RAPID: Coronavirus-Driven Aerosol Reductions in East Asia and the Effect on Atmospheric Dynamics

Geosciences - The goal of this project is to determine how China?s government-mandated COVID-19 quarantine during February 2020 altered the meteorological conditions in which the disease was being transmitted. During the height of the COVID-19 outbreak in East Asia, the Chinese government authorized closure of many industrial facilities, temporarily and dramatically reducing air pollution in East China. The swift reduction of particulate emissions, which can weaken the intensity of incoming solar energy, would have likely allowed more sunlight to pass through the atmosphere, thereby increasing surface air temperature during the quarantine. Because pathogen transmission can be retarded in warmer and more humid conditions, increased surface air temperatures concurrent with quarantine-reduced aerosols may represent another, yet unintentional, mechanism by which large-scale lockdowns can slow the spread of COVID-19. This project will employ satellite imagery and weather model simulations to determine the extent to which reduced air pollution altered air temperature, as well as several other meteorological conditions, during February 2020 in East China. The findings of this project will also reveal additional important information about how atmospheric particulates influence regional weather patterns on a normal, non-quarantine basis.

This project will mine daily satellite images of NO2, aerosol optical depth (AOD), and air temperature as well as in-situ data from the World Meteorological Organization and Aerosol Robotic Network (AERONET) to assess the co-evolution of pollution decreases and air temperature increases. Additionally, the project will employ the Weather Research and Forecasting (WRF) model coupled with chemistry (WRF-Chem) in a numerical modeling experiment for February 2020 over East China, whereby one simulation is initialized with normal emissions and the second simulation reduces emissions commensurate with the satellite observations collected during February 2020. This project will yield three key products: (1) Daily database of NO2, AOD, and surface, 925-, and 850-hPa temperature over East China, both absolute values and departure from climatology; (2) Two one-month weather simulations for typical emissions and COVID-19-reduced emissions over China; (3) The net impact of aerosol radiative effects on air temperature, as well as a summary of any changes to circulation, cloud cover, and precipitation. These products are valuable for the COVID-19 pandemic, as well as future disease outbreaks, because they can inform how quarantines and lockdowns potentially impede pathogen transmission via aerosol reductions and associated meteorological feedbacks.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.