The Airports, Air Quality, and Asthma (AAA) Study

NCT07047430 | Recruiting

• 1 other identifier: STUDY00019144
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

For children with asthma, exposure to indoor air pollution increases the risk of a serious asthma exacerbation, which can be life-threatening. Interventions aimed at improving indoor air quality, including use of a portable air cleaner with a high-efficiency particulate air (HEPA) filter, can reduce this risk, but the effectiveness, feasibility and acceptability of HEPA air cleaners varies by setting. In collaboration with a community health worker (CHW) delivered asthma education program, the investigators are conducting a randomized clinical trial to evaluate the effectiveness of HEPA air cleaners to improve indoor air quality and child asthma health in South King County of Washington state, a vulnerable community impacted by air pollution from airports and highway traffic. Key features of the Airports, Air Quality and Asthma (AAA) design include integration of CHWs into study procedures, including CHWs recruited from community-based organizations, into multiple aspects of the trial protocol. The investigators aim to recruit up to N=60 children with asthma randomized into intervention and control groups in a 1:1 ratio, conduct baseline assessments of indoor air quality and airway health, and collect repeated assessments of air quality and airway health during the three-month intervention period and after the trial concludes. Study findings will inform future approaches to integrate HEPA air cleaners into existing CHW asthma education programs in this and similar communities.

Conditions

Pediatric Asthma

Keywords

air quality; indoor air; portable air cleaner; pediatric asthma; community health workers

Outcome Measures

Primary Outcomes (2)

• Symptom days over 7 days

  Symptom days were assessed through brief weekly online surveys sent to caregivers. A symptom-day was defined as any day in the past week when the child had asthma symptoms or used quick-relief medication. Caregivers reported the number of days with symptoms (e.g., coughing, wheezing, shortness of breath, nighttime awakenings), any unscheduled medical visits, and whether the child had a respiratory infection. They also noted how many nights the child slept at home, any issues with the indoor air cleaner, and its usage frequency. Symptom scores ranged from 0 to 7, with high scores indicating more days experienced for that symptom. Study staff monitored the weekly caregiver survey to ensure that the child's symptoms were not worsening over the course of the study.

  Repeated measure, assessed on a weekly basis throughout the 3 month observation period.

• Change in Asthma Control Score

  The Child Asthma Control Test (C-ACT) is a short seven-question survey used to characterize child asthma control based on parent and child report of symptoms over the prior 30 days. The C-ACT has been validated for ages 4-11 years old and shown to have good psychometric properties. A C-ACT score is calculated based on responses, ranging from 0 to 27, with higher values reflecting better asthma control, and a score of 19 or lower considered to reflect inadequate, or "poor," control. This test is administered at the beginning and at the end of the research study. The change in child Asthma Control Test (C-ACT) score between baseline and post-intervention is used to assess the benefit of reducing indoor air pollution in the child's bedroom. Study team staff review responses on the baseline survey to address missing data or participant confusion during the study visit.

  From the baseline visit until the end of study follow-up, 3 months later.

Study Arms (2)

Effective portable air cleaner (HEPA)

EXPERIMENTAL

During the baseline home visit, a Winix 9800 air cleaner is installed in the child's bedroom and paired with data logging energy use monitor as well as air quality monitor. Households randomized to the intervention group receive an air cleaner with a pre-filter, carbon filter, and with the HEPA air filter pre-installed.

Device: Portable air cleaner with HEPA filter

Control portable air cleaner (less effective).

SHAM COMPARATOR

During the baseline home visit, a Winix 9800 air cleaner is installed in the child's bedroom. In the sham group, the Winix 9800 true HEPA filter and activated carbon filter which were removed via an internal modification not visible to the user. The air cleaner still included a washable fine mesh pre-filter that captures large airborne particles. Households randomized to the sham group receive an air cleaner with only the pre-filter and without the carbon filter, and HEPA air filter.

Device: Less effective portable air cleaner (no HEPA)

Interventions

Portable air cleaner with HEPA filter DEVICE

The Winix 9800 is a true HEPA air cleaner that has been AHAM (Association of Home Appliance Manufacturers) Verifide® for rooms that are 500 square feet in size. The air cleaner has a washable fine mesh pre-filter that captures large airborne particles, an activated carbon filter that reduces volatile organic compounds and odors, and a true HEPA filter that captures 99.99% of airborne allergens as small as 0.003 microns in size.

