UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION III 1650 Arch Street Philadelphia, Pennsylvania 19103



### DATE: OCT

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### 62010 SUBJECT: Technical Support Document Regarding Ozone Monitoring Data

— Delaware, Maryland, Pennsylvania; One-Year Extension for Attaining the 1997 8-Hour Ozone Standard for the Delaware, Maryland, and Pennsylvania Portions ofthe Philadelphia-Wilmington-Atlantic City Moderate Nonattainment Area



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. FROM: MariaA. Pino, Air Quality Planmng Specialist Office ofAir Program Planning
TO: File
THRU: BrianK. Rehn, Acting Associate Director Office ofAir Program Planning

This documentprovides atechnical review ofthe air quality monitoring dataused to supportthe approval ofthe attainment date extension requests for the Delaware, Maryland, and Pennsylvania portions ofthe Philadelphia-Wilmington-Atlantic City nonattainment area (PhiladelphiaArea), which is classified as moderate forthe 1997 8-hour ozone national ambient air quality standard (NAAQS).

A. BACKGROUND
The Philadelphia Area consists ofCecil County in Maryland; Bucks, Chester, Delaware, Montgomery and Philadelphia Counties in Pennsylvania; the entire State ofDelaware; and Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, Mercer, Ocean, and Salem Counties inNew Jersey. Since this areawas classified as amoderate ozone nonattainment area, the statutory ozone attainment date, as prescribed by section 181(a) ofthe Clean Air Act (CAA), is June 15, 2010. The Commonwealth ofPennsylvania and the States ofMaryland and Delaware (the States) requested a one-year attainment date extension forthe Philadelphia on January 8, 2010, March 12, 2010, and May 18, 2010, respectively. The States’ requested thatthe attainment date be extended to June 15, 2011.
Section 172(a)(2)(C) ofsubpart 1 ofthe CAAprovides forEPAto extend the attainment date for
an areaby one year ifthe State has complied with all the requirements and commitments pertaining to the area in the applicable implementationplan and no more than a minimal number ofexceedances ofthe NAAQS has occurred in the attainmentyear. Up to two one-year extensions may be issued for a single nonattainmeflt area. Section 181 (a)(5) ofsubpart 2contains a similarprovision forthe ozone NAAQS, but instead ofproviding for an extension where there has been a “minimal” number ofexceedances, it allows an extension only ifthere is no more than one exceedance ofthe NAAQS in the yearproceeding the extension year. However, the language in sectiori 181 (a)(5) reflects the form ofthe 1-hour ozone NAAQS and notthe 1997 8-hour ozone NAAQS. In EPA’s Final Rule To Implementthe 8-Hour Ozone National AmbientAir Quality

—Phase 1(69 FR 23951), known as the Phase I rule, EPA sets forthhow sections 172(a)(2)(C) and 181(a)(5) apply to an area subjectto the 1997 8-hour ozone NAAQS. These requirements, codified in 40. CFR 51.907, are as follows: An areawill meetthe requirement ofsection 172(a)(2)(C)(ii) or 181 (a)(5)(B) ofthe CAA pertaining to 1-year extensions ofthe attainment date if: (a) Forthe first 1-year extension, the area’s 4th highest daily 8-hour average in the attainmentyear is 0.084 ppm or less. (b) Forthe second 1-year extension, the area’s 4thhighest daily 8-hour value, averaged overboth the original attainment year and the first extension year, is 0.084 ppm or less. (c) Forpurposes ofparagraphs (a) and (b) ofthis section, the area’s 4th highest daily 8- hour average shall be from the monitor withthe highest4th highest daily 8-hour average ofall the monitors thatrepresentthat area.

B. EVALUATION OF AIR QUALITY MONITORING DATA
I. DataRequirements
As stated above, for the first 1-year extension, the area’s 4 th highest daily 8-hour average in the attainmentyear is 0.084 ppm or less. In order to determine ifthis criterion has been met, the data handling conventions ofAppendix I of40 CFR 50 (Appendix I) mustbe followed. This appendix sets out the datahandling conventions and calculations necessary for determining whetherthe 1997 8-hour ozone NAAQS have been met at any given ambient ozone air quality monitoring site.
Forthe PhiladelphiaArea, the ozone season extends from the beginning ofApril throughthe end ofOctober. A complete ozone season consists of214 monitoring days. According to Appendix I, at least 75% data capture is required each year. For years where there is less than 75% data completeness, certain data substitution is allowed.
“When computing whetherthe minimum data completeness requirements have been met, meteorological or ambient datamay be sufficient to demonstrate thatmeteorological conditions onmissing days were not conducive to concentrations above the level ofthe standard. Missing days assumed less than the level ofthe standard are counted for the purpose ofmeeting the data completeness requirement, subjectto the approval ofthe appropriate Regional Administrator.”

