Impacts of Residential Indoor Air Quality and Environmental Risk Factors on Adult Asthma-Related Health Outcomes in Chicago, IL.

Background Residential environments are known to contribute to asthma. Objective To examine the joint impacts of exposures to residential indoor and outdoor air pollutants and housing risk factors on adult asthma-related health outcomes. Methods We analyzed >1-year of data from 53 participants from 41 homes in the pre-intervention period of the Breathe Easy Project prior to ventilation and filtration retrofits. Health outcomes included surveys of asthma control, health-related quality of life, stress, and healthcare utilizations. Environmental assessments included quarterly measurements of indoor and outdoor pollutants (e.g., HCHO, CO, CO 2 , NO 2 , O 3 , and PM), home walk-throughs, and surveys of environmental risk factors. Indoor pollutant concentrations were also matched with surveys of time spent at home to estimate indoor pollutant exposures. Results Cross-sectional analyses using mixed-effects models indicated that lower annual average asthma control test (ACT) scores were associated ( p < 0.05) with higher indoor NO 2 (concentration/exposure: β = −2.42/−1.57), indoor temperature ( β = −1.03 to −0.94), and mold/dampness ( β = −3.09 to −2.41). In longitudinal analysis, lower ACT scores were also associated ( p < 0.05) with higher indoor NO 2 concentrations ( β = −0.29), PM 1 (concentration/exposure: β = −0.12/−0.24), PM 2.5 (concentration/exposure: β = −0.12/−0.26), and PM 10 (concentration/exposure: β = 10.14/-0.28). Emergency department visits were associated with poorer asthma control [incidence rate ratio (IRR) = 0.84; p < 0.001], physical health (IRR = 0.95; p < 0.05), mental health (IRR = 0.95; p < 0.05), higher I/O NO 2 ratios (IRR = 1.30; p < 0.05), and higher indoor temperatures (IRR = 1.41; p < 0.05). Significance Findings suggest that residential risk factors, including indoor air pollution (especially NO 2 and particulate matter), higher indoor temperature, and mold/dampness, may contribute to poorer asthma control. Impact This study highlights the importance of residential indoor air quality and environmental risk factors for asthma control, health-related quality of life, and emergency department visits for asthma. Two timescales of mixed models suggest that exposure to indoor NO 2 and particulate matter, higher indoor temperature, and mold/dampness was associated with poorer asthma control. Additionally, emergency department visits were associated with poorer asthma control and health-related quality of life, as well as higher I/O NO 2 ratios and indoor temperatures. These findings deepen our understanding of the interrelationships between housing, air quality, and health, and have important implications for programs and policy.