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Designation Recommendation for the 2010 Sulfur Dioxide NAAQS

The following is the content of a letter sent to the Regional Administrator at the USEPA, Judith A. Enck. The letter was signed on June 1, 2011 by J. Jared Snyder, Assistant Commissioner, Office of Air Resources, Climate Change & Energy.

On June 2, 2010, EPA strengthened the primary National Ambient Air Quality Standard (NAAQS) for sulfur dioxide (SO2) by establishing a new, 1- hour primary NAAQS at the level of 75 parts per billion (ppb). This revision of the NAAQS requires New York, as a partner with EPA in administering the Clean Air Act, to make recommendations to EPA no later than June 2, 2011 for areas to be designated attainment, nonattainment and/or unclassifiable. As such, on behalf of Governor Andrew Cuomo, I am submitting New York State's attainment designation recommendations for the new standard.

EPA has noted, for a short-term 1-hour SO2 NAAQS, that it is more technically appropriate, efficient, and effective to use modeling as the principal means of assessing compliance for medium to larger sources, and to rely more on monitoring for groups of smaller sources and sources not conducive to modeling. While such an approach is consistent with EPA's historical approach and its longstanding guidance for assessing individual and combination of sources of SO2, the Department does not believe that it is appropriate for determining the attainment status for an entire metropolitan area where adequate monitoring exists. Still, to determine compliance with the new 1-hour SO2 NAAQS, EPA anticipates utilizing an approach for implementation that would use monitoring and refined dispersion modeling of SO2 sources to determine compliance. The Department is committed to completing the modeling to determine whether individual sources by themselves or in combination with other sources might cause modeled violations of the 1-hour SO2 NAAQS, but is recommending that areas be designated based on current monitoring data.

In the preamble to the June 22, 2010 Final Rule (75 FR 35520), EPA outlined the expected process for initially determining attainment status. EPA was concerned that, while monitoring data is available for many areas, modeling has not been completed for most sources that could contribute significantly to nonattainment. As such, the initial process provides that where a monitored violation occurs, the area will be designated as "nonattainment". If monitoring reveals no violations, the attainment status of the area will be designated as "unclassifiable" since modeling results will not be available to provide a complete analysis of air quality in a given area. An area would not be designated as "attainment" unless there is adequate monitoring data and all applicable sources have been modeled.

EPA's March 24, 2011 guidance memorandum entitled "Area Designations for the 2010 Revised Primary Sulfur Dioxide National Ambient Air Quality Standard" states, "EPA may initially designate an area as attainment if it is clear that it meets the SO2 NAAQS. EPA does not believe it would be appropriate to do so without appropriate refined dispersion modeling and, where available, air quality monitoring data indicating no violations of the NAAQS."

The Department believes that this reliance on modeling is inappropriate and unnecessary in New York given that its comprehensive network is sufficient to establish whether the air quality within areas in New York is in attainment. Source-specific modeling has historically been a part of the permitting process where the potential exists for an exceedance of a NAAQS, thereby making such modeling a permitting issue. New York expects to continue this practice of using source-specific modeling to identify both existing and future situations in which the NAAQS may be exceeded and where controls are necessary at specific sources. However, if future routine modeling reveals that an exceedance of the NAAQS might occur, this will be dealt with on a case-by-case basis. This approach is already provided for in New York's air quality program under provisions such as Title 6 of New York Code of Rules and Regulations §200.6 which states, "Notwithstanding the provisions of this Subchapter, no person shall allow or permit any air contamination source to emit air contaminants in quantities which alone or in combination with emissions from other air contamination sources would contravene any applicable ambient air quality standard and/or cause air pollution. In such cases where contravention occurs or may occur, the commissioner shall specify the degree and/or method of emission control required."

This initial attainment designation recommendation, therefore, is based solely on New York's SO2 monitoring results, as modeling, in any case (using a refined dispersion model), would not be completed prior to the June 2, 2010 deadline for initial attainment designations and is, in the Department's opinion, unnecessary given the extensive monitoring data coverage and results presented in this submission as well as the authority cited above in 6 NYCRR Part 200. The Department also believes that it is inappropriate to place an entire metropolitan area under the specter of nonattainment if it has an adequately-sited population exposure-monitoring network that is documenting attainment. If an individual source or combination of sources is causing a potential localized violation of the NAAQS, it is more appropriate and effective to focus efforts to address nonattainment on these sources rather than requiring the entire area to undergo the state implementation plan process.

