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New York City Metropolitan Area 24-hour PM2.5 Nonattainment Area Boundary Determination

In establishing the nonattainment area boundaries for the New York metropolitan area and the other counties in the New York CMSA, the five counties of New York City and the counties surrounding New York City were evaluated in light of the nine factors mentioned above to determine the attainment status of this area as well as the potential influence of this area on the counties of Connecticut and New Jersey. The counties under consideration were those that comprise the New York Consolidated Metropolitan Statistical Area. This CMSA consists of the five New York City counties, as well as Dutchess, Orange, Putnam, Nassau, Rockland, Suffolk, and Westchester counties.

1. Air Quality

An area with a monitor that records a violation of the PM2.5 NAAQS must be designated nonattainment. The NYSDEC monitoring network for PM2.5 began operations in 1999 and based on the most recent three years of monitoring data from the 2004-2006 as well as data for previous years (see Table 2), a number of exceedances occurred in monitors in New York County, Bronx County and Kings County. In accordance with Section 107(d)(1)(A) of the CAA, these exceedances are sufficient to classify these counties as nonattainment.

Monitors in the other counties of the New York CSMA are in compliance with the 24-hour PM2.5 NAAQS for this period. Of these counties, the monitoring data for those locations north of the New York City area indicate a decrease in the levels of ambient PM2.5. This is illustrated in the case of the Newburgh monitor in Orange County where the monitored values are consistently below the 35 µg/m3 standard by a sufficient margin (5 to 7 µg/m3 for 2002-2004, 2003-5005 and 2005-2006) to suggest that the northernmost counties in the CMSA are in attainment with the 24-hour NAAQS for PM2.5.

In addition to measurement of PM2.5 mass concentration, the collection and analysis of chemical species of PM2.5 and meteorological analysis can help in the evaluation of emission source contribution to PM2.5 exceedances. When evaluating emissions and their impact on ambient PM2.5 concentrations, it is important to recognize that the location and type of emissions have a significant influence on their impacts. The major chemical components of PM2.5 are sulfate, nitrate, ammonium, organic carbon, elemental carbon, and crustal-related compounds (soil or dust). The proportions of these compounds vary by location and are influenced by local source contribution and regional transport attributed to meteorological conditions.

Figure 31 shows the average contribution to PM2.5 compounds at the New York Botanical Garden (NYBG) monitoring site located in the Bronx. The Bronx site represents an urban location, which is typical of the proposed PM2.5 boundary for New York City. Comparison of the sulfate fraction and mass shows that sulfate is much higher for the high PM2.5 days. In general, sulfate and organic carbon are strong regional contributors to both rural and urban PM2.5 concentrations monitored in New York State.

Figure 3 - New York Botanical Garden (Bronx) Speciation Data

New York Botanical Garden (Bronx) Speciation Data

Additionally, Figure 42 shows the average concentration of several species in the Pinnacle State Park rural site located in Western New York State. As would be expected, nitrate concentrations are higher at the urban location than at the rural location, indicating that the urban sources of nitrate precursors (ammonia and nitric acid) are presented at higher concentrations. Elemental carbon concentrations are also much less at the Pinnacle site due to the much smaller number of local combustion processes, including mobile sources.

Figure 4 - Pinnacle State Park Speciation Data

Pinnacle State Park Speciation Data

2. Meteorological Influence

To assess the influence of weather patterns on observed PM2.5 mass concentration in New York City, the meteorological conditions associated with the days on which the highest 5% of PM2.5 readings occurred were examined for the 2004-2006 period of interest. These dates occurred in both summer (July and August) and during the colder weather (November and February). In each case, the winds were light and variable during times when there was no indication of long range transport through "corridors." Most periods of any steady wind were off the ocean. High concentrations under light wind conditions are often seen, especially at times of frontal passage, which was occurring at the periods evaluated.

