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

Official title

Energy Recovery Ventilation and Air Cleaner Interventions to Improve Indoor Air Quality, Mold Control, and Asthma-Related Health Outcomes Among Inner-City Children and Adults in Low-Income Households

Overview

The primary goal of this study is to investigate the comparative long-term (i.e., 1-year) effectiveness of energy recovery ventilators (ERVs) and portable air cleaners (PACs) in reducing indoor air pollutants and mold levels and improving asthma-related health outcomes in inner-city children and adults with asthma in low-income households in the Dallas-Fort Worth (DFW) metropolitan area, TX. Secondary goals include: (1) examining associations among asthma outcomes, exposure to indoor air pollutants and mold, and housing-related factors, (2) conducting a cost-benefit analysis of ERV and PAC interventions for improving IAQ, mold control, and health outcomes, and (3) evaluating the utility of cost-effective methods and protocols for measuring IAQ and mold for indoor air pollution epidemiology studies and for providing practical information to patients and their physicians. Using a double-blind, placebo-controlled randomized controlled trial, 80 households will be assigned to receive active or placebo versions of ERVs or PACs. Environmental exposures and housing conditions will be monitored alongside comprehensive health assessments, including lung function tests and validated surveys on asthma control, quality of life, stress, and sleep quality.

Detailed 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.

Interventions

• Device Energy Recovery Ventilator
  A mechanical ventilation system that exchanges stale indoor air with fresh outdoor air while transferring heat and moisture between the incoming and outgoing air streams
• Device Portable Air Cleaner
  A standalone home device that filters indoor air to remove particulate matter, allergens, and other pollutants
• Device Energy Recovery Ventilator (Sham)
  A home-installed ERV unit that operates in recirculation mode only, providing no fresh air exchange or heat/moisture transfer, serving as a placebo for study purposes.
• Device Portable Air Cleaner (Sham)
  A portable air cleaner that appears to operate like an active unit but does not contain a HEPA filter and does not clean the air, serving as a placebo for study purposes

Primary outcome measures

• Pulmonary Function (Spirometry) [Time frame: Baseline; 6 months; 18 months; 24 months]
• Asthma Control Test Score [Time frame: From enrollment to the end of intervention at 1 month (24 months in total)]

Secondary outcome measures (4)

• Asthma-Related Quality Of Life (Adults) [Time frame: Baseline; 6 months; 18 months; 24 months]
• Asthma-Related Quality Of Life (Children) [Time frame: Baseline; 6 months; 18 months; 24 months]
• Stress Levels [Time frame: Baseline; 6 months; 18 months; 24 months]
• Sleep Quality [Time frame: Baseline; 6 months; 18 months; 24 months]

Eligibility criteria

Inclusion criteria

• Individuals with physician-diagnosed asthma, including both adults and children aged 5-17
• Homeowners living in the DFW metropolitan area, TX

Exclusion criteria

• Participants living in homes with any smokers

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Treatment

Study locations

United States · 2 centers

• University of Texas at Arlington — Arlington
• Rebuilding Together North Texas — Plano

Publications

• Stephens B, Kang I, Jagota K, Elfessi Z, Karpen N, Farhoodi S, Heidarinejad M, Rubinstein I. Study protocol for a 1-year, randomized, single-blind, parallel group trial of stand-alone indoor air filtration in the homes of US military Veterans with moderate to severe COPD in metropolitan Chicago. Trials. 2025 Jun 4;26(1):196. doi: 10.1186/s13063-025-08880-0. PMID 40468409
• Kang I, McCreery A, Azimi P, Gramigna A, Baca G, Hayes W, Crowder T, Scheu R, Evens A, Stephens B. Impacts of residential indoor air quality and environmental risk factors on adult asthma-related health outcomes in Chicago, IL. J Expo Sci Environ Epidemiol. 2023 May;33(3):358-367. doi: 10.1038/s41370-022-00503-z. Epub 2022 Nov 30. PMID 36450925
• Kang I, McCreery A, Azimi P, Gramigna A, Baca G, Abromitis K, Wang M, Zeng Y, Scheu R, Crowder T, Evens A, Stephens B. Indoor air quality impacts of residential mechanical ventilation system retrofits in existing homes in Chicago, IL. Sci Total Environ. 2022 Jan 15;804:150129. doi: 10.1016/j.scitotenv.2021.150129. Epub 2021 Sep 8. PMID 34798726

Identifiers

NCT: NCT07196436 · 2025-0280 · HUD TXHHU0097-24

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