Human Biological Responses to Low Level Ozone

Air pollutants including ozone have been implicated in affecting health outcomes. In
particular, high level ozone exposure has been shown to affect pulmonary function and cause
pulmonary inflammation. Troubling community-based work has implicated high ozone levels as
being correlated with increased pediatric asthma ED visits. Because of adverse health
effects, EPA standards for safe ozone levels have been set, currently at 0.07 ppm. Still, it
is estimated that 100 million Americans live in areas where ozone levels periodically remain
above the EPA standard. And while this EPA standard had been set based on available data, it
remained unclear at the time whether naturalistic low-level ozone exposure, such as
fluctuations between 0.06-0.08 ppm throughout the day, might affect health as well.

This group previously examined lung function and inflammatory response in adults exposed to
low-level ozone, 0.06 ppm exposure for 6.6 hours, while undergoing intermittent moderate
exercise. The investigators found that in response to low-level ozone exposure (0.06 ppm)
with exercise, lung function declines and neutrophilic airway inflammation is observed. What
remains unclear, is whether low-level ozone alone - without exercise - will cause similar
health effects.

To mimic exposure to ozone on a typical summer day in a polluted city, the investigators will
expose subjects to a varying level of ozone, form 0.06 ppm to 0.08 ppm, rather than a
constant 0.07ppm. The variation from 0.06ppm to 0.08ppm, then back to 0.06ppm will occur each
hour.

Inclusion Criteria:

1. Males and females between 18 and 50 years of age.

2. Vital signs within normal limits on admission to the study: SpO2 > 94%, systolic blood
pressure between 150-90 mm Hg, diastolic blood pressure between 100-60 mm Hg,
afebrile.

3. FEV1 of at least 80% of predicted.

Exclusion Criteria:

1. 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, chronic thyroid disease, or kidney disease.

2. Use of systemic or inhaled steroids.

3. Use of NSAID or aspirin within 7days of each study visit, and inability to withhold
these medications prior to each session of the study.

4. Pregnant or nursing women

5. Use of cigarettes or other inhaled nicotine products within the past year, or more
than a lifetime 5 pack year history of cigarette smoking.