Title: | On the Relevancy of Observed Ozone Increase during COVID-19 Lockdown to Summertime Ozone and PM(2.5) Control Policies in China |
Author(s): | Kang M; Zhang J; Zhang H; Ying Q; |
Address: | "Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China. Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, Texas 77843-3136, United States" |
DOI: | 10.1021/acs.estlett.1c00036 |
Abstract: | "In February 2020, China's strict lockdown policies led to significant reductions in anthropogenic nitrogen oxides (NO(x)) emissions, and notable increases in surface ozone (O(3)) followed in many urban areas, raising concerns about potential rises in summertime O(3) due to NO(x) emission controls. On the basis of O(3) isopleths from a series of air quality simulations under different levels of NO(x) and volatile organic compound (VOC) emission reductions, we found that such concerns are not necessary. As NO(x) emissions have been reduced in recent years for particulate matter control, future NO(x) reductions are generally favorable for summertime maximum daily average 8-h (MDA8) O(3) reductions. Decreases in summertime O(3) due to NO(x) reductions will also lead to lower atmospheric oxidation capacity, characterized by decreased OH and NO(3) concentrations, resulting in further reduction of secondary inorganic aerosols (nitrate, sulfate, and ammonium ion, NSA) formation. VOC emission reductions help to further reduce MDA8 O(3) and are needed to control HCHO and primary air toxics simultaneously, but they are ineffective in reducing NSA. This study indicates that a nationwide NO(x) emission reduction policy has great potential in controlling O(3) and PM(2.5) simultaneously. However, its effectiveness could be greatly reduced when applied on a limited spatial scale" |
Notes: | "PubMed-not-MEDLINEKang, Mingjie Zhang, Jie Zhang, Hongliang Ying, Qi eng 2021/03/24 Environ Sci Technol Lett. 2021 Mar 24; 8(4):289-294. doi: 10.1021/acs.estlett.1c00036. eCollection 2021 Apr 13" |