Aerosol-photolysis interaction reduces particulate matter during wintertime haze events

Jiarui Wu; Naifang Bei; Bo Hu; Suixin Liu; Yuan Wang; Zhenxing Shen; Xia Li; Lang Liu; Ruonan Wang; Zirui Liu; Junji Cao; Xuexi Tie; Luisa T Molina; Guohui Li

doi:10.1073/pnas.1916775117

Aerosol-photolysis interaction reduces particulate matter during wintertime haze events

Proc Natl Acad Sci U S A. 2020 May 5;117(18):9755-9761. doi: 10.1073/pnas.1916775117. Epub 2020 Apr 16.

Authors

Jiarui Wu^{1

2}, Naifang Bei³, Bo Hu⁴, Suixin Liu^{1

2}, Yuan Wang⁵, Zhenxing Shen², Xia Li^{1

2}, Lang Liu^{1

2}, Ruonan Wang^{1

2}, Zirui Liu⁴, Junji Cao^{1

2}, Xuexi Tie¹, Luisa T Molina⁶, Guohui Li^{7

2}

Affiliations

¹ Key Lab of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, 710061 Xi'an, Shaanxi, China.
² Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, 710061 Xi'an, Shaanxi, China.
³ School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, 710049 Xi'an, Shaanxi, China.
⁴ State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, 100029 Beijing, China.
⁵ Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125.
⁶ Molina Center for Energy and the Environment, La Jolla, CA 92037.
⁷ Key Lab of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, 710061 Xi'an, Shaanxi, China; ligh@ieecas.cn.

Abstract

Aerosol-radiation interaction (ARI) plays a significant role in the accumulation of fine particulate matter (PM_2.5) by stabilizing the planetary boundary layer and thus deteriorating air quality during haze events. However, modification of photolysis by aerosol scattering or absorbing solar radiation (aerosol-photolysis interaction or API) alters the atmospheric oxidizing capacity, decreases the rate of secondary aerosol formation, and ultimately alleviates the ARI effect on PM_2.5 pollution. Therefore, the synergetic effect of both ARI and API can either aggravate or even mitigate PM_2.5 pollution. To test the effect, a fully coupled Weather Research and Forecasting (WRF)-Chem model has been used to simulate a heavy haze episode in North China Plain. Our results show that ARI contributes to a 7.8% increase in near-surface PM_2.5 However, API suppresses secondary aerosol formation, and the combination of ARI and API results in only 4.8% net increase of PM_2.5 Additionally, API increases the solar radiation reaching the surface and perturbs aerosol nucleation and activation to form cloud condensation nuclei, influencing aerosol-cloud interaction. The results suggest that API reduces PM_2.5 pollution during haze events, but adds uncertainties in climate prediction.

Keywords: aerosol–photolysis interaction; aerosol–radiation interaction; particulate pollution.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.