This study will examine how breathing wildfire-related air pollution (WRAP) for one hour affects healthy adults. The main question the study will answer if the effect of WRAP exposure on p-tau, a blood marker of cognitive decline. The changes in p-tau concentrations after exposure to WRAP will be compared to the changes in p-tau after exposure to clean air.

Participants will:

• Have 2 study visits - one visit with exposure to clean air and one visit with exposure to simulated wildfire smoke
• Have blood drawn before and after each exposure
• Complete cognitive tests and memory tasks before and after each exposure

• Exposures will take place in a booth-like exposure chamber (1 x 0.7 x 1.8 m) with glass upper panels. One person will be exposed at a time.
• Simulated wildfire smoke will be generated by burning pine wood at a temperature that mimics smoldering combustion. The levels of smoke introduced into the exposure chamber are similar to those found during outdoor bonfires and wildfire events. The levels of particulate matter (PM) will be closely monitored during the exposure.

Inclusion Criteria:

• Healthy
• Non smoker
• Weight at least 110 pounds
• Between ages 18 and 40 years old

Exclusion Criteria:

• Claustrophobia or not comfortable in enclosed spaces.
• Colorblindness.
• Inability to hear verbal instructions.
• Cardiovascular disease which, in the opinion of the investigator, would elevate the participant's risk of adverse effects to WRAP exposure. This includes a history of stroke.
• Diabetes requiring the use of insulin.
• Pregnancy (A pregnancy test will be provided to you).
• Current asthma (an asthma attack within the past five years).
• History of childhood asthma.
• Medications which may affect cognition such as beta-blockers and CNS depressants.
• Respiratory symptoms in the previous 4 weeks (cough, wheezing, shortness of breath, etc.) which, in the opinion of the investigator, would elevate the participant's risk of adverse effects to WRAP exposure.
• Use of sedating cold/allergy medications in the previous week.
• Use of marijuana in the previous week.
• Consumption of alcohol in the previous 24 hours.
• Kidney or liver disease.
• Thyroid disease.
• High blood pressure.
• Cancer.
• Parkinson's disease.
• Pacemaker.
• Hay fever.

There is no plan to make individual participant data available to other researchers.

outside laboratories processing blood samples