# FINAL

Delaware

State Implementation Plan (SIP) Revision



## Demonstrat ion that Amendments to

Section 2.0 of 7 DE Admin Code 114 2

, Control of NO

x 

## Emissions from Industrial Boilers and Process Heaters at Petroleum Refineries Do not Interfere with Any App licable

Requirement of the Clean Air Act

Delaware Department of Natural Resources and Environmental Control



# April 11, 20111

1. Introduction

In November 200 9

, Del awa re promulgated Section 2.0 of 7 DE Admin Code 1142,

Control of NO

x Emiss ions from Industrial Boilers and Process Heaters at Petroleum Refineries

. In June 2010

, Section 2.0 of 1142 was approved by the E nvironmental Protection Agency (E PA ) into Delaware’s State Implementation Plan (SIP) ( 75 FR 31711 )

.

The purpose of Section 2.0 of 7 DE Admin Code 1142 is to reduce nitrogen oxides (NO

x ) emissions from large industrial boilers and process heaters that are located at petroleum

refineries. This reduction in NO

x emissions from the affected units w ould aid in t he attainment

and ma intenance of any national ambient air quality standard (NAAQS)

, and any other applicable requirement that is affected by NO

x emissions

. NAAQSs and applicable requirements that are affected by NO

x emissions are:

Ozone NAAQS

. NO

x emissions impact air qual ity relative to ozone . This is because ozone is formed through a reaction in the atmosphere between NO

x and volatile organic compounds ( VOC ) in the presence of heat and sunlight (i.e., NO

x and VOC are precursors to the formation of ozone). T he air qualit y in Delaware is designated under

Section 107 of the Clean Air Act (CAA) as not meeting the 1997 health based NAAQS of 0.08 ppm for ozone. In addition, the EPA issued a revised 8

- hour ozone NAAQS of 0.075 ppm in March 2008

, and has proposed to reconsider that revised NAAQS in January of 2010. The air quality in Delaware i s anticipated to be designated as non

attainment under the new ozone NAAQS.

Under th e 1997 ozone NAAQS the entire state of Delaware is included as part of a Philadelphia based non

- a ttainment area (NAA). Delaware submitted to the EPA an attainment demonstration SIP in July 2007 which demonstrated that the NAA would attain compliance with th at NAAQS by 2010

. EPA has not yet issued area designations

for th e 2008 revised NAAQS, and has not yet finalized its reconsideration of th e 2008

revised NAAQS

.

Fine Particulate Matter (PM 2.5 ) NAAQS

. NO

x emissions contribute to the formation of nitrate particulates in the atmosphere, and nitrate particles are PM 2.5 (i.e., they are particles with an aerodynamic diameter of 2.5 microns or less). T he air quality in New Castle County Delaware is designated under Section 107 of the CAA as not meeting the

1997 health based NAAQS for PM 2.5

. In addition, the EPA issued a revised PM 2.5 NAAQS in 2006.

Under th e 1997 NAAQS New Castle County Delaware is included as part of a Philadelphia based NAA. Delaware submitted to the EPA an attainment demonstration

SIP in April 2008 which demonstrated that the NAA would attain compliance with the NAAQS by 2010 1

. Relative to th e 2006 PM 2.5 N AAQS

, New Castle County Delaware is

1 Based on 2007

- 2009 monitoring data, New Castl e County has attained the 1997 NAAQS for the annual and daily

standard.2

designated as non

- attainment for the daily standard, and is included as part of the Philadelphia based NAA . T he attainment demonstration SIP is due in December 2012. 2

Visibility. NO

x emissions contribute to the formation of PM 2.5 , and PM 2.5 is a visibility impairing pollutant under the federal regional haze program. Visibility impairing

emission from Delaware have been determined to “significantly” 3 impact one (1) federal

class 1 ar ea
, Brigantine National Wildlife Area, in New Jersey.