The high concentrations associated with light and variable winds are indicative of the influence of local sources, especially in the core counties of the New York metropolitan area. The influence of local sources would tend to decrease further up the Hudson Valley with the drop in the density of sources and population, and the decrease in mobile source emissions. The highest concentrations occurred at several monitors in New York City on the same days, indicating that the high PM2.5 concentrations were area-wide, rather than being associated with a given source near any one monitor. Without sustained air movement from the direction of areas outside of the New York metropolitan area, significant particulate matter (PM) would not have been transported in from surrounding counties in New York or other states, and the contribution to impacts from the surrounding areas on the days that measured values were highest would have been minimal. This is the same conclusion reached in the prior analyses of high concentrations submitted in the February 2004 attainment recommendations for PM2.5.

3. Population Density and Degree of Urbanization Including Commercial Development

To address the population density and degree of urbanization criterion, various demographics and economic indicators were examined for New York City, Long Island, and the Mid-Hudson Valley counties comprising the New York CMSA. Figure 5 depicts the population density of the entire state. As can be seen from the figure, the population of the New York CMSA is quite dense in the five counties making up New York City and in the portions of the contiguous counties close to the City, and in the western portion of Suffolk County. As the distance north of the New York Metropolitan area increases, the density is considerably lower, especially in Dutchess, Orange, and Putnam Counties where the character is more rural.

The labor force for the Hudson Valley, New York City and Long Island areas are expected to increase for at least the period 2004-2014. Data from the New York State Department of Labor3 indicates that employment will increase between 6% and 10% over this period, suggesting that commercial growth can be expected to increase as well. This range of numbers is slightly less in comparison to the national average increase of 10.9% for approximately the same period4.

Figure 5 - New York Population Density

New York Population Density

4. Traffic and Commuting Pattern

Traffic and commuting patterns within the New York CMSA are complex and diverse, and reflect the differences in population and employment between New York City and the surrounding counties. As discussed above, the population of New York City itself as well as the other counties, and the workforce, will continue to increase.

As would be expected, given New York City's extensive transit infrastructure, the greatest percent of commutes by New York City residents are done by public transportation. For the rest of the New York CMSA, the majority of the journey to work is done by driving, utilizing the extensive highway system already in place to commute within the area. However, a significant number of commuters from other counties take advantage of the public transportation (rail and bus) options to reach the urban centers.

The breakdown of commuting options according to the United State Census Bureau for the New York CMSA5 as a whole is summarized in Table 3 below. It demonstrates that public transportation is the most commonly used commuting mode in the region, with commuters who drive alone as the second largest group. Still, with 1,253,745 commuters driving alone, the potential for mobile source emissions from cars, trucks and vans is quite high.

Table 3 - Commuting Modes for the New York CMSA
Commuting Mode Number of Commuters Percent
Car, truck, or van -- drove alone 1,253,745 32.0
Car, truck, or van -- car pooled 276,070 7.0
Public Transportation 1,912,519 48.7
Walked 309,611 7.9
Other means 40,824 1.0
Work at home 131,842 3.4
Total Commuters 3,924,611 100
Mean travel time to work 37.3 minutes --

An examination of the Vehicle Miles Traveled (VMT) for the New York CMSA counties was also done. As can be seen in Table 4 below, high VMT's occurred in 2005 for the counties through which commuter traffic would most frequently occur, and where residential and commercial traffic were high in the more densely populated counties. The outlying Dutchess, Putnam and Rockland county VMT's, however, were significantly lower than the Long Island counties and several of the core New York metropolitan counties. The lower VMT figure for Richmond County reflects the more residential character of the area as well as a degree of isolation from the central metropolitan counties of New York City.

Table 4 - New York CMSA 2005 Vehicle Miles Traveled6

2005 Vehicle Miles Traveled (VMT)
County VMT (Millions)
Bronx 4721
Dutchess 3180
Kings 4900
Nassau 11920
New York 4378
Orange 4696
Putnam 3085
Queens 7839
Richmond 2002
Rockland 2731
Suffolk 19815
Westchester 9166

5. Expected Growth

The NYMTC's regional population projections were examined to determine expected growth within the New York CMSA. Growth in the labor force and employment is discussed in I.3. above.

