Lungs on Fire: Wildfire Smoke, Incident Diseases, Susceptible Populations, and Community Values in Canada

NCT07536178 | Not Yet Recruiting

• 3 other identifiers: H25-02833LG3-193738RFA 24-2
• Study Type: interventional
• Target: 24
• Locations: 0 countries
• Sites: N/A

Brief Summary

Wildfire smoke (WFS) is the leading climate-related risk in Canada and the main source of harmful air pollution. While short-term breathing problems caused by smoke are well known, there is limited knowledge on how repeated exposure contributes to long-term lung disease. This study is a controlled human exposure to varying concentrations of WFS in a safe setting. By comparing the effects of different concentrations, this research will improve understanding of health impacts, identify who may be most vulnerable to exposures, and explore biological changes that could lead to chronic illness.

Conditions

Asthma; Chronic Obstructive Pulmonary Disease (COPD); Lung Cancer

Keywords

Wildfire Smoke; Chronic Lung Disease; Air Pollution; Controlled Human Exposure Study; Environmental Health; PM2.5

Outcome Measures

Primary Outcomes (2)

• Effects of PM2.5 exposures and concentration on exhaled nitric oxide.

  Measurement of fractional exhaled nitric oxide (FeNO).

  Comparison of the different arms over the span of 4 months.

• Effects of PM2.5 exposures and concentration on Cambridge Neuropsychological Test Automated Battery (CANTAB)

  Computational testing using CANTAB to determine e.g. 5-choice reaction time and percent correct all delays.

  Comparison of the different arms over the span of 4 months.

Secondary Outcomes (10)

• Effects of PM2.5 exposures and concentration on sputum cell numbers.

  Comparison of the different arms over the span of 4 months.

• Effects of PM2.5 exposures and concentration on brain functional connectivity.

  Comparison of the different arms over the span of 4 months.

• Effects of PM2.5 exposures and concentration on oxidative stress.

  Comparison of the different arms over the span of 4 months.

• Effects of PM2.5 exposures and concentration on lung inflammatory markers.

  Comparison of the different arms over the span of 4 months.

• Effects of PM2.5 exposures and concentration on lung imaging.

  Comparison of the different arms over the span of 4 months.

Other Outcomes (3)

• Effects of PM2.5 exposures and concentration on breath volatile organic compounds.

  Comparison of the different arms over the span of 4 months.

• Effects of PM2.5 exposures and concentration on airway microbial taxon abundance.

  Comparison of the different arms over the span of 4 months.

• Effects of PM2.5 exposures and concentration on symptoms.

  Comparison of the different arms over the span of 4 months.

Study Arms (3)

Arm A) Three repeated exposures to a low air pollution concentration

EXPERIMENTAL

Three consecutive days with a 2-hour woodsmoke exposure at 35 µg/m3 of PM2.5 each day.

Other: Woodsmoke (Lodgepole Pine) exposure

Arm B) Three repeated exposures to a moderate air pollution concentration

EXPERIMENTAL

Three consecutive days with a 2-hour woodsmoke exposure at 105 µg/m3 of PM2.5 each day.

Other: Woodsmoke (Lodgepole Pine) exposure

Arm C) Single exposure to a higher air pollution concentration

EXPERIMENTAL

Two consecutive days of 2-hour filtered air exposures, followed by 1 day with a 2-hour woodsmoke exposure at 315 µg/m3 of PM2.5.

Other: Woodsmoke (Lodgepole Pine) exposure; Other: Filtered air exposure

Interventions

Woodsmoke (Lodgepole Pine) exposure OTHER

Woodsmoke will be freshly generated using a furnace tube burning dried, ground lodgepole pine (Pinus contorta) to achieve the nominal PM2.5 (particulate matter with an aerodynamic diameter of less than or equal to 2.5 micrometres) concentrations specified for each study arm.

Arm A) Three repeated exposures to a low air pollution concentration; Arm B) Three repeated exposures to a moderate air pollution concentration; Arm C) Single exposure to a higher air pollution concentration

Filtered air exposure OTHER

Exposures to HEPA filtered air, as a control.

Arm C) Single exposure to a higher air pollution concentration

Eligibility Criteria

• Age: 19 Years - 80 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Healthy Adults between the ages of 19 to 80 (12 of each biological sex assigned at birth).

You may not qualify if:

• Current smoker (within six months before screening; potential to confound exposure effects).
• History or current diagnosis of any respiratory conditions (including, but not limited to asthma or chronic obstructive pulmonary disease (COPD), asthma/COPD overlap) or other medical conditions that the study physician determines may impact participant safety.
• Any comorbidities or other concerns identified by the study physician which may impact study participation.
• For participants of child-bearing potential: Current pregnancy, or plans to become pregnant during study enrolment.

Sponsors & Collaborators

• University of British Columbia: lead

MeSH Terms

Conditions

Asthma; Pulmonary Disease, Chronic Obstructive; Lung Neoplasms

Condition Hierarchy (Ancestors)

Bronchial Diseases; Respiratory Tract Diseases; Lung Diseases, Obstructive; Lung Diseases; Respiratory Hypersensitivity; Hypersensitivity, Immediate; Hypersensitivity; Immune System Diseases; Chronic Disease; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Respiratory Tract Neoplasms; Thoracic Neoplasms; Neoplasms by Site; Neoplasms

Study Officials

• Chris Carlsten, MD, MPH

  University of British Columbia

  PRINCIPAL INVESTIGATOR

Central Study Contacts

PJ (Parteek) Johal, BCS

CONTACT

604-875-5132; p.johal@ubc.ca

Agnes Yuen, BSc

CONTACT

604-875-4111; agnes.yuen@ubc.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Blinding of exposures will be performed by the air pollution exposure laboratory (APEL) engineer. Participant coordination and testing will be conducted by a researcher without knowledge of which study arm a given participant is undergoing. The study investigator will be blinded to which study arm participants are undergoing. All assays will be performed by personnel who do not know the exposure conditions of individual samples.
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: Participants will act as their own controls, as they will complete all three study arms: Arm A) Three consecutive days with a 2-hour woodsmoke exposure at 35 µg/m3 of PM2.5 each day. Arm B) Three consecutive days with a 2-hour woodsmoke exposure at 105 µg/m3 of PM2.5 each day. Arm C) Two consecutive days of 2-hour filtered air exposures, followed by 1 day with a 2-hour woodsmoke exposure at 315 µg/m3 of PM2.5. The study arms will be separated by 4-week washout periods.

Study Record Dates

• First Submitted: April 3, 2026
• First Posted: April 17, 2026
• Study Start: April 1, 2026
• Primary Completion (Estimated): August 31, 2029
• Study Completion (Estimated): August 31, 2030
• Last Updated: April 17, 2026

Record last verified: 2026-04