Monitoring Air Pollution in Greek Urban Areas During the Lockdowns, as a Response Measure of SARS-CoV-2 (COVID-19).

UNLABELLED: On March 11, 2020, the World Health Organization declared COVID-19 (SARS-CoV-2) a pandemic. Countries all over the world imposed restriction measures, in an attempt to limit the expansion of the pandemic. Provided that human activities in large urban areas affect air quality, we studied the concentrations of gaseous pollutants ΝΟ, ΝΟ2, O3, C6H6, and particulate matter PM10 in the air, through gas pollution measuring stations in the center of Athens (Greek capital), the center of Piraeus (Greece's largest port), Athens International Airport (most international and domestic flights within Greece). We monitored and compared the concentrations of ΝΟ, ΝΟ2, O3, C6H6, and ΡΜ10, of 2020 to those of the previous years and found that the primary air pollutants, ΝΟ, ΝΟ2, and C6H6, recorded decreased compared to those of the past years. The O3, which is produced secondarily at the ground of the earth being inversely dependent on NO/NO2, had in most cases increased. The particulate matter PM10, although reduced by the cessation of human activities, was inextricably linked to natural conditions, such as wind velocity and direction transporting African desert dust masses through storms, during which at certain periods was showing increased in concentrations.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11270-022-06024-7.