Observed Home Dampness and Mold Are Associated with Sustained Spikes in Personal Exposure to Particulate Matter Less than 10 μm in Diameter in Exacerbation-Prone Children with Asthma.

RATIONALE: Home dampness and mold are associated with asthma severity and exacerbations, but little is known about the nature of these exposures in at-risk children.

OBJECTIVES: To test the hypothesis that observed dampness, water damage, and mold in the home are associated with higher exposure to particulate matter less than 10 μm in diameter in a cohort of at-risk children with asthma.

METHODS: We performed a pilot study in 8- to 16-year-old children with exacerbation-prone asthma (n = 29; Denver Asthma Panel Study). Exposure to particulate matter less than 10 μm in diameter was measured over ∼72 hours with personal wearable monitors (MicroPEM [RTI International] and iTrack Micro GPS tracker) and stationary bedroom-located monitors (PEM, MSP Corporation). Mean percentage personal monitored time was 93% (95% confidence interval, 90-96%). Mean and spikes of real-time exposure to particulate matter less than 10 μm in diameter were calculated and, for personal monitored samples, partitioned into exposure while at home, school, or other locations. We defined a sustained spike exposure as a continuous period of 20 minutes or longer during which levels were greater than 50 μg/μL over the participant's minimum levels, using a 2-minute moving average of the particulate matter measurements. Mold and dampness were assessed by detailed home inspection.

RESULTS: Visible water damage/moisture/mold and mold/mildew were common in the homes of exacerbation-prone children: bathroom, 60% and 46%; basement, 30% and 34%; kitchen, 22% and 39%; living room, 20% and 2%; bedroom, 12% and 2%; and other rooms, 21% and 7%, respectively. Personal and bedroom filter-based levels of particulate matter less than 10 μm in diameter were associated with home cumulative measures of water damage/moisture/mold (personal r2  = 0.13, P = 0.02; bedroom r2  = 0.19, P = 0.006; analysis of variance) and mold/mildew (personal r2  = 0.11, P = 0.04; bedroom r2  = 0.18, P = 0.008). Real-time integrated particulate matter less than 10 μm in diameter during sustained spike exposures that occurred when participants were home (normalized by total duration of sustained spike exposures) was associated with cumulative drips/leaks/wet areas (r2  = 0.27; P = 0.004), mold/mildew (r2  = 0.15; P = 0.04), and water damage/moisture/mold (r2  = 0.14; P = 0.04). Other measures of exposure to particulate matter less than 10 μm in diameter from personal or stationary monitors were not associated with home dampness or mold indicators.

CONCLUSIONS: Although mold exposure was not directly quantified in the respirable aerosol in this study, observations of home dampness and mold were associated with sustained spikes in respirable particulate matter less than 10 μm in diameter that was measured by wearable real-time monitors. In our cohort of at-risk children, this finding could imply that mold may exert respiratory health effects via sustained spikes in exposure and help to guide future studies and interventions to reduce these spikes and improve asthma outcomes.