Probabilistic Health Risks of Indoor BTEX and Indoor/Outdoor NO 2 in Preschools in Pretoria, South Africa
Mandla Bhuda, Kemisetso D. Malatji, Mamagase S. Nchabeleng, Joyce ShirindeABSTRACT
Air pollution is a major environmental health risk. The study aimed to evaluate the non‐carcinogenic and carcinogenic health risks of indoor BTEX and indoor/outdoor NO 2 in preschools at Melusi informal settlement. Materials and Methods Eight preschools in Melusi, City of Tshwane, were included. A total of 36 Radiello passive samplers measured indoor BTEX and indoor/outdoor NO 2 over 14 consecutive days. The United States Environmental Protection Agency (U.S. EPA) human health risk assessment model was used to estimate non‐carcinogenic and carcinogenic health risks. Mean indoor concentrations were 7.4 µg/m 3 (benzene), 7.7 µg/m 3 (toluene), 2.8 µg/m 3 (ethylbenzene), and 2.3 µg/m 3 (xylenes). Mean NO 2 levels were 15.6 µg/m 3 indoors and 17.8 µg/m 3 outdoors. Hazard quotient values were below the safe threshold of 1 for all BTEX among the subgroups (range: 0.002–0.267), when U.S. EPA reference values were applied. The cancer risks were 5.8 × 10 − 5 for benzene and 6.9 × 10 − 6 for ethylbenzene. Indoor BTEX and indoor/outdoor NO 2 health risks were evaluated across different subgroups, indicating both non‐carcinogenic and carcinogenic health risks in preschools at Melusi informal settlement. These findings underscore the urgent need for air pollution mitigation strategies in informal settlements and similar settings.