Participant-collected household dust for assessing microorganisms and semi-volatile organic compounds in urban homes

Dust samples collected by researchers and study participants from 43 U.S. urban homes were analyzed and compared to evaluate the feasibility of using participant-collected samples to assess indoor environmental exposures. The microbial and chemical composition of participant-collected (and shipped) samples were compared to researcher-collected samples from the same household, using dust recovered from each home's heating, ventilation, and air conditioning (HVAC) filter. The bacterial and fungal communities present in all dust samples were determined via MiSeq 16S and ITS sequencing, and the concentrations of 27 semi-volatile organic compounds (7 orthophosphates, 6 phthalates, and 14 brominated flame retardants) were determined via GC-MS. Self-report data on the home environment was collected via an online survey of study participants. While the researcher-collected samples (RCS) yielded greater mass than the participant-collected samples (PCS), the alpha and beta diversities of the bacterial and fungal communities recovered in the RCS and PCS were not significantly different, indicating that PCS is a viable option for indoor microbiome studies of residential homes. The microbial communities recovered in both cases reflected the dominance of human-associated bacterial taxa and outdoor-associated fungal taxa with similar pathogen-associated taxa present in each sample type. In both PCS and RCS, the amount of carpet in the home and the frequency of bleach use had a significant effect on the composition of fungal communities. Semi-volatile organic compounds (SVOCs) of potential human health concern, were commonly detected in the homes. Organophosphates and phthalates were recovered at a similar frequency in both PCS and RCS. Measured SVOC concentration levels were consistent with previous indoor studies although differences were observed between PCS and RCS for several SVOCs. This study demonstrates the potential and challenges associated with participant-collected dust samples for indoor environment studies.