Nitrogen Dioxide Designations
Answers to the following questions can be found by scrolling down or by clicking on the question of interest. If you need further information, please use the contact information provided.
What does nonattainment mean?
What does designation mean?
What will my area need to do to improve air quality if it is designated nonattainment for Nitrogen Dioxide?
How can I participate in the designation process?
Where can I go for further information?
- What does nonattainment mean?
The Clean Air Act identifies six common air pollutants that are found all over the United States. These pollutants can injure health, harm the environment and cause property damage. EPA calls these pollutants criteria air pollutants because the agency has developed health-based criteria (science-based guidelines) as the basis for setting permissible levels in the air we breath. Nitrogen dioxide is a criteria pollutant. EPA establishes national ambient air quality standards for each of the criteria pollutants. These standards apply to the concentration of a pollutant in outdoor air. If the air quality in a geographic area meets or is cleaner than the national standard, it is called an attainment area; areas that don't meet the national standard are called nonattainment areas.
In order to improve air quality in a nonattainment area, states must draft a plan known as a state implementation plan (SIP). The plan outlines the measures that the state will take in order to improve air quality. Once a nonattainment area meets the standards and additional redesignation requirements in the Clean Air Act [Section 107(d)(3)(E)], EPA will designate the area to attainment as a "maintenance area."
- What does designation mean?
States and tribes submit recommendations to the EPA as to whether or not an area is attaining the national ambient air quality standards for a criteria pollutant. The states and tribes base these recommendations on air quality data collected from monitors at locations in urban and rural settings. After working with the states and tribes and considering the information from air quality monitors, EPA will then "designate" an area as attainment or nonattainment for the nitrogen dioxide (NO2) standard. If an area is designated as nonattainment it signifies to the public that the air in the area is unhealthy to breathe.
- What will my area need to do to improve air quality if it is designated nonattainment for NO2?
- States with designated nonattainment areas are required under the Clean Air Act to develop a State Implementation Plan and submit it to EPA within three years. (Tribes may elect to develop tribal implementation plans but are not required to do so.) This plan must include enforceable measures for reducing air pollutant emissions. The plan must also provide steps for the area to attain the NO2 standards as quickly as possible, and the area must show how it will make reasonable progress toward attaining the standards.
In assessing how quickly an area can attain the standards, states should consider the air quality improvements that can be achieved from a combination of national, state, and local measures. For example, states should take into account existing emission reduction programs, plus any new programs or regulations that can be implemented within the state or local nonattainment area.
- How can I participate in the designation process?
You can follow the designation process for the NO2 standard in your state by contacting your state environmental agency, attending public hearings related to the designations process in your area, and keeping informed about the current status of the designations process from this Web site and state Web sites. Information such as technical data to be considered in designating NO2 areas, can be found at the Nitrogen Oxides NAAQS Implementation Technical Information Page
- Where can I go for further information?
If you would like further information, please visit the Contact Us page.