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Transportation Conformity Highlights

August 2007

Prepared by the Office of Natural and Human Environment Federal Highway Administration

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EPA Releases Policy Guidance on Use of November 2006 Update to AP-42 for Re-entrained Road Dust for SIP Development and Transportation Conformity.In August, EPA released guidance about changes made to the AP-42 methods for road dust in November 2006, and how and when to use them in PM2.5 SIPs and transportation plan and TIP conformity determinations. AP-42 is EPA's compilation of data and methods for estimating average emission rates from a variety of activities and sources from various sectors. The November 1, 2006 update to AP-42 methods used for calculating PM2.5 re-entrained road dust emissions revise the approved version of AP-42 for PM2.5 and PM10 road dust calculations, and will result in 40% less PM2.5 road dust from paved roads and 33% less PM2.5 road dust from unpaved roads. The PM10 road dust estimates remain unchanged from the previous version of AP-42. The guidance can be found at:

STAQS 2007 Held in Savannah, Georgia.The fourth biannual Southern Transportation and Air Quality Summit (STAQS 2007) was held on August 28 - 30 in Savannah, Georgia. Over 160 participants traveled from around the country to hear from technical experts, peers and others doing important work in the field of transportation and air quality. The three-day summit provided an unparalleled opportunity for attendees to address current and upcoming issues; established and emerging technologies; and best practices related to the field of air quality. This year's summit began with a primer on transportation conformity for new practitioners; however, the primary focus this year was the evolving issue of air toxics as well as particulate matter pollution. Other topics addressed were climate change, the health effects of transportation related pollutants and the challenging regulatory environment. The final day of STAQS 2007 concluded with break-out sessions in which participants could choose from topics of interest. Lastly, participants heard about innovative measures from around the country that reduce emissions. For more information on STAQS contact Mike Roberts at


EPA Issues Proposed Rule on Changes in the Ozone NAAQS.On July 11, EPA posted its proposed rule for revisions to the ozone NAAQS in the Federal Register. EPA proposes to revise the level of the 8-hour ozone standard to a level within the range of 0.070 to 0.075 parts per million (ppm). The EPA also proposes to specify the level of the primary standard to the nearest thousandth ppm. EPA solicits comment on alternative levels down to 0.060 ppm and up to and including retaining the current 8-hour standard of 0.08 ppm (effectively 0.084 ppm using current data rounding conventions). Comments on the proposed rule must be received by October 9, 2007. For more information, see:

Training Opportunities

FHWA Resource Center Training Activities. FHWA's Resource Center Air Quality Technical Services Team is available to offer air quality-related training opportunities and information is available at: For further information, contact: Mike Roberts at 404-562-3928 or at

Introduction to Transportation Conformity.The NTI Introduction to Transportation Conformity course is scheduled for November 13-15, 2007 in Indianapolis, IN. A course will also be scheduled this fall in Sacramento, CA. Two more courses, with locations undetermined at this time will be offered before June 30, 2008. For more information, see:

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FHWA Resource Center Air Quality Team Contacts:

Updated: 10/20/2015
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