Ozone and NOx data
Information on atmospheric nitrogen (NOx) and ozone
(O3) were obtained from the Tropospheric Monitoring
Instrument (TROPOMI), hosted by the European Space Agency’s (ESA)
Sentinel‐5P satellite under the Copernicus programme
(https://sentinel.esa.int/web/sentinel/missions/sentinel-5p). The
Sentinel-5 Precursor mission is the first Copernicus mission dedicated
to monitoring our atmosphere and provides information and services on
air quality, climate, ozone (O3) and Nitrogen dioxide
(NO2) between the surface and the top of the troposphere
and the ozone layer. The spatial resolution of the Sentinel-5P is 7×3.5
km. Data of O3 and NO2 were extracted
using the NASA Panoply 4.11.1 software (NASA 2020) (Fig. 2).
To generate mean NO2 and O3 values over
our specific sites, we extract daily values from TROPOMI layers between
may 2019 (first of the TROPOMI-Sentinal5P products was released at the
end of April 2019) and September 2019. We did not include data from 2020
in our mean calculation, due to the unusual change in human activity
caused by covid-19 health crises. While nitrogen oxides are one of the
several precursor of ozone (Mills et al. 2013),
O3 and NO2 are not correlated
(cor = 0.070; p-value = 0.421).