Particulate Matter 2.5 (PM2.5)
On November 15, 2013, the U.S. Environmental Protection Agency (EPA) proposed a rule to clarify PM2.5 implementation requirements to the states for current 1997 and 2006 nonattainment areas. In response to a D.C. Circuit Court decision addressing the role subpart 4 of Part D, title 1 of the Clean air Act in implementing the fine particle pollution (PM2.5) air quality standards.
As part of the actions taken by EPA areas that were designated nonattainment for the 1997 and/or 2006 PM2.5 standards were initially designated as “moderate” by operation of law. The deadline for submitting attainment related and nonattainment NSR SIP elements required under subpart 4 was December 31, 2014.
On December 2, 2014 the Imperial County Air Pollution Control District Board of Directors fully approved the "Imperial County 2013 SIP for the 2006 24-hr PM2.5 Moderate Nonattainment Area" plan.
On December 18, 2014 the California Air Resources Board approved the Imperial County 2013 State Implementation Plan for the 2006 24-hour PM2.5 Moderate Nonattainment Area. Final PM2.5 Plan