Publication Date:
2023-06-15
Description:
Here we presented a combination study of PM〈sub〉2.5〈/sub〉 water-soluble ionic composition and PM〈sub〉2.5〈/sub〉 acidity of aerosol samples collected from urban site (CNEMC) in Beijing, China, from 2016-2020, to assess the response of secondary inorganic species in PM〈sub〉2.5〈/sub〉 to the emission reduction and reveal the characteristics and main driving factors of aerosol pH variation. The averaged SO〈sub〉4〈/sub〉〈sup〉2-〈/sup〉, NO〈sub〉3〈/sub〉〈sup〉-〈/sup〉, and NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉 concentration was 8.9, 16.6 and 8.2 μg m〈sup〉-3〈/sup〉 at CNEMC site during autumn-winter seasons, driving the rapid increase of PM〈sub〉2.5〈/sub〉 during pollution. The ISORROPIA II model was employed to predict PM〈sub〉2.5〈/sub〉 pH in autumn-winter seasons, with an average of 3.9 (1.4~6.9) and 4.4 (2.4~6.9) during pollution and non-polluted periods, all acidic. Based on the continuous observations and simulation throughout 2020, PM〈sub〉2.5〈/sub〉 pH showed a significant seasonal cycle pattern. Aerosols in summer were more acidic (pH range: 1-3), while aerosols in winter were less acidic (pH range: 3-6) and fluctuated more violently. We also conducted a sensitivity analysis of PM〈sub〉2.5〈/sub〉 pH to changing meteorological parameters and SNA levels. Overall, temperature was found to be the main factor driving the seasonal and interannual variations in aerosol pH. This result may provide a scientific basis for formulating regional air quality improvement strategies, and provide a new perspective for exploring the influence of meteorological factors on atmospheric chemical processes.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
Permalink