Table 5 below presents the expected population changes in the area proposed to be nonattainment for the period 2000-2015. With the exception of Nassau County, population increases are expected. In several cases, the increases are anticipated to be relatively large, such as the 21% increase in Richmond County over the 15-year period. Others, such as Rockland and Westchester Counties, are small relative to the 10.9% national average.

Table 5 - Population by County for 2000 through 20157

Projected Population by County, 2000 to 2015
County 2000 2005 2010 2015 Change 2000-2015
Number Total Percent Change (2000-2015) Percent Change per Year
Bronx 1,332,650 1,380,366 1,425,170 1,469,206 136,556 10.25 0.68
Kings 2,465,326 2,502,793 2,531,424 2,554,579 89,253 3.62 0.24
Nassau 1,334,544 1,326,167 1,312,166 1,300,125 -34,419 -2.58 -0.17
New York 1,537,195 1,566,485 1,587,098 1,600,353 63,158 4.11 0.27
Orange 341,367 355,711 370,521 386,015 44,648 13.08 0.87
Queens 2,229,379 2,340,043 2,452,109 2,567,898 338,519 15.18 1.01
Richmond 443,728 475,040 505,844 537,493 93,765 21.13 1.41
Rockland 286,753 290,580 291,706 291,618 4,865 1.70 0.11
Suffolk 1,419,369 1,442,694 1,456,195 1,466,808 47,439 3.34 0.22
Westchester 923,459 927,263 926,798 925,714 2,255 0.24 0.02

6. Emission Inventory

Fine particulate consists of both primary and secondary particles. Primary particles are generally coarse particles that are directly emitted into the atmosphere from motor vehicles, power generation facilities, industrial facilities, and residential wood and forest product burning sources. Secondary particles are formed from precursor gases reacting in the atmosphere from the combination of various pollutants: oxides of sulfur (SOx), oxides of nitrogen (NOx), volatile organic compounds (VOCs), and ammonia (NH3). These pollutants are emitted from many of the same emission sources as precursors of ozone.

Table 6a below presents the 2005 emissions for VOC, CO, NOx, SOx and total PM for the counties in the New York CMSA. Table 6b shows the percent contribution for each county by pollutant.

Table 6a - 2005 Emissions of Particulate Matter and its Precursors for the New York CMSA Counties8

County VOC NOx SOx NH3 PM2.5 OC EC PMFINE (Crustal)
Bronx 24227 14362 3787 620 1106 300 235 484
Dutchess 15005 7955 4683 938 1711 589 194 879
Kings 53275 27886 8478 717 2230 581 472 966
Nassau 44885 31877 6347 1471 2149 675 416 907
New York 43628 36742 13380 907 3522 1140 724 1328
Orange 17309 18631 33148 1841 2637 653 281 1523
Putnam 7831 5367 1127 475 636 221 85 317
Queens 45443 40922 18791 1212 2976 724 706 1200
Rockland 13140 12777 12855 544 1296 194 133 821
Suffolk 71255 54932 47555 2713 4408 1098 738 2140
Westchester 34544 24755 4858 1113 1751 548 399 713
Richmond 13004 9466 2623 266 790 152 155 441
Area Totals 383546 285672 157632 12817 25212 6875 4538 11719
Table 6b - 2005 Emission Percent Contributions of Particulate Matter and its Precursors for the New York CMSA Counties
County VOC NOx SOx NH3 PM2.5 OC EC PMFINE (Crustal)
Bronx 6.32 5.03 2.40 4.84 4.39 4.36 5.18 4.13
Dutchess 3.91 2.78 2.97 7.32 6.79 8.57 4.28 7.50
Kings 13.89 9.76 5.38 5.59 8.84 8.45 10.40 8.24
Nassau 11.70 11.16 4.03 11.48 8.52 9.82 9.17 7.74
New York 11.37 12.86 8.49 7.08 13.97 16.58 15.95 11.33
Orange 4.51 6.52 21.03 14.36 10.46 9.50 6.19 13.00
Putnam 2.04 1.88 0.71 3.71 2.52 3.21 1.87 2.71
Queens 11.85 14.32 11.92 9.46 11.80 10.53 15.56 10.24
Rockland 3.43 4.47 8.16 4.24 5.14 2.82 2.93 7.01
Suffolk 18.58 19.23 30.17 21.17 17.48 15.97 16.26 18.26
Westchester 9.01 8.67 3.08 8.68 6.95 7.97 8.79 6.08
Richmond 3.39 3.31 1.66 2.08 3.13 2.21 3.42 3.76
Area Totals 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00

