EPA sets national air quality standards to protect public health. The standard for ozone is based on an 8‐hour average ozone concentration. In 1997, EPA set an 8‐hour ozone standard of 80 parts per billion. In 2008, EPA lowered the standard to 75 parts per billion. When ozone levels are above the standard, health effects from ozone are more likely, especially for vulnerable populations.
The chart above shows the fourth highest daily maximum 8‐hour ozone concentration for each year for the years 2006 to 2011. Compliance with the air quality standard is determined by averaging these values over a three year period.
Metro East Community Air Project
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