Asthma Intervention With Residential Ventilation and Air Cleaner (AIRVAC) Study

Description

This study will evaluate the long-term effectiveness of energy recovery ventilators (ERVs) and portable air cleaners (PACs) in reducing indoor concentrations of air pollutants and mold, and improving health outcomes among children and adults with asthma. The study design will utilize a double-blind, placebo-controlled, 4-arm, parallel-group, randomized controlled trial with 1-year observation and 1-year intervention periods. Eligible children (n ≥ 40) and adults (n ≥ 40) with asthma from 80 households will be recruited from an applicant pool for RTNTX home retrofit programs. Participants will be randomized to receive one of four different interventions midway through the study: (1) ERV, (2) sham/placebo ERV, (3) PAC, or (4) sham/placebo PAC. All participants and field research team will be blinded to whether participants receive the active or sham/placebo intervention. ERVs will be equipped with minimum efficiency reporting value (MERV) 13 filters to capture particulate matter from incoming outdoor air, while sham/placebo ERVs will be modified to operate only in recirculation mode (no outdoor air ventilation). PACs will have high efficiency particulate air (HEPA) and carbon filters, whereas sham/placebo PACs will have the HEPA and carbon filters removed, leaving only the pre-filters. These objectives will be achieved through a combination of (i) baseline housing condition assessments for characterizing housing-related factors such as housing conditions, health and safety issues, and basic building performance, that may contribute to asthma exacerbations and affect the installation of ERVs, (ii) field measurements of indoor air pollutants (i.e., PM, VOCs, NO2, CO, and CO2) and mold levels (both air and surface samples), and (iii) comprehensive asthma outcome assessments via participant-reported health surveys for asthma control, asthma-related quality of life, stress, and sleep quality. Asthma control will be tracked monthly using the Asthma Control Test (ACT) for adults and the Childhood Asthma Control Test (C-ACT) for children. Quality of life, stress, and sleep will be assessed during home visits using validated instruments, including the 36-Item Short Form Health Survey (SF-36) and the Pediatric Quality of Life Inventory (PedsQL) for quality of life; the Perceived Stress Scale (PSS) and the Patient-Reported Outcomes Measurement Information System (PROMIS) Pediatric Stress measure for stress; and PROMIS Adult and Pediatric Sleep measures for sleep quality.

Results from the research are expected to identify practical and effective commercially available systems that can (1) investigate the long-term effects of different mechanisms between ERVs and PACs on IAQ, mold, and health outcomes in asthmatic children and adults; (2) provide novel data on associations among asthma outcomes, indoor air pollution and mold exposure, and housing-related factors; (3) evaluate the long-term health benefits, including reduced direct costs for asthma and estimated mortality attributable to improved IAQ and mold, versus the total costs of interventions; and (4) investigate the utility of low-cost sensors for assessing housing-related hazards and epidemiology studies, and for providing actionable information on IAQ and mold levels to patients and their physicians.