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

NCT ID: NCT07047430

Last Updated: 2025-07-02

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 60 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2024-06-01
• Study Completion Date: 2027-06-01

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.

Detailed Description

Communities in proximity to airports face increased exposures to air pollution generated from both roadway and aircraft traffic. Exposure to particulate air pollution increases risk of an asthma exacerbation ("asthma attack") and, consequently, the possibility of an emergency room or urgent care visit. Puget Sound communities near flight paths have higher baseline rates of asthma and higher rates of asthma-related emergency room visits. For this study, the investigators will test whether an indoor air quality intervention involving HEPA air filtration units can address disparities in indoor air pollution and asthma health in neighborhoods around the Seattle Tacoma (SeaTac) International airport. Previous studies have reported benefits to deploying HEPA filters in indoor spaces, including improved air quality, as well as, reduced frequency of asthma symptoms and exacerbations, which can lead to urgent care visits and hospitalizations. However, it is unknown whether a similar intervention will be effective for children with asthma exposed to airport-related pollution, specifically.

Researchers with the University of Washington, Department of Environmental and Occupational Health Sciences, with experience in pediatric airway health, air pollution monitoring, methods for improving air quality, and epidemiology will conduct this work. They will assess the effectiveness of an indoor air quality intervention in reducing exposure to indoor pollutants and avoiding asthma symptom flare-ups for children with asthma living near SeaTac International airport.

To conduct this study, a sample of children referred to the Public Health - Seattle & King County (PHSKC) Community Health Worker (CHW) Asthma Program and their caregivers will be recruited. Enrolled children and caregivers will be followed for 3 months in the AAA research study before they begin the CHW Asthma Education Program. Each will be randomized to an intervention group, which involves indoor air filtration using a HEPA air filter unit, or a control group, which receives an air filtration unit that may not reduce PM2.5 and ultrafine particulates, types of pollution specific to air and road traffic. About 60 families will participate in total across the two-year study period (January 2024 through June 2025).

The primary research questions assessed in this study are A) Does adding a HEPA filter intervention to the existing asthma education program improve asthma outcomes? and B) Is there an indoor air quality benefit to using an indoor HEPA filter in the homes impacted by aircraft-related air pollution?

Currently, the Community Health Worker (CHW) Asthma Program provides a range of educational services, a green cleaning kit, a HEPA vacuum and mattress encapsulation materials. It does not provide a portable HEPA filter for the participant's home bedroom. The purpose of this project is to assess the added benefit of adding the HEPA unit to future asthma education program interventions.

Caregivers will complete weekly questionnaires to track the occurrence of asthma symptoms, a marker of asthma exacerbations, and health care utilization for asthma. Air quality inside and outside the homes will be monitored. When the study is completed, the investigators will determine whether families in the intervention group had better air quality and improved asthma symptoms during the follow-up period. These findings will be disseminated to the community with the help of the CHWs.

Conditions

Pediatric Asthma

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: SUPPORTIVE_CARE
• Blinding Strategy: DOUBLE

Study Groups

Effective portable air cleaner (HEPA)

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.

Group Type: EXPERIMENTAL

Portable air cleaner with HEPA filter

Intervention Type: 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.

Control portable air cleaner (less effective).

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.

Group Type: SHAM_COMPARATOR

Less effective portable air cleaner (no HEPA)

Intervention Type: 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.

Interventions

Portable air cleaner with HEPA filter

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.

Intervention Type: DEVICE

Less effective portable air cleaner (no HEPA)

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.

Intervention Type: DEVICE

Other Intervention Names

HEPA; Portable air cleaner; Air Filter; portable air cleaner; HEPA filter removed

Eligibility Criteria

Inclusion Criteria

• 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.

Exclusion Criteria

• 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.

• Minimum Eligible Age: 6 Years
• Maximum Eligible Age: 12 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University of Washington

OTHER

Sponsor Role: lead

Responsible Party

Elena Austin

Assistant Professor, Environmental & Occupational Health Sciences

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Elena Austin, Sc.D.

Role: PRINCIPAL_INVESTIGATOR

University of Washington

Locations

University of Washington

Seattle, Washington, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Christine Loftus, PhD, MPH

Role: CONTACT

cloftus@uw.edu

206-753-9079

Facility Contacts

Elena Austin, ScD

Role: primary

elaustin@uw.edu

206-221-6301

Maria Tchong-French

Role: backup

mtchong@uw.edu

206-685-0465

References

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.

Reference Type: DERIVED

PMID: 41041530 (View on PubMed)

Provided Documents

Document Type: Informed Consent Form

View Document

Related Links

https://deohs.washington.edu/aaa-study

Project site detailing intervention design and planned phases.

Other Identifiers

STUDY00019144

Identifier Type: -

Identifier Source: org_study_id