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Mr. Conrad Simon 

Director 

Air and Waste Management Division 

July 20, 1995 

United States Environmental Protection Agency 

Region II 

290 Broadway 

New York, New York 10007-1866 

Dear Mr. Simon: 

Michael D. Zagata 

Commissioner 

The purpose of this letter is twofold. This letter represents a preliminary 

submission for the PM10 (particulate matter with an aerodynamic diameter smaller than 

ten microns) State Implementation Plan due July 20, 1995. Certain deficits in the 

planning process have slowed plan development, thus New York State is not in a 

position to submit a fully modelled attainment demonstration at this time . .Be assured 

that efforts (to be described later) are still moving forward to complete the PM10 

attainment demonstration as quickly as possible. 

Additionally, I am writing to request that the United States Environmental 

Protection Agency (EPA) redesignate New York County as attaining the PM10 National · 

Ambient Air Quality Standard (NAAQS). 

I would like to begin with the latter issue. The measured PM10 levels in 

New York County, New York State's only PM10 nonattainment county, have not 

exceeded the PM10 NAAQS since 1992. In fact, with the exception of 1994, ambient 

levels of PM10 have been dropping steadily, city-wide, since 1988. Also, it has been 

determined that the PM10 problem in New York County is diesel vehicle exhaust related. 

Furthermore, ambient PM10 levels measured at rooftop monitoring sites have not 

approached the magnitude recorded at the Madison Avenue, street level, sampling 

location. Therefore, the PM10 problem has been determined not to be area-wide, but 

rather a "hot-spot" or site specific problem. 

New York County was designated as nonattainment for PM10 on 

January 20,1994. This designation was based on data collected at the Madison 
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Mr. Conrad Simon 2. 

Avenue sampling location in Manhattan. The precise location of this monitor is the 

Eastern side of Madison Avenue, mid block between 47 and 48 Streets, two meters 

from the ground. The Madison Avenue monitoring site is the only site in the county 

which has recorded violations of the PM10 NAAQS. All PM10 violations recorded to date 

are violations of the annual NAAQS (not to exceed an arithmetic mean of 50 J..l.g/m3 for 

three consecutive calendar years), as opposed to violations of the 24-hour PM10 

NAAQS (not to exceed 150 J..l.g/m3 in a 24 hour period more than once during three 

consecutive years) which have never been recorded in Manhattan. Please find 

ambient air monitoring data for the Madison Avenue site and a rooftop site located at 

Public School 59 in Attachment 1. 

Madison Avenue was chosen as a street level PM10 monitoring site for the high 

diesel bus volumes running along its corridor and its striking urban canyon 

characteristics, perhaps the most exaggerated canyon of all the major thoroughfares in 

Manhattan. When compared to Fifth Avenue, which is similarly populated with diesel 

vehicles, Madison Avenue is narrower by 21 feet. It is hypothesized that the narrower 

canyon at Madison Avenue entraps the particulate matter more readily than the wider 

streets. 

Madison Avenue has recorded exceedances of the annual PM10 NAAQS during 

the years 1990 and 1991. From 1992 to the present, there have been no exceedances 

of the PM10 annual standard, although during 1994 several high PM10 values were 

recorded, pushing the 1994 average above 50 J..l.g/m3

• These 1994 readings, however, 

did not result in a violation of the annual PM10 NAAQS. Preliminary first quarter, 1995 

PM10 data for Madison Avenue has not been as high as the first quarter 1994 data. 

Other PM10 sampling sites in the New York Metropolitan area have not recorded 

annual ambient levels of PM10 nearly as high as those measured at Madison Avenue 

nor were there any exceedances of the annual PM10 NAAQS at those sites. A PM10 

monitor located on the rooftop of the Bowery Savings Bank, located on Seventh 

Avenue at 34 Street, measured the highest overall non-Madison Avenue annual PM10 

reading, in 1989, of 44 J..l.Qim3. Of further note, PM10 levels have been dropping rather 

steadily since 1988, city-wide. The city-wide average was 35 J..l.Q/m3 in 1989 and 

dropped quite steadily to 28 J..l.g/m3 by 1993. Data for 1994 seems a bit higher across 

the board for all sites, not just Madison Avenue. Explanations for this downward trend 

could be the diesel engine emission regulations adopted in March 1985, which reduced 

emissions significantly from diesel vehicles during the years 1988 to 1994. Also, ozone 

control programs adopted to reduce the amount of secondary formation which occurs in 

the atmosphere have the extra benefit of reducing the amount of secondary particulate 

generated in the atmosphere. 

