Air Quality: EPA's Integrated Science Assessments (ISAs)
(PDF, 1251 pp, 40 MB,
Ozone is a gas that occurs both in the Earth's upper atmosphere and at ground level where it is a key component of urban smog. Ground-level ozone causes a variety of effects on human health, vegetation, and ecosystems and it affects climate. Human exposure to ozone is associated with respiratory and cardiovascular effects as well as premature death. Ozone exposure causes visible foliar injury, decreases plant growth and affects ecosystem community composition.
Peak ozone levels typically occur during hot, dry, stagnant summertime conditions. Millions of Americans live in areas where ozone levels exceed EPA's health-based air quality standards, primarily in parts of the Northeast, the Lake Michigan area, parts of the Southeast, southeastern Texas, and parts of California.
EPA's ozone research efforts are focused on improving emissions estimates, determining health and ecological effects, and improving modeling capabilities. EPA's National Center for Environmental Assessment periodically evaluates the latest research concerning the public health and welfare effects of ozone and publishes the most up-to-date findings in an assessment called the Integrated Science Assessment for Ozone. This document provides the scientific basis for the establishment of the most current national air quality standards for ozone. [See the history of Ozone for more detailed information]
- Basic information about ozone
- Ozone and Your Patients' Health Training for Health Care Providers
- Ozone regulations
- National Ozone Air Quality Forecasts
- Clean Air Act