During the COVID-19 pandemic, air pollution emerged as an area of strong scientific and general public interest, and information from the Copernicus Atmosphere Monitoring Service (CAMS) has been in great demand.
From the early days of COVID-19, questions were raised about the potential benefits of lockdown measures for air quality and the links between wider health issues, air pollution and the virus.
An area on the CAMS website was established, dedicated to COVID-19. This facilitated a very strong uptake of data products, confirming CAMS as a go-to source for timely and accurate information and expertise about air pollution.
The CAMS team looked in detail at how lockdown measures (such as restrictions on travel and other activity) affected air pollution. CAMS helped convey caveats about the interpretation of data, pointing to the importance of considering weather conditions, which can affect pollution levels, along with any changes in emissions of pollutants and their precursors.
A specific study used data from Sentinel-5P/TROPOMI (tropospheric monitoring instrument) and machine learning techniques to estimate changes in NO2 (emitted from traffic and burning of fossil fuels) accounting for changes in both emissions and weather.
The CAMS regional and global modelling systems have the advantage that they can be run with either ‘business as usual’ (BAU) emissions or the reduced emissions actually seen in 2020, in order to quantify the effects of COVID restrictions.
Indeed, a ‘COVID-19’ 2020 European emissions dataset was prepared for CAMS by the Barcelona Supercomputing Center, from publicly available data, such as mobility/traffic information and energy and flight statistics. These emissions were then used in the ensemble of 11 regional air quality models involved in CAMS, alongside control experiments with BAU emissions.
The main conclusions were that over Europe, during March and April 2020 surface concentrations of NO2 were estimated to have more than halved in some places as a result of COVID restrictions, but there were marked differences across the region. Over China, reductions of 20–30% in fine particulate concentrations were estimated for February 2020.
CAMS modelling work made a major contribution to the Air Quality in Europe 2020 Report, produced by the European Environment Agency, which featured a specific section looking at COVID-19 and air pollution. CAMS has also been very actively supporting the World Meteorological Organization’s efforts to support governments worldwide in assessing the impact of meteorology and air quality impacts on the pandemic.
CAMS data have also been used in studies looking at health impacts related to air pollution and COVID-19. Epidemiologists are investigating several questions. Have the reductions in NO2 and particulates led to a decrease in deaths related to air pollution? Can exposure to air pollution contribute to reduced immune response and higher risk of developing severe COVID-19? To what extent is the virus transmitted by inhalation of fine particulate matter that could have been contaminated?
For example, one ongoing study is examining the short- and long-term impacts of air pollution on COVID-19 development and outcome. It is looking at the exposure to air pollution of over a thousand elderly people in France and Belgium, from 2018 to early 2020. CAMS data about air pollutants, UV radiation and weather parameters are being used for this. The complete spatial coverage of CAMS data, the availability of past data and their high quality have proved extremely valuable for such studies.