January 13, 2011

Mr. Shawn M. Garvin (3RAOO)Regional AdministratorU. S. Environmental Protection AgencyRegion III

1650 Arch Street

Philadelphia, Pennsylvania 19103-2029

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j\P3O RECEIVED

JAN 2 02011

Divii Dl16L;OF (3APOO)

Dear Administrator Garvin:

On January 22, 2010, the U.S. Environmental Protection Agency (EPA) strengthened the

National Ambient Air Quality Standards (NAAQS) for nitrogen dioxide (NO 2)by adding a new 1-hourprimary standard of 100 parts per billion (ppb) (3-year average of the 95th percentile daily maximum 1-

hour concentration). Section 107(d) of the Clean Air Act (CAA) requires the Governor of each State tosubmit to the EPA a list of all areas (or portions thereof) in the State, designating each as nonattainment,attainment, or unclassifiable. This letter fulfills Delaware’s obligations under Section 107(d) of the CAA.

Area Description and Monitoring Data

Delaware is composed of three counties, namely New Castle, Kent and Sussex, laying from

north to south. The northern portion of New Castle County lies above the Chesapeake and DelawareCanal, a waterway that connects the Chesapeake Bay with the Delaware Bay. This part of New CastleCounty is more metropolitan and industrialized than the remainder of Delaware. The remainder of

Delaware lies south of the Chesapeake and Delaware Canal, and comprises the southern portion of New

Castle County, and all of Kent and Sussex Counties.

Delaware currently monitors NO2 at its monitoring site near Martin Luther King Boulevard,

which is located in the city of Wilmington (New Castle County). The measured ambient NO2

concentrations for 2007 through 2009 at this monitor are shown in the table below.

NO2Concentration (ppb)

98th Percentile Daily

1st max 1-hour 2rn1 max 1-hour Maximum 1-hour

Year Concentration Concentration Concentration

2007 75 73- 642008 149 75 682009 68 62 54

3-year average of 98th Percentik 62 Daily Maximum 1-hour Concentratior
Along with the new hourly NO2 NAAQS, the EPA has established new near-road monitoring

network requirements that are anticipated to go into effect January 2013. Delaware does not operate a

near-roadway monitor, and understands that it will not be required to perform near-roadway monitoring under these new requirements. With this understanding, Delaware believes its current NO2 monitoring

network is adequate and complete.

Attainment/Nonattainment Recommendation

Because Delaware does not have the required 75% data completeness from its existing NO2

monitoring network, all three counties in Delaware should be designated as unclassifiable for the new 1-

hour NO2 NAAQS. Despite this unclassifiable recommendation, we believe the data we do have

strongly indicates that the air quality in Delaware currently is in attainment for the new NO2standard.

Delaware anticipates requesting re-designation to attainment once 3-years of complete data are obtained.

Thank you for your consideration of the above recommendations. If you have any questions

concerning this submittal or would like to discuss it further, please contact Mr. Au Mirzakhaliii, the

Director of our Division of Air Quality, at (302)739-9402.

Sincerely,

Jack A. Markell

Governor

pc: Diana Esher, EPA, Region III

Coffin P. O’Mara, DNREC

Dave Small, DNREC

Ali Mirzakhaliii, DNREC