The types of emission sources of particulate matter in the New York CMSA vary widely. Combustion processes are the main source of PM, but precursor emissions also contribute significantly. Sources include fossil fuel combustion in heating as well as mobile sources such as trucks, cars and buses. A number of large electric utility plants presently operate not only in New York City itself, but also in the Mid-Hudson and Long Island counties. There are also many industrial and commercial operations, as well as gasoline transfer and use, from which VOC emissions originate. All of these contribute to the exceedances monitored for the 2004-2006 period either through direct emission of particulate matter or its precursors.

Of particular note in the above tables are the low emissions from Dutchess and Putnam Counties in comparison to the other areas. These emissions result in a minor contribution of these two counties to the overall ambient level of particulate matter.

The Department is currently assessing its stationary, point, mobile and area source PM2.5 emission inventory preparation plans since the inventory will be a necessary component of its PM2.5 State Implantation Plan submission in April of 2008. Projections are not presently available for all of these pollutants. In general, emissions of particulate matter and its precursors can be expected to decrease as a result of programs such as the Clean Air Interstate Rule that affect large emitters in both New York State and downwind states. Improvements in mobile emissions are also expected as older, higher emitting cars and trucks age-out and are replaced by newer vehicles with lower emissions, and as a result of the cleaner fuel requirements for diesel. Emission reduction efforts for particulate matter associated with the April 2008 PM2.5 SIP as well as the Regional Haze SIP will also decrease the concentrations of fine particulate in the ambient air.

7. Geography/Topography

Geography and topography are considerations when physical features, such as high mountains and narrow valleys contribute to nonattainment. The most significant features of the CMSA are the Hudson River Valley that enters the area from the north, and the presence of the Atlantic Ocean. The effect of the river valley tends to be more local in nature and does not affect the region as a whole. The presence of the ocean affects weather and climate overall. However, this affects all of the states and other areas along the east coast and does not exacerbate the transport for the New York area alone. Finally, there are no counties that are severely disproportionate in their dimensions (north-south vs. east-west, for example) that would magnify or otherwise affect the other factors that influence air quality.

8. Jurisdictional Boundaries

The five counties, or boroughs, of New York City represent a distinct jurisdictional boundary compared to the other areas in the New York portion of the CMSA. New York City has historically been active in developing emission control strategies for most of these areas and transit options to address excessive pollutant levels because of its high degree of urbanization. Most recently, New York City has proposed their PlaNYC strategy that will address environmental improvements in a number of media, including air quality. Included in PlaNYC are retrofits to school buses, ferries, garbage trucks, taxis, and construction vehicles, along with stationary source emission reductions from energy efficiency and clean residential fuel measures.

Additionally, jurisdictional boundaries are further delineated within the New York Metropolitan Transportation Council (NYMTC), the Metropolitan Planning Organization for Rockland, Westchester, Nassau and Suffolk counties and New York City. The NYMTC serves as the central planning body for three Transportation Coordinated Councils (TCCs); the New York City TCC, the Nassau Suffolk TCC and the Mid-Hudson TCC. These three TCCs are independent of each other, each developing Transportation Improvement Programs (TIPS) based on respective transportation needs.

