The Cincinnati Asthma Prevention Study (CAPS) remains one of the most rigorous air purifier trials ever conducted. Researchers at Cincinnati Children's Hospital Medical Center, funded by the National Institutes of Health, enrolled 225 children aged 6–12 with physician-diagnosed asthma who were exposed to secondhand smoke at home. In a double-blind, randomized design, each household received either two working Austin Air HealthMate purifiers or two identical sham units — indistinguishable from the real thing — one in the child's bedroom and one in the main living area. Neither the families nor the researchers knew which was which. The trial ran for twelve months and was published in Pediatrics, the journal of the American Academy of Pediatrics.
Independently Conducted · Peer-Reviewed
Ten Studies.
Eight Institutions.
One Air Purifier.
Austin Air units have been named in the methods sections of peer-reviewed research at Cincinnati Children's, Johns Hopkins, the University of Connecticut and more — tested in real homes, against sham units, by researchers we did not pay and did not direct.
Why Independent Research Matters
Most air purifiers are sold on claims. Austin Air is sold on evidence.
The indoor air quality industry is filled with bold marketing. Nearly every air purifier on the market promises to remove allergens, reduce pollution, and improve health. But how many have actually been tested — by independent research hospitals and universities, using rigorous scientific methodology, with results published in peer-reviewed journals?
Austin Air has. Beginning in 2001 with a landmark pediatric asthma study at Cincinnati Children's Hospital, and continuing through research at Johns Hopkins University, the University of Washington, Tufts University, Franklin W. Olin College of Engineering, the University of Connecticut, Illinois Institute of Technology, and the University of Massachusetts Lowell, Austin Air units have been placed in real homes and measured against sham units by independent investigators.
Below, every study is presented in full — what was tested, who conducted it, what was found, and where you can read the source research for yourself. Research is only worth citing if you report it honestly, so the findings below are stated exactly as the investigators reported them.
The Research Record
The Studies
Listed chronologically. Eight published, two in progress. Every one independently conducted and peer-reviewed.
Johns Hopkins researchers ran a three-arm randomized trial in 100 Baltimore homes with unvented gas stoves, testing which intervention best reduced indoor nitrogen dioxide (NO₂) — a combustion byproduct and respiratory irritant that is particularly dangerous for people with asthma and COPD. Homes were randomized to receive one of three interventions: replacement of the gas stove with an electric stove, installation of a ventilation hood over the existing stove, or placement of portable Austin Air HealthMate purifiers with HEPA and carbon filters. NO₂ was measured at baseline, one week, and three months.
Johns Hopkins, working with the Baltimore City Health Department, studied one of the most vulnerable populations in indoor air quality: pregnant women and mothers of infants living in a home with a smoker. Each participating household received two Austin Air HealthMate Standard purifiers — 100 units donated by Austin Air — alongside secondhand smoke education. This was a single-arm feasibility study (no control group), designed to test whether the intervention was practical and whether it moved the needle on exposure.
The Home Air in Agriculture Pediatric Intervention (HAPI) study, run by the University of Washington's Department of Environmental & Occupational Health Sciences, worked with 75 randomized families in the Yakima Valley — a region facing heavy indoor air pollution from intensive crop farming, dairy operations, and pesticide use. All families had children with asthma, ages 6 to 12. One group received an asthma education program alone; the other received the same education plus two Austin Air Pet Machine 410 HEPA purifiers — one in the child's sleeping area and one in the main living area.
Key Findings — Asthma Outcomes: In secondary analysis, children in HEPA homes had a 65% lower risk of any unplanned clinical utilization (IRR 0.35; 95% CI: 0.13–0.94), a 57% lower risk of ever meeting the cutoff for poorly controlled asthma (IRR 0.43; 95% CI: 0.21–0.89), and a lower risk of reporting symptoms in the prior two weeks (IRR 0.71; 95% CI: 0.52–0.98). Austin Air was not involved in the study design, recruitment, or analysis.
Published in Hypertension, the journal of the American Heart Association, this was the first randomized controlled trial to show that reducing traffic-related air pollution (TRAP) prevents acute increases in blood pressure. Researchers from Tufts University and Franklin W. Olin College of Engineering (Dr. Scott Hersey) used a three-period crossover design: 77 participants each attended three two-hour sessions in a room beside an interstate highway, separated by one-week washout periods, and were exposed to high, medium, and low TRAP concentrations. Those exposure levels were created by varying ventilation and by adjusting the number and blower setting of the HEPA units in the room.
The CLEAN AIR Study is among the most rigorous trials ever conducted on air purification and respiratory disease. Johns Hopkins researchers enrolled 116 former smokers with moderate-to-severe COPD and randomly assigned them, double-blind, to receive either two active Austin Air HealthMate HM400 purifiers or two identical sham units, followed for six months. The primary endpoint was change in the St. George's Respiratory Questionnaire (SGRQ), a validated measure of respiratory quality of life.
