Asthma, AllergicNCT04109807
Effects of Low Dose Ozone on Airway Inflammatory Responses in Adults With Asthma - Sedentary Nasal Ozone (Asthma SNOZ)
A study testing Ozone and FA in people with Asthma, Allergic, run by University of North Carolina, Chapel Hill at 1 site in United States.
Trial summary
To determine if low levels of ozone (O3) encountered on a typical day in Chapel Hill will decrease spirometric values in mild asthmatics. Read more about this study
- Who is it for?
- Ages 18 to 45 years
- Conditions the study is for
- Asthma, Allergic
- What is being tested?
- Ozone and FA
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 18 participants
- Where
- 1 siteUnited States
- Study dates
- 16 Dec 2019to Aug 2027
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- 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
Who cannot join
- 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.
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- 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
Trial locations and contacts
1 site in 1 country.
United States1 site
University of North Carolina CEMALB
Chapel Hill, North Carolina, 27599
About this study
Official title: Effects of Low Dose Ozone on Airway Inflammatory Responses in Adults With Asthma Asthma SNOZ
To determine if low levels of ozone (O3) encountered on a typical day in Chapel Hill will decrease spirometric values in mild asthmatics.
Read the detailed description
Short-term exposure to ambient air ozone has been recognized for decades to be adversely associated with impacts on the respiratory system. Indeed the evidence is such that the Environmental Protection Agency (EPA) has determined that there is a causal relationship, and even lowered the 8-hour exposure standard to 0.07 parts per million (ppm) in 2015. Controlled human exposure studies and epidemiological studies have consistently observed ozone-associated decrements in lung function and increased respiratory symptoms. Most controlled human exposure studies have been performed with high ozone concentrations. Additionally, epidemiologic studies have focused on populations engaged in outdoor activities (increasing ozone exposure through increased minute ventilation), or in cities such as Los Angeles or Mexico City where ambient ozone levels are especially high. Evidence has recently emerged that exposure to low ozone concentrations also produces adverse health effects, especially among susceptible groups including children with asthma.
The objective of this study is to examine if low level ozone exposure (compared to a clean air exposure), reflective of a typical metropolitan summer day, will cause decrements in lung function and measurable upper and lower airway inflammation in mild asthmatics (who are not on asthma controller medications) while performing typical daily activities.
- Conditions
- Asthma, Allergic
- Being tested
- Ozone, FA
- Medical subject headings
- Asthma
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
OzoneOther
ozone exposure
FAOther
Filtered air exposure
| Study group | Role | What they receive |
|---|---|---|
| 6 hour Filtered Air (FA) followed by O3 exposure | Experimental | For the first exposure session, participants are exposed to filtered air (FA) for 6 hours. For the second exposure session, the same participant will be exposed to ozone at a concentration of 0.07ppm for 6 hours. Receives: Other: Ozone; Other: FA |
| 6 hour O3 exposure followed by FA exposure | Experimental | For the first exposure session, a participant will be exposed to ozone at a concentration of 0.07ppm for 6 hours. For the second exposure session, the same participant will be exposed to FA for 6 hours. Receives: Other: Ozone; Other: FA |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Percent (%) predicted forced expiratory volume at one second (FEV1)
Change from baseline %predicted FEV1 post-O3 versus post-air exposure.
Measured: 6 hours post-O3 versus post-air exposure versus pre-exposure
Secondary outcomes (10)
Change in Percent (%) predicted forced vital capacity (FVC)
Change from baseline %predicted FVC post-O3 versus post-air exposure.
