The primary objective of this study is to better understand the correlation between the different types of inflammation and infection of the airways during exacerbations. Secondary objectives are to understand the susceptibility to infections and methods to assess the inflammatory response and airway responsiveness during infections. To attain these objectives we will compare the total cells, percentage of neutrophils, percentage of eosinophils in sputum and nasal secretions, sputum fibrinogen, sputum total lactate dehydrogenase, microbial load in sputum and nasal secretions, exhaled nitric oxide, p H of exhaled breath condensate, serum procalcitonin, intensity of urinary 3-bromotyrosine, 3-chlorotyrosine, 3, 5- dibromotyrosine and dityrosine, symptom score, FEV1 and Mannitol PD15 at different time points during an exacerbation, compare the activity of toll like receptors (2,4,7,9) and natural killer T cells during the stable phase of disease with the number of infective exacerbations during the course of one year and test the feasibility of mannitol challenge testing as a method to induce sputum and measure airway hyperresponsiveness. Our approach will be to identify 100 patients with variable (asthma) or chronic airflow limitation (COPD), reporting within 2 to 5 days of the onset of an exacerbation during the course of one year. The clinical, physiological, inflammatory, microbiological and immunological parameters will be assessed on the day of presentation (day 0), day 7, 14 and at 6 to 8 weeks. The information collected at 6 to 8 weeks will serve as baseline data, if the patient is clinically stable at this point in time. If the patient has a next exacerbation during the course of the trial, then the same procedure will be followed.