EPA issued a final rule on May 6, 2005, (70 FR 24280) that adds the following transportation related PM<INF>2.5</INF> precursors to the transportation conformity regulations: nitrogen oxides (NO<INF>X</INF>), volatile organic compounds (VOCs), sulfur oxides (SO<INF>X</INF>), and ammonia (NH<INF>3</INF>). The final rule specifies when each of these precursors must be considered in conformity determinations in PM<INF>2.5</INF> nonattainment and maintenance areas before and after PM<INF>2.5</INF> 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.