The SO2 Emissions Monitoring System

The form of the NAAQS provides that compliance with the standard will be based in part on the three-year average of the 99th percentile of the annual distribution of daily maximum 1-hour average concentrations for designated areas subject to SO2 monitoring.

Because EPA plans to use a hybrid approach combining air quality modeling and monitoring to determine compliance with the new SO2 health standard, it is requiring fewer monitors than originally proposed, but also setting specific minimum requirements that inform States on where they are required to place SO2 monitors.

In revising the ambient air monitoring requirements for SO2, New York may need to make adjustments to the existing monitoring network in order to ensure that monitors meeting the network design regulations for the new 1-hour SO2 NAAQS are sited and operational by the designated deadline of January 1, 2013.

New York State's existing SO2 monitoring locations are shown below; this includes all monitors and all networks as of calendar year 2009:

Map of NYS showing SO2 monitoring sites 2011

EPA's final network design siting requirements also require monitors to be "sited at locations where they can meet any one or more of the following objectives:

(1) Source-Oriented Monitoring: This is accomplished with a monitor sited to determine the impact of significant sources or source categories on air quality.
(2) Highest Concentration: This is assessed by a monitor sited to measure the highest concentrations expected to occur in the area covered by the network.
(3) Population Exposure: This is assessed by a monitor sited to measure typical concentrations in areas of (relatively) high population density.
(4) General Background: This is assessed by placing a monitor in an area to determine general background concentrations.

All of the existing SO2 monitors in New York meet one or more of these siting requirements.

Based on EPA's guidelines, New York anticipates the following deployment of monitors throughout New York State in order to meet EPA siting requirements:

Designated Metropolitan Statistical Area Recommended Monitoring1 Existing Monitoring2
Buffalo-Niagara Falls
Population: 1,124,309
1 3
New York-Northern New Jersey-Long Island
Population: 19,006,798
3 4
Population: 853,919
1 3
Population: 672,525
1 1
Population: 1,034,090
1 1
Population: 643,794
1 1

Operation of the monitor in the Poughkeepsie-Newburgh-Middletown area began in May of 2011. With existing monitors meeting or exceeding EPA's guidelines, we believe that New York has a comprehensive, existing network of monitors that fully meets EPA's final network design siting requirements.

Monitoring Results

Ambient air monitoring plays a key role in determining initially whether New York is in attainment with the new 1- hour NAAQS. The Department has calculated the following Design Values in accordance with EPA's criteria (the 3-year average of the 99th percentile of the daily maximum1-hour average concentrations) for the following rolling three year periods for monitoring locations for which SO2 monitoring data was available beginning in 2005 (values in parts per billion, ppb):

