05-10853. Transportation Conformity Rule Amendments for the New PM2.5

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Final rule; correction.

SUMMARY:

EPA issued a final rule on May 6, 2005, (70 FR 24280) that adds the following transportation related PM_2.5 precursors to the transportation conformity regulations: nitrogen oxides (NO_X), volatile organic compounds (VOCs), sulfur oxides (SO_X), and ammonia (NH₃). The final rule specifies when each of these precursors must be considered in conformity determinations in PM_2.5 nonattainment and maintenance areas before and after PM_2.5 state air quality implementation plans (SIPs) are submitted. The preamble to the final rule contains two minor errors. This notice is intended to correct these errors. All other preamble and regulatory text printed in the May 6, 2005, final rule is correct.

The Department of Transportation (DOT) is EPA's federal partner in implementing the transportation conformity regulation. We have consulted with DOT on the development of these corrections, and DOT concurs.

DATES:

Effective Date: June 6, 2005.

FOR FURTHER INFORMATION CONTACT:

Angela Spickard, State Measures and Conformity Group, Transportation and Regional Programs Division, U.S. Environmental Protection Agency, 2000 Traverwood Road, Ann Arbor, MI 48105, [e-mail], [phone].

SUPPLEMENTARY INFORMATION:

EPA issued a final rule on May 6, 2005, (70 FR 24280) that amended the transportation conformity rule (40 CFR part 93) to include the following transportation-related PM_2.5 precursors: nitrogen oxides (NO_X), volatile organic compounds (VOCs), sulfur oxides (SO_X), and ammonia (NH₃). The final rule specifies when each of these precursors must be considered in conformity determinations in PM_2.5 nonattainment and maintenance areas before and after PM_2.5 state air quality implementation plans (SIPs) are submitted. The preamble to the May 6, 2005, final rule contains two minor errors. This notice is intended to correct these errors.

First, EPA is correcting one paragraph and its corresponding footnote in the discussion on Volatile Organic Compounds in Section III.B. Rationale for This Final Rule (70 FR 24284). This paragraph discusses the contribution of VOC emissions from biogenic sources (e.g., trees) to PM_2.5 air quality issues. The version of the paragraph printed in the May 6 final rule preamble incorrectly characterizes the existing data and analyses of biogenic source VOC emissions obtained from the PM Supersites Program. This notice corrects the paragraph regarding EPA's understanding of the PM Supersites research and provides the public with the most current reference information.

The incorrect paragraph begins at the bottom of the second column on page 24284 of the May 6 notice with “Additional research is also needed to determine * * *” This paragraph should be stricken and replaced with the following:

“Additional research is also needed to determine the sources of VOC emissions that contribute most to PM_2.5 air quality issues. For example, according to the NARSTO Fine Particle Assessment,⁵ secondary sources may contribute up to 50 percent of secondary organic mass, particularly in areas where photochemical transformations of emissions from biogenic sources (e.g., trees) are significant. In addition, data obtained from the Particulate Matter Supersites Program suggest that biogenic emissions may contribute significantly to secondary organic aerosols during days of peak PM_2.5. Analysis of air quality samples collected in Pittsburgh from 2001 through 2002 indicates that as much as half of the organic aerosol during peak periods may be attributable to biogenic sources (e.g., trees) as opposed to anthropogenic sources (i.e., man-made sources such as power plants and motor vehicles).^6 7 The Supersites Program has also collected data on the contribution of biogenic source emissions in other locations in the U.S., including Atlanta, Georgia.^8 9 However, these findings have not yet been published and peer-reviewed. The contribution of biogenic emissions to PM_2.5 air quality issues is important because biogenic emissions cannot be controlled.”

The footnote five on page 24284 of the May 6 notice should be stricken and replaced with the footnote five below. In addition, new footnotes six through nine are added in the corrected paragraph:

“⁵ McMurry, P., Shepherd, M., Vickery, J. (ed.) Particulate Matter Science for Policy Makers—A NARSTO Assessment. Cambridge: Cambridge University Press, 2004.

⁶ Cabada J. C., S. N. Pandis, R. Subramanian, A. L. Robinson, A. Polidori, and B. Turpin (2004) Estimating the secondary organic aerosol contribution to PM_2.5 using the EC tracer method, Aerosol Sci. Technol., 38S, 140-155.

⁷ Millet D. B., N. M. Donahue, S. N. Pandis, A. Polidori, C. O. Stanier, B. J. Turpin, and A. H. Goldstein (2005) Atmospheric volatile organic compound measurements during the Pittsburgh Air Quality Study: Results, interpretation, and quantification of primary and secondary contributions, J. Geophys. Res., 110, D07SO7, 10.1029/2004JD004601.

⁸ ‘Sources of carbon in PM_2.5 based on 14C and tracer analysis,' Edgerton, Eric S., John J. Jansen, Mei Zheng and Benjamin E. Hartsell (September 2004), 8th International Conference on Carbonaceous Particles in the Atmosphere, Vienna, Austria.

⁹ ‘Source apportionment of PM_2.5 using a three-dimensional air quality model and a receptor model,’ Park, S-K, L. Ke, B. Yan, A. G. Russell, M. Zheng (2005), Proceedings of an AAAR international specialty conference—Particulate Matter Supersites Program and Related Studies, Atlanta, Georgia.”

Second, EPA is correcting a footnote in Section III.C.5. State of the Science (70 FR 24288) and renumbering two footnotes in this section. Footnotes six and seven in the May 6 final rule should be renumbered as footnotes 10 and 11 in the text referencing the footnotes at the top of the third column on page 24288, and in the footnotes themselves. Footnote seven in the May 6 final rule (corrected to be footnote 11 in this notice) provides a reference to the draft NARSTO Fine Particulate Assessment issued in February 2003. EPA is correcting this footnote to include the reference for the final NARSTO report. EPA believes it is important to make this correction to avoid confusion and provide the public with the most current published information.

The correct footnote is as follows:

“¹¹ McMurry, P., Shepherd, M., Vickery, J. (ed.) Particulate Matter Science for Policy Makers—A NARSTO Assessment. Cambridge: Cambridge University Press, 2004.”

No changes are being made to the final rule language or other preamble language published on May 6, 2005, through this action. EPA finds good cause to make this correction notice effective less than 30 days after publication in the Federal Register. The final rule published on May 6 will become effective on June 6, 2005. Today's correction notice does not make any changes to the final rule. This correction notice only clarifies explanatory text and corrects reference citations in the preamble to the final rule which are intended to provide the public with EPA's rationale for its decision. Therefore EPA concludes that it will be in the public interest to have this correction notice also become effective on June 6, 2005.

Authority: 42 U.S.C. 7401-7671q.

Dated: May 25, 2005.

Jeffrey R. Holmstead,

Assistant Administrator for Office of Air and Radiation.