Trends of anthropogenic sources in a Southeastern Mediterranean coastal site over five years

A five-year study of PM 10 concentrations was carried out from 2017 to 2021 in the port of a Mediterranean coastal city, with an annual collection rate approaching 50% of the days. The chemical composition of the PM 10 dataset was analyzed to assess changes in both natural sources and the effects of regulations and mitigation measures on PM 10 and its precursors. While overall PM 10 concentrations remained stable over the study period, the analysis suggests that mitigation measures have contributed to a reduction in daily exceedances of PM 10 levels in the area. Using positive matrix factorization, seven distinct PM 10 sources were identified and ranked by their contribution: road traffic, bulk materials + dust resuspension, aged sea salt, Saharan intrusion, fresh sea salt, shipping emissions, and ammonium sulphate. Further analysis showed decreasing trends over the five-year period for road traffic, shipping, and ammonium sulphate sources, and increasing trends for Saharan intrusion and aged sea salt sources. No significant trends were observed for the bulk materials + dust resuspension and fresh sea salt sources. Although the measures taken by the Port of Alicante did not lead to a reduction in the PM 10 average concentrations of this source, they did reduce the number of exceedance episodes. On the other hand, the efforts to reduce emissions from shipping and traffic succeeded in reducing the contribution of these sources. • Notable decrease in traffic source contributions aligns with vehicle fleet renewal. • The decrease in the shipping source coincides with the IMO2020 sulphur regulations. • Bulk material mitigations cut exceedance days, but its contribution stay unchanged.