It should be noted that the counties that are proposed for inclusion in the New York Metropolitan PM2.5 Nonattainment Area are the same as those included in the present nonattainment area for the annual PM2.5 NAAQS by EPA. The latter nonattainment area was established by EPA and encompasses a larger area than that recommended by the Department. The Department disagreed with EPA's delineation of the nonattainment area for the annual standard and chose to litigate the issue. The results of this litigation may change these boundaries. However, it is not expected that this would affect the Department's recommendations for the 24-hour standard, given the more local impacts associated with the 24-hour standard, the 24-hour averaging basis for the NAAQS that is the subject of this submittal, the larger number of monitors exceeding the 24-hour standard in the New York City counties, and the values close to the 24-hour standard in the counties surrounding New York City.

9. Level of Current Emission Controls

The level of emission control in New York City has been very restrictive since it is a 1-hour severe ozone nonattainment area, as well a nonattainment area for 8-hour ozone and PM10. The Department has submitted several state implementation plans over the years to address emissions that occur in these areas which have resulted in reductions in many source sectors. To ensure future maintenance, and as required by the CAA saving provisions, previously measures used to reach attainment are still applicable and provide ancillary PM2.5 benefits. Some of the local and area-wide measures have included stationary source VOC and NOx Reasonably Available Control Technology (RACT) measures, excessive truck and bus idling limitations, the taxi enhanced inspection and maintenance (I/M) program, and the enhanced I/M requirement for automobiles in the ozone nonattainment area.

Areas outside of the New York City boundaries are additionally subject to state and federal control requirements. Nassau, Suffolk, Westchester, and Rockland counties, as well as the lower portion of Orange County, were classified as severe 1-hour ozone nonattainment areas. The result of this were lower thresholds for the application of VOC and NOx RACT in these areas as well as the imposition of additional New Source Review requirements. Dutchess and Putnam counties, and the upper portion of Orange County, were not included in the serious nonattainment area but, rather, were classified as moderate nonattainment.

Conclusions for the New York City Metropolitan PM2.5 Nonattainment Area:

After considering the nine factors required by EPA guidance, the Department recommends that ten counties in the New York State portion of the New York CMSA be classified as nonattainment. This area is shown in Figure 6 below, and includes Bronx, Kings, New York, Orange, Queens, Richmond, Rockland, Nassau, Suffolk & Westchester Counties. This is appropriate when the exceedances in several New York City counties are considered, as well as the existence of emissions that occur on a regional basis as a result of urbanization, transportation and the steady growth projected to occur in these counties. Although the monitored values in Orange County are relatively low, it is included due to the large sources that are located here including the Danskammer, Lovett and Roseton generating stations.

Dutchess and Putnam Counties, the other areas encompassed by the New York CMSA, are not recommended for inclusion in the New York Metropolitan nonattainment area due to:

  • Their smaller contribution to emissions as seen in the 2005 inventory in Tables 6a and 6b above,
  • Indications that monitored levels of PM2.5 decrease significantly further up the Hudson Valley at levels well below the standard,
  • Lower population density,
  • Smaller degree of traffic volume and congestion as indicated by the lower VMT's in Table 4 above,
  • A lesser influence on the air quality of the metropolitan area as a whole, given the indications that the impact of local sources have a strong influence on the days of greatest concentration, and
  • The more rural nature aspect of these counties.

Along with other efforts that are already under way to control particulate matter and its precursors, the Department intends to develop a state implementation plan for the 1997 annual PM2.5 standard and, three years after the establishment of the nonattainment area, for the 2006 standard that will reduce the emissions of PM2.5 and its precursors, and bring the area into compliance with the NAAQS according the requirements of the Act.

Figure 6 - New York City Metropolitan PM2.5 Nonattainment Area

New York City Metropolitan PM2.5 Nonattainment Area


1 Taken from the Department's February 13, 2004 "Analysis in Support of New York State's Boundary Recommendation for the New York City Fine Particulate (PM2.5) Nonattainment Area"

2 Ibid






8 It should be noted that these emissions were produced by EPA, and may change when the Department's final 2005 inventory is prepared. However, the Department does not expect that the conclusions reached in this analysis will be affected.