T he State of Delaware submitted to the EPA in September 2009 a Visibility SIP that met the requirements of Part C to Title I of the CAA. This SIP primarily relied upon SO 2 reductions, because sulf

ate was determined by the Regional Planning Organizations to be the main cause of visibility impairment in Class I areas. However, the SIP also partially

relied on reduction s in NO

x emissions to demonstrate that Delaware has met its 2018 visibility relate d goals.

Nitrogen Diox id e (NO 2 ) NAAQS

. NO

x emissions, by definition, directly impact

ambient NO 2 concentrations. T he air quality in Delaware is designated under Section 107

of the CAA as meeting the current annual NO 2 NAAQS. In F ebruary 2010

, the EPA

r evised the annual NO 2 NAAQS and issued a new hourly NO 2 NAAQS.

EPA has not issued designations of areas under th e 2010 revised NAAQS

, and State recommendations for designation of areas are due to the EPA in January 2011

.

Section 2.0 of 7 DE Admin C ode 1142 does not limit emissions of any pollutant other

than NO

x . Section 2.0 cover s nine ( 9 ) emission units at the Delaware City Refinery , and imposes compliance date s between 2007 and 2012, depending on the particular emission unit.

In 2009 the oper ations of equipment at the Delaware City Refinery were discontinued, and

in 2010 the refinery ownership changed from Premcor Refining Group Inc. to Delaware City Refining Company, LLC (“DCRC”). Two actions related to this change in ownership impact

Delawa re’s SIP :

On May 28, 2010

, the Delaware Department of Natural Resources and Environmental

Contr o l ( the Department ) reached a n enforcement settlement with Premcor. This

settlement , among other things, terminated the 2008 FCCU NOx Agreement which had requi red the Premcor fluid catalytic cracking unit CO boiler to meet a 20 parts per million ( ppm ) NO

x emission limitation by May 1, 2009. 4

2 B ased on 2007

- 2009 monitoring data, New Castle County has already attained the 2006 PM 2.5 NAAQS.

3 As a result of the consultation process, t he M iddle Atlantic and Northeast Vis ibility Union (M ANE

- VU ) States defined contributions to Class I areas as “significant” if a State contributed at least 2 percent of total sulfate observed on the 20 percent worst visibility days in 2002. Based on the MANE

- VU Contribution Assessment and th e application of the “≥ 2% SO 2 rule,” emissions from Delaware were determined to contribute to visibility degradation exclusively to the Brigantine Wilderness Class I area (note that NOx was not the primary pollutant of concern in this round of Regional Ha ze SIPs)

.

4 2008 Consent Decree with Premcor Refinery at Delaware City, The FCCU NOx Agreement3 On May 31, 2010 the Departmen t and DCRC reached an agreement on DCRC’s acquisition , restart and operation of the Delawar e City Refinery. One element of that agreement provides that the Departmen t will propose to revise Section 2.0 of 7 DE

Admin Code 1142 to pr o v i de for a f acil i ty

- wide NO

x emission cap compliance

alternative

.

I n a separate regulatory pro cess
, Delaware is proposing to revise Section 2 .0 of 7 DE

Admin Code 1142 to ( 1) provide for the control of NO

x from the Fluid Catalytic Cracking Unit

CO boiler to the level that was previously required by the 2008 consent agreement, and ( 2) provide for a facility

- wide NOx e mission cap compliance alternative

. Th e purpose of th is SIP

revision is to demonstrate that t he se revisions to Section 2 .0 of 7 DE Admin Code 114 2 will not

interfere with attainment or maintenance of any NAAQS

, or any other applicable requirement of

the CAA

.

Questions or comments regarding this SIP revision should be addressed to Ronald A.

Amirikian , P lanning Branch Manager, Division of Air Quality, Delaware Department of Natural Resources and Environmental Control, at (302) 739

- 9402 or ronald.amirikian@state.de.us

.

2. Impact Analysis

Section 2.0 of 7 DE Admin Code 1142 sets emission limits only for the pollutant NO

x , and only impacts the Delaware City Refinery (i.e., the Delaware City Refinery is the only petroleum refinery within the State of Delaware). This analysis consider s the effect the revisions

to Section 2.0 of 7 DE Admin Code 1142 have on applicable requirements for which NOx emissions are a precursor or pollutant of interest. That is, the pollutants ozone, PM 2.5 , visibility,

and NO 2

.

