(VCCEP) Tier 1 Pilot Submission for BENZENE - Tera

The EPA Office of Air Quality Planning and Standards (OAQPS) collects emissions inventory
data for hazardous air pollutants (HAP) pursuant to the 1990 amendments to the Clean Air Act.
The most recent emissions inventory available in final form is the September 21, 2001 revision
to the 1996 National Toxics Inventory (NTI). The NTI emissions estimates are based on the
following sources of data:
• State and local air pollution control agency HAP inventories;
• OAQPS Maximum Achievable Control Technology (MACT) databases;
• Toxic Release Inventory (TRI) data;
• Mobile source estimates from the EPA’s Office of Mobile Sources; and
• Area source emission estimates using emissions factors and activity data.
Emission quantities for four general source categories are provided for the chemicals in the NTI
database, including:
• Major sources (stationary facilities with potential to emit 10 tons of any one
toxic air pollutant or 25 tons of more than one pollutant);
• Area and other sources (such as biomass burning including wildfires and
agricultural burning, as well as small facilities with emissions less than that of
major sources);
• On-road mobile sources (vehicles that travel on roads and highways such as
cars, trucks and buses); and
• Non-road mobile sources (mobile sources that are not found on roads such
as lawn mowers, snowmobiles, and heavy construction vehicles).
Figure 5.1 shows the relative contribution of the various sources to the total benzene emissions
on a nationwide basis based on the NTI 1996 database. It should be noted that the contribution
from biomass and other area sources is greater in rural areas (i.e., 31%), as there is less of a
contribution from motor vehicles and more likely to be biomass burning. In addition, the relative
contribution from biomass varies from year to year as a function of the size and number of
wildfires in the U.S.
Benzene VCCEP Submission
March 2006
30