Health Effects of Wood Smoke and Traffic-Related Air Pollution Exposures: a Necessary Comparison (WADE)

December 17, 2024 updated by: Christopher Carlsten, University of British Columbia
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.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

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.

Study Type

Interventional

Enrollment (Estimated)

48

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

  • Name: Parteek Johal
  • Phone Number: 604-875-5132

Study Locations

  • Canada
    • British Columbia
      • Vancouver, British Columbia, Canada, V5Z 1M9
        • University of British Columbia
        • Contact:
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

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).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Filtered Air (FA)
Participants will be exposed to 2 hours of high-efficiency particulate air (HEPA) filtered air (FA).
Other: Filtered Air (FA)
Exposure to HEPA filtered air, as a control
Active Comparator: Wood Smoke (WS)
Participants will be exposed to 2 hours of controlled wood smoke (WS) standardized to 300ug/m^3 of particulate matter with a diameter of 2.5 micrometers or less (PM2.5).
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).
Active Comparator: Diesel Exhaust (DE)
Participants will be exposed to 2 hours of controlled diesel exhaust (DE) as a model of traffic-related air pollution (TRAP) standardized to 300ug/m^3 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 Names:
  • Traffic-Related Air Pollution
Active Comparator: Diesel Exhaust and Wood Smoke (DEWS)
Participants will be exposed to 2 hours of combined controlled diesel exhaust (DE) and wood smoke (DEWS) standardized to 300ug/m^3 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).
Other Names:
  • Air Pollution

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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).
Differentially count lung cells.
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 biomarkers of inflammation (serum amyloid A (SAA), c-reactive protein (CRP), chemokine ligand 18 (CCL18), and fibrinogen) in RNA.
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 lung biomarkers of inflammation (serum amyloid A (SAA), c-reactive protein (CRP), chemokine ligand 18 (CCL18), and fibrinogen) in protein.
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 biomarkers of inflammation (CX3CL1, CCL23, CXCL8, SAA, MMP9, MMP12, APOB, APOM, SOD1, NQO1, HMOX1, CAT, CYP1B1, CYP1A2, NFE2L2 and AHRR) in RNA.
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 circulating protein biomarkers of inflammation (CX3CL1, CCL23, CXCL8, SAA, MMP9, MMP12, APOB, APOM, SOD1, NQO1, HMOX1, CAT, CYP1B1, CYP1A2, NFE2L2 and AHRR).
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.
Within-individual change in airway resistance, as measured by impulse oscillometry (resonant frequency (Fres) and peripheral airway resistance (R5-R20)) across exposures to woodsmoke and/or diesel exhaust relative to filtered air.
Through study completion, anticipated ~5 months.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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).
Differentially count nasal cells.
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).
Measurement of fractional exhaled nitric oxide (FeNO) in parts per billion (ppb).
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).
Visual analog score (0-100) questionnaire will be completed, with a higher score indicating a worse outcome.
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).
Lung function as evaluated by spirometry (e.g. FEV1).
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).
Measurement of peak nasal inspiratory flow (PNIF).
Comparison of the different arms (over the span of ~5 months).

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of British Columbia

Investigators

  • Principal Investigator: Chris Carlsten, MD, University of British Columbia

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

July 1, 2025

Primary Completion (Estimated)

December 31, 2026

Study Completion (Estimated)

December 31, 2029

Study Registration Dates

First Submitted

October 23, 2024

First Submitted That Met QC Criteria

December 17, 2024

First Posted (Actual)

March 25, 2025

Study Record Updates

Last Update Posted (Actual)

March 25, 2025

Last Update Submitted That Met QC Criteria

December 17, 2024

Last Verified

December 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • H24-00776

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Participant data that underlie the results reported in accepted articles for publications, after deidentification (text, tables, figures, and appendices).

IPD Sharing Time Frame

Immediately following publication. No end date.

IPD Sharing Access Criteria

Researchers who provide a methodologically sound proposal to the PI to complement the approved study aims.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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