2. 1

. Baseline NO

x emissions from the Delaware City Refinery

.

Ozone. 2002 i s the SIP base year for planning associated with the 1997 0.08 ppm ozone NAAQS. Actual 2002 base year NO

x emissions from t he Delaware City Refinery were 3,555 TPY. For the 2008 revised NAAQS, which is currently being reconsidered , a SIP planning base year has not yet been determined. The most current emission inventory is 2008, and actual 2008 NO

x emissions from the Delawa re City Refinery were 2 ,5 2 5 TPY

.

PM 2.5 . 2002 is the SIP base year for planning associated with the 2008 PM 2.5 15 ug/m 3
annual, and the 65 ug/m 3 daily NAAQSs . Base year 2002 NO

x emissions are identical

to those identified under ozone above. For the 2008 revised NAAQS

, a SIP planning base year has not yet been determined. The most current emission inventory is 2008,

and actual 2008 NO X emissions from the Delaware City Refinery were those identified

under ozone above

.

Visibility. 2002 is the SIP base y ear for planning associated with D elaware’s 2008 Visibility SIP. Base year 2002 NO

x emissions are those identified under ozone above.4

NO 2 . F or the 2010 revised NAAQS

, area designation has not yet occurred, and a SIP planning base year has not yet bee n determined. The most current emission inventory is 2008, and actual 2008 NO

x emissions from the Delaware City Refinery were those

identified under ozone above

.

2. 2 . Projected NO

x emissions from the Delaware City Refinery under current (i.e., before

r evision) Section 2.0 of 7 DE Admin Code 1142

.

Ozone. Delaware’s 2007 Ozone SIP demonstrates that compliance with the 1997 0.08ppm ozone NAAQS will be achieved in 2009, based on 2009 projected emission

levels. 2002 was the SIP base year, and 2002 base ye ar NOx emissions (see 2.1 above) were projected to 2009 by applying factors that account for projected growth and controls. The projection calculations are explained in detail in the 2007 ozone SIP.

The following five (5) emission units received post

- 200 2/Pre

- 2009 emission controls that were relied upon in the 2007 ozone SIP calculations 5 :

Boiler 1 (Unit 80

- 1)

– 80% control from 7 DE Admin Code 1142 6

Boiler 2 (Unit 80

- 2)

– 80% control from 7 DE Admin Code 1142
Crude Unit vacuum Heater (Unit 21

- H

- 2)

– 60% control from 1142 Fluid Catalytic Cracking Unit CO Boiler

– 86.7% control from 2008

Consent Decree 7

Methanol Plant Heater 41

- H

- 1

– 100% control from 2003 shut down

Resultant 2009 attainment year emissions from the Delaware City Refinery (i.e., those

after the application of growth, the 41

- H

- 1 shutdown, the control of Units 80

- 1, 80

- 2, 21

- H

- 2, and the Cracker CO boiler) were estimated at 2,855 TPY.

PM 2.5 . Delaware’s 2008 PM 2.5 SIP d emonstrates that compliance with the 1997 15 ug/m3 annual, and the 65 ug/ m3 daily standards will be achieved in 2009, based on 2009 projected emission levels. 2002 was the SIP base year, and 2002 base year NOx emissions (see 2.1 above) were projected to 2009 by applying factors that account for projected growth and controls. The projection calculations are those discussed under

ozone above

.

Visibility. Delaware’s 200 9 Visibility SIP is based on 2018 projected emission levels

.

