Presenter Bio: Insung Kang
Ph.D. Candidate in Architectural Engineering at Illinois Institute of Technology
Background and Aim. Healthy home interventions, including ventilation and filtration, have the potential to improve indoor air quality (IAQ) and respiratory health outcomes, although empirical evidence of their effectiveness remains limited. This paper presents the key findings of the Breathe Easy Study, which was designed to improve IAQ and asthma-related health outcomes by installing residential mechanical ventilation systems in forty existing homes in Chicago, IL.
Methods. Mechanical ventilation system retrofits and, in eligible homes, central air filtration upgrades (MERV 10), were installed midway through an over 2-year-long pseudo-randomized parallel-group intervention study of 51 asthmatic adults in 40 homes in Chicago, IL. Each home had at least one self-reported adult resident with asthma and received one of three types of ventilation systems half-way through the study: continuous exhaust-only system, intermittent central-fan-integrated-supply (CFIS) system, or continuous balanced system with an energy recovery ventilator (ERV).
Measurements and Main Results. A selection of indoor and outdoor pollutants, including size-resolved particles (0.3-10 µm), ozone (O3), nitrogen dioxide (NO2), carbon dioxide (CO2), carbon monoxide (CO), and formaldehyde (HCHO), and environmental conditions were measured quarterly in each home. We assessed monthly asthma control using the Asthma Control TestTM (ACT) and baseline and end-line health-related quality of life using the SF-12 survey and stress using the Perceived Stress Scale (PSS) survey. Indoor-to-outdoor (I/O) ratios of the following pollutants were significantly lower across all homes after the ventilation system retrofits: CO2 (11%), NO2 (10%), and particulate matter (33-42%, depending on the size of particles). Healthy home interventions were significantly associated with a 3.6% (95% CI: 1.9–5.3%) improvement in ACT scores. Effect modification stratified by three intervention groups indicated that there were significant increases in ACT scores among participants with intermittent CFIS systems (3.3% increase in ACT; 95% CI: 0.8–5.9%) and participants with continuous balanced ERV systems (5.2% increase in ACT; 95% CI: 1.5–9.0%).
Conclusions. Our results provide new empirical evidence that ventilation and filtration strategies may improve both IAQ and asthma control.