Johns Hopkins researchers are studying the effects of HEPA air filtration on airborne particulate exposure in the environment of infants and very young children — among the most physiologically vulnerable populations to indoor air pollution. Infants and toddlers spend the majority of their time indoors, breathe at higher rates relative to body weight than adults, and have developing respiratory and neurological systems that are particularly sensitive to fine particulate matter. Austin Air units are deployed in participating households.
The Home Air Filtration for Traffic-Related Air Pollution (HAFTRAP) study, led by Dr. Doug Brugge at the University of Connecticut, used a randomized crossover design among people living near high-traffic roadways: each participant used a HEPA Austin Air purifier for one month and a sham unit for one month, with a washout period between. The blood pressure results were published in the Journal of the American College of Cardiology; a secondary analysis of cognitive function was published in Scientific Reports. The units used were custom-built HealthMates fitted with HEPA media only — no carbon or zeolite — because the researchers wanted to isolate the effect of removing particles specifically.
Led by Dr. Brent Stephens of Illinois Institute of Technology and Dr. Israel Rubinstein of the Jesse Brown VA Medical Center in Chicago, this is among the most ambitious air purification studies yet undertaken. Eighty US military Veterans with moderate-to-severe COPD are being randomized to receive either a fully functioning Austin Air HealthMate (HEPA, activated carbon, and zeolite) or a sham unit — for one full year. The study population is expected to be predominantly African American and largely from historically underserved Chicago neighborhoods, making this an investigation into health equity alongside clinical outcomes. Participants assigned to sham units receive working purifiers at the conclusion of the trial.
Led by Dr. Susan R. Woskie and published in the peer-reviewed journal Toxics, this study examined how effectively Austin Air HealthMate HEPA/carbon purifiers reduce two of the most consequential indoor pollutants — nitrogen dioxide (NO₂) and fine particulate matter (PM2.5) — in homes where gas stoves are a primary pollution source. Sixty-seven low-income households in Lowell, Massachusetts participated over twelve months. Researchers collected baseline measurements for the first four months, then introduced the purifiers and continued monitoring, using linear mixed models to isolate the effect of purifier use while controlling for stove usage and other household variables.
Our role in this research — stated plainly
In several of these studies, Austin Air donated the units or supplied them at a discount. We are telling you this because you should hear it from us, not from someone else.
In every case, the published papers state that Austin Air had no role in the study design, the conduct of the trial, the analysis of the data, or the interpretation of the results. The research was funded by the National Institutes of Health, the U.S. Department of Housing and Urban Development, and the institutions themselves.
We supplied the machines. We did not supply the conclusions.
The Bottom Line
Tested where it counts: in real homes.
Independent trials are expensive, slow, and risky — the results are never guaranteed, and some of ours came back mixed. We publish them anyway. Ten studies. Eight independent institutions. Research spanning childhood asthma, COPD, cardiovascular health, cognitive function, prenatal exposure, and environmental justice. We know of no other air purifier manufacturer with a comparable body of independent, peer-reviewed research on its actual products.
Frequently Asked Questions
What does it mean that Austin Air is "clinically studied"?
It means that actual Austin Air units — not generic HEPA filters, not a competitor's device — were placed in real homes and tested against sham units by independent researchers, with results published in peer-reviewed journals. Most air purifier brands reference general HEPA literature or in-house lab tests. Austin Air units are named in the methods sections of published research at Cincinnati Children's, Johns Hopkins, the University of Connecticut, and others. We know of no other air purifier manufacturer with a comparable published record.
What have the studies actually shown?
Honestly and specifically: 18.5% fewer unscheduled asthma-related medical visits in children (Cincinnati Children's, double-blind RCT). Fewer COPD exacerbations (IRR 0.32) and less rescue medication use (IRR 0.54) in former smokers with COPD, with the primary endpoint met among consistent users (Johns Hopkins CLEAN AIR). Clinically important systolic blood pressure reductions in people with elevated baseline BP, and 12% faster executive-function test scores in adults 40+ (UConn HAFTRAP). 36% less NO₂ and 45% less PM2.5 in homes with gas stoves (UMass Lowell). Significant PM2.5 and cotinine reductions for non-smoking pregnant women (Johns Hopkins).
Which Austin Air products were used in the studies?
The Austin Air HealthMate (including the HM400 and HealthMate Standard) is the model used across the great majority of this research — Cincinnati Children's, Johns Hopkins CLEAN AIR, the Johns Hopkins NO₂ and secondhand-smoke studies, the Illinois Tech Veterans trial, and UMass Lowell. The UConn HAFTRAP study used custom-built HealthMate units fitted with HEPA media only (no carbon or zeolite), because those researchers were isolating the effect of particle removal specifically. The HealthMate is available directly from Austin Air today.
Did Austin Air pay for or influence these studies?
No. In several studies Austin Air donated the units or provided them at a discount — and we disclose that openly. But the research itself was funded by the National Institutes of Health, the U.S. Department of Housing and Urban Development, and the participating institutions. Every published paper states that Austin Air had no role in study design, conduct, data analysis, or interpretation. Several studies reported null or mixed findings, which is the clearest evidence that the investigators were writing what they found, not what we wanted.
Can an air purifier really make a difference in my health?
The evidence is strongest for people with existing respiratory conditions, cardiovascular risk, or meaningful exposure to indoor or traffic-related pollution — and it is strongest when the unit is actually run consistently. The Johns Hopkins CLEAN AIR study makes this point unusually clearly: benefits were significant among participants who used their purifiers more than 80% of the time, and the trial did not reach its primary endpoint when non-adherent participants were included.
An air purifier is not a treatment and not a cure. It reduces your exposure to airborne pollutants. In several rigorous trials, that reduction was associated with measurable clinical improvements. It is also not a substitute for medical care, for a smoke-free home, or for removing the source of the pollution where you can.
How long do Austin Air purifiers need to run to be effective?
In these studies, purifiers were typically run continuously throughout the study period, which ranged from one month to twelve months. The Johns Hopkins CLEAN AIR Study found that participants who ran their purifiers consistently showed significantly greater benefit than those who did not — adherence was the difference between the trial hitting its primary endpoint and missing it. Austin Air recommends running your purifier continuously on a low or medium setting, particularly in bedrooms overnight. The units are designed for continuous operation and are quiet enough at low settings to run during sleep.
What does "medical grade" mean for an air purifier?
"Medical grade" refers to filter technology and particle removal performance equivalent to that used in hospital and clean room environments. Austin Air uses True HEPA media that captures 99.97% of airborne particles at 0.3 microns — the most penetrating particle size — combined with a deep bed of activated carbon and zeolite that adsorbs gases, VOCs, and chemical compounds that HEPA alone cannot remove. Austin Air purifiers are purely mechanical: no ozone, no ionization, no UV, no byproducts.
Please note that "medical grade" describes filtration performance. Austin Air purifiers are not medical devices and are not intended to diagnose, treat, cure, or prevent any disease.
Are Austin Air purifiers safe to use around babies, children, and pregnant women?
Yes. Austin Air units are purely mechanical filters — they produce no ozone, no ionization byproducts, and no UV radiation. They add nothing to the air.
Research has been conducted specifically in these populations: the Johns Hopkins secondhand-smoke study was run in homes of pregnant women and infants living with a smoker and found significant reductions in PM2.5 and in cotinine for the non-smoking mothers (though not in the infants). The Cincinnati Children's trial studied children with asthma over twelve months and found significantly fewer unscheduled asthma-related medical visits. An ongoing Johns Hopkins study is examining particulate exposure in infants and young children.
To be clear about the limits: an air purifier reduces airborne particles. It is not a substitute for a smoke-free home, and it is not a treatment for any condition.
Ready to breathe the difference?
The same purifiers used in this research are available directly from Austin Air.
Shop Austin Air PurifiersExplore Our ResearchReferences & Bibliography
Every claim on this page is drawn from the peer-reviewed publications below. Where a study is still in progress, its protocol or registration is cited and no outcome is claimed. Austin Air donated or discounted the units in several of these studies and had no role in study design, conduct, analysis, or interpretation. The participating institutions do not endorse Austin Air or its products.
- Lanphear BP, Hornung RW, Khoury J, Yolton K, Lierl M, Kalkbrenner A. Effects of HEPA Air Cleaners on Unscheduled Asthma Visits and Asthma Symptoms for Children Exposed to Secondhand Tobacco Smoke. Pediatrics. 2011;127(1):93–101. DOI: 10.1542/peds.2009-2312 · PMID: 21149427. (Cincinnati Asthma Prevention Study — Austin Air HealthMate; NIH-funded, grant RO1-65731.)
- Paulin LM, Diette GB, Scott M, McCormack MC, Matsui EC, Curtin-Brosnan J, Williams DL, Shea M, Breysse PN, Hansel NN. Home interventions are effective at decreasing indoor nitrogen dioxide concentrations. Indoor Air. 2014;24(4):416–424. DOI: 10.1111/ina.12085 · PMID: 24329966. (Johns Hopkins — Austin Air HealthMate.)
- Rice JL, Brigham E, Dineen R, Muqueeth S, O'Keefe G, Regenold S, Koehler K, Rule A, McCormack M, Hansel NN, Diette GB. The feasibility of an air purifier and secondhand smoke education intervention in homes of inner city pregnant women and infants living with a smoker. Environmental Research. 2018;160:524–530. DOI: 10.1016/j.envres.2017.10.024 · PMID: 29089103. (Johns Hopkins — Austin Air HealthMate Standard; single-arm feasibility study.)
- Riederer AM, Krenz JE, Tchong-French MI, Torres E, Perez A, Younglove LR, Jansen KL, Hardie DC, Farquhar SA, Sampson PD, Karr CJ. Effectiveness of portable HEPA air cleaners on reducing indoor PM2.5 and NH3 in an agricultural cohort of children with asthma: a randomized intervention trial. Indoor Air. 2021;31(2):454–466. DOI: 10.1111/ina.12753 · PMID: 32996146. (University of Washington HAPI — Austin Air Pet Machine 410; air-quality outcomes.)
- Karr CJ, et al. Randomized trial of a portable HEPA air cleaner intervention to reduce asthma morbidity among Latino children in an agricultural community. Environmental Health. DOI: 10.1186/s12940-021-00816-w · ClinicalTrials.gov: NCT04919915. (University of Washington HAPI — asthma outcomes.)
- Hudda N, Eliasziw M, Hersey SO, et al. Effect of Reducing Ambient Traffic-Related Air Pollution on Blood Pressure: A Randomized Crossover Trial. Hypertension. 2021. DOI: 10.1161/HYPERTENSIONAHA.120.15580. (Tufts University & Olin College — up to seven Austin Air HealthMate 400 units used, alongside one unit from another brand, to create the exposure conditions.)
- Hansel NN, Putcha N, Woo H, Peng R, Diette GB, Fawzy A, Wise RA, Romero K, Davis MF, Rule AM, Eakin MN, Breysse PN, McCormack MC, Koehler K. Randomized Clinical Trial of Air Cleaners to Improve Indoor Air Quality and Chronic Obstructive Pulmonary Disease Health: Results of the CLEAN AIR Study. American Journal of Respiratory and Critical Care Medicine. DOI: 10.1164/rccm.202103-0604OC · PMID: 34449285 · ClinicalTrials.gov: NCT02236858. (Johns Hopkins — Austin Air HealthMate HM400, double-blind vs. sham.)
- Brugge D, Eliasziw M, Thanikachalam M, et al. Effect of HEPA Filtration Air Purifiers on Blood Pressure: A Pragmatic Randomized Crossover Trial. Journal of the American College of Cardiology. 2025. DOI: 10.1016/j.jacc.2025.06.037. (University of Connecticut HAFTRAP — custom Austin Air HealthMate units, HEPA media only.)
- Pellegrino N, Eliasziw M, Fortinsky R, Brugge D, et al. Effect of HEPA filtration air purifiers on cognitive function: a secondary outcome analysis of a pragmatic randomized crossover trial. Scientific Reports. DOI: 10.1038/s41598-026-48063-8. (HAFTRAP secondary analysis.)
- 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;26:196. DOI: 10.1186/s13063-025-08880-0 · ClinicalTrials.gov: NCT05913765. (Illinois Institute of Technology & Jesse Brown VA — Austin Air HealthMate. Protocol only; no results reported.)
- Kadiri K, Turcotte D, Gore R, Bello A, Rajabiun S, Heavner K, Woskie SR. Effectiveness of HEPA/Carbon Filter Air Purifier in Reducing Indoor NO2 and PM2.5 in Homes with Gas Stove Use in Lowell, Massachusetts. Toxics. 2025;13(12):1030. DOI: 10.3390/toxics13121030. (University of Massachusetts Lowell — Austin Air HealthMate; pre/post design, pollutant outcomes only.)
- Johns Hopkins University. Effects of HEPA filtration on airborne particulate exposure in infants and young children. Research in progress; no results reported. Listed for transparency only.
For Healthcare Providers
Become an Austin Air Dealer
If you're a physician or healthcare provider, you've seen the evidence. Across ten independent clinical trials — from Johns Hopkins to the University of Connecticut — Austin Air purifiers have delivered measurable improvements in COPD outcomes, asthma control, cognitive function, and cardiovascular health. Now you can offer the same clinically validated technology directly to your patients.
Austin Air's medical dealer program allows healthcare practices to carry and recommend medical-grade air purifiers as a trusted, evidence-backed solution — not a supplement store shelf product. Your patients trust your recommendations. Give them something that's earned that trust in peer-reviewed journals.
- Backed by 10 independent clinical trials — published results, not manufacturer claims
- Medical-grade True HEPA + activated carbon filtration used in Johns Hopkins research
- Dedicated support and pricing for healthcare practices
- Patient-ready materials and clinical evidence summaries included
- No ozone, no ionization, no UV — safe for the most vulnerable patients
- Trusted by researchers at Cincinnati Children's, UConn, Illinois Tech, and more
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Fill out the form below and an Austin Air specialist will be in touch with dealer pricing, program details, and clinical resources for your practice.
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