TY - JOUR
T1 - Abundant NH3 in China Enhances Atmospheric HONO Production by Promoting the Heterogeneous Reaction of SO2 with NO2
AU - Ge, Shuangshuang
AU - Wang, Gehui
AU - Zhang, Si
AU - Li, Dapeng
AU - Xie, Yuning
AU - Wu, Can
AU - Yuan, Qi
AU - Chen, Jianmin
AU - Zhang, Hongliang
N1 - Publisher Copyright:
Copyright © 2019 American Chemical Society.
PY - 2019/12/17
Y1 - 2019/12/17
N2 - High levels of HONO have frequently been observed in Chinese haze periods and underestimated by current models due to some unknown sources and formation mechanisms. Combining lab-chamber simulations and field measurements in Xi'an and Beijing, China, we found that NH3 can significantly promote HONO formation via the reduction-oxidation of SO2 with NO2 in the aqueous phase of hygroscopic particles (e.g., NaCl). Concentrations of HONO formed in the aerosol phase showed an exponential increase (R2 = 0.91) with NH3 levels under the chamber conditions and a linear growth with NH3 levels in the two Chinese cities. The uptake coefficient of NO2 on NaCl particles ranged from 2.0 × 10-5 to 1.7 × 10-4, 3-4 orders of magnitude larger than that on water droplets. Our results further showed that HONO formed from the aerosol phase accounted for 4-33% of the total in the chamber, indicating that aerosol-phase formation is an important source of HONO in China, especially in haze periods. Since NH3, SO2, and NO2 abundantly coexist in China, the positive effect of NH3 on HONO formation could enhance the atmospheric oxidizing capacity in the country, causing severe secondary aerosol pollution. Our work suggests that NH3 emission control is imperative for mitigating air pollution in China.
AB - High levels of HONO have frequently been observed in Chinese haze periods and underestimated by current models due to some unknown sources and formation mechanisms. Combining lab-chamber simulations and field measurements in Xi'an and Beijing, China, we found that NH3 can significantly promote HONO formation via the reduction-oxidation of SO2 with NO2 in the aqueous phase of hygroscopic particles (e.g., NaCl). Concentrations of HONO formed in the aerosol phase showed an exponential increase (R2 = 0.91) with NH3 levels under the chamber conditions and a linear growth with NH3 levels in the two Chinese cities. The uptake coefficient of NO2 on NaCl particles ranged from 2.0 × 10-5 to 1.7 × 10-4, 3-4 orders of magnitude larger than that on water droplets. Our results further showed that HONO formed from the aerosol phase accounted for 4-33% of the total in the chamber, indicating that aerosol-phase formation is an important source of HONO in China, especially in haze periods. Since NH3, SO2, and NO2 abundantly coexist in China, the positive effect of NH3 on HONO formation could enhance the atmospheric oxidizing capacity in the country, causing severe secondary aerosol pollution. Our work suggests that NH3 emission control is imperative for mitigating air pollution in China.
UR - https://www.scopus.com/pages/publications/85075679716
U2 - 10.1021/acs.est.9b04196
DO - 10.1021/acs.est.9b04196
M3 - 文章
C2 - 31710467
AN - SCOPUS:85075679716
SN - 0013-936X
VL - 53
SP - 14339
EP - 14347
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 24
ER -