Also known as: HEPA, Portable air cleaner, Air Filter

Effective portable air cleaner (HEPA)

Less effective portable air cleaner (no HEPA) DEVICE

Winix 9800 air cleaner, with data logging energy use monitor is installed in the child's bedroom. In the sham group, the Winix 9800 true HEPA filter and activated carbon filter were removed. This was an internal modification and not visible to the user. The air cleaner still included a washable fine mesh pre-filter that captures large airborne particles.

Also known as: portable air cleaner, HEPA filter removed

Control portable air cleaner (less effective).

Eligibility Criteria

• Age: 6 Years - 12 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17)

You may qualify if:

• Child is 6-12 years old with a health care provider-diagnosed asthma.
• Caregiver is comfortable in participating in all study activities in English (communicating with study staff by phone and completing online surveys).
• Caregiver is familiar with the child's daily asthma health.
• Residence within 10 miles of Seattle-Tacoma International Airport as determined by zip code
• Child resides in caregiver's home at least five nights a week on a regular basis and has no plans to move in the next three months.

You may not qualify if:

• Child has severe asthma at baseline. Severe asthma was defined in consultation with pediatric pulmonologists to be caregiver-reported asthma symptoms every day over the past 14 days and/or two or more inpatient hospitalizations for asthma in the past 12 months.
• Households were excluded if there were multiple individuals within the same household with asthma eligible for the King County CHW Asthma Program or had severe asthma.

Sponsors & Collaborators

• University of Washington: lead

Study Sites (1)

University of Washington

Seattle, Washington, 98195, United States

RECRUITING

Related Publications (2)

• Loftus CT, Lim P, Capps J, Shirai JH, Tchong-French M, Austin E. The Airport Air Quality and Asthma (AAA) indoor air intervention trial for children with asthma: Protocol for a community-based study in South King County, Washington State. Trials. 2025 Nov 27;26(1):596. doi: 10.1186/s13063-025-09286-8.

  PMID: 41310837 DERIVED

• Loftus C, Lim P, Capps J, Shirai J, Tchong-French M, Austin E. The Airport, Air Quality and Asthma (AAA) Indoor Air Intervention Trial for Children with Asthma: Protocol for a Community Based Study in South King County, Washington State. Res Sq [Preprint]. 2025 Sep 22:rs.3.rs-7181465. doi: 10.21203/rs.3.rs-7181465/v1.

  PMID: 41041530 DERIVED

Related Links

• Project site detailing intervention design and planned phases.

MeSH Terms

Interventions

Air Filters

Intervention Hierarchy (Ancestors)

Filtration; Chemistry Techniques, Analytical; Investigative Techniques; Equipment and Supplies

Study Officials

• Elena Austin, Sc.D.

  University of Washington

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Christine Loftus, PhD, MPH

CONTACT

206-753-9079; cloftus@uw.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, CARE PROVIDER
• Masking Details: Participants and CHWs are masked to intervention status. The research team, including those who attend the home visit or manage and analyze data, are not masked.
• Purpose: SUPPORTIVE CARE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor, Environmental & Occupational Health Sciences

Model Details: The design is a parallel group, two-arm randomized superiority trial. After enrollment, participating households are block randomized to either an intervention group or a control group in a 1:1 ratio overall and further balanced 1:1 within groups by household smoking status, defined as reported presence vs. absence of smoking household members. At the start of the trial, an indoor air cleaner is set up in the bedroom of the participating child. Air cleaners in intervention group homes are outfitted with a set of three filters (pre-filter, activated carbon filter, and HEPA filter) while those in control group homes receive an air cleaner with only a pre-filter. All households are followed for a three-month observation period that coincides with administration of the intervention.

Study Record Dates

• First Submitted: June 4, 2025
• First Posted: July 2, 2025
• Study Start: June 1, 2024
• Primary Completion (Estimated): June 1, 2026
• Study Completion (Estimated): June 1, 2027
• Last Updated: July 2, 2025

Record last verified: 2025-06

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, CSR, ANALYTIC CODE
• Time Frame: The study protocol, analysis plan is currently being prepared as an open-source publication to be shared with other researchers. The clinical study report and analytic code will be shared with researchers through open-source publication.
• Access Criteria: A data management plan is available through dmptool.org allowing researchers to identify and request data elements that are not available through open source mechanisms.

Locations

US (1)