Unveiling the Characteristics of Indoor Chemical Mixtures and Their Health Risks across China

Exposure to chemicals is a significant risk factor affecting human health, yet uncovering the risks posed by complex indoor chemical mixtures remains an immense challenge. In this study, we systematically screened 969 semivolatile organic compounds (SVOCs) in 395 indoor dust and silicone passive air samples from 31 Chinese provinces. A total of 216 SVOCs were detected across 201 bedrooms, with 95 compounds codetected in both dust and air samples. We found that SVOC concentrations in indoor air were significantly correlated with indoor temperature (r = 0.19) and relative humidity (r = -0.34) and were also significantly influenced by region, season, ventilation time, and interior finishes. Daily intakes of ΣSVOCs from indoor air were 3.15 to 13.6 times those from indoor dust for infants, toddlers, children, teenagers, and adults. The cumulative noncarcinogenic and carcinogenic risks of indoor SVOC mixtures were non-negligible across five age groups, with 15.9-38.8% and 9.5-50.7% of sites exceeding acceptable levels, respectively. Notably, the risk posed by inhaling gaseous SVOCs accounted for 49.6% to 82.8% of the total risk, surpassing the risk from ingestion and dermal uptake of dust. Overall, this study contributes valuable insights into indoor chemical mixtures and their health risks, informing targeted interventions.