Connecticut Department of Energy & Environmental Protection

Emergency Burn Ban In Effect 10/26/24 - An emergency burn ban is now in effect for all Connecticut State Parks, Forests, and Wildlife Management areas, prohibiting the use of all outdoor grills, firepits, and campfires, and the kindling and use of flame outdoors. DEEP and local agencies are working to contain several active fires across the state. Please avoid all affected State Parks and Forests, as well as the blue-blazed Mattabesett Trail. The Enduro Trail in Voluntown and portions of North Stonington within the Pachaug State Forest are closed at this time. Please note that today's forest fire danger report remains at an 'extreme' level. More information about the current fire danger, burn ban and recommended safety measures can be found here

Nitrogen Dioxide

Nitrogen dioxide (NO2) is a  yellowish brown, highly reactive gas that is the primary ingredient in formation of ground-level ozone.  It is formed from high temperature combustion such as in power plants and automobile engines. In addition to its role in ozone formation, recent scientific evidence links short-term NO2 exposures, ranging from 30 minutes to 24 hours, with adverse respiratory effects including airway inflammation in healthy people and increased respiratory symptoms in people with asthma.  Studies also show a connection between breathing elevated short-term NO2 concentrations, and increased visits to emergency departments and hospital admissions for respiratory issues, especially asthma.

All of Connecticut has been in attainment of the annual National Ambient Air Quality Standard (NAAQS) for nitrogen dioxide since well before the Clean Air Act was amended in 1990.  On January 22, 2010, the U.S. Environmental Protection Agency (EPA) finalized revisions  to the NAAQS for NO2, adopting a 1-hour standard of 100 ppb and retaining the existing annual standard of 53 ppb. In 2018, EPA concluded this standard was still adequate to protect public health and retained this standard. 

EPA has designated all of Connecticut as “unclassifiable/ attainment” for the 1-hour NO2 NAAQS. See below for the documentation regarding designations.

EPA Retains the Existing NO2 Standard Without Revision. April 18, 2016 (PDF)

Infrastructure SIP revision for the 2010 NO2 NAAQS, January 2, 2013

EPA's Rulemaking Finalizing NO2 Designations (PDF)

EPA's NO2 Designation Letter, January 20, 2012 (PDF)

Governor Rell's NO2 Designation Request, December 17, 2010 (PDF)

Air Quality Trends - Nitrogen Dioxide

Additional Information

EPA Nitrogen Oxides (NOx) Resources

National Ambient Air Quality Standards (NAAQS)

Content last updated June 12, 2018