Patient description: A 39-year-old man came to the clinic with cough and shortness of breath that was not relieved by his inhaler. He had these symptoms for 5 days during the past 2 weeks. He doubled his oral corticosteroids in the past week. He is a chef with a history of asthma for 3 years, suffering from frequent cough, wheezing, and shortness of breath and chest tightness. The symptoms become more bothersome within 1-2 hours of starting work every day and worsen throughout the work week. His symptoms improve within 1-2 hours outside the workplace. Spirometry was performed revealing a forced expiratory volume in the first second (FEV1) of 63% of the predicted. His past medical history is significant for seasonal allergic rhinitis in the summer. He doesn't smoke or use illicit drugs. His family history is significant for asthma in his father and sister. He currently uses inhaled corticosteroid (ICS) and fluticasone 500 mcg/salmeterol 50 mcg, one puff twice daily.

Clinical trial eligibility criteria: eligible ages (years): 18.0-55.0,  Exposure to Pollution Inhalation of Ozone Healthy Individuals Specific 1. Physical exams will be performed by study physicians during the screening visit (IRB approved EPA protocol 95-EPA-66). 2. Normal lung function (pre or post albuterol), defined by Knudson 1976/1984 as FVC of > 75 % of that predicted for gender, ethnicity, age and height FEV1 of > 75 % of that predicted for gender, ethnicity, age and height FEV1/FVC ratio of > 75 % of predicted values. 3. Oxygen saturation of > 96 %. 4. Ability to tolerate intervals of moderate exercise Mild to Moderate Asthmatics 1. Physical exams will be performed by study physicians during the screening visit (IRB approved EPA protocol 95-EPA-66) where diagnosis will be judged by EPA physicians. 2. Mild/Moderate asthmatics as defined by NHLBI guidelines. 3. Positive history of asthma (wheezing, chest tightness, and reversible airway obstruction); 4. Baseline FEV1/FVC ≥ 60%; 5. Oxygen saturation of ≥ 94% 6. Ability to tolerate moderate exercise  Healthy Individuals 1. A history of chronic illnesses such as diabetes, rheumatological diseases, immunodeficiency state, known clinically significant cardiac disease (including myocardial infarction, congestive heart failure and angina), chronic respiratory diseases such as chronic obstructive pulmonary disease, and lung cancer. 2. If the subject is pregnant, attempting to become pregnant or breastfeeding. 3. Allergy to any medications which may be used or prescribed in the course of this study. 4. Subjects currently taking mega doses of vitamins and supplements, homeopathic/naturopathic medicines or medications which may impact the results of the PM and/or ozone challenge or interfere with any other medications potentially used in the study (to systemic steroids and beta blockers). Subjects must refrain from all over the counter anti-inflammatory agents including those for allergies, and naproxen, and anti-oxidants for a period of one week prior to exposure. Medications not specifically mentioned here may be reviewed by the investigators prior to a subject's in the study. 5. Smoking history within 2 years of the study. 6. Use of inhaled steroids, cromolyn, or leukotriene inhibitors (Montelukast, Zafirkulast, etc) initiated within the past month (except for use of cromolyn exclusively prior to exercise). Patients must be on a stable regimen of therapy. 7. Untreated hypertension (> 150 systolic, > 90 diastolic) 8. Dementia. 9. Unspecified illnesses, which in the judgment of the investigator might increase the risk associated with PM inhalation challenge or exercise, will be a basis for exclusion. 10. History of skin allergy to tape or electrodes. 11. Subjects who do not understand or speak English 12. Subjects who are unable to perform moderate exercise for bronchoscopy: 1. Any food or fluids after midnight prior to bronchoscopy 2. FEV1/FVC ratio less than 60% predicted on AM of bronchoscopy. 3. Regular use of aspirin or other nonsteroidal anti-inflammatory drugs (which inhibit platelet function). Mild to Moderate Asthmatics Use of oral steroid therapy within the past month 2. Physician directed emergency treatment for asthma exacerbation within the preceding 6 months. 3. Abnormal EKG that precludes evaluating heart rate variability. 4. Aside from mild/moderate asthma, a history of chronic illnesses such as diabetes, rheumatological diseases, immunodeficiency state, known clinically significant cardiac disease (including myocardial infarction, congestive heart failure and angina), chronic respiratory diseases such as chronic obstructive pulmonary disease or severe asthma, and cancer (possible exception for history of nonmelanoma skin cancer). 5. If the subject is pregnant, attempting to become pregnant or breastfeeding. 6. Allergy to any medications which may be used or prescribed in the course of this study 7. Subjects currently taking mega doses of vitamins and supplements, homeopathic/naturopathic medicines or medications which may impact the results of the PM challenge or interfere with any other medications potentially used in the study (to systemic steroids and beta blockers). Subjects must refrain from all over the counter anti-inflammatory agents including those for allergies, and naproxen, and anti-oxidants for a period of one week prior to exposure. Medications not specifically mentioned here may be reviewed by the investigators prior to a subject's in the study. 8. Dosing level of an inhaled steroid must be consistent with mild asthma as outlined by the NHLBI NAEPP guidelines. Regular use of oral corticosteroids, or use of inhaled steroid at doses typically used for severe asthma, will result in of that individual from the protocol. 9. Severe asthmatics as defined by: nighttime symptoms of cough or wheeze greater than 1 time per week at baseline, daily exacerbation of asthma or requirement for albuterol due to asthma symptoms (cough, wheeze, chest tightness, but not to prophylactic use of albuterol prior to exercise), more than mild interference with normal activity, any episode of physician directed emergency treatment for asthma requiring oral corticosteroid therapy within the past twelve months. 10. Smoking history within 2 years of study. 11. Use of inhaled steroids, cromolyn, or leukotriene inhibitors (Montelukast, Zafirkulast, etc) initiated within the past month (except for use of cromolyn exclusively prior to exercise). Patients must be on a stable regimen of therapy. 12. History of skin allergy to tape or electrodes. 13. History of respiratory diseases other than allergic rhinitis and asthma 14. Untreated hypertension (> 150 systolic, > 90 diastolic) 15. Dementia. 16. Unspecified illnesses, which in the judgment of the investigator might increase the risk associated with PM inhalation challenge or exercise, will be a basis for exclusion. 17. Subjects who do not understand or speak English 18. Subjects who are unable to perform moderate exercise for bronchoscopy: 1. Any food or fluids after midnight prior to bronchoscopy 2. FEV1/FVC ratio less than 60% predicted on AM of bronchoscopy. 3. Regular use of aspirin or other nonsteroidal anti-inflammatory drugs (which inhibit platelet function)