5 Note that the Crude Unit Atmospheric Heater (Unit 21

- H

- 701) is regulated by 7 DE Admin Code 1142. 1142 imposes a limit of 0.04 lb/mmbtu, however, this limit was previously imposed in 1996 as a LAER limit pursuant to

7 DE Admin Code 1125. Unit 21

- H

- 701 will remain subject to the 0.04 lb/mmbtu limit independent of 7 DE Admin

Code 1142 because it was a NSR derived limitation

6 2.0 of 7 DE Admin Code 1142, Contr ol of NOx Emissions From Industrial Boilers and Process Heaters at Petroleum Refineries, Effective 2008. Note: this regulation was revised effective 11/11/2009, and the 11/11/2009 revision was approved into the DE SIP at 75 FR 31711 on June 4, 2010.

7 Co nsent Decree with Premcor Refinery at Delaware City, The FCCU NOx Agreement

.5

Section 2.0 of 7 DE Admin Code 1142 provides for compliance dates between 2009 and

2012. In 2012 the requirements of 7 DE Admin Code are fully implemented. As part of

Delaware’s 200 9 Visibility SIP, 2002 NOx emissions from the Delaware City Refinery were projected to be 2,761 TPY, and 2,774 TPY , for 2012 and 2018, respectively.

The 1142 related N Ox controls relied upon in the Visibility SIP were:

Boiler 1 (Unit 80

- 1)

– 80% control from 7 DE Admin Code 1142
Boiler 2 (Unit 80

- 2)

– 80% control from 7 DE Admin Code 1142
Crude Unit vacuum Heater (Unit 21

- H

- 2)

– 60% control from 1142 Fluid Catalytic Cra cking Unit CO Boiler

– 86.7% control from 2008

Consent Decree

Methanol Plant Heater 41

- H

- 1

– 100% control from 2003 shut down

Boilers 80

- 3 and 80

- 4

– 100% control from shutdown on or before May 1,

2011. 8

NO 2

. F or the 2010 revised NAAQS

, area de signation has not yet occurred. The 2002 and

2008 actual NO

x emissions, and the 2009, 2012 and 2018 projected NO

x emissions discussed above are used to evaluate the impact that the revisions to Section 2.0 of 7 DE

Admin Code 1142 would have on future NO 2 NAAQS pla nning.

2. 3 . Revision to Section 2.0 of 7 DE Admin Code 1142.

Delaware is revi sing Section 2.0 of 7 DE Admin Code 1142 to ( 1) provide for the control

of NOx emissions from the Fluid Catalytic Cracking Unit CO Boiler (Unit 23

- H

- 3) that

was previously req u ired under a 2008 consent decree , and ( 2) provide for, as an option, compliance with a facility

- wide NOx cap as an alternative to unit specific NOx emission

limitations.

The initial facility

- wide cap is being established at the level of Premcor’s actual 2008

NOx emissions (i.e., 2,525 T P Y ) , and will decline in two step decreases , as follows:

2,525 tons per year, evaluated over each twelve (12) consecutive month rolling period, for any twelve (12) month rolling period ending on or before January 2014.

2,225 tons per year, evaluated over each twelve (12) consecutive month rolling period, commencing with the twelve (12) month rolling period beginning on December 31, 2013 and ending on December 31, 2014.

1,650 tons per year, evaluated over each twelve (1 2) consecutive month rolling period, commencing with the twelve (12) month rolling period beginning on December 31, 2014 and ending on December 31, 2015.

8 Note that in the current Delaware SIP Boilers 3 and 4 are not required to shutdown, a nd the allowable emission rate for Boilers 1, 3 and 4 were finalized at 0.015 lb/mmbtu limit, 24

- hour rolling average basis. See also footnote 4.6

Under the revised Section 2.0 of 7 DE Admin Code 1142, either all of the unit specific

NOx emission li mitation s apply or the facility

- wide cap apply at all times (i.e., there is n o gap in compli a n c e ).

2. 4 . Impact of Revised 7 DE Admin Code 1142 on ozone, PM 2.5 , visibility and NO 2 , (i.e., the requirements for which NO

x emission s are a precursor or pollut ant of interest )

.

