Trans-regional pollution between different areas within South – Eastern Romania is very strong

High levels of atmospheric pollution degrade air quality, affect the climate and have significant impacts on human health. The climate maps show that the region of South-Eastern Romania (SERO) has started to be to be affected by significant climate changes. Therefore, the spatial variations of the trace gases (NO₂, CO, SO₂, and O₃) by investigating their levels and variations in the atmosphere both from ground based measurements, but also from remote sensing in different areas of this region need to be investigated. The selected sites (urban, suburban and rural types) are subject to different sources of pollution and represent well the pollution spread over a larger area within SERO region. A database (2019-2021) was created for each site considering the ground-based data retrieved from Romanian National Air Quality Network, the remote-sensing data retrieved from the Sentinel 5P TROPOMI instrument and also, for one of the sites studied, we used the data available from Pandonia Global Network Pandora instrument. The meteorological parameters were extracted from the European Centre for Medium-Range Weather Forecasts (ECMWF) Era5 single level products and pressure level products.

During the observation period, univariate and bivariate LISA cluster maps indicate the spatial and temporal behavior is linked to local and regional pollution sources, social behavior and the level of economic development. Trans-regional pollution between different areas within SERO region was found to be very strong. Moreover, the statistical analysis of studied trace gasses (NO₂, CO, SO₂, and O₃) in the areas with lowest concentrations and highest concentrations confirmed the need to take in consideration more factors than just pollution sources (such as traffic, industry type, agricultural and biomass burning activities etc.). Results show that the complexity of atmospheric pollution is related to more than just the identification of pollution sources. It implies the necessity to take into account additional metadata. They also highlights important information on the distribution and variation of selected trace gases, with the potential to help the policy makers in addressing measures to reduce these pollutants.

Acknowledgment: BM work was supported by the University of Bucharest, PhD research grant. The partial support from NO Grants 2014-2021, under Project EEA-RO-NO-2019-0423, contract no 31/01.09.2020 is also acknowledged. We thank R.V. Chiritescu for providing LISA maps.