The Role of Macrophage Activation in Lung Injury Following Ozone Exposure

Exclusion Criteria: * Cardiovascular disease * Respiratory disease * Recent (within 4 weeks) respiratory or COVID-19 symptoms * Diabetes * Pregnancy * HIV Infection * History of smoking within the past 5 years. * Orthopedic or rheumatologic conditions which would interfere with cycle use * Inability to produce a sputum plug at screening * Daily use of antioxidant supplements, excluding those in a multivitamin. These supplements include Vitamin C or E, selenium, beta-carotene, lycopene, lutein, zeaxanthin and ginkgo biloba. Supplements taken less frequently but at least once a week will be reviewed by the principal investigator for eligibility determination.