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

University of British Columbia

Status: Not yet enrolling

Conditions: Allergic Rhinitis; Healthy Individuals

Treatments: Other: Diesel Exhaust (DE); Other: Wood Smoke (WS); Other: Filtered Air (FA); Other: Diesel Exhaust and Wood Smoke (DEWS)

Study type: Interventional

Funder types: Other

Identifiers

NCT06749093

H24-00776

Details and patient eligibility

About

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.

Full 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.

Enrollment: 48 estimated patients

Sex: All

Ages: 19 to 40 years old

Volunteers: Accepts Healthy Volunteers

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).

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Triple Blind

---

48 participants in 4 patient groups, including a placebo group

Filtered Air (FA)

Placebo Comparator group

Description:

Participants will be exposed to 2 hours of high-efficiency particulate air (HEPA) filtered air (FA).

Treatment:

Other: Filtered Air (FA)

Wood Smoke (WS)

Active Comparator group

Description:

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).

Treatment:

Other: Wood Smoke (WS)

Diesel Exhaust (DE)

Active Comparator group

Description:

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).

Treatment:

Other: Diesel Exhaust (DE)

Diesel Exhaust and Wood Smoke (DEWS)

Active Comparator group

Description:

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).

Treatment:

Other: Diesel Exhaust and Wood Smoke (DEWS)