City County Location Three Year 99th Percentile Average (ppb)
2005-07 2006-08 2007-09 2008-10
Albany Albany Loudonville Reservoir - 300 Albany Shaker Rd 22.0 21.0 20.0 18.0
New York Bronx Harding Lab - 200th Street And Southern Blvd 56.3 N/A N/A N/A
New York Bronx IS 52 - 681 Kelly St 68.3 59.7 53.7 46.0
New York Bronx Pfizer Lab - 200th Street and Southern Boulevard N/A N/A 54.1 52.7
Dunkirk Chautauqua STP - Wright Park Drive, Dunkirk 61.5 54.0 49.7 N/A
Westfield Chautauqua 8150 Hardscrabble Road, Westfield 32.1 29.1 29.2 22.7
Chemung Elmira Water Treatment Plant - Sullivan St. 24.7 22.7 20.0 15.7
Buffalo Erie Trailer -185 Dingens Street 30.7 25.0 22.3 18.3
Tonawanda Erie 192 Brookside Terrace West N/A N/A 39.0 36.0
Tonawanda Erie STP - 779 Two Mile Creek Road3 118.7 88.0 N/A N/A
Wilmington Essex ASRC (SUNY) Base of Whiteface Mtn - Wilmington 10.0 9.1 8.3 6.4
Paul Smiths Franklin Route 86&30, Paul Smith's College 9.2 8.7 7.9 6.3
Arietta Hamilton Piseco Lake Airport 10.4 9.5 9.0 6.8
Old Forge Herkimer Nicks Lake Campground - 278 Bisby Road 9.9 9.3 9.1 6.9
Georgetown Madison Camp Georgetown - Crumb Hill Road 20.0 18.3 17.0 12.7
Rochester Monroe Rg&E Substation - 2 Yarmouth Road 52.0 49.7 43.3 27.7
East Meadow Nassau Eisenhower Park - 740 Merrick Ave At Old Country Rd 39.3 40.0 39.7 34.7
New York New York PS 59 - 228 E. 57th Street, Manhattan 62.7 55.0 N/A N/A
Niagara Falls Niagara Frontier Ave At 55th Street 21.7 21.6 22.3 19.1
East Syracuse Onondaga 5895 Enterprise Parkway 17.0 15.0 14.3 12.3
Carmel Putnam NYSDEC Field Headquarters - Gypsy Trail Road 21.9 18.5 17.7 15.0
New York Queens Queens College - 65-30 Kissena Blvd Parking Lot#6 44.3 39.3 N/A 31.7
Grafton Rensselaer Grafton Lakes State Park - 194 Shaver Pond Road 16.2 16.0 14.7 12.3
Schenectady Schenectady Mt. Pleasant HS - 1121 Forest Rd. 23.0 20.3 20.0 18.7
Addison Steuben Pinnacle State Park - 8301 Ackerson Road N/A N/A 23.6 19.6
Holtsville Suffolk 57 Division Street 56.0 52.7 47.0 39.4
Highmount Ulster Belleayre Mountain Cross Country Ski Area 15.5 14.3 12.1 9.5

The results show that only one monitoring station (Sewage Treatment Plant in Tonawanda, NY) exceeded the new, 1-hour SO2 NAAQS of 75 ppb during the four three-year design value periods shown, recording Design Values of 118.7 ppb and 88.0 ppb for the 2005-07 and 2006-08 three-year periods, respectively. The monitor was moved in 2007 to the 192 Brookside Terrace West location 0.2 miles away for the reasons noted in the table's footnote.

Since this is the only monitor that recorded SO2 values that exceed the new, 1-hour SO2 NAAQS, these values were examined more closely. Because of the monitor's proximity to the new monitor, Design Values were calculated for the years that were missing data at that location by substituting the values for the adjacent monitor instead; that allowed us to calculate values for all three-year Design Value periods, for both monitors. Those three-year Design Value periods are shown below in red in order to distinguish them from the non-substituted values:

2005-07 2006-08 2007-09 2008-10
192 BROOKSIDE TERRACE WEST 87.3 62.2 39.03 36.0
STP, 779 TWO MILE CREEK ROAD 118.7 88.0 64.9 30.4

Plotting those values on a chart (along with the average of both locations), we observed a downward trend in monitored SO2 values for both locations. Those values are graphically illustrated below:

SO2 Design Values for Tonawanda Monitors showing a decrease in parts per billion from 2005 to 2010

With a decreasing trend in SO2 values clearly demonstrated for these two monitoring locations from 2005 to the present, it can be reasonably concluded that this monitoring location does not present an area of heightened concern for the new 1-hour SO2 NAAQS.

The overall, statewide site monitoring results are summarized below, showing the three year averaged SO2 Design Values for all SO2 monitors for each three-year Design Value period, beginning in 2005:

Statewide Averages of SO2 Design Values declined from 2005 to 2010

Adjacent States:

In addition to assessing the existing monitoring data within New York State, the Department has also assessed the SO2 monitoring data from neighboring states of Connecticut and New Jersey, as both are part of the New York-Northern New Jersey-Long Island-Connecticut Metropolitan Statistical Area, or "MSA". This assessment is necessary in order to determine if New York emissions contribute significantly to nonattainment in, or interfere with maintenance by, any other state as a result of the interstate transport of pollutants.

The map on the following page shows the outline of the New York-Northern New Jersey-Long Island-Connecticut MSA as well as the location of the SO2 monitoring sites within this MSA, and their corresponding 2009 Design Values.

