Airborne fungi in the homes of children with asthma in low-income urban communities: The Inner-City Asthma Study

Background: Despite growing evidence of the importance of exposure to fungi as an environmental risk factor for asthma, few data have been reported on the exposure to airborne fungi of asthmatic children living in US inner cities. Objective: We sought to examine the spectrum and concentration of fungi in the air inside and outside of the homes of mold-sensitive children with asthma living in US cities. We also analyzed the relationship of the concentration of fungi in indoor air to home characteristics. Methods: We performed a home environmental survey and measured the concentrations of culturable airborne fungi inside and outside the homes of 414 mold-sensitive children with asthma in 7 urban communities. Results: The airborne fungi encountered indoors generally paralleled those found outdoors, and the similarities between communities were more striking than the differences. Indoor fungal concentrations were correlated with outdoor concentrations measured on the same day, suggesting the need to adjust for the outdoor concentration in analyses by using the indoor concentration as an indicator of the relative moldiness of a home. The concentration of fungi in indoor air in excess of outdoor air-that is, the indoor-outdoor difference-was significantly related to home characteristics, including dampness, having a cat, and cockroach infestation. Conclusion: Mold-sensitive children with asthma living in urban communities across the US are exposed to airborne fungi in indoor and outdoor air. The concentrations of fungi are higher in homes with dampness problems, cockroach infestation, and cats. The indoor-outdoor difference in the concentration of airborne fungi may provide a valuable metric for investigations of the role of fungal exposure as a risk factor for asthma.