2IL Recorded Air Quality Monitoring Data
The States submitted complete, quality assured air qualitymonitoring data into the Air Quality Management System (AQS). EPA then concurred on the States’ data. Attached are two AQS reports forthe 2007-2009 ozone seasons. The firstreportis forthe Delaware, Maryland, and Pennsylvaniaportions ofthe Philadelphia Area. The second reportis forthe New Jersey Portion ofthe PhiladelphiaArea. Table 1, below, summarizes those reports.
As shown below in Table 1, all 8-hour ozone 4 th maximum air quality monitoring values in the PhiladelphiaArea were 0.084 ppm or less in 2009. In fact, the highest 4t1 maximum value in the Philadelphiain 2009 was .074 ppm. Table 1. 2007-2009 8-Hour Ozone Air Quality Monitoring Data for the Philadelphia Area

Monitoring City County State Year % Days Valid Days 4 thMax Site ID Observed Measured Value 10-001-0002 Notinacity Kent DE 2007 99 211 .078 2008 100 213 .081 2009 99 211 .066 10-003-1007 Not in a city New Castle DE 2007 99 211 .081 2008 99 212 .078 2009 90 193 .068 10-003-10 10 Not in a city New Castle DE 2007 94 202 .086 2008 95 203 .082 2009 53 113 .068 10-003-1013 Wilmington New Castle DE 2007 100 213 .077 2008 100 214 .077 2009 97 207 .069 10-005-1002 Seaford Sussex DE 2007 98 210 .081

. 2008 99 211 .081 2009 98 209 .067 10-005-1003 Lewes Sussex DE 2007 51 109 .080 2008 100 214 .079 2009 97 207 .069 24-015-0003 Not in a city Cecil MD 2007 98 209 .092 2008 97 207 .088 2009 94 201 .072 42-017-0012 Bristol Bucks PA 2007 80 172 .102 2008 98 210 .089 2009 100 213 .074 42-029-0100 Not in a city Chester PA 2007 93 200 .081 2008 99 212 .084 2009 98 210 .067 42-045-0002 Chester Delaware PA 2007 99 211 .086 2008 100 214 .081 2009 98 210 .065

3Monitoring City County State Year % Days Valid Days 4 thMax Site ID Observed Measured Value 42-091-0013 Norristown Montgomery PA 2007 98 209 .084

• 2008 97 207 .084 2009 100 214 .070 42-101-0004 Philadelphia Philadelphia PA 2007 100 213 .073 2008 98 209 .062

, 2009 99 212 .059 42-101-0014 Philadelphia Philadelphia PA 2007 99 211 .081 42-101-0024 Philadelphia Philadelphia PA 2007 100 213 .095

. 2008 100 214 .087 2009 71 152 .072 42-101-0136 Philadelphia Philadelphia PA 2007 82 175 .082 34-001-0005 Galloway Atlantic NJ 2007 92 197 .072 Township 34-001-0006 Notin a city Atlantic NJ 2007 92 196 .078 2008 95 204 .072 2009 94 201 .071 34-007-0003 Camden Camden NJ 2007 97 207 .092 2008 81 174 .083 34-007-1001 Not in a city Camden NJ 2007 92 196 .091 2008 98 210 .082 2009 96 205 .071 3401 1-0007 Vineland Cumberland NJ 2007 98 210 .083 2008 98 210 .079 2009 99 212 .072 34-015-0002 Not in acity Gloucester NJ 2007 86 183 .089 2008 96 206 .089 2009 99 211 .071 34021-0005 Lawrence Mercer NJ 2007 97 207 .094 Township 2008 99 212 .079 2009 97 208 .071 34-029-0006 Not in a city Ocean NJ 2007 95 203 .086

. 2008 100 213 .085 2009 98 210 .071

III. Data Issues
A. Less than 75% data completeness for 2009 data Philadelphia County In 2009, monitor42-101-0024 in Philadelphia County, PA, recorded data for 71% ofthe required days. Failure ofan exhaust fanpump causedthe monitorto be out ofoperation for 42 days, from September 16, 2009 to October 26, 2009. On April 29, 2010, thePhiladelphiaDepartment of

