Semivolatile organic compounds in US high schools: Concentrations and associations with building characteristics and seasonal variations

High schools contain various sources that can release semivolatile organic compounds (SVOCs) including phthalates and other plasticizers, polybrominated diphenyl ethers (PBDEs) and organophosphate flame retardants (OPFRs) and pesticides. In this study, concentrations of 42 SVOCs were measured in settled dust (N = 70), heating, ventilation, and air conditioning (HVAC) filter dust (N = 13), and indoor air (N = 24) across four sampling events in each of seven high schools in central Texas, United States. Both legacy and emerging SVOCs were widely detected. Statistically significant positive correlations were found amongst the concentrations of several SVOCs in pairwise settled dust, HVAC filter dust, and indoor air, suggesting that HVAC filter dust is a promising quantitative forensic technique for investigating SVOC concentrations indoors. OPFRs had higher concentrations in air for classrooms with carpet, while PBDEs had higher air concentrations in computer classrooms. The concentrations of SVOCs in portable classrooms were generally higher than those in permanent classrooms. Significantly higher concentrations of several SVOCs were found in settled dust during the colder season compared to those of the warmer season. These results suggest the substantial influences of flooring types, building types, and seasonal variations on indoor SVOC concentrations in high schools.