Risk assessment of volatile organic compounds from aged asphalt: Implications for environment and human health

Abstract

The recycling of aged asphalt offers significant economic benefits. However, its utilization may pose environmental and health risks. Limited research has been conducted to assess the health and environmental risks associated with volatile organic compounds (VOCs) emitted from aged asphalt. To investigate the environmental affects and health risks of VOCs from aged asphalt, this study conducted quantitative research through indoor simulation experiments, where different types of aged asphalt were prepared and analyzed for their VOCs release characteristics and associated risks. The findings of the study indicate noticeable differences in the VOCs release characteristics, environmental impacts, and health risks of aged asphalt, influenced by the asphalt type and aging method. Compared to the virgin asphalt, the concentration of VOCs in aged asphalt can be reduced by up to 88.38 %, resulting in a decreased impact on the environment and health. The content of alkanes, alkenes & alkynes, aromatics, and halogenated hydrocarbons in asphalt decreases, and oxygenated volatile organic compounds (OVOCs) became the primary components. In 70# and 90# virgin asphalt, alkanes, alkenes, and aromatics contribute 82.9 % and 87.3 %, respectively, to ozone generation, while in aged bitumen (except UV90#), OVOCs contribute more than 90 %. Alkanes and aromatics in the VOCs of the original asphalt contribute more than 90 % to the formation of secondary organic aerosols, while alkanes and OVOCs play this role in the aged asphalt. Although the release concentration of VOCs and the associated environmental and health risks are reduced after asphalt aging, they should not be disregarded. This study will contribute to accelerating the prevention and control of traffic pollution promoting green and sustainable development in transportation.