Effects of the COVID-19 Lockdown on Air Quality as seen by IAGOS In-situ Data

Abstract:

The European Research Infrastruture IAGOS (In-service Aircraft for a Global Observing System) is dedicated to global monitoring of atmospheric composition, including trace gases, aerosols and clouds. It makes use of the global air transportation system, with instruments mounted on commercial aircraft. The infrastructure and its predecessor program MOZAIC (Measurement of Ozone and Water Vapour on Airbus In-service Aircraft) have been providing regular in-situ observations with high spatial resolution for more than two decades, thus contributing to a better understanding of climate change and global air quality. In particular, IAGOS provides routine in-situ information on the vertical distribution (0-12 km) of pollutants in the troposphere during landing and take-off phases of the flight which are compared with the Copernicus Atmosphere Monitoring Service (CAMS) service in NRT (Near Real Time) and later, with reanalysis products (CAMS-84 project).

With the quick spread of the infection beyond the Chinese borders between late January and mid-February, the global COVID-19 pandemic was declared by the World Health Organization in March 2020. The serious threat to public health led countries to adopt lockdown and other coordinated restrictive measures worldwide. Observations from a number of early studies suggest that these measures had a significant impact on air quality during this period.

Deutsche Lufthansa has been supporting IAGOS since the beginning of MOZAIC, and the IAGOS system installed on the Lufthansa aircraft constitute one of the most comprehensive data sets of the IAGOS database. Currently, the IAGOS equipment is installed on two Lufthansa aircraft. One of these passenger aircraft was transformed into a cargo carrier which allowed to operate throughout the lockdown period. IAGOS vertical profiles of ozone and CO were sampled by Lufthansa above Frankfurt during both winter and spring 2020. The comparison of these profiles with the climatological variability suggests that the anomalies in ozone and CO are related to an impact of the temporary reduction of both regional and global emissions during COVID-19 lockdowns. These results are examined in detail together with the performance of the CAMS models during this unprecedented period.