UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street Philadelphia, Pennsylvania 19103

DATE: May 11, 2011

SUBJECT: Technical Support Document for Virginia ’s A mendments to 9VAC5

Chapter 20

– General Provisions and 9VAC5 Chapter 30

- Ambient Ai r Quality Standards for Nitrogen Dioxide

FROM: Gregory Becoat, Environmental Scientist /s/

Office of Air Program Planning

TO: File

THRU: Cristina Fernandez, Associate Director /s/

Office of Air Program Planning

A . BACKGROUND

This technical sup port document (TSD) evaluates the March 4, 2011 submittal of the Virginia State Implementation Plan (SIP) revision pertaining to the ambient air quality standard for nitrogen dioxide ( NO 2 )

.

The Clean Air Act (CAA) specifies that EPA must re

- evaluate the a ppropriateness of its various air quality standards every five years . As part of the process, EPA reviewed the

latest research and determined that revised standard s for NO 2 were necessary to protect public health. EPA revised the level of the primary sta ndard by setting a new 1

- hour NO 2 standard at a level of 100 parts per billion (ppb) in order to protect against adverse health

effects associat ed with short

- term exposure to NO 2 . EPA also retained the current annual

average NO 2 standard of 53 ppb in orde r to protect against adverse health effects associated with long

- term exposure to NO 2

. EPA promulgated the more stringent primary national ambient air quality standards ( NAAQS ) for NO 2 on February 9 , 2010 (75 FR 6 474 )

.

B . STATE SUBMITTAL

On March 4, 2 011, the Commonwealth of Virginia submitted a regulation revision A 10,

which consists of amendments to the Commonwealth ’s existing regulations in order to update the list of appendices under documents incorporated by reference and to add the new primary 1

- hour standard for NO 2 . Virginia = s revision incorporates the revised NO 2 standard into the Code of Virginia (9VAC5 Chapter 30). In addition, the list ofappendices to 40 CFR p art 5 1 was updated under “Documents i ncorporated by r eference”

(9VAC5

- 20

- 21). T he effective date of this regulation is August 18, 2010.

This SIP revision amends regulation 9VAC5

- 20

- 21, “Documents i ncorporated by

r eference” by adding the new Appendix S to the list of federal documents incorporated by

reference. Appendix S was added to 4 0 CFR p art 50 when the revised NO 2 standard was promulgated on February 9, 2010 (75 FR 6 474 )

.

This SIP revision amends regulation 9VAC5

- 30

- 70, “Oxides of nitrogen with nitrogen

dioxide as the indicator” in order to (1) specify that NO 2 is the indicat or for oxides of nitrogen, (2) limit the 53 ppb standard to the annual primary standard and change the unit of measurement from annual arithmetic mean concentration to annual average concentration, (3) add the new primary 1

- hour standard of 100 ppb , (4) sp ecify reference methods used to measure the standard, and (5) specify how the primary annual and 1

- hour standard and the secondary standard are attained.

C. EPA EVALUATION

Virginia’s SIP revisions for the ambient air quality standards for NO 2 are consi stent with

the Federal standards.

D. CONCLUSIONS AND RECOMMENDED AGENCY ACTION

This SIP revision request satisfies all requirements for an acceptable SIP revision

. EPA approval of the SIP revision is recommended.