Patient description: The patient is a 15-year-old boy with asthma diagnosed a year ago. He presents with shortness of breath, chest tightening and cough. According to his mother, he didn't respond to the usual corticosteroid inhaler. He was admitted to the emergency department with diagnosis of severe asthma exacerbation. He is a candidate for general corticosteroid therapy. Spirometry revealed a forced expiratory volume in the first second (FEV1) of 60% of the predicted. His past medical history is non-significant. His family history is significant for asthma in his mother and his uncle. He used to be treated with combination of inhaled corticosteroids and Zafirlukast.

Clinical trial eligibility criteria: eligible ages (years): 18.0-50.0,  Healthy Subjects must be 18-50 years of age to be eligible for study participation 2. Subjects must be willing to and able to provide informed consent and participate in all study procedures 3. Normal lung function, defined as (Knudson 1976/1984 predicted set) Forced Vital Capacity (FVC) of > 80% of that predicted for gender, ethnicity, age and height Forced Expiratory Volume in the first second (FEV1) of > 80% of that predicted for gender, ethnicity, age and height FEV1/FVC ratio of > 0.75 of that predicted for gender, ethnicity, age and height 4. Oxygen saturation of > 94% Normal blood pressure (Systolic between 150 Diastolic between 90-60 mm Hg) 5. Symptom Score (defined in section "f") no greater than 6 (out of a possible 24) for total symptom score with a value no greater than 2 for any one score  Any chronic medical condition considered by the PI as a contraindication to the exposure study including significant cardiovascular disease, diabetes requiring medication, chronic renal disease, or chronic thyroid disease. 2. Physician directed emergency treatment for asthma exacerbation within the preceding 3 months. 3. Moderate or Severe asthma 4. Exacerbation of asthma more than 2x/week that would be characteristic of a person of moderate or severe persistent asthma as outlined in the current NHLBI guidelines for diagnosis and management of asthma. 5. Nighttime symptoms of cough or wheeze greater than 1x/week at baseline (not during a clearly recognized viral induced asthma exacerbation) which would be characteristic of a person of moderate or severe persistent asthma as outlined in the current NHLBI guidelines for diagnosis and management of asthma 6. Daily requirement for albuterol due to asthma symptoms (cough, wheeze, chest tightness) which would be characteristic of a person of moderate or severe persistent asthma as outlined in the current NHLBI guidelines for diagnosis and management of asthma. (Not to prophylactic use of albuterol prior to exercise). 7. History of intubation for asthma 8. Daily use of NSAIDs, or inability to withhold NSAIDs for 4 days prior to dosing. 9. Use of medications that may impact the results of the study to but not limited to, systemic corticosteroids, beta blockers. 10. Cigarette smoking > 1 pack per month. 11. BMI>35. 12. Pregnant or breast feeding women will not be included. 13. Subjects who are employed within the past 6 months in an occupation with high risk for endotoxin exposure, such as grain storage sites or swine containment. 14. Subjects will be deferred after any acute, non-chronic medical condition requiring treatment, such as bronchitis, pneumonia or febrile illness for a minimum of 4 weeks after complete resolution of symptoms. -