Measured: 6 hours post-O3 versus post-air exposure versus pre-exposure
Change in Percent eosinophils in induced sputum
% eosinophils in induced sputum (24 hrs post ozone - post air)
Measured: 24 hours post-O3 versus post-air exposure
Change in Percent (%) neutrophils in induced sputum
% neutrophils in induced sputum (24 hrs post ozone - post air)
Measured: 24 hours post-O3 versus post-air exposure
Change in Eosinophils per mg of induced sputum
Eosinophils per mg of induced sputum (24 hrs post ozone - post air)
Measured: 24 hours post-O3 versus post-air exposure
Change in neutrophils per mg of induced sputum
Neutrophils per mg of induced sputum (24 hrs post ozone - post air)
Measured: 24 hours post-O3 versus post-air exposure
Change in Cytokine concentrations in induced sputum picograms per milliliter (pg/mL)
Cytokine and via Mesoscale in induced sputum (pg/mL)
Measured: 24 hours post-O3 versus post-air exposure
Change in Cytokine concentrations in Nasal Epithelial Lining Fluid (NELF)
Cytokine via Mesoscale in NELF
Measured: 6 hours post-O3 versus post-air exposure
Change in Change in cytokine concentrations in Nasal Epithelial Lining Fluid (NELF)
Cytokine and via Mesoscale in NELF
Measured: 24 hours post-O3 versus post-air exposure
Change in Fraction of Exhaled Nitric Oxide (FENO) levels in parts per billion (PPB)
Changes in FeNO levels in ppb (6 hours post ozone - post air)
Measured: 6 post-O3 post-air exposure versus pre-exposure
Change in FENO levels in parts per billion (PPB)
Changes in FeNO levels in ppb (24 hours post ozone - post air)
Measured: 24 hours post-O3 versus post-air exposure
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Sep 2019
- Study start16 Dec 2019
- Primary completionAug 2027 (estimated)
- Study completionAug 2027 (estimated)
Why it stopped: Enrollment for this study was stopped due to Covid and will resume once it is determined acceptable to do inhalational challenges. rebuilding chambers after EPA was shut down.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Asthma, AllergicStudies of the same condition, open and under way.
- More trials run by University of North Carolina, Chapel HillThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 18 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of North Carolina, Chapel Hill
- Sponsor type
- University, hospital or other
- Collaborators
- Environmental Protection Agency (EPA), North Carolina State University
- Responsible party
- Sponsor
- Investigators
- David Peden, MD, Principal investigator, UNC SOM
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04109807
- Sponsor's protocol ID
- 18-2425
- Status last verified
- Dec 2025
- First submitted
- 23 Sep 2019
- Last updated
- 17 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Deidentified individual data that supports the results will be shared beginning 9 to 36 months following publication provided the investigator who proposes to use the data has approval from an Institutional Review Board (IRB), Independent Ethics Committee (IEC), or Research Ethics Board (REB), as applicable, and executes a data use/sharing agreement with UNC.
Study at a glance
From the registry record, last updated by the sponsor on 17 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Low Dose Ozone on Airway Inflammatory Responses in Adults With Asthma Asthma SNOZ
- ClinicalTrials.gov ID
- NCT04109807
- Acronym / sponsor ID
- 18-2425
- Conditions
- Asthma, Allergic
- Study type
- Interventional
- Recruitment status
- SuspendedReason stopped: Enrollment for this study was stopped due to Covid and will resume once it is determined acceptable to do inhalational challenges. rebuilding chambers after EPA was shut down.
- Enrolment
- 18 participants (estimated)
- Lead sponsor
- University of North Carolina, Chapel HillUniversity, hospital or other
- Collaborators
- Environmental Protection Agency (EPA), North Carolina State University
- Study start
- 16 Dec 2019 (actual)
- Primary completion
- Aug 2027 (estimated)
- Study completion
- Aug 2027 (estimated)
- First posted
- 30 Sep 2019 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
To determine if low levels of ozone (O3) encountered on a typical day in Chapel Hill will decrease spirometric values in mild asthmatics.
