1 

ATTACHMENT 

Connecticut’s Recommended Designations for the 2012 PM2.5 NAAQS 

(December 2013) 

Introduction

Particulate matter (PM) pollution includes both solid particles and liquid droplets found in air. 

Many manmade and natural sources emit PM directly or emit other pollutants that react in the 

atmosphere to form PM. These solid and liquid particles come in a wide range of sizes. 

Particles less than 10 micrometers in diameter (PM10) pose a health concern because they can be 

inhaled into and accumulate in the respiratory system. Particles less than 2.5 micrometers in 

diameter (PM2.5) are referred to as "fine" particles and are believed to pose the largest health 

risks. Because of their small size (less than 5% of the average width of a human hair), fine 

particles can lodge deeply into the lungs. 

Health studies have shown a significant association between exposure to fine particles and 

premature mortality. Other important effects include aggravation of respiratory and 

cardiovascular disease (as indicated by increased hospital admissions, emergency room visits, 

absences from school or work, and restricted activity days), lung disease, decreased lung 

function, asthma attacks, and certain cardiovascular problems such as heart attacks and cardiac 

arrhythmia. Individuals particularly sensitive to fine particle exposure include older adults, 

people with heart and lung disease, and children. 

Sources of fine particles include all types of combustion activities (motor vehicles, power plants, 

wood burning, etc.) and certain industrial processes. Particles with diameters between 2.5 and 10 

micrometers are referred to as "coarse." Sources of coarse particles include crushing or grinding 

operations, and dust from paved or unpaved roads. 

Sections 108 and 109 of the Clean Air Act (CAA) govern the establishment, review, and 

revision, as appropriate, of the National Ambient Air Quality Standards (NAAQS) to provide 

protection for the nation’s public health (“primary” NAAQS) and the environment (“secondary” 

NAAQS). The CAA requires the U.S. Environmental Protection Agency (EPA) to conduct 

periodic reviews (at five-year intervals) of the science upon which the standards, as well as the 

standards themselves, and to promulgate appropriate revisions. EPA has established NAAQS for 

both PM10 and PM2.5. The remainder of this document focuses on the PM2.5 NAAQS. 

The EPA first promulgated NAAQS for fine particles (PM2.5) in July 19971

, establishing 

identical primary and secondary standards for both 24-hour and annual average times at 65 

micrograms per cubic meter (μg/m3

) and 15.0 μg/m3, respectively. Based on EPA’s review of 

new health information gathered during the next required review cycle, EPA subsequently 

tightened the primary and secondary 24-hour PM2.5 NAAQS in 20062

 to 35 μg/m3. All of 

 

1 62 FR 38652 (July 18, 1997). 2 71 FR 61144 (October 17, 2006). 
2 

Connecticut is currently designated by EPA as attainment for both the 1997 and 2006 PM2.5 

NAAQS3. 

On December 14, 2012, the EPA finalized the most recent revisions4

 to the PM2.5 NAAQS, 

concluding that recent health studies warranted adoption of a more stringent annual standard of 

12.0 micrograms per cubic meter (μg/m3

), while retaining both the 24-hour PM2.5 standard of 35 

μg/m3

 and the secondary standards. 

Designation Process for the 2012 Annual PM2.5 NAAQS

After the EPA establishes or revises a NAAQS, the CAA requires the EPA and states to take 

steps to ensure that the new or revised standard is met. The first step, known as the initial area 

designations, involves identifying areas of the country that either meet or do not meet the new or 

revised NAAQS along with the nearby areas contributing to violations. Section 107(d)(1) of the 

CAA provides up to one year after adoption of a new or revised NAAQS for each state to submit 

recommendations to EPA identifying areas within the state’s borders that comply with the 

standard or that violate or contribute to nearby violations of the standard. If, after evaluating a 

state’s recommendations, EPA believes the available evidence supports a designation different 

from the state’s recommendation, then EPA must provide the state at least a 120-day period to 

comment on the potential modification prior to promulgating final designations. The CAA 

requires EPA to complete the designation process within two years after adoption of a new or 

revised NAAQS, unless the Administrator determines that there is insufficient information. In 

such cases, EPA may take up to one additional year to promulgate initial area designations. 

