Increases in air pollution are associated with increases in deaths from cardiovascular disease, but the investigators know little about how ozone air pollution affects the cardiovascular system. The investigators proposed study will determine the effects of ozone on blood vessel and heart function that could worsen illness in people with underlying heart disease. This will be accomplished by studying healthy volunteers who inhale ozone in a controlled clinical study, and also by studying their exposure to ozone and other pollutants during their normal daily activities. The investigators will study volunteers who may be at increased risk for the effects of ozone because of genetic susceptibility. Understanding the effects of ozone on the heart and circulation can help establish appropriate air pollution standards, and provide strategies to protect the most susceptible people.

Inclusion Criteria:

• Healthy,
• Never-smokers with normal spirometry based on the standards published by Morris and co-workers (Morris et al. 1971), and
• A normal electrocardiogram. -

Exclusion Criteria:

• Any history of habitual smoking.
• Marijuana smoking within the past 5 years.
• Pregnancy.
• Any history of significant organ impairment, chronic respiratory disease, ischemic heart disease, active psychiatric disorder or current drug or alcohol abuse.
• Occupation involving regular, heavy dust or particle exposure, such as welding, mining, foundry work.
• FEV1 < 75% of predicted at baseline screening.
• Subjects with atopy or allergic rhinitis will not be excluded as long as they do not require regular treatment with antihistamines or systemic steroids.
• Subjects on certain prescription medications such as prednisone or statins will be excluded. Use of other medications will be considered on an individual basis. Subjects will not be asked to discontinue prescription medications for the purposes of this study.
• Hypertension (blood pressure higher than 140/90 mmHg or on antihypertensive medication).
• Subject lives outside the Rochester metropolitan area.