Mobile sources consist of on-road motor vehicles and other mobile sources.
On-road motor vehicles consist of passenger cars, trucks, buses and motorcycles. Emissions from on-road motor vehicles are a major portion of the emission inventory and are estimated using computer models developed by ARB. These are referred to as EMFAC and BURDEN, the latest available version, EMFAC2007 v2.3 was used in this inventory.
These sources include boats and ships, trains, aircraft, garden, farm and construction equipment. Various methodologies are used to estimate emissions from these sources. Emission factors and methodologies for these sources are provided by ARB and EPA. Aircraft mix and activity data specific to each airport are used in estimating emissions at airports.