The role of sulfate and its corresponding S(IV) NO2 formation pathway during the evolution of haze in Beijing
The role of sulfate and its corresponding S(IV) NO2 formation pathway during the evolution of haze in Beijing
复制标题
硫酸盐及其相应的S(IV)NO2形成途径在北京雾霾演化过程中的作用
DOI：
10.1016/j.scitotenv.2019.06.096
复制
发表时间：
2019
影响因子：
9.8
通讯作者：
Kang Hui
中科院分区：
文献类型：
--
作者：
Yue Fange;Xie Zhouqing;Zhang Pengfei;Song Shaojie;He Pengzhen;Liu Cheng;Wang Longquan;Yu Xiawei;Kang Hui
To better understand the role of stationary sources during the evolution of haze, we investigated sulfate formation characteristics at different stages of four haze events in Beijing, China. The mass fraction of sulfate in PM2.5increased while that of nitrate declined slightly during the worsening process of most haze events, consistent with higher ratios of SO42−/NO3−on haze days (0.50 on average) than those on clean days (0.32 on average). Further calculations indicated that sulfate had a higher mass growth rate than nitrate during the haze-worsening process, probably due to regional transport of sulfate from heavy industrial areas accompanied by increased sulfate secondary transformation during polluted periods. We quantitatively evaluated the contribution of the S(IV) + NO2reaction (pH-dependent) in sulfate formation during the haze evolution. The production rate (PS(IV)+NO2) of the S(IV) + NO2pathway ranged from 1.97 × 10−4to 5.91 (mean: 0.39) μg·m−3·h−1. Its proportion to sulfate total heterogeneous production rate (PS(IV)+NO2/Phet) was generally correlated positively with PM2.5concentrations, indicating the relative importance of this pathway on haze days. Due to the mutual restriction between aerosol pH and aerosol liquid water content (ALWC) during haze evolution, the relative contribution of the S(IV) + NO2pathway to sulfate heterogeneous formation was generally limited to 40%.
