Pollution, Isotonic Nasal Wash, NSAID Evaluation

The goal of this clinical exposure study is to investigate the inflammatory and airway responses to controlled wood smoke exposure, a model for wildfire-related air pollution, and how these responses change with Otrivin Natural Saline Nasal Spray and Advil Extra Strength Liqui-Gels 400mg, used within their approved indications for clearing the nasal passages and the relief of pain and inflammation, respectively, in healthy adult participants. The main questions it aims to answer are: * How does controlled wood smoke exposure affect airway inflammation, and how does this response change with Advil use? * How do the nasal effects of wood smoke exposure change with Otrivin Natural saline nasal spray use? Researchers will compare the effects of wood smoke exposure and these interventions versus filtered air and placebo using a crossover design, where each participant will be compared to themselves. Participants will complete questionnaires, breathing tests, nasal sampling and blood collections before and after each exposure.

Inclusion Criteria: 1. Healthy adults aged 19-65 years, inclusive, with no active respiratory or other medical conditions that may affect study outcomes; 2. no use of tobacco, vaping devices, or cannabis within the previous 6 months and a lifetime smoking history of less than 0.5 pack-years; 3. no known hypersensitivity or allergy to Advil (ibuprofen); and 4. female participants must be postmenopausal, surgically sterile, or using medically accepted contraception, and must not be pregnant or nursing during the study. Exclusion Criteria: 1. Body mass index (BMI) ≥35 kg/m²; 2. unable to withhold antihistamines, leukotriene antagonists, immunotherapy, or corticosteroid medications for the duration of the study; 3. active medical conditions that may affect respiratory or inflammatory outcomes or increase risk during controlled wood smoke exposure, including asthma, allergic rhinitis, chronic obstructive pulmonary disease (COPD), active infections, diabetes, long COVID, tuberculosis, or heart conditions; 4. planned hospitalization(s) or blood donation during the study period; and (e) high background exposure to air pollution or dust through residence, leisure activities, or occupation; 5. Are taking other NSAIDs at the time of the active portion of the study; 6. high background exposure to air pollution or dust through residence, leisure activities, or occupation; and 7. current participation in another research study involving a study drug or controlled exposure, or participation in one within 4-weeks before screening.