Carbon isotope compositions and TC/OC/EC levels in atmospheric PM10 from Lower Silesia (SW Poland): Spatial variations, seasonality, sources and implications

PM₁₀ samples were collected at eight monitoring (urban, industrial and regional background) stations during 2011 in SW Poland (Voivodeship of Lower Silesia) with the objectives of identifying their potential sources, as well as of quantitatively estimating the anthropogenic impact on their carbon content by coupling carbon stable isotope compositions of the total carbon (TC) with organic (OC) and elemental carbon (EC) concentrations. Results showed that (i) the highest OC and EC concentrations measured at the five urban background stations were 11.9 and 1.9 μg m⁻³, respectively, with an average δ¹³CTC of −26.5 ± 1.13‰. Annual average concentrations measured (ii) at the industrial and (iii) the two regional stations were similar for OC (6.9 and 6.4 μg m⁻³, respectively) and EC (0.9 and 0.8 μg m⁻³, respectively) with average δ¹³CTC of −27.4 ± 0.81 and −27.6 ± 0.99‰, respectively. This indicates that similar contamination sources explain the PM₁₀ levels at stations (ii) and (iii), however significantly different from the source(s) influencing station (i). Moreover, using an isotope mass balance that incorporates δ¹³CTC and OC and EC concentrations, we show that while during the heating season coal is the dominant source of aerosol contamination (with contributions ranging from 5.1 to 73.8 μg m⁻³), during the vegetative season road traffic is the dominant one (with contributions ranging from 2.2 to 20.2 μg m⁻³). These large ranges confirm the spatiotemporal heterogeneity of air contamination, even within such a small monitoring area, and should be taken into consideration for future implementation of air quality management measures at larger, e.g. national and international, scales.