EPA’s final rulemaking promulgating the 2012 PM2.5 NAAQS specifies the schedule5 to 

establish designations in accordance with CAA Section 107(d)(1). State recommendations for 

attainment and nonattainment areas and boundaries are due by December 13, 2013. The initial 

state recommendations should be based on air quality data from the years 2010 through 2012. 

EPA intends to respond to states’ initial recommendations by August 14, 2014. States will then 

have the opportunity to comment on EPA’s response, and to provide any new information and 

analyses to EPA. In most cases, 2013 ambient PM2.5 monitoring data will be available in time 

for states to update their recommendations and for EPA to include the data when determining 

final designations.

 

3

 EPA recently granted final approval for Connecticut’s Redesignation and Maintenance Plan for the southwestern 

portion of the state (i.e., Fairfield and New Haven Counties). EPA previously included those counties as part of the 

New York/New Jersey/Connecticut (NY/NJ/CT) nonattainment area for the 1997 annual and 2006 24-hour PM2.5

NAAQS (78 FR 58467, September 24, 2013). 4 78 FR 3086 (January 15, 2013, with a NAAQS effective date of March 18, 2013. 5 78 FR 3250. 
3 

Summary of Connecticut’s PM2.5 Air Quality Data

As of the end of 2012, the Connecticut Department of Energy and Environmental Protection 

(DEEP) operated a network6

 of eleven PM2.5 monitors throughout the state, recognized by EPA 

as meeting Federal Reference Method (FRM) criteria. Two of the sites, Criscuolo Park in New 

Haven and McAuliffe Park in East Hartford, operate on a daily sample schedule while all the 

other sites operate on a 1-in-3 day sample schedule. Two sites, Waterbury and Criscuolo Park in 

New Haven, operate collocated PM2.5 FRM samplers on a 1-in-6 day sample schedule. 

Figure 1 shows the locations and lists the 2012 annual PM2.5 design values7 for each of DEEP’s 

PM2.5 monitoring sites, as well as those located in the New York and New Jersey portions of the 

NY/NJ/CT maintenance area. Table 1 provides yearly details for the Connecticut monitors for 

each of the three years used to determine the 2012 design value, for comparison to the annual 

(12.0 μg/m3

) NAAQS. (For informational purposes, design values are also included for 

comparison the 24-hour NAAQS of 35 μg/m3

). All monitors recorded 2012 design values that 

comply with the PM2.5 NAAQS. The highest measured 2012 annual design value was 9.4 μg/m3

, 

recorded at both the Bridgeport and the New Haven State Street monitoring stations. 

Table 1. 2012 PM2.5 Design Values for Connecticut 

2010 

(μg/m3

)

2011 

(μg/m3

) 

2012 

(μg/m3) 

2012 Design 

Values 

(μg/m3) 

Site Name Site ID 

98th 

%tile 

Daily 

Annual 

Average 

98th 

%tile 

Daily 

Annual 

Average 

98th 

%tile 

Daily 

Annual 

Average 

24-Hr 

DV 

Annual 

DV 

Bridgeport 09-001-0010 23.3 8.8 23.7 10.0 21.5 9.3 23.0 9.4 

Danbury 09-001-1123 25.7 9.1 24.8 9.6 21.6 8.4 24.0 9.0 

Norwalk 09-001-3005 23.0 8.7 25.2 10.0 22.5 8.6 24.0 9.1 

Westport 09-001-9003 24.2 8.6 28.7 9.5 19.5 8.0 24.0 8.7 

East Hartford 

McAuliffe 09-003-1003 24.2 7.6 24.3 8.9 18.0 7.3 22.0 8.0 

East Hartford 

High St 09-003-2006 23.5 8.6 23.2 9.3 20.3 8.5 22.0 8.8 

Cornwall 09-005-0005 19.1 6.0 17.0 5.7 15.0 5.5 17.0 5.7 

New Haven 

Criscuolo 09-009-0027 25.5 8.9 27.5 10.1 20.6 8.3 25.0 9.1 

New Haven 

State St 09-009-1123 23.9 9.0 26.6 10.0 22.0 9.2 24.0 9.4 

Waterbury 09-009-2123 25.7 9.2 24.3 9.9 20.6 8.4 24.0 9.2 

Norwich 09-011-3002 21.3 7.8 22.6 9.0 19.7 7.6 21.0 8.1 

 

