Health Effects of Wood Smoke and Traffic-Related Air Pollution Exposures: a Necessary Comparison
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Filtered Air (FA), Wood Smoke (WS), Diesel Exhaust (DE), Diesel Exhaust and Wood Smoke (DEWS).
- Who it may be relevant to
- Registry conditions: Healthy Individuals, Allergic Rhinitis. Basic parameters: 19 years — 40 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Canada
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Overview
Accumulating evidence demonstrates that breathing air pollutants leads to devastating increases in sickness and death worldwide over time. However, there is little data comparing the effects of different types of air pollution on health. In Canada, traffic-related air pollution and wood smoke (wildfires and wood burning for heating) are very common air pollutants. This study aims to safely complete a controlled human exposure study to test how these air pollution types acutely affect health.
Detailed description
Healthy adult participants (total 48; 24 of each biological sex assigned at birth) will breathe filtered air (control), wood smoke (WS), diesel exhaust (DE), and DE plus WS (DEWS) each for 2 hours, with 4 weeks between each exposure (washout). Before and after each exposure, participants will answer questions, perform breathing tests, and give blood samples. At 24 hours after each exposure, participants will undergo a bronchoscopy to collect samples from their lungs.
The study will look at what (if any) are the differences between breathing in fresh air (filtered air - FA) or polluted air containing either wood smoke (WS), diesel exhaust (DE) or diesel exhaust plus wood smoke (DEWS). The research team will use wood smoke generated from pine wood, since it is one of the most common types of wood found in Western Canadian forests where forest fires occur.
The investigators will evaluate multiple endpoints as detailed in the Outcome Measures section. For each applicable endpoint, the investigators will evaluate stratified analyses and effect modification by biological sex, participant age, gene score, and microbiomes.
Interventions
- Other Filtered Air (FA)
Exposure to HEPA filtered air, as a control - Other Wood Smoke (WS)
Wood smoke (WS) standardized to 300µg/m³ of particulate matter with a diameter of 2.5 micrometers or less (PM2.5). - Other Diesel Exhaust (DE)
Diesel exhaust (DE) standardized to 300µg/m³ of particulate matter with a diameter of 2.5 micrometers or less (PM2.5). - Other Diesel Exhaust and Wood Smoke (DEWS)
Combined diesel exhaust and wood smoke standardized to 300µg/m³ of particulate matter with a diameter of 2.5 micrometers or less (PM2.5).
Primary outcome measures
- Woodsmoke (WS) and/or diesel exhaust (DE) exposure effects on inflammatory cells in the lungs. [Time frame: Comparison of the different arms (over the span of ~5 months).]
- Within-individual change in lung transcriptomic biomarkers of inflammation following exposure to woodsmoke and/or diesel exhaust. [Time frame: Through study completion, anticipated ~5 months.]
- Within-individual change in lung protein biomarkers of inflammation following exposure to woodsmoke and/or diesel exhaust. [Time frame: Through study completion, anticipated ~5 months.]
- Within-individual change in circulating transcriptomic biomarkers of inflammation following exposure to woodsmoke and/or diesel exhaust. [Time frame: Through study completion, anticipated ~5 months.]
- Within-individual change in circulating protein biomarkers of inflammation following exposure to woodsmoke and/or diesel exhaust. [Time frame: Through study completion, anticipated ~5 months.]
- Within-individual change in airway resistance following exposures to woodsmoke and/or diesel exhaust. [Time frame: Through study completion, anticipated ~5 months.]
Secondary outcome measures (5)
- Woodsmoke (WS) and/or diesel exhaust (DE) exposure effects on inflammatory cells in the nose. [Time frame: Comparison of the different arms (over the span of ~5 months).]
- Within-individual changes in exhaled nitric oxide following woodsmoke (WS) and/or diesel exhaust (DE) exposures. [Time frame: Comparison of the different arms (over the span of ~5 months).]
- Woodsmoke (WS) and/or diesel exhaust (DE) exposure effects on symptoms, stress and perceptions. [Time frame: Comparison of the different arms (over the span of ~5 months).]
- Woodsmoke (WS) and/or diesel exhaust (DE) exposure effects on lung function. [Time frame: Comparison of the different arms (over the span of ~5 months).]
- Woodsmoke (WS) and/or diesel exhaust (DE) exposure effects on nasal resistance. [Time frame: Comparison of the different arms (over the span of ~5 months).]
Eligibility criteria
Inclusion criteria
- Age 19-40
- Healthy, with no history of respiratory disease
- Lifetime non-smoker and non-vaper.
Exclusion criteria
- Pregnant, planning to become pregnant, or breastfeeding during the study period (confirmed through pregnancy tests at each visit if applicable)
- Frequent WS or DE exposures (e.g. home fireplace used for heating/cooking, or employment in transportation, mining, or as a firefighter).
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Allocation
- Randomized
- Model
- Crossover
- Masking
- Triple blind
- Primary purpose
- Basic science
Study locations
Canada · 1 center
- University of British Columbia — Vancouver
Identifiers
NCT: NCT06749093 · H24-00776