A Comparative Study of Air Pollutant Concentrations before the COVID-19 Pandemic and in the New Normal in the Región de Murcia (Spain)

Abstract

The management of the COVID-19 pandemic, which required global lockdowns and mobility restrictions, positively impacted air quality (especially the concentrations of primary pollutants). With the progressive return to normal activity during the last few months of 2020 and 2021, air pollutant concentrations were expected to rise again. In this work, together with meteorological conditions and traffic intensity, the concentrations of NO, NO2, O3, PM10, and SO2 measured at three different locations (urban, industrial, and rural) in southeast Spain, from January 2016 to December 2021, were analyzed. For the three locations, PM10 concentrations did not change significantly in 2020 or 2021. SO2 concentrations did not experience changes at the industrial site in 2020 or 2021, but SO2 concentrations did slightly increase in five months of 2021 in the urban location (with a maximum monthly average concentration of 11 μg·m−3). In 2020, NO and NO2 concentrations were, in general, lower than those measured in previous years (2016–2019). Interestingly, at the urban site (San Basilio), the levels of NO and NO2 were significantly lower in 2021 than in 2020 despite the higher traffic intensity in 2021. While the concentrations of NO and NO2 decreased, in VOC-limited areas, O3 concentrations increased. This was clearly observed at the industrial and the urban sites. Despite the increase, O3 concentrations were still below the European O3 target value for the protection of human health. An analysis of new registrations of EVs and HEVs in the latter years and their impact on the vehicle fleet of Murcia and, subsequently, on road emissions was carried out. Regardless of the steep increase in environmentally friendly vehicles in 2021, their share of the vehicle fleet is still negligible; thus, the lower concentrations of NO and NO2 are likely due to more favorable weather conditions in 2021 than in 2020.