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): 19.0-92.0,  COPD Men of ages 18 and 30 (Dates of birth 1973-1985) or 55-92 years old (Dates of birth 1911-1948). 2. Must not currently be a cigarette smoker. If an ex-smoker then has not smoked for at least 10 years and consumption were no more than 10 pack years. 3. Agrees to volunteers for the study and willing to sign the informed consent form. 4. There were negative/normal screening tests for the following 1. Responses to the questionnaire deny current and prior respiratory diseases (including asthma, emphysema, chronic bronchitis, sinusitis and interstitial lung d9sase) and no current respiratory complaints (e.g., cough, wheezing, shortness of breath, allergic rhinitis, and sinusitis). Subjects must not be taking any cardiac medications or admit to a physician-diagnosed cardiac condition. 2. "Normal" spirometry measurements with FEV1 & FVC greater than 75% predicted and FEV1/FVC more than 69% 3. Impedance oscillometry were within normal limits 4. "Negative" physical examination of the chest with absence of wheezing and crackles on auscultation of the chest. 5. Exhaled nitric oxide concentration is less than 35 ppb for younger and less than 65 ppb for older groups  men of: ages < 18, 31-54 and >92 years old; 2. current cigarette smokers or exsmokers who have smoked within the past 10 years and/or smoked more than 10 pack/years; 3. refusal to volunteer for the study and not willing to sign the informed consent form; 4. screening test not considered "normal" by physician/PI and showing one or more of the following: 1. one or more positive response to the questionnaire(e.g., current or past respiratory diseases including asthma, emphysema, chronic bronchitis, sinusitis and interstitial lung disease; and/or; current respiratory complaints (e.g., cough, wheezing, shortness of breath, allergic rhinitis, and sinusitis) and/or; admitting to taking a cardiac medication and/or; or physician-diagnosed cardiac condition (e.g., coronary heart disease, angina, myocardial infarction, valvular heart disease, cardiomyopathy, etc.); 2. Abnormal spirometry measurements (FEV1 &/or FVC <75% predicted and FEV1/FVC <69%); 3. "Positive" physical examination (performed by Physician/PI) with presence of wheezing and/or crackles on auscultation of the chest; 4. Impulse oscillometry >4 times normal limits; 5. Exhaled nitric oxide of >35ppb for younger group and >65 ppb for older group. -