4Public HealthAir Management Services (AMS), which runs the air quality monitoring network in Philadelphia County, submitted a data substitution analysis forthis monitor forthe 2009 ozone season. That analysis, dated March 29, 2010, uses the data substitutionprovisions ofAppendix I to 40 CFRPart 50 to determine that 29 days in that42-day period ofdown time had metrological conditions that were not conducive to ozone formation above the level ofthe 2008 ozone NAAQS, 0.075 ppm. Based onthis analysis, AMS requested thatmissing monitoring data for those 29 days be counted in determining data completeness for 2009. EPA Regional Administrator Shawn M. Garvin approved thatrequestin a letter dated May 17, 2010. AMS’s data substitution analysis and EPA’s approval letter are attached.
New Castle County In New Castle County, DE, monitor 10-003-1010 recorded data on 53% ofthe required days in 2009. The Delaware Department ofNatural Resources and Environmental Control (DNREC) submitted a data substitution analysis forthis monitor forthe 2009 ozone season. That analysis, dated July 19, 2010, uses the data substitution provisions ofAppendix Ito 40 CFR Part 50 to determine that 55 ofthe days when monitor 10-003-10 10 was down in 2009 had metrological conditions that were not conducive to ozone formation above the level ofthe 2008 ozone NAAQS, 0.075 ppm. Based onthis analysis, DNREC requested thatmissing monitoring data for those 55 days be counted in determining data completeness for 2009. EPA Regional Administrator Shawn M. Garvin approvedthatrequestin a letter dated September 24, 2010. DNREC’s data substitution analysis and EPA’s approval letter are attached.

B. Monitor Shutdowns Philadelphia County In Philadelphia County, monitors 42-101-0014 and 42-101-0136 were shut down in 2007. AMS had askedEPA ifit could discontinue some monitors. EPA advised AMS that monitor42-101- 0024, located atNortheast PhiladelphiaAirport, was the high ozone site, and therefore it needed to stay. The monitor atthe AMS laboratory (monitor 42-101-0004) was a Photochemical Assessment Monitoring Stations (PAMS) site, where ozone monitoring was required. Therefore, that monitor also needed to remain inplace. The PhiladelphiaAreahad more ozOne sites then what was minimally required. In addition, the ozone design values forboth sites considered for shutdownwere below .085 ppm. Therefore, EPA approved the shutdowns ofmonitors 42-101- 0014 and 42-101-0 136 withthe approval ofAMS’s July 1, 2008 Annual Network Plan.
Atlantic County New Jersey Department ofEnvironmental Protection (NJDEP) operated a monitoring site (34- 00 1-0005) in Galloway Township, Atlantic County. A new monitoring site atthe Visitor Center ofthe Edwin B. Forsythe National Wildlife Refuge in Brigantinebecame available andNJDEP started running an 03 analyzer atthis new site (34-001-0006) inApril of2007. NJDEP operated the site in Galloway Township and in Brigantine for several months to obtain overlapping ozone data. NJDEP then shut down monitor 34-001-0005 in Galloway Township in midNovember 2007 since the two sites were very close to each other and recorded similar values.

5.Camden County The NJDEP shut down monitor 34-007-0003 in Camden County in 2008. The Camden Lab station, which had been in operation since 1968, was unexpectedly discontinued on September 29, 2008 due to lack ofsecurity atthe station. TheNJDEP in coordination with EPA is actively pursuing the establishment ofa new station in Camden.

Attachments:

- EPA AQS Quick LookReport (AMP45O), dated June 22, 2010, containing 2007- 2009 ozone air quality data forthe Delaware, Maryland, and Pennsylvaniaportions ofthe Philadelphia Area.

- EPA AQS Data Quality IndicatorReport (AMP255), dated August 11, 2010, for 2009 for the State ofDelaware.

- EPA AQS Data Quality IndicatorReport (AMP255), dated August 11, 2010, for 2009 for the State ofMaryland.

- EPA AQS Data Quality Indicator Report (AMP255), datedAugust 11, 2010, for 2009 for the Commonwealth ofPennsylvania.

- EPA AQS Quick Look Report (AMP45O), dated June 28, 2010, containing 2007- 2009 ozone air quality data forthe New Jersey portions ofthe PhiladelphiaArea.

- May 17, 2010 EPA letterto AMS approving AMS

‘s March 29, 2010 Data Substitution Analysis, submitted to EPA by letter dated April 9, 2010.

- AMS’s March 29, 2010 Data SubstitutionAnalysis forAQS Site ID: 42-101-0024, submitted via cover letter dated April 9, 2010.

- September 24, 2010 EPA letter to DNREC approving DNREC’s July 15, 2010 Data Substitution Analysis, submitted to EPA by letter dated July 19, 2010.

- DNREC’s July 15, 2010 Data SubstitutionAnalysis forBrandywine, AQS SitelO-003-1010, submitted via cover letter datedJuly 19, 2010.

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