9.15 to 158.8 ng/m in winter and from 2.02 to 9.39 ng/m in summer. Nitro catechols (NCs), nitro phenols (NPs), and nitro salicylic acids (NSAs) are the main components in ΣNACs, with NCs being dominant in particulate phase and NPs being dominant in the gas phase. Correlation analysis between different pollutant species revealed that coal and biomass combustions were the major sources of NACs in the northern cities during wintertime, while secondary formation dominated NACs in the southern cities during summertime. The contribution of ΣNACs to brown carbon (BrC) light absorption ranged from 0.85 to 7.98 % during the wintertime and 2.07–6.44 % during the summertime. The mass absorption efficiency at 365 nm (MAE) were highest for 4-nitrocatechol (4NC, 17.4–89.0 m/g), 4-methyl-5-nitrocatechol (4M5NC, 15.0–76.9 m/g), and 4-nitroguaiacol (4NG, 11.7–59.8 m/g). The formation of NCs and NG through oxidation and nitration of catechol and guaiacol led to a significant increase in aerosol light absorption. In contrast, NPs and NSAs formed by the photonitration and photooxidation in liquid phase showed high polarity but low light absorption ability, and the proportions of (NPs + NSAs) in the light absorption of ΣNACs were lower than 15.3 % in the six megacities.

Gas-particle phase partitioning NACs Optical absorption Source identification Spatial and seasonal variation

SCI ; EI

英语

其他

ENVIRONMENT/ECOLOGY

2-s2.0-85191741520

Scopus

1.Department of Environmental Sciences and Engineering,Xi'an Jiaotong University,Xi'an,710049,China
2.Air Quality Research Division,Science and Technology Branch,Environment and Climate Change Canada,Toronto,Canada
3.School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen,518055,China
4.Division of Atmospheric Sciences,Desert Research Institute,Reno,NV89512,United States
5.Instruments Analysis Center of Xi'an Jiaotong University,Xi'an,710049,China
6.Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing,100029,China

Huang，Shasha,Shen，Zhenxing,Yang，Xueting,et al. Nitroaromatic compounds in six major Chinese cities: Influence of different formation mechanisms on light absorption properties[J]. Science of the Total Environment,2024,930.

Huang，Shasha.,Shen，Zhenxing.,Yang，Xueting.,Bai，Gezi.,Zhang，Leiming.,...&Cao，Junji.(2024).Nitroaromatic compounds in six major Chinese cities: Influence of different formation mechanisms on light absorption properties.Science of the Total Environment,930.

Huang，Shasha,et al."Nitroaromatic compounds in six major Chinese cities: Influence of different formation mechanisms on light absorption properties".Science of the Total Environment 930(2024).