The addition of emission limits to Section 2.0 of 7 DE Admin Code 1142 applicable to

Unit 23

- H

- 3 do not in any way change the emission limits for this unit. That is, the

emissions limit for Unit 23

- H

- 3 do not change, but only the veh icle by which these emission limits will be enforced is changing (i.e., it will be enforced through Section 2.0 of 7 DE Admin Code 1142 instead of a consent agreement). In other words, no change is being made that could upset the status quo

.

With th e rev ision to 2.0 of 7 DE Admin Code 1142 described in 2. 3 above, the Delaware City Refinery may comply by either ( 1) complying with all of the unit specific emission

limitations specified in 7 DE Admin Code 1142 , or ( 2) complying with the applicable facility

- w ide NOx emission cap.

Complying with all of the unit specific emission limitations specified in 7 DE Admin

Code 1142

.

T his is the current compliance mechanism in Section 2.0 of 7 DE Admin Code 1142.

Therefore , since overall no change is being made to the unit specific emission rates

this co mpliance option would not impact any NAAQS or applicable requirement (i.e., no chang e is being made that could upset the status quo )

.

Complying with the applicable facility

- wide NO X emission cap. U nder this compli ance option

, emission u nits will not be subjected to the unit specific emission

limitatio ns of Section 2.0 of 7 DE Admin Code 1142, and instead the entire facility will be subject to a facility

- wide NO X cap.

Compliance with the 7 DE Admin Code 1142 faci lity

- wide caps is required monthly,

on a 12

- month rolling basis. For standards where compliance is demonstrated on an annual or longer basis, an annual cap is generally consistent with a NAAQS with an annual averaging period.

The NO 2 and PM 2.5 NAAQS bo th have a standard which is averaged on an “annual”

basis. For the NO 2 annual NAAQS, this is the arithmetic average of all of the reported 1

- hour values (40 CFR Part 50, Appendix S). For both of the PM 2.5 annual NAAQS s (1997 and 2006), the annual standar d design value, which is based upon 3 years of valid annual means, is compared to the NAAQS (40 CFR Part 50 Appendix N). The design value is an average of three annual means over three consecutive years. An annual mean is the average of the average value s for each of the four quarters in a calendar year; the average value for each quarter is the average of the daily values for that quarter.7 As long as the cap set by 7 DE Admin Code 1142 is lower than a baseline condition (i.e., 7 DE Admin Code 1142 bef ore amendment), a conclusion that the revised

Section 2.0 of 7 DE Admin Code 1142 will cause no worsening of air quality is supported.

The table below summarizes the Delaware City Refinery NO X emission data presented in 2. 1 and 2.2 above

.

Year NO X (TPY )

2002 ( actual ) 3,555

2008 ( actual ) 2,525

2009 ( projected ) 2,855

2012 ( projected ) 2,761

2018 ( projected ) 2,774

As discussed in 2.3 above

, the facility

- wide NO X cap will start at 2,525 TPY, and decline to 1,650 TPY in 2015. This declining cap optio n provides for emissions that

are lower than the actual and projected emission levels under the current unit specific control option. This indicates that the facility

- wide NO X emission cap compliance option will not negatively impact the 1997 and 2006 ann ual PM 2.5 NAAQS s
, the 2010

annual NO 2 N AAQS, and visibility related goals

Complying with the applicable facility

- w ide NO X emission cap

– Additional Analysis

. For standards where compliance is demonstrated on a more frequent basis, additional analysis is needed. This is because a 12

- month rolling total could provide for higher emissions on a seasonal or a daily basis.

The 1997 and 2008 ozone NAAQS s is directl y related to the highest concentration averaged over an 8

- hour period in any one (calendar) day . T he 2010 daily NO 2 NAAQS is determined by comparing the 1

- hour primary standard design value, which is the average of three annual 98th percentile values, to the NAAQS (40 CFR Part 50, Appendix S). Likewise, compliance with the 1997 and 2006 24

- hour PM 2.5 NAAQS s is determined by comparing the 24

- hour standard design value, which is an average the annual 98 th percentile values for each of three years (40 CFR Part 50 Appendix N).

