4 The record articles

Final Area Designations for the 2012 Annual PM2.5 Standard

Posted: February 23rd, 2015

Author: All4 Staff 

As recounted in Dan Dix’s historic 4 the Record Article, on December 14, 2012, U.S. EPA announced the revised annual National Ambient Air Quality Standard (NAAQS) for fine particulate matter (PM2.5; PM with a diameter less than or equal to 2.5 microns). In this announcement, U.S. EPA reduced the primary annual PM2.5 standard from 15.0 micrograms per cubic meter (μg/m3) to 12.0 μg/m3, which is based on the three (3)-year average of the annual arithmetic mean. Using air quality monitoring data collected for calendar years 2011 through 2013, U.S. EPA has now promulgated initial area designations for most areas of the U.S. with respect to the 2012 annual PM2.5 NAAQS.

Before we look at the specific designations, let’s take look at a regulatory timeline for this ruling. Back on December 18, 2014, U.S. EPA issued final area designations for the 2012 annual PM2.5 NAAQS. On January 15, 2015 the boundaries for air quality designations for the 2012 annual PM2.5 NAAQS were published in the Federal Register. In this ruling, U.S. EPA announced that the final PM2.5 designation decisions will be effective 90 days following the date of publication of the January 15, 2015 Federal Register [i.e. April 15, 2015]. While this date is fast approaching, there is another regulatory date that is also quickly approaching. If a state chooses to submit complete, quality assured certified monitoring data from the 2014 calendar year to U.S. EPA by February 27, 2015 that suggests a change of designation status is appropriate for any area within that state, upon agreement from U.S. EPA, the designation promulgated in the January 15, 2015 Federal Register will be withdrawn and another designation will be issued that reflects the inclusion of 2014 data [i.e., a three (3)-year period based on 2012 through 2014].

Now let’s take a look into the specific area designations based on the 2012 annual PM2.5 NAAQS. U.S. EPA has designated areas as nonattainment, unclassifiable, or unclassifiable/attainment. A complete listing of the initial designations for states and territories can be found on the U.S. EPA website located here. U.S. EPA has designated 14 areas in six (6) states as “nonattainment.” These areas include counties with monitors measuring a violation of the standard as well as nearby counties contributing to a violation by emitting PM2.5 pollution, or precursor pollutants that form PM2.5 [e.g. sulfur dioxide (SO2), nitrogen oxides (NOX), volatile organic compounds (VOC), and ammonia (NH3)]. These nonattainment areas have been initially classified as “Moderate.” In addition, U.S. EPA has designated three (3) areas as unclassifiable because these areas have ambient air quality sites that lack complete data for the 2011 through 2013 calendar years. U.S. EPA also has deferred initial area designations for ten (10) areas where available data are insufficient to determine whether the area(s) are meeting or are not meeting the 2012 annual PM2.5 NAAQS. U.S. EPA is using additional time to assess relevant information and promulgate initial designations for these unclassifiable areas through a separate rulemaking action.

What does this mean for area(s) designated as nonattainment? As required in the Clean Air Act (CAA), these areas are subject to planning and emission reduction requirements. Within the next several months, U.S. EPA intends to propose an implementation rule to assist states in developing implementation plans for meeting the 2012 annual PM2.5 NAAQS. These implementation plans must be submitted to the U.S. EPA within 18 months of effective date of the area designations. In addition, these areas are also subject to additional New Source Review (NSR) preconstruction requirements. As always, consider how these new area designations may affect your facility and know where your facility stands with regards to the 2012 annual PM2.5 NAAQS.

These ongoing issues with respect to PM2.5 continue to underscore a message that ALL4 has been shouting since 2012 – if you do not know where your facility stands with respect to compliance with the 2012 annual PM2.5 NAAQS, it is imperative to conduct modeling now to evaluate the feasibility of future expansion projects.

Stay tuned on updates concerning future 2012 annual PM2.5 NAAQS rulemaking/designations.


    Sign up to receive 4 THE RECORD articles here. You'll get timely articles on current environmental, health, and safety regulatory topics as well as updates on webinars and training events.
    First Name: *
    Last Name: *
    Location: *
    Email: *