The Impact on Urban Air Quality of the COVID-19 Lockdown Periods in 2020: The Case of Nicosia, Cyprus

The purpose of this study is to assess the impact of the lockdown measures in 2020 on the urban air quality in Nicosia capital city, in Cyprus-an island-country in the East Mediterranean-which is often affected by transboundary dust pollution. The study focuses on three criteria pollutants, nitrogen dioxide (NO2), carbon monoxide (CO) and Particulate Matter (PM10), taken from three Air Quality Monitoring Stations; two urban stations and one reference-background. The results of this study show that the decrease in traffic, which is the main source of high concentrations of pollutants in the urban area, reached up to 66.5% during the lockdown. At the beginning of the lockdown period, it exhibited a downward trend of 29% for CO concentration, and downward trend 43% for NO2 and PM10 concentrations. The NO2 concentration exhibited an upward trend towards the end of the lockdown; with the indication that this was due to meteorological conditions relevant to the monitoring stations and the transport of NO2 concentrations from sources that cannot be tracked. PM10 concentrations exhibited a varying behaviour as observed in the trends, where the decreasing trend was followed by an increasing trend due to transboundary air pollution episodes occurring in the same period.