Detailed description
Short-term exposure to ambient air ozone has been recognized for decades to be adversely associated with impacts on the respiratory system. Indeed the evidence is such that the Environmental Protection Agency (EPA) has determined that there is a causal relationship, and even lowered the 8-hour exposure standard to 0.07 parts per million (ppm) in 2015. Controlled human exposure studies and epidemiological studies have consistently observed ozone-associated decrements in lung function and increased respiratory symptoms. Most controlled human exposure studies have been performed with high ozone concentrations. Additionally, epidemiologic studies have focused on populations engaged in outdoor activities (increasing ozone exposure through increased minute ventilation), or in cities such as Los Angeles or Mexico City where ambient ozone levels are especially high. Evidence has recently emerged that exposure to low ozone concentrations also produces adverse health effects, especially among susceptible groups including children with asthma.
The objective of this study is to examine if low level ozone exposure (compared to a clean air exposure), reflective of a typical metropolitan summer day, will cause decrements in lung function and measurable upper and lower airway inflammation in mild asthmatics (who are not on asthma controller medications) while performing typical daily activities.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| 6 hour Filtered Air (FA) followed by O3 exposure | Experimental | Other: Ozone, Other: FAFor the first exposure session, participants are exposed to filtered air (FA) for 6 hours. For the second exposure session, the same participant will be exposed to ozone at a concentration of 0.07ppm for 6 hours. |
| 6 hour O3 exposure followed by FA exposure | Experimental | Other: Ozone, Other: FAFor the first exposure session, a participant will be exposed to ozone at a concentration of 0.07ppm for 6 hours. For the second exposure session, the same participant will be exposed to FA for 6 hours. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- 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
Key exclusion criteria (12 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Ozoneozone exposure | Other | 6 hour Filtered Air (FA) followed by O3 exposure, 6 hour O3 exposure followed by FA exposure |
| FAFiltered air exposure | Other | 6 hour Filtered Air (FA) followed by O3 exposure, 6 hour O3 exposure followed by FA exposure |
Primary outcome
Change in Percent (%) predicted forced expiratory volume at one second (FEV1)
Time frame: 6 hours post-O3 versus post-air exposure versus pre-exposure
Change from baseline %predicted FEV1 post-O3 versus post-air exposure.
10 secondary outcomes
Change in Percent (%) predicted forced vital capacity (FVC)
Time frame: 6 hours post-O3 versus post-air exposure versus pre-exposure
Change in Percent eosinophils in induced sputum
Time frame: 24 hours post-O3 versus post-air exposure
Change in Percent (%) neutrophils in induced sputum
Time frame: 24 hours post-O3 versus post-air exposure
Change in Eosinophils per mg of induced sputum
Time frame: 24 hours post-O3 versus post-air exposure
Change in neutrophils per mg of induced sputum
Time frame: 24 hours post-O3 versus post-air exposure
Change in Cytokine concentrations in induced sputum picograms per milliliter (pg/mL)
Time frame: 24 hours post-O3 versus post-air exposure
Change in Cytokine concentrations in Nasal Epithelial Lining Fluid (NELF)
Time frame: 6 hours post-O3 versus post-air exposure
Change in Change in cytokine concentrations in Nasal Epithelial Lining Fluid (NELF)
Time frame: 24 hours post-O3 versus post-air exposure
Change in Fraction of Exhaled Nitric Oxide (FENO) levels in parts per billion (PPB)
Time frame: 6 post-O3 post-air exposure versus pre-exposure
Change in FENO levels in parts per billion (PPB)
Time frame: 24 hours post-O3 versus post-air exposure
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Dec 2025.
- Individual participant dataSharing planned: Yes. Deidentified individual data that supports the results will be shared beginning 9 to 36 months following publication provided the investigator who proposes to use the data has approval from an Institutional Review Board (IRB), Independent Ethics Committee (IEC), or Research Ethics Board (REB), as applicable, and executes a data use/sharing agreement with UNC.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
David Peden, MD principal investigator
UNC SOM
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Ozone and FA in people with Asthma, Allergic, run by University of North Carolina, Chapel Hill at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: paused, as of the sponsor's last update on 17 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Percent (%) predicted forced expiratory volume at one second (FEV1) (time frame: 6 hours post-O3 versus post-air exposure versus pre-exposure). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Dec 2025.