In 1993, the New York State Department of Environmental Conservation (DEC), 

in conjunction witt) the Desert Research Institute (DRI), initiated a study to determine 

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Mr. Conrad Simon 3. 

where the ambient PM10 at the Madison Avenue sampling site originated. Diesel buses 

were suspected to be the primary contributors. The study employed optical 

microscopy, scanning electron microscopy, x-ray fluorescence, Fourier-transform 

infrared spectroscopy, and chemical mass balance techniques to determine the 

sources of PM10 and the quantities of PM10 associated with those sources. It was 

established that 52.8% of PM10 collected at Madison Avenue was attributable to diesel 

exhaust. Of the remainder, 6% was automobile exhaust, 8.5% road dust, 8. 7% 

ammonium nitrates, 13% ammonium sulfates, 6% sea salt, 4% iron particulate and 1% 

residual oil combustion products (indicative of oil heating). The DRI report is included 

in Attachment 2. 

The DRIIDEC study implicates diesel vehicles as the largest and most 

controllable segment of the PM10 sources identified. Any offsets obtained from 

automotive or stationary sources of PM10 would be unlikely to have a significant benefit. 

Road dust is difficult to control, and natural sources of PM10 are uncontrollable. 

Ammonium sulfates and nitrates are generally secondarily formed particulate from 

precursors generated outside of the nonattainment area, and consequently do not fall 

within New York State's jurisdiction. As diesel vehicles are the largest direct source of 

PM10 in Manhattan, any PM10 offsets obtained from this segment could be quite sizable. 

Certain federal measures promise to significantly reduce the amount of particulate 

matter emitted by heavy duty diesel vehicles, buses in particular. 

These diesel vehicles will be affected by federal particulate matter (PM) control 

measures from which significant reductions are expected. As the problem is 

recognized as a hot-spot only, the federal PM control measures will have large impacts 

at specific locations heavily trafficked by diesel vehicles. On March 24, 1993, a final 

rule was published in the Federal Register regarding particulate emission regulations 

for 1993 bus engines and 1994 and later bus engines. These regulations follow a 

requirement published on March 15, 1985, 50FR1 0653, which required new diesel 

trucks (as opposed to buses) to adhere to particulate emission standards set for 1988, 

1991 and 1994. The March 1993 requirement was followed by a similar action 

published on April 21, 1993, specifying particulate matter emission requirements for 

rebuilt or retrofitted 1993 or earlier model year urban bus engines. These bus engine 

standards promise significant reductions in particulate matter emissions and the Part 5 

model reflects these emission benefits. The model, when run for the years 1990, 1995 

and 2000 predicts a significant drop in tailpipe particulate emissions. There is a 

distinct benefit associated with the emission requirements of these federal mandates. 

The emission factors alone, incorporated into the Part 5 model, represent this. For 

example, the model predicts a drop of 44% between the exhaust emissions of a model 

year 1995 bus and a model year 2000 bus. Heavy-heavy duty diesel vehicle engine 

emissions factors drop 41% during those model years. This decrease in emissions will 

greatly offset any vehicle growth during those years. We note that EPA has recently 

announced an initiative to further reduce emissions of NOx and possibly PM from diesel 
Mr. Conrad Simon 

engines. Also, the Federal low sulfur diesel fuel regulation, 55 FR3421 0, adopted on 

August 21, 1990, effective October 1,1993, promotes further reduction of PM10 when 

combined with the aforementioned diesel truck and bus engine emission standards. 

Please find New York City DEP's Part 5 model results and observations in 

Attachment 3. 

4. 

Concentrations of ambient PM10 at the Manhattan hot-spot seem directly related 

to the total volume of diesel vehicles and street geometry. Specifically, in the case of 

New York's nonattainment site in midtown Manhattan, at Madison Avenue, the problem 

is almost directly related to publicly owned diesel buses and the Avenue's geometric 

characteristics. In the period from March 1992 through December 1993, DEC 

performed a rapid assessment of particulate matter concentrations at several 

Manhattan locations impacted heavily by diesel vehicles. Two locations were identified 

as potential PM10 hot-spots. These sites are at 37th Street between Seventh and 

Eighth Avenues and Canal Street at the intersection of West Broadway. The portable 

PM monitors used in this study are not reference instruments as they collected 

particulate matter somewhat larger than PM10• Therefore, these sites are scheduled to 

have permanent PM10 reference instruments installed at or very near these exact 

locations. Please see Attachment 4 for draft results of this rapid assessment. 

New York State is pursuing the identification of PM10 hot-spots, since it has been 

determined that the New York PM10 problem exists on a microscale level. Despite the 

current PM10 nonattainment designation in place for New York County, the county has 

come into attainment, as far as the State can determine, and therefore the State must 

ask EPA for a redesignation of the county to attainment of the PM10 NAAQS. The State 

is and will continue to pursue the identification of PM10 hot-spots, but, thus far, has 

found no other sites to be in nonattainment of the PM10 NAAQS besides Madison 

Avenue. Federal control measures which are or will shortly be activated, will further 

reduce PM10 to such an extent that these emission controls will offset any growth that 

can occur in the future. The State further believes these measures will serve to 

maintain the standard, but until the Part 5 model is functioning properly, we cannot fully 

demonstrate this strategy. 

