Variations of the urban PM2.5 chemical components and corresponding light extinction for three heating seasons in the Guanzhong Plain, China

Julian Shi; Suixin Liu; Yao Qu; Ting Zhang; Wenting Dai; Peiyun Zhang; Rui Li; Chongshu Zhu; Junji Cao

doi:10.1016/j.jenvman.2022.116821

Variations of the urban PM_2.5 chemical components and corresponding light extinction for three heating seasons in the Guanzhong Plain, China

J Environ Manage. 2023 Feb 1:327:116821. doi: 10.1016/j.jenvman.2022.116821. Epub 2022 Nov 25.

Authors

Julian Shi¹, Suixin Liu², Yao Qu², Ting Zhang², Wenting Dai², Peiyun Zhang², Rui Li¹, Chongshu Zhu³, Junji Cao⁴

Affiliations

¹ CAS Center for Excellence in Quaternary Science and Global Change, KLACP, and SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Xi'an Institute for Innovative Earth Environment Research, Xi'an, 710061, China; Shaanxi Key Laboratory of Atmospheric and Haze-fog Pollution Prevention, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain, Shaanxi, Xi'an, 710499, China.
² CAS Center for Excellence in Quaternary Science and Global Change, KLACP, and SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Shaanxi Key Laboratory of Atmospheric and Haze-fog Pollution Prevention, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain, Shaanxi, Xi'an, 710499, China.
³ CAS Center for Excellence in Quaternary Science and Global Change, KLACP, and SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Shaanxi Key Laboratory of Atmospheric and Haze-fog Pollution Prevention, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain, Shaanxi, Xi'an, 710499, China. Electronic address: chongshu@ieecas.cn.
⁴ CAS Center for Excellence in Quaternary Science and Global Change, KLACP, and SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Shaanxi Key Laboratory of Atmospheric and Haze-fog Pollution Prevention, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China; National Observation and Research Station of Regional Ecological Environment Change and Comprehensive Management in the Guanzhong Plain, Shaanxi, Xi'an, 710499, China.

PMID: 36442450
DOI: 10.1016/j.jenvman.2022.116821

Abstract

In order to investigate the variations of PM_2.5 (particulate matter with an aerodynamic diameter less than 2.5 μm) chemical components responding to the pollution control strategy and their effect on light extinction (b_ext) in the Guanzhong Plain (GZP), the comparisons of urban atmospheric chemical components during the heating seasons were extensively conducted for three years. The average concentration of PM_2.5 decreased significantly from 117.9 ± 57.3 μg m^-3 in the heating season 1 (HS1) to 53.5 ± 31.3 μg m^-3 in the heating season 3 (HS3), which implied that the effective strategies were implemented in recent years. The greatest contribution to PM_2.5 (∼30%) was from Organic matter (OM). The heightened contributions of the secondary inorganic ions (SNA, including NO₃^-, SO₄^2-, and NH₄⁺) to PM_2.5 were observed with the values of 34% (HS1), 41% (HS2), and 42% (HS3), respectively. The increased percentages of NO₃^- contributions indicated that the emission of NOx should be received special attention in the GZP. The comparison of PM_2.5 chemical compositions and implications across major regions of China and the globe were investigated. NH₄NO₃ was the most important contributor to b_ext in three heating seasons. The average b_ext was decreased from 694.3 ± 399.1 Mm^-1 (HS1) to 359.3 ± 202.3 Mm^-1 (HS3). PM_2.5 had a threshold concentration of 75 μg m^-3, 64 μg m^-3, and 57 μg m^-3 corresponding to the visual range (VR) < 10 km in HS1, HS2, and HS3, respectively. The enhanced impacts of the oxidant on PM_2.5 and O₃ were observed based on the long-term variations in PM_2.5 and OX (Oxidant, the sum of O₃ and NO₂ mixing ratios) over the five heating seasons and PM_2.5 and O₃ over six summers from 2016 to 2021. The importance of coordinated control of PM_2.5 and O₃ was also investigated in the GZP.

Keywords: Chemical components; Heating seasons; Light extinction; PM(2.5) pollution; the Guanzhong Plain.

MeSH terms

Aerosols / analysis
Air Pollutants* / analysis
Air Pollution* / analysis
China
Environmental Monitoring
Heating
Particulate Matter / analysis
Seasons

Substances

Air Pollutants
Particulate Matter
Aerosols