Comparison of metal pollution and health risks of urban dust in Beijing in 2007 and 2012.

Urban dust in cities is a useful indicator of ambient environmental conditions and a sink for pollutants emitted through various natural and human activities. In this study, metal distributions in urban dust samples collected in 2007, using vacuuming, and 2012, using brushing, were compared. Experiments comparing the vacuuming and brushing methods were performed and translation equations were developed to correct the vacuuming results so that they could be compared with the brushing results. Cadmium concentrations were lower in 2012 than 2007; this could be because many industries moved out of the Beijing region after 2007. Concentrations of Cr, Cu, and Zn changed slightly, which could result from a combination of decreased industrial pollution and increased traffic pollution. A health risk assessment found that except for Cr, exposure to metals in urban dust in the Beijing study area would not cause serious health impacts on residents in 2007 or 2012. However, the health risk for children was higher than for adults in both years. Chromium had the highest hazxard index (0.44) and the highest carcinogenic risk (4.16 × 10-6).