Asphalt fume concentration distribution and health risk in tunnel paving area

During tunnel paving, it is difficult to dissipate the asphalt fumes released by the hot asphalt mixture, and the accumulating fumes is a threat to the health of on-site workers. This study used a portable VOC detector to monitor the distribution of asphalt fume concentration during paving of the Wushaoling No. 4 highway tunnel. Based on the theory of equivalent toxicity of benzopyrene, it evaluated the health risk to workers using the Monte Carlo method. The results show that the concentration of asphalt fumes was influenced by the wind direction and the relative position of the fumes’ source. Moreover, asphalt fumes intake was closely related to the worker’s labor intensity. For paving upwind, asphalt fumes presented a greater health risk to more people, compared to paving downwind, but most of workers were at high health risk regardless of wind direction. Although it is difficult to eliminate every risk in tunnel paving, wearing gloves and masks can significantly reduce the health risk of asphalt fumes. Controlling the concentration of asphalt fumes below 0.4 mg/m³ can keep the carcinogenic risk faced by workers at an acceptable level.