On average, since 1990, the Washington metropolitan area has exceeded the one-hour ozone standard six days every summer.
Federal law permits an average of one exceedance per summer at a monitor location.
EPA is especially concerned about the effect of air pollution on the most vulnerable populations, including children, the elderly, and people with respiratory problems. EPA studied recent scientific and medical information to determine if the one-hour ozone standard and the standard for small particles were stringent enough to protect public health. The region will begin to measure air quality in comparison to these new standards in the next few years and determine if the region's air quality meets the new requirements. I and II Attainment Plans will improve air quality and help the region to meet these new standards. If the air quality in the Washington area does not meet the new standards, the region may need to take additional action beyond that currently included in the Phase I and Phase II attainment plans.