Map of NY-NY-CT CSA showing 2009 1-hour SO2 design values

The calculated SO2 annual 99th percentile values4, and the calculated Design Values for 2008-10 for the New Jersey counties located within the New York-Northern New Jersey-Long Island-Connecticut MSA are shown below. None of the Design Values exceed the 1-hour SO2 NAAQS of 75 ppb:

Monitored SO2 Concentrations in NJ (ppb) Annual 99th Percentile Values*
Site 2008 2009 2010 Average
Chester 49 33 35 39
Elizabeth Trailer 41 34 30 35
Bayonne 31 36 27 31
Jersey City 31 26 21 26
Elizabeth 20 22 11 18
Hackensack 18 22 9 17

* Sites that are within the NY-Northern NJ-Long Island-Connecticut MSA only.

The New Jersey Design Values for 2008-2010, graphically illustrated below, show that values are well below the new 1-hour SO2 NAAQS of 75 ppb:

NJ SO2 design values for 2008-10 for NY-NJ-LI-CT MSA monitoring sites

Similarly, monitoring sites downwind from New York within the Connecticut portion of the New York-Northern New Jersey-Long Island-Connecticut MSA all show Design Values in recent years well below the 75 ppb standard:

Southwest CT 1-hr SO2 comparison of 3-year design value average to 1-hour standard

The last instance of a 3-year rolling Design Value exceeding the new 1-hour SO2 NAAQS of 75 ppb in southwest Connecticut (MSA) occurred in 1999 at the Bridgeport monitoring site.

Since there are no monitors indicating non-attainment in either state in recent years, New York State cannot, at this time, be deemed to contribute to, or interfere with, attainment of the new 1-hour SO2 NAAQS in other states within the NY-Northern NJ-Long Island-Connecticut MSA, which includes northern New Jersey and the southwestern part of Connecticut.

To aid in our assessment of SO2 attainment designations for New York, we have also constructed and attached a map showing the location of all SO2 monitors in New York, as well as the location of all 100 TPY-and-greater emission sources (as of 2008), and the boundaries of all Core-Based Statistical Areas (CBSAs). The map provides a visual guide for assessing the relationships between these three important elements. While the absence of 100 tpy-and-greater sources in a particular CBSA is not, in and of itself, evidence of attainment, the presence of a compliant monitor within the same CBSA is an additionally compelling argument for attainment designation for that particular area. As such, we note that the Elmira and Utica-Rome CBSAs all have monitors with recent Design Values well below the new standard, and contain no 100 tpy-and-greater SO2 sources within their boundaries.


The Department is recommending that all areas of New York be designated as "attainment", with the exception of the Poughkeepsie-Middletown-Newburgh CBSA, which we recommend be designated as "unclassifiable" since sufficient data to make an attainment determination has not yet been collected. We believe that for all other areas of New York State, based on existing monitoring data, there is sufficient evidence demonstrating attainment of the new NAAQS Primary Standard. In addition, no non-attainment is indicated based on the monitoring data, in either New York State or adjoining states in the New York-Northern NJ-Long Island-Connecticut MSA. As such, the Department recommends that the following CBSAs, as well as the remainder of the State, be designated as "attainment" with respect to the new, 1-hour NAAQS for SO2:

  • New York - northern New Jersey - Long Island, NY - CT
  • Buffalo-Niagara Falls
  • Albany-Schenectady-Troy
  • Rochester
  • Syracuse
  • Kingston
  • Ithaca
  • Binghamton
  • Elmira
  • Utica-Rome

We believe that each of these recommendations is consistent with Section 107(d) of the Clean Air Act.

Should you have any questions regarding these recommendations, please do not hesitate to contact me at (518) 402-8537 or David J. Shaw, Director of the Department's Division of Air Resources, at (518) 402-8452.


1 Source: Bob Judge and Mazeeda Khan. NESCAUM MAC Meeting Presentation entitled, "Overview of New Monitoring Requirements for NAAQS", October, 2010
2 Source: Bureau of Air Quality Surveillance, Division of Air Resources, NYS Department of Environmental Conservation
3 This monitoring station was relocated in 2007 to the 192 Brookside Terrace West address as part of the Tonawanda Community Air Quality Study. This site borders a residential neighborhood and the industrial complex, and is approximately 0.2 mile northeast of the original 779 Two Mile Creek Road site location.
4 Highest daily 1-hour 99th percentile value on an annual basis.

Map of NYS showing SO2 emission sources and monitor locations