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Abstract:
Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polycyclic aromatic hydrocarbons (PAHs) are toxic pollutants produced by incomplete combustion. Household fuel combustion in rural homes is an understudied and potentially highly exposing source. We constructed a model of indoor exposure of Tibetan herdsmen and villagers to PCDD/Fs and PAHs, evaluated against measurements. Indoor PCDD/F concentrations for herdsmen and villagers are predicted to be 198–8912 and 313–5700 fg m−3 (95% confidence interval [CI]), respectively. For PAHs, these ranges are 793–9483 and 509–5497 ng m−3 (95% CI), respectively. The PCDD/F values are higher than those encountered in ambient air of Beijing on haze days. Daily intakes of PCDD/Fs for children (4.17–111 fg toxic equivalent (TEQ) d−1 kg–1) were higher than those for adolescents (1.88–50.0 fg TEQ d−1 kg−1) and adults (1.63–43.4 fg TEQ d−1 kg−1). Cancer risks associated with PCDD/F exposure for rural Tibetan residents ([0.18–7.08] × 10−5 for herdsmen and [0.36–4.92] × 10−5 for villagers; 95% CI) were similar to those for workers in metallurgical plants ([1.44–4.19] × 10−5). The family income and lifestyle were identified as key factors influencing household fuel use. Rural Tibetans are exposed to indoor POP pollution produced by household fuel combustion and the risks associated with this should be mitigated.
