Identifying high-risk volatile organic compounds in residences of Chinese megacities: A comprehensive health-risk assessment.

Indoor volatile organic compounds (VOCs) pose considerable health hazards. However, research on hazardous VOCs in Chinese residences has been conducted on a limited spectrum. This study used Monte Carlo simulations with data from Beijing, Shanghai, and Shenzhen to assess VOC health risks in Chinese homes. We identified high-risk VOCs and analyzed the impact of geographic location, age group, activity duration, and inhalation rate on VOC exposure, including lifetime risks. Formaldehyde, acrolein, naphthalene, and benzene posed the highest risks. Notably, acrolein made the leading contribution to non-cancer risks across all megacities. Naphthalene had elevated cancer and non-cancer risks in Shenzhen. This study highlights the need to investigate acrolein and naphthalene, which are currently unregulated but pose substantial health risks. The cumulative cancer risk (TCR) decreases from adults to children, while the cumulative non-cancer risk (HI) is higher for children. In all cities, the average TCR for adults exceeds the tolerable threshold of 10-4, and the average HI values surpass the safety threshold of 1. Nearly 100 % of the population faces a lifetime cancer risk above 10-4, and over 71 % face a non-cancer risk exceeding 10 (tenfold the benchmark). This study underscores the critical need for developing control strategies tailored to VOCs.