Regardless of whether or not New York County is redesignated to attainment of 

the PM10 NAAQS, New York State will submit an attainment demonstration to address 

the county's January 20, 1994 designation of moderate PM10 nonattainment. New York 

State is unable to submit this attainment demonstration on this date primarily due to 

problems encountered with the mobile source particulate emissions model, Part 5. 

While EPA released its Part 5 model in July, the model has not yet been 

officially designated for use in completing PM10 attainment designations. New York 

State believes that additional work must be completed on the model before it will 

properly predict future PM10 contributions. The lack of this modelling tool puts 
Mr. Conrad Simon 5. 

New York State in a difficult position, as the area is now in attainment and federal 

control measures should allow for both maintenance and attainment demonstrations. 

The tool needed to make these demonstrations is not yet available to us. The State is 

committed to completing this work in conjunction with EPA, the City of New York, 

affected government agencies, environmental groups and others. 

Our main difficulty with the Part 5 model lies in the way the model calculates 

fugitive dust. Our best local input data, when run in the Part 5 model, used in 

conjunction with the known PM10 background levels, significantly over predicts 

microscale PM10 concentrations measured at the Madison Avenue monitoring site. Of 

secondary concern is the emission factor that is supplied for the heavy-heavy duty 

diesel engines. 

Default fugitive dust predictions of the Part 5 model are generally much higher 

than would be expected in Manhattan. The model's prediction of fugitive/road dust is 

greatly affected by vehicle volume, roadway silt loading and average vehicle weight. 

Changes in any of these defaults can affect modeling results vastly. The default 

roadway silt values given for Madison Avenue estimate extremely high fugitive dust 

emissions, thus New York State applied the actual silt loading factor for this location, a 

number significantly lower than the model default. The modeling exercise, using the 

actual silt loading factor, resulted in a much more realistic estimate of fugitive PM10 

emissions. Although, when actual vehicle weights were input into the model (the 

default is 3 tons/vehicle, whereas transit buses weigh on the order of 20 tons/vehicle, 

the first two lanes on Madison Avenue being populated primarily by diesel transit buses 

during peak hours), the modeled PM10 due to fugitive dust again increased well beyond 

reasonable limits. This second, vehicle weight related issue has developed recently 

and the New York City Department of Environmental Protection (DEP) is grappling with 

it along with DEC. Any guidance from EPA as to how to resolve this issue would be 

appreciated. 

Another concern which DEP has shared with DEC, regarding the Part 5 model 

deals with the emission factors supplied for vehicles other than heavy urban buses, 

especially the heavy-heavy duty diesel engines. No emission factor speed adjustments 

are supplied in Part 5 for vehicles other than buses. This seems unrealistic. Heavyheavy duty diesel vehicles are of most interest here because their emission factors are 

closer to those of the heavy urban bus group than any other vehicle class, yet even 

these emission factors do not approach those of the buses. Emission factors for 

heavy-heavy duty diesel trucks vary from 1.215 grams per mile (g/mile) for 1990 trucks 

to 0.262 g/mile for 1999 trucks. In contrast, bus emission factors, depending on the 

driving cycle, vary from 7.722 g/mile in 1990 for the heavy urban bus cycle (3.9 mph) to 

0.195 g/mile for the transit bus cycle (18.5 mph). Without a speed adjustment for all 

vehicle types, it is questioned whether realistic PM10 emissions are modeled by Part 5. 

This is a concern which merits the attention of the model developers. We understand 

Mr. Conrad Simon 7. 

In conclusion, New York State requests that EPA redesignate New York County 

as attainment of the PM10 NAAQS. Regardless, the State will make every effort to 

submit an Attainment Demonstration/Maintenance Plan as soon as concerns with the 

Part 5 model can be resolved. New York will work closely with EPA to make this 

submittal a timely one. 

Attachments 

cc: Commissioner Zagata (w/attach.) 

G. Spielmann " 

C. Barrella II 

D. Sterman " 

G. Sheffer II 

bee: T. Allen II 

B. Baker, USEPA II 

J. Paisey, USEPA II 

G. Kelpin, NYCDEP II 

B. Kirch, NYSDOT II 

D. Shaw II 

C. McCarthy II 

Sincerely, 

/) /] 1:7 ~//f~ 

ArthurJ. 

Director 

Fos~~~ Division of Air Resources