Environmental Engineering Reference
In-Depth Information
Fig. 1.
Cancer-risk weighted emissions of toxic air contaminants are shown (a, top left) by
pollutant type, (b, bottom left) by source type, and (c, right panel) mapped in the central Bay Area
4. Evaluation of the Inventory
To evaluate emissions estimates for on-road diesel emissions, we compared diesel
fuel consumption from CARB's EMFAC2007 model with diesel fuel consumption
from the California Department of Transportation's (Caltrans) California Motor
Vehicle Stock, Travel and Fuel Forecast (MVSTAFF) model. The two methods
provided similar estimates of diesel fuel consumption from on-road motor vehicles
in the Bay Area in 2005 (about 1 million gal/day).
To evaluate emissions estimates for off-road diesel emissions, we compared
CARB's OFFROAD2007 model fuel consumption estimates with Bay Area diesel
fuel production used for off-road sources. (Diesel fuel sold in California for off-road
use is tax exempt and dyed red to distinguish it from taxed fuel.) OFFROAD2007's
diesel fuel consumption for the Bay Area
-
when tallied with estimates from other
off-road categories (commercial boats, cargo-handling equipment, and trains) not
included in OFFROAD2007
-
totaled about 80% of on-road diesel fuel usage.
