Quantitative analysis of influencing factors to aerosol pH and its responses to PM2.5 and O3 pollution in a coastal city

Ke Xu; Liqian Yin; Qiaoling Chen; Dan Liao; Xiaoting Ji; Keran Zhang; Yu Wu; Lingling Xu; Mengren Li; Xiaolong Fan; Fuwang Zhang; Zhi Huang; Jinsheng Chen; Youwei Hong

doi:10.1016/j.jes.2024.03.044

Quantitative analysis of influencing factors to aerosol pH and its responses to PM_2.5 and O₃ pollution in a coastal city

J Environ Sci (China). 2025 May:151:284-297. doi: 10.1016/j.jes.2024.03.044. Epub 2024 Apr 2.

Authors

Ke Xu¹, Liqian Yin², Qiaoling Chen³, Dan Liao⁴, Xiaoting Ji³, Keran Zhang⁵, Yu Wu⁶, Lingling Xu³, Mengren Li², Xiaolong Fan², Fuwang Zhang⁷, Zhi Huang⁸, Jinsheng Chen³, Youwei Hong⁹

Affiliations

¹ Center for Excellence in Regional Atmospheric Environment, Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; School of Life Sciences, Hebei University, Baoding 071000, China; Fujian Key Laboratory of Atmospheric Ozone Pollution Prevention, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
² Center for Excellence in Regional Atmospheric Environment, Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Fujian Key Laboratory of Atmospheric Ozone Pollution Prevention, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
³ Center for Excellence in Regional Atmospheric Environment, Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China; Fujian Key Laboratory of Atmospheric Ozone Pollution Prevention, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
⁴ College of Environment and Public Health, Xiamen Huaxia University, Xiamen 361024, China.
⁵ Center for Excellence in Regional Atmospheric Environment, Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; College of Resources and Environment, Fujian Agriculture and Forest University, Fuzhou 350002, China; Fujian Key Laboratory of Atmospheric Ozone Pollution Prevention, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
⁶ Center for Excellence in Regional Atmospheric Environment, Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; College of Chemical Engineering, Huaqiao University, Xiamen 361021, China; Fujian Key Laboratory of Atmospheric Ozone Pollution Prevention, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
⁷ Environmental Monitoring Center of Fujian, Fuzhou 350003, China.
⁸ Xiamen Institute of Environmental Science, Xiamen 361021, China.
⁹ Center for Excellence in Regional Atmospheric Environment, Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; School of Life Sciences, Hebei University, Baoding 071000, China; University of Chinese Academy of Sciences, Beijing 100049, China; College of Resources and Environment, Fujian Agriculture and Forest University, Fuzhou 350002, China; Fujian Key Laboratory of Atmospheric Ozone Pollution Prevention, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China. Electronic address: [email protected].

PMID: 39481940
DOI: 10.1016/j.jes.2024.03.044

Abstract

Aerosol acidity (pH) plays an important role in the multiphase chemical processes of atmospheric particles. In this study, we demonstrated the seasonal trends of aerosol pH calculated with the ISORROPIA-II model in a coastal city of southeast China. We performed quantitative analysis on the various influencing factors on aerosol pH, and explored the responses of aerosol pH to different PM_2.5 and O₃ pollution levels. The results showed that the average aerosol pH was 2.92 ± 0.61, following the order of winter > spring > summer > autumn. Sensitivity tests revealed that SO₄^2-, NH_x, T and RH triggered the variations of aerosol pH. Quantitative analysis results showed that T (37.9%-51.2%) was the main factors affecting pH variations in four seasons, followed by SO₄^2- (6.1%-23.7%), NH_x (7.2%-22.2%) and RH (0-14.2%). Totally, annual mean meteorological factors (52.9%) and chemical compositions (41.3%) commonly contributed the aerosol ΔpH in the coastal city. The concentrations of PM_2.5 was positively correlated with aerosol liquid water content (R² = 0.53) and aerosol pH (R² = 0.26), indicating that the increase in pH was related with the elevated NH₄NO₃ and decreased SO₄^2-, and also the changes of T and RH. The O_x (O₃ + NO₂) was moderately correlated with aerosol pH (R² = -0.48), attributable to the fact that the proportion of SO₄^2- increased under high T and low RH conditions. The study strengthened our understanding of the contributions of influencing factors to aerosol pH, and also provided scientific evidences for chemical processes of atmospheric particles in coastal areas.

Keywords: Aerosol acidity; Aerosol liquid water; Coastal city; Fine particular matter (PM(2.5)); Ozone (O(3)).

MeSH terms

Aerosols* / analysis
Air Pollutants* / analysis
Air Pollution / analysis
Air Pollution / statistics & numerical data
China
Cities
Environmental Monitoring*
Hydrogen-Ion Concentration
Ozone* / analysis
Particulate Matter* / analysis
Seasons

Substances

Particulate Matter
Aerosols
Air Pollutants
Ozone