A132-16
Non-negligible impacts of clean air regulations on the reduction of tropospheric NO2 over East China during the COVID-19 pandemic observed by OMI and TROPOMI
Non-negligible impacts of clean air regulations on the reduction of tropospheric NO2 over East China during the COVID-19 pandemic observed by OMI and TROPOMI
Friday, 11 December 2020: 16:45
Virtual
Abstract:
We study the variation of tropospheric NO2 vertical column densities (TropNO2VCDs) over East China during
the 2005–2020 lunar new year (LNY) holiday seasons to understand factors on the reduction of tropospheric
NO2 during the outbreak of COVID-19 in East China using Ozone Monitoring Instrument (OMI) and TROPOspheric
Monitoring Instrument (TROPOMI) observations. TropNO2VCDs from OMI and TROPOMI reveal sharp reductions
of 33%–72% during 2020 LNY holiday season and the co-occurring outbreak of COVID-19 relative to
the climatological mean of 2005–2019 LNY holiday seasons, and 22%–67% reduction relative to the 2019 LNY
holiday season. These reductions of TropNO2VCD occur majorly over highly polluted metropolitan areas with
condensed industrial and transportation emission sources. COVID-19 control measures including lockdowns and
shelter-in-place regulations are the primary reason for these tropospheric NO2 reductions over most areas of East
China in 2020 LNY holiday season relative to the 2019 LNY holiday season, as COVID-19 control measures may
explain ~87%–90% of tropospheric NO2 reduction in Wuhan as well as ~62%‐–89% in Beijing, Yangtze River
Delta (YRD) and Sichuan Basin areas. The clean air regulation of China also contributes significantly to reductions
of tropospheric NO2 simultaneously and is the primary factor in the Pearl River Delta (PRD) area, by explaining
~56%‐–63% of the tropospheric NO2 reduction there.
the 2005–2020 lunar new year (LNY) holiday seasons to understand factors on the reduction of tropospheric
NO2 during the outbreak of COVID-19 in East China using Ozone Monitoring Instrument (OMI) and TROPOspheric
Monitoring Instrument (TROPOMI) observations. TropNO2VCDs from OMI and TROPOMI reveal sharp reductions
of 33%–72% during 2020 LNY holiday season and the co-occurring outbreak of COVID-19 relative to
the climatological mean of 2005–2019 LNY holiday seasons, and 22%–67% reduction relative to the 2019 LNY
holiday season. These reductions of TropNO2VCD occur majorly over highly polluted metropolitan areas with
condensed industrial and transportation emission sources. COVID-19 control measures including lockdowns and
shelter-in-place regulations are the primary reason for these tropospheric NO2 reductions over most areas of East
China in 2020 LNY holiday season relative to the 2019 LNY holiday season, as COVID-19 control measures may
explain ~87%–90% of tropospheric NO2 reduction in Wuhan as well as ~62%‐–89% in Beijing, Yangtze River
Delta (YRD) and Sichuan Basin areas. The clean air regulation of China also contributes significantly to reductions
of tropospheric NO2 simultaneously and is the primary factor in the Pearl River Delta (PRD) area, by explaining
~56%‐–63% of the tropospheric NO2 reduction there.