In addition to the comparison between the actual and projected emissions and the facility

- wide cap discussed above, s easonal variations were evaluated. The Department analyz ed monthly crude oil throughputs from the crude oil tank farm, which is an indicator of the capacity factor of the refinery. Historical throughput is

use ful data to analyze because such data supports a conclusion that utilization will not drastically vary by month in the future. Four (4) years, 2005 through 2008, were evaluated (see table below).8 Crude Tank Farm Throughput (%)

2005 2006 2007 200 8 January 8.4 7.6 8.7 10.2 February 7.6 8.0 6.7 8.3

March 6.9 8.1 8.2 9.8 April 8.2 8.5 8.2 8.3 May 9.4 8.7 8.7 7.8

June 9.1 8.4 8.6 9.4 July 9.4 8.6 9.0 10.0 August 8.8 8.8 8.8 10.0 September 9.5 8.5 7.8 10.0

October 8.4 8.5 8.7 10.1

November 6 .7 8.2 8.2 3.9 *

December 7.7 8.3 8.4 2.2 *

*Note: November and December of 2008 are determined to be not representative of normal operations. The refinery was running as significantly reduced rates during

these months because the crude unit had its turn around in November 2008 and the Coker was down. Because of this 2008 was not evaluated further.

Based on 2005, 2006 and 2007 crude tank farm throughput, the Department concludes there is a slight bias high during the ozone season months. However, given the monthly deviation is slight ( 36

- month average percent is 8.3, and the standard

deviation from th e average is 0.7), and given that the facility

- wide NOx caps are less

than the recent actual and projected emissions , the Depar tment concludes that refinery operations in the future will be essentially uniform throughout the year, and the 12

- month rolling caps are consis tent with NAAQS and other applicable require ments

.

In addition to crude oil throughputs from the crude oil tank farm, the Department has

al so analyzed the variability of daily emissions from the Delaware City Refinery. This was done by analyzing a ctual historical NO X emissions for th e refinery units that

are covered by 7 DE Admin Code 1139, “Nitrogen Oxides (NO X ) Budget Trading Program.” Th e NO X emission s from units subject to 7 DE Admin Code 1139 are monitored by continuous emission monitoring systems (CEMS). Historical NOx

emissions data for these units were obtained from EPA’s Clean Air Market’s Division (CAMD) at http://camddataandmaps.epa.gov/gdm for calendar years 2005 through

2007.

Analysis of Daily Average NO X Emissions: The daily average NO X emissions for all units reporting to CAMD, in TPD, for CY2005, 2006, and 2007, by mont h, are as

follows:9 Daily Average NO X Emissions (TPD)

2005 2006 2007
January 8.6 5.7 7.3
February 8.7 8.4 7.4

March 8.1 8.3 6.8
April 8.2 8.0 6.7
May 8.3 8.3 6.2

June 8.8 7.9 6.8
July 7.7 6.2 7.1
August 7.0 5.7 7.6
September 7.5 6.3 6.7

Octob er 6.0 8.2 7.2

November 5.0 7.9 7.2

December 6.2 6.1 7.5

S tdev 1.2 1.1 0.4

A verage 7.5 7.2 7.0

T he daily average NO X emissions for each month between January 2005 and

December 2007 is within one ( 1 ) standard deviation of the annual average daily NO X emissions for each month for all three (3) years, except for June 2005 (which is 1.03

standard deviations from the average ). This indicates there is little variation in daily

NO X emissions from month to month , and that operations under a 12

- month roll ing total facility

- wide NO X cap will not result in high daily NO X emissions during times of bad air quality, and would not negatively impact applicable requirements

.

