Weather-Climate Anomalies and Regional Transport Contribute to Air Pollution in Northern China During the COVID-19 Lockdown.

ABSTRACT: Two persistent and heavy haze episodes during the COVID-19 lockdown (from 20 Jan to 22 Feb 2020) still occur in northern China, when anthropogenic emissions, particularly from transportation sources, are greatly reduced. To investigate the underlying cause, this study comprehensively uses in-situ measurements for ambient surface pollutants, reanalysis meteorological data and the WRF-Chem model to calculate the contribution of NO_x emission change and weather-climate change to the "unexpectedly heavy" haze. Results show that a substantial NO_x reduction has slightly decreased PM_2.5 concentration. By contrast, the weakest East Asian winter monsoon (EAWM) in the 2019-2020 winter relative to the past decade is particularly important for haze occurrence. A

SUBMITTER: Zhao S 

PROVIDER: S-EPMC9877581 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature