Everyday ozone may harm asthma sufferers more than thought
NCT ID NCT04109807
First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This study looks at how breathing in low levels of ozone—similar to what you might encounter on a typical day in Chapel Hill—affects lung function and airway inflammation in adults with mild asthma. Researchers will compare ozone exposure to filtered air in 18 participants. The goal is to see if even small amounts of ozone can cause breathing problems or inflammation.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- ozone exposure
- What this could lead to
- If successful, this could help understand how everyday ozone levels impact people with asthma, potentially guiding air quality recommendations.
- What could go wrong
- This is a small, early-phase study with only 18 participants, so results may not apply broadly. The trial is currently suspended, which may delay findings.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
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About 18 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Dec 2019
- Expected to finish
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Aug 2027
An estimate. End dates often move.
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 45 years
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
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Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Ages 18-45, both sexes included * Mild intermittent asthma, defined as daytime asthma symptoms no more than 2 times per week, night time asthma symptoms no more than 2 times per month, FEV1 \>80% of predicted, and asthma exacerbation requiring oral steroids 1 time or less per year. * Good general health as evidenced by medical history * Vital signs will be within normal limits on admission to the study: oxygen saturation by pulse oximetry (SpO2) \> 94%, systolic blood pressure between 150-90 mm Hg, diastolic blood pressure between 100-60 mm Hg, afebrile. * FEV1 of at least 80% of predicted at baseline * Able to provide informed consent * Proof of Covid Vaccination Exclusion Criteria: * Any chronic medical condition considered by the PI as a contraindication to the exposure study including significant cardiovascular disease, diabetes, chronic renal disease, chronic thyroid disease, history of chronic infections/immunodeficiency, history of tuberculosis * Physician directed emergency treatment for an asthma exacerbation within the preceding 12 months * Orthopedic injuries or impediments that would preclude bicycle or treadmill exercise * Viral upper respiratory tract infection within 4 weeks of challenge. * Any acute infection requiring antibiotics within 4 weeks of exposure or fever of unknown origin within 2 weeks of challenge. * Individuals who use daily controller medication for asthma. Pre-treatment with a short acting bronchodilator prior to exercise is allowed. * Nasal surgery within 6 months * Mental illness or history of drug or alcohol abuse that, in the opinion of the investigator, would interfere with the participant's ability to comply with study requirements. * Any recent or current use of nicotine * History of intubation for asthma * Pregnancy or nursing an infant as EPA strictly prohibits intentional exposure for research to this population. * Covid infection in the past 90 days
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
1 site. The list below names each one and where it is.
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The official record
The full official record for this study. This one lists no contact details, but it is the first place any would appear.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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University of North Carolina CEMALB
Chapel Hill, North Carolina, 27599, United States
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