PM10 Planning Efforts

Connecticut DEEP began monitoring for PM10 in 1984.  In 1990, the U.S. EPA designated the City of New Haven as nonattainment for the PM10 standard.  By 2005, as a result of local control strategies implemented during the early 1990’s, monitored levels improved to the point that Connecticut requested that EPA redesignate the City of New Haven as an attainment area for PM10.  EPA approved the request in October 2005.  Meanwhile, in January 2005, Fairfield and New Haven counties, together with counties in New York and New Jersey, were designated by EPA as nonattainment for the new PM2.5 standard.

PM10 Standards

  • The 24-hour PM10 national ambient air quality standard (NAAQS) is 150 µg/m3 with no more than one expected exceedance per year.  The annual PM10 standard (previously set at 50 µg/m3, expected annual arithmetic mean) was revoked as of December 2006 due to a lack of evidence linking health problems to long-term exposure to coarse particle pollution. 
  • Connecticut is currently in attainment for the 24-hour NAAQS for PM10.
  • No violations of the PM10 NAAQS have been measured in Connecticut since the early 1990’s, at which time corrective measures were implemented in the City of New Haven to reduce localized PM10 emissions.
  • PM10 levels in New Haven are far enough below the NAAQS that the Connecticut Department of Energy and Environmental Protection (CT DEEP) gained EPA approval in 2005 redesignating the area to attainment and establishing a Limited Maintenance Plan (LMP) for the area. (See Redesignation to Attainment and Limited Maintenance Plan for the City of New Haven PM10 Nonattainment Area for further information).
  • CT DEEP is maintaining a network of PM10 monitors. If future violations of the PM10 standards occur, contingency plans will be implemented (as described in the LMP).

Content last updated on December 31, 2019