Long-range source apportionment of black carbon and carbon monoxide over Cyprus using FLEXPART and global emission inventories

Recent studies show that effective pollution control strategies have led to a significant reduction in air pollution in Cyprus. However, the same studies attributed a large number of pollution episodes to the long-range transport of pollutants from regional sources. Black carbon (BC) and carbon monoxide (CO), with a lifetime of several weeks to several months in the troposphere, are considered reliable aerosol and gaseous pollutants to quantify the contribution of regional sources. This study aims to investigate the contribution of anthropogenic sources to atmospheric pollutants over the Eastern Mediterranean. Using FLEXPART, a Lagrangian dispersion model, the origin and residence time of air masses over Cyprus from Europe and the MENA region have been simulated with a temporal resolution of 3 hours for each day of 2019. Then, by coupling FLEXPART simulations to global emission inventories, including MACCity and CAMS-GLOB, the contribution of sources to CO and BC simulations in Cyprus was determined separately for each sector and country in the study area. Results show that CO concentrations are mainly modulated by sources in Turkey. Secondary sources are found in MENA (Iran, Iraq, and Syria) in the cold period of the year and in Eastern (Ukraine and Russia) and Western Europe (Germany and Italy) in the warm seasons. While CAMS-GLOB simulations identify the main sources in agricultural (in the cold period) and residential (in the warm period) sectors, traffic sources have also been identified with the largest contributions in MACCity simulations. Regarding BC simulations, most sources are found in Turkey in the agricultural (in CAMS-GLOB simulations) and industrial (in MACCity simulations) sectors. Local sources were found influential only in the MACCity BC simulations. This can be attributed to uncertainties in the emission inventories and in the simulations of atmospheric residence times. Our results can inform policy- and decision-makers in implementing efficient abatement strategies, improving air quality, and reducing human exposure.