Distribution and Risk Assessment of VOCs in Road Dust Across Different Urban Areas

Volatile organic compounds (VOCs) are significant pollutants in urban road dust, but their distribution and associated health risks remain unclear. VOC distribution in road dust from six distinct urban areas in Beijing Daxing District, China was systematically investigated. Eighteen VOCs were detected, with the highest load in commercial areas (7.73 mu g/g), followed by industrial parks (6.38 mu g/g), residential areas (3.35 mu g/g), leisure areas (2.79 mu g/g), traffic areas (2.01 mu g/g) and urban-rural fringe (1.85 mu g/g), much lower than in air and water phases. Typical VOCs in road dust include methyl tertiary butyl ether (MTBE) (0.82-1.24 mu g/g), benzene series compounds (0.02-4.19 mu g/g) and volatile halogenated alkanes (0.002-0.095 mu g/g). Incomplete combustion of road vehicle fuels is the key source of VOCs. Particular attention was given to VOCs in typical sites within the urban-rural fringe, known for their unique pollution characteristics. The VOCs loads were ranked as follows: Gas Stations (2.61-2.62 mu g/g) > Intersection (1.41 mu g/g) > Main Road (1.34 mu g/g) > University Gate (1.27 mu g/g). Increased vehicle activity and frequent stalling contribute to higher VOCs accumulation in road dust. Health risk assessment indicates there is no appreciable non-carcinogenic risk associated with exposure to road dust VOCs. Further research should consider VOCs in the broader environmental context, including air and water.