{"title":"Impacts of TROPOMI-Derived NOX Emissions on NO2 and O3 Simulations in the NCP during COVID-19","authors":"Yizhi Zhu, Cheng Liu*, Qihou Hu*, Jiahua Teng, Daian You, Chengxin Zhang, Jinping Ou, Ting Liu, Jinan Lin, Tianyi Xu and Xinhua Hong, ","doi":"10.1021/acsenvironau.2c00013","DOIUrl":null,"url":null,"abstract":"<p >NO<sub>2</sub> and O<sub>3</sub> simulations have great uncertainties during the COVID-19 epidemic, but their biases and spatial distributions can be improved with NO<sub>2</sub> assimilations. This study adopted two top-down NO<sub><i>X</i></sub> inversions and estimated their impacts on NO<sub>2</sub> and O<sub>3</sub> simulation for three periods: the normal operation period (P1), the epidemic lockdown period following the Spring Festival (P2), and back to work period (P3) in the North China Plain (NCP). Two TROPOspheric Monitoring Instrument (TROPOMI) NO<sub>2</sub> retrievals came from the Royal Netherlands Meteorological Institute (KNMI) and the University of Science and Technology of China (USTC), respectively. Compared to the prior NO<sub><i>X</i></sub> emissions, the two TROPOMI posteriors greatly reduced the biases between simulations with in situ measurements (NO<sub>2</sub> MREs: prior 85%, KNMI −27%, USTC −15%; O<sub>3</sub> MREs: Prior −39%, KNMI 18%, USTC 11%). The NO<sub><i>X</i></sub> budgets from the USTC posterior were 17–31% higher than those from the KNMI one. Consequently, surface NO<sub>2</sub> levels constrained by USTC-TROPOMI were 9–20% higher than those by the KNMI one, and O<sub>3</sub> is 6–12% lower. Moreover, USTC posterior simulations showed more significant changes in adjacent periods (surface NO<sub>2</sub>: P2 vs P1, −46%, P3 vs P2, +25%; surface O<sub>3</sub>: P2 vs P1, +75%, P3 vs P2, +18%) than the KNMI one. For the transport flux in Beijing (BJ), the O<sub>3</sub> flux differed by 5–6% between the two posteriori simulations, but the difference of NO<sub>2</sub> flux between P2 and P3 was significant, where the USTC posterior NO<sub>2</sub> flux was 1.5–2 times higher than the KNMI one. Overall, our results highlight the discrepancies in NO<sub>2</sub> and O<sub>3</sub> simulations constrained by two TROPOMI products and demonstrate that the USTC posterior has lower bias in the NCP during COVD-19.</p>","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":null,"pages":null},"PeriodicalIF":6.7000,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsenvironau.2c00013","citationCount":"3","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Environmental Au","FirstCategoryId":"1085","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acsenvironau.2c00013","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, ENVIRONMENTAL","Score":null,"Total":0}
引用次数: 3
Abstract
NO2 and O3 simulations have great uncertainties during the COVID-19 epidemic, but their biases and spatial distributions can be improved with NO2 assimilations. This study adopted two top-down NOX inversions and estimated their impacts on NO2 and O3 simulation for three periods: the normal operation period (P1), the epidemic lockdown period following the Spring Festival (P2), and back to work period (P3) in the North China Plain (NCP). Two TROPOspheric Monitoring Instrument (TROPOMI) NO2 retrievals came from the Royal Netherlands Meteorological Institute (KNMI) and the University of Science and Technology of China (USTC), respectively. Compared to the prior NOX emissions, the two TROPOMI posteriors greatly reduced the biases between simulations with in situ measurements (NO2 MREs: prior 85%, KNMI −27%, USTC −15%; O3 MREs: Prior −39%, KNMI 18%, USTC 11%). The NOX budgets from the USTC posterior were 17–31% higher than those from the KNMI one. Consequently, surface NO2 levels constrained by USTC-TROPOMI were 9–20% higher than those by the KNMI one, and O3 is 6–12% lower. Moreover, USTC posterior simulations showed more significant changes in adjacent periods (surface NO2: P2 vs P1, −46%, P3 vs P2, +25%; surface O3: P2 vs P1, +75%, P3 vs P2, +18%) than the KNMI one. For the transport flux in Beijing (BJ), the O3 flux differed by 5–6% between the two posteriori simulations, but the difference of NO2 flux between P2 and P3 was significant, where the USTC posterior NO2 flux was 1.5–2 times higher than the KNMI one. Overall, our results highlight the discrepancies in NO2 and O3 simulations constrained by two TROPOMI products and demonstrate that the USTC posterior has lower bias in the NCP during COVD-19.
期刊介绍:
ACS Environmental Au is an open access journal which publishes experimental research and theoretical results in all aspects of environmental science and technology both pure and applied. Short letters comprehensive articles reviews and perspectives are welcome in the following areas:Alternative EnergyAnthropogenic Impacts on Atmosphere Soil or WaterBiogeochemical CyclingBiomass or Wastes as ResourcesContaminants in Aquatic and Terrestrial EnvironmentsEnvironmental Data ScienceEcotoxicology and Public HealthEnergy and ClimateEnvironmental Modeling Processes and Measurement Methods and TechnologiesEnvironmental Nanotechnology and BiotechnologyGreen ChemistryGreen Manufacturing and EngineeringRisk assessment Regulatory Frameworks and Life-Cycle AssessmentsTreatment and Resource Recovery and Waste Management