Particle size, carbon composition and sources of indoor dust in Nanchang, China

Abstract

Indoor dust is an enriched environmental media for lots of chemical pollutants, while indoor pollutants pose high exposure level and health risks to humans. In this work, indoor dust samples from four types of indoor environments (residence near steel plant, residence near road, student dormitory and rural kitchen) in Nanchang city were collected and their particle sizes and carbon components were analyzed. The sources of carbon components were traced based on the distribution of carbon components and the correlation between the components. The particle size distribution mainly presents a bimodal mode (0.1–3 and 10–40 μm size intervals, accounting for 8.9% and 7.4%). The average OC and EC in the as-collected indoor dust samples were 34.1 and 52.7 mg/g for residences around the steel plant, 43.9 and 41.4 mg/g for residences adjacent to the road, 119.3 and 66.4 mg/g for students' dormitories, 73.5 and 49.8 mg/g for rural kitchens, respectively. A strong correlation between OC and Char was observed, indicating strong homology between the sources of the two components. In addition, the correlation between two of EC1, OC2, and OC3 (OC2 and OC3 are fractions of OC and EC1 is a fraction of EC) were significant, indicating a large contribution of motor vehicle exhaust to indoor dust. The average ratios of OC/EC and Char/Soot suggest the contribution of automobile exhaust, indoor smoking and biomass combustion to indoor dust. The results of this work provide a scientific, convenient, and reliable approach to explore the source of particulate matter indoors based on the distribution of carbon components.