EMISSION INVENTORY SOURCE CATEGORY

METHOD SUMMARY

These categories are an inventory of the total organic gas (TOG) emissions resulting from the use of solvents in degreasing operations in the manufacturing and maintenance industries. The category of Cold Cleaning - Batch, Conveyor, Sprayer Gun includes emissions from solvents used in degreasing equipment which are either cold or are heated to below their boiling point to dissolve contaminants. The equipment types of this category are used with eleven different solvent types. The category of Vapor Degreasing - Batch and Conveyor includes emissions from solvents used in degreasing equipment which are heated above their boiling point producing a vapor to remove contaminants. The equipment types of this category are used with seven different solvent types. The category, Handwiping, refers to the application of solvent by hand to the surface to be cleaned. This category has 14 different solvent types. The 1993 emission estimates from this source category are primarily based on the E.H. Pechan and Associates, Inc. (Pechan) 1996 report titled, "Solvent Cleaning/Degreasing Source Category Emission Inventory."

ACTIVITY DATA SOURCE: To estimate degreasing emissions, Pechan collected activity data by surveying solvent users in two major groups: Manufacturing and Maintenance. The industries determined to use degreasing solvents were split into nine groups based on Standard Industrial Codes (SICs). Pechan used facility data from Dun and Bradstreet, a supplier of business/marketing information, to represent the universe of facilities to sample from.

EMISSION FACTOR SOURCE: Emissions were estimated for 32 equipment and solvent pairs (ESPs). Three emission variables were used to estimate emissions: an activity factor, an emission factor, and a user's fraction. The activity factor for the Manufacturer's survey is gallons of solvent used minus gallons solvent recycled per total number of employees at a facility. The activity factor for the Maintenance survey, is the amount of solvent added to the degreaser to maintain an operational level.

For the Manufacturer's survey the emission factor for pure solvents is the density of the solvent. The emission factor for solvent blends is the density of the solvent multiplied by the total organic gas (TOG) content of the solvent; exhaust controls were taken into account if used. For the Maintenance survey the emission factors are the density of the solvent and no exhaust controls were used.

The purpose of the user's fraction is to determine the proportion of facility employees using a particular ESP in particular industries. The user's fraction is calculated using the survey data.

Mining operations/Other Trades and Agricultural equipment were not included in the user Universe determined by Pechan. Emissions from these sources were estimated by Pechan using data from Safety-Kleen. These emissions were added to the appropriate Maintenance category.

To allocate the emissions to California counties and districts, total employment data by Standard Industrial Code (SIC) for each county was used from U.S. Census Bureau (Census Bureau). Total emissions from solvent cleaning/degreasing are calculated with this methodology. Point sources, facilities that emit greater than 25 tons per year