Seasonal variability of trace elements in fine particulate matter (PM2.5) in a coastal city of northern Poland – profile analysis and source identification
A large group of trace elements (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Ti, V, Zn) was measured for the first time in 226 air samples collected at the coastal monitoring station in Gdynia (northern Poland), in the period from January 12th to August 30th, 2019. The 24-h measurements included fine particles (PM2.5) concentrations, meteorological parameters and backward air mass trajectory analyses. The monthly mean PM2.5 mass concentration ranged from 17.3 µg m-3 to 55.0 µg m-3, and the peak value of 167 µg m-3 was found in February. Overall, considerable differences in the trace element concentrations were observed. However, their seasonal distribution was not similar. In particular, elements such as Cd, Cu, Mo, Ni, V and Zn showed significantly higher concentrations (p < 0.05) in winter compared to spring or summer. The winter peak of trace element concentrations in PM2.5 indicated that local power plants and fossil fuel/coal combustion in residential sector were the major anthropogenic sources of air pollutants. Based on multivariate analysis (PCA) for the standardized database (14 elements and PM2.5), significant contribution of different sources and processes was identified, i.e. local traffic emission, local/regional coal/oil burning in power plants and domestic heating units, industrial activities, petrochemical industry and maritime transport. The Cu/Fe ratios revealed that both local traffic and brake-wear emission considerably influenced chemical composition of PM2.5. In addition, the results of V/Ni ratio suggested local mixed industrial sources (petrochemical refinery, industrial plants) with possible contribution from port area and shipping activities to the total PM2.5 loadings. The local ship emission was more pronounced during summer period.