EMISSION INVENTORY SOURCE CATEGORY

METHOD SUMMARY

This category includes 1993 estimates of fugitive dust particulate matter entrained by vehicular travel on paved roads. Road dust emissions are estimated for freeways and expressways, major streets and highways, collector streets, and local streets. Vehicle exhaust, brake wear, and tire wear are computed separately as part of the mobile source emission inventory.

ACTIVITY DATA SOURCE:  Activity data is from two sources. County-specific vehicle miles traveled (VMT) on paved roads is from the Air Resources Board's mobile sources emission inventory and air districts. Caltrans HPMS (Highway Performance Monitoring System) data are used to estimate the fraction of travel on each of the four road types in each county.

EMISSION FACTOR SOURCE:  The emission factor used is from EPA's AP-42 document, Section 13.2.1. California specific roadway silt loading inputs to the EPA emission factor equation were measured by Midwest Research Institute (MRI) in 1995. A default average vehicle fleet weight value of 2.4 tons is used in the equation for most of the State.

TEMPORAL DATA:  Temporal Data is the same as is used for the on-road motor vehicle exhaust emissions because it tracks overall vehicular activity. Daily activity has peaks at 7:00 a.m. and 4:00 p.m., with less activity at other hours. Weekly activity dips slightly on the weekends. Monthly activity has slight decreases during the winter months.

DATE OF THE LAST UPDATE:  July 1997

GROWTH PARAMETER:  Freeways and major roads are grown based on increases in roadway center-line miles. For most of the State an average center-line growth value is used. Collector and local roads are grown based on VMT changes.

STATEWIDE EMISSIONS SUMMARY (1993 - ANNUAL AVERAGE TONS / DAY)

CES No.	TOG	CO	NOX	SOX	PM
83618	0.00	0.00	0.00	0.00	205.2
83626	0.00	0.00	0.00	0.00	319.2
83634	0.00	0.00	0.00	0.00	61.5
83642	0.00	0.00	0.00	0.00	255.4
Total	0.00	0.00	0.00	0.00	841.2

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