6

 For details, see DEEP’s 2013 Annual Air Monitoring Network Plan, approved by EPA on September 17, 2013. 7

 PM2.5 design values are determined in accordance with Appendix N to 40CFR50. 
4 

Figure 1. 2012 PM2.5 Annual Design Values 
5 

Figures 2 and 3 show annual and 24-hr design values trends for the period from 2001 through 

2012 at Connecticut longest operating monitor locations. Both depict steady downward trends, 

especially over the most recent five-year period. All Connecticut monitors have measured 

compliance with the 2012 annual PM2.5 NAAQS since at least 2009. 

Figure 2. Annual PM2.5 Design Value Trends for Connecticut (2001-2012)

Figure 3. 24-hour PM2.5 Design Value Trends for Connecticut (2001-2012) 

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

PM2.5 Concentration (μg/m3)

PM2.5 Annual Design Values Of Connecticut's

Longest Running Monitoring Sites

Bridgeport‐09‐001‐0010

Danbury‐09‐001‐1123

Norwalk 09‐001‐3005

Westport 09‐001‐9003

East Hartford McAuliffe‐09‐003‐1003

New Haven State St‐09‐009‐1123

Waterbury‐09‐009‐2123

Norwich Court House 09‐011‐3002

New Haven Criscuolo‐09‐009‐0027

Annual NAAQS = 12 μg/m3

Cornwall 09‐005‐0005

0

5

10

15

20

25

30

35

40

45

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

PM2.5 Concentration (μg/m3)

PM2.5 24‐Hr Design Values of Connecticut's

Longest Running Monitoring Sites

Bridgeport‐09‐001‐0010

Danbury‐09‐001‐1123

Norwalk 09‐001‐3005

Westport 09‐001‐9003

East Hartford McAuliffe‐09‐003‐1003

New Haven State St‐09‐009‐1123

Waterbury‐09‐009‐2123

Norwich Court House 09‐011‐3002

New Haven Criscuolo‐09‐009‐0027

24‐hour NAAQS= 35.0 μg/m3

Cornwall 09‐005‐0005
6 

Improvement in Connecticut’s PM2.5 air quality is attributed to federal and state emission control 

programs that have resulted in significant emission reductions of directly emitted PM2.5 and 

important precursor species (e.g., sulfur dioxide and nitrogen oxides) that contribute to the 

formation of secondary fine particles in the atmosphere. 

Connecticut’s recently approved Redesignation Request and Maintenance Plan for the 1997 and 

2006 PM2.5 NAAQS includes emission estimates and projections. Figure 4 summarizes 

estimated annual PM2.5 emissions in 2007, 2017 and 2025 by major source sector for the 

Connecticut portion of the NY-NJ-CT PM2.5 maintenance area, as well for the entire 

maintenance area. Overall, directly emitted PM2.5 is projected to decrease by more than 20% 

between 2007 and 2025. 

Figure 4. PM2.5 Emission Projections 2007-2025 

Figures 5 and 6 provide the same information for NOx and SO2 emissions, respectively, which 

are known precursors to secondary PM2.5 formation. Emissions of NOx and SO2 are projected to 

decrease by more than 50% and 40%, respectively, between 2007 and 2025. These significant 

reductions in PM2.5-related emissions will further improve air quality and ensure that 

Connecticut remains in compliance with the PM2.5 NAAQS.
7 

Figure 5. NOx Emission Projections 2007-2025 

Figure 6. SO2 Emission Projections 2007-2025 
8 

Recommendation

The analyses presented above demonstrate that all monitors in Connecticut have measured 

compliance with the 2012 annual PM2.5 NAAQS since at least 2009. Adopted federal and state 

emission control programs are expected to continue the ongoing decline in PM2.5-related 

emissions into the foreseeable future, ensuring continued compliance with the PM2.5 NAAQS. 

Therefore, in accordance with CAA Section 107(d)(1), Connecticut recommends that EPA 

designate the entire state of Connecticut as attainment for the 2012 annual PM2.5 NAAQS.