Size-fractionated water-soluble ions during autumn and winter: Insights into volatile ammonium formation mechanisms in Shanghai, a megacity of China

Ye, Xingnan; Tao, Ye; Liu, Yuxuan; Wang, Ruyu; Li, Qing; Yang, Xin; Chen, Jianmin

doi:10.1016/j.aeaoa.2019.100011

Cited by 1 publication

(1 citation statement)

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“…The vehicle number and industrial coal consumption of ZS was 7.6-24.7% and 21.1-80.4% of those in the other five cities, respectively, suggesting a relatively high contribution from stationary sources to PM 2.5 over mobile sources in ZS. In summer, all the ratios of NO 3 − to SO Ammonia (NH 3 ) usually acts as the major alkaline species for the neutralization in the formation process of NO 3 − and SO 4 2− in PM 2.5 [51][52][53], which mostly exist in the forms of (NH 4 ) 2 SO 4 , NH 4 HSO 4 , and NH 4 NO 3 [54,55]. In this study, the correlations between the equivalent concentrations of the sum of NO As shown in Table 2, concentrations of SO4 2− increased along with the increase in SO2 concentrations in the six cities, implying that the formation of particulate SO4 2− was significantly influenced by the emission of SO2.…”

Section: Ratio Of Nomentioning

confidence: 99%

The Characteristics and Impact Factors of Sulfate and Nitrate in Urban PM2.5 over Typical Cities of Hangzhou Bay Area, China

Wang,

Ding,

et al. 2023

Atmosphere

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PM2.5 pollution over Hangzhou Bay area, China has received continuous attention. In this study, PM2.5 samples were collected simultaneously in six typical cities in Zhejiang Province from 15 October 2019 to 15 January 2020 (autumn and winter) and from 1 June to 31 August 2020 (summer), and major water-soluble ions were analyzed. Average concentrations of NO3− and SO42− in the six cities were 3.93–15.64 μg/m3 and 4.61–7.58 μg/m3 in autumn and winter, with mass fractions of NO3− and SO42− in PM2.5 up to 19.6–34.2% and 13.6–26.3%, respectively, while in summer, they were 1.23–2.64 μg/m3 and 2.22–4.14 μg/m3, with mass fractions of 7.0–15.0% and 14.7~25.1%. Both NO3− and SO42− were mostly from gas-to-particle transformation of precursors. High relative humidity in the six cities was suggested to significantly promote the formation of NO3− and SO42−, particularly in autumn and winter, while enhanced atmospheric oxidation favored the formation of SO42− in summer. However, the formation of NO3− was inhibited under a high temperature of >15 °C. The concentrations of SO42− and NO3 were mostly correlated with each other among the six cities. Potential source contribution function analysis indicated that both SO42− and NO3− were mostly from local pollution of Hangzhou Bay area in Zhejiang Province and also transported from Shanghai and the southern region of Jiangsu Province. This study contributed to the understanding of regional characteristics of SO42− and NO3− in Hangzhou Bay area and suggested that joint prevention and control efforts should be strengthened to reduce regional PM2.5 pollution.

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