Spatial and temporal analysis of organic and black carbon mass concentrations in Lithuania

Abstract

Both organic carbon (OC) and black carbon (BC) mass concentrations were measured in Lithuania at coastal/marine (Preila), rural (Rūgšteliškis), and urban background (Vilnius) environments have been analyzed to infer the spatial and temporal distributions of the OC/BC ratios from May 2013 to October 2014. OC/BC ratios reflected the location of the different sites, as well as possible different sources influencing air quality. The results from an industrialized and populated urban background area indicated that biomass combustion for heating contributed to BC and OC mass concentration. Typically, BC mean concentrations (±st.deviation) were higher in urban areas (1.72(±1.22 μg·m-3)) than in rural (0.40(±0.35 μg·m-3)) and coastal/marine (0.53(±0.43 μg·m-3)) during warm and cold (2.34(±2.15); 0.77(±0.52) and 0.84(±0.50) μg·m-3, respectively) periods, while OC concentrations were higher in urban backgrounds (5.91(±1.99 μg·m-3)) and rural areas (4.56(±3.98 μg·m-3)) during warm periods. The air mass backward trajectory analysis indicated influence of local sources in urban environment and strong influence of long-range transport in rural environment. A clear seasonal dependence of OC/BC ratios was observed at rural and urban environments. The highest OC/BC ratios were calculated in coastal/marine (6.3) and rural (9.5) environments in summer.