Analysis of Highest Single Day NO X Emissions: The highest single day’s NO X emissions for all units reporting to CAMD, in TPD, for calendar years 2005, 2006, and 2007, by month, are as follows:

Highest Single Day NO X Emissions

(TPD)

2005 2006 2007
January 11.0 7.5 8.8
February 9.8 9.4 9.1

March 10.5 9.5 8.2
April 9.4 11.4 13.0
May 10.8 9.4 7.2

June 11.1 9.1 7.9
July 9.6 7.8 8.610 August 8.5 7.1 8.9
September 9.4 8.1 8.1

October 11.3 10.2 8.9

November 6.5 10.0 9.0

December 8.3 7.2 8.6

Stdev 1.4 1.3 1.4

Average 9.7 8.9 8.8

Delaware’s air quality is generally worst in t he hot summer months of June, July and August. The highest single day NO X emission from the Delaware City Refinery were generally outside of this period. In all three (3) of the years analyzed the highest daily NO X emissions occurred during months were a ir quality is generally good in Delaware (i.e., October for 2005

, and April for 2006 and 2007)

. In addition, only in

t hree ( 3 ) months out of the thirty

- six (36) months (i.e., October 2005, April 2006, and April 2007) analyzed did the highest single day NO X emission exceed the highest single day annual average plus one (1) standard deviation. This indicates that operations under a 12

- month rolling total facility

- wide NO X cap will not provide for high emission s on bad air quality days, and will not negative ly impact applicable requirements.

Analysis of the Number of Day s that NO X Emissions exceed Annual Average plus 1

standard deviation : The table below shows the number of days were daily NO X emission were greater than the annual average emissions plus one (1) standard

deviation.

Number of D ays NO X Emissions

Were Greater T han Annual Average P lus 1 Standard Deviation

2005 2006 2007
January 4 4 9
February 4 5 5

March 2 8 2
April 4 2 3
May 4 5 4

June 6 5 4
July 5 2 5
August 4 7 3
September 6 8 4

October 5 3 4

November 5 5 4

December 3 6 411 Out of these three (3) years, the maximum number of days that the daily NOx emissions exceed the mean/average plus one (1) standard deviation was only 9 (January 2007). On only seven ( 7 ) out of these thi rty

- six ( 36 ) months did the daily

NOx emissions exceed o ne (1) standard deviation more than 5 times. And, the number of times the daily NO X emissions exceeded one (1) standard deviation is

constant from month to month.

The above analysis indicates that r elative to the 1997 ozone NAAQS , the planning assumptions used in the 2007 attainment demonstration SIP would not be undermined by

the revisions to Section 2.0 of 7 DE Admin Code 1142. This is because refinery operations do not vary significantly from mon th to month, and actual emissions levels do not vary significantly over an ozone season or do not vary significantly on a daily basis

within the months of the ozone season. Relative to the 2008 ozone NAAQS , planning is now underway but base year and attai nment years have not yet been set. Preservation of the status quo air quality will prevent interference with Delawares’ obligations to develop timely attainment demonstrations, and no interference with the ozone N AAQS (i.e., no change is being made that w ould upset the status quo)

.

Relative to the daily standard of the 2006 PM2.5 NAAQS (which sets a lower threshold

than t he 1997 daily NAAQS and would address the daily standard under the 1997 NAAQS for which New Castle County is in attainment), the above a nalysis also indicates that the planning assumptions used in the 2008 attainment demonstration SIP would not be undermined by the revisions to Section 2.0 of 7 DE Admin Code 1142 (i.e., a 12

- month rolling cap is consistent with attainment because refinery utilization and emissions do not vary significantly from month to month or from day to day).

Relative to the NO 2 NAAQS , area designations have not yet occurred. Because refinery operations do not vary significantly from month to month, and actual emissio ns levels do not vary significantly over the year, preservation of the status quo air quality will prevent interference with Delawares’ obligations to develop timely attainment demonstrations,

and no interference with the NO 2 NAAQS (i.e., no change is bein g made that would upset the status quo).

3. Conclusion

Delaware con cludes that the revisio ns to Section 2 .0 o f 7 DE Admin Code 114 2 to 1) include the NOx control requirement for the Fluid Catalytic Cracking Unit CO boiler that were previously provided for in a 2008 consent agreement and 2) provide f or a facility

- wide NOx cap compliance alternative will not interfere with attainment or maintenance of any NAAQS or any other applicable requirement of the CAA