Guidance for Creating Annual On-Road Mobile Source Emission Inventories for PM2.5 Nonattainment Areas for Use in SIPs and Conformity

摘要

The purpose of this document is to provide areas that are nonattainment or maintenance for the annual PM2.5 national ambient air quality standard (standard) with guidance on developing annual PM2.5 on-road motor vehicle emissions estimates to meet state air quality implementation plan (SIP) and transportation conformity requirements. For previous and existing air quality standards (e.g., 1-hour ozone, 8-hour ozone, PM10 and carbon monoxide (CO)), areas typically have been required to examine a typical summer or winter day because areas were violating a standard established for a time period of 24 hours or less. As a result, these areas have developed on-road motor vehicle SIP inventories, motor vehicle emissions budgets (budgets), and regional emissions analyses1 for transportation conformity determinations using modeling inputs and parameters that were specific to a typical day within a particular season. However, all areas currently designated nonattainment for PM2.5 are violating the annual standard for this pollutant. In order to be consistent with this standard, these areas must develop annual emission inventories for the purpose of developing SIP budgets and demonstrating transportation conformity. This guidance provides information on how areas should fulfill these requirements.