|EPA intended PM2.5 designations. Click to enlarge.|
The US Environmental Protection Agency (EPA) announced intended designations (e.g., attainment, nonattainment) for the 24 hour PM2.5 (Particulate Matter) standard, revised in 2006 (earlier post), for all state lands and for tribal areas in the US.
The agency notified 25 states that they currently meet the fine particle standards, while the remaining states have at least one area under consideration for a nonattainment designation. A nonattainment area would include counties with monitors violating the 24-hour standard and nearby counties that contribute to that violation.
EPA will make formal designations of attainment and nonattainment areas in December 2008, after states and tribes comment on the proposals and if needed, provide additional information. EPA is also soliciting public response to the proposed designations.
Once designations take effect, they become a component of state, local and tribal governments efforts to reduce fine particle pollution to meet national standards. Designations also help let the public know whether their air quality is healthy.
Exposure to fine particle pollution can cause serious health problems, ranging from increased hospital admissions and doctor and emergency department visits for respiratory and cardiovascular disease, to nonfatal heart attacks, to premature death. In September 2006, EPA tightened the 24-hour PM2.5 standard from 65 micrograms per cubic meter (µg/m3) to 35 µg/m3—a decrease of 46%.
After EPA sets a new National Ambient Air Quality Standard (NAAQS) or revises an existing NAAQS, EPA formally identifies or “designates” areas as attainment/unclassifiable (meeting the standard or expected to be meeting the standard despite a lack of monitoring data), nonattainment (not meeting the standard), or unclassifiable (insufficient data to classify).
States and tribes provided their initial designation recommendations in December 2007 based on the most recent three years of air quality monitoring data, generally 2004 to 2006. EPA plans to make final designations in December 2008 using air quality monitoring data from 2005, 2006 and 2007.