Spatio-temporal analysis of air quality and its relationship with COVID-19 lockdown over Dublin

Air pollution has become one of the biggest challenges for human and environmental health. Major pollutants such as Nitrogen Dioxide (NO [Formula: see text]), Sulphur Dioxide (SO [Formula: see text]), Ozone (O [Formula: see text]), Carbon Monoxide (CO), and Particulate matter (PM(10) and PM(2.5)) are being ejected in a large quantity every day. Initially, authorities did not implement the strictest mitigation policies due to pressures of balancing the economic needs of people and public safety. Still, after realizing the effect of the COVID-19 pandemic, countries around the world imposed a complete lockdown to contain the outbreak, which had the unexpected benefit of causing a drastic improvement in air quality. The present study investigates the air pollution scenarios over the Dublin city through satellites (Sentinel-5P and Moderate Resolution Imaging Spectroradiometer) and ground-based observations. An average of 28% reduction in average NO [Formula: see text] level and a 27.7% improvement in AQI (Air Quality Index) was experienced in 2020 compared to 2019 during the lockdown period (27 March–05 June). We found that PM(10) and PM(2.5) are the most dominating factor in the AQI over Dublin.