OAR Policy and Guidance Metarecord
Limited Maintenance Plan for PM10: Fact Sheet
Limited Maintenance Plan Option for Moderate PM10 Nonattainment Areas
|Signed by: Unsigned
Air Quality Strategies and Standards Division (OAQPS) / Lydia Wegman
| EPA Document Number:
ENVIRONMENTAL PROTECTION AGENCY
Clean Air Act
Many PM10 nonattainment areas have been meeting the national ambient air quality standards for five years or more and have a low risk of future exceedances. A policy is needed that would allow both states and EPA to deal more efficiently with low risk areas so that our limited resources can be focused on higher priority areas, including areas that still are not meeting the standard or at risk of continued nonattainment. This policy option provides a simplified approach to meeting maintenance plan requirements for areas with acceptably low risks of future nonattainment. This is based on a 1 in 10 year probability of exceeding the PM10 NAAQS. The LMP is a streamlined approach because it does not require areas that meet its qualification criteria to perform dispersion modeling, or to project emissions into the future, or to meet certain conformity requirements. All other requirements related to redesignation requests must still be met (i.e., an approved SIP, the area must be meeting the NAAQS, an attainment inventory, etc.).
The basis of the policy is an in depth statistical analysis of the air quality data of all the PM10 monitoring sites in the country over the past 10 years. EPA looked at the design values of all sites and their relationship to the PM10 NAAQS, and their variability from year to year. Our analysis showed that these sites have had a minimum of five years of clean air quality data, little or no emissions growth and no substantial growth expected, and the statistical record of their data indicates that there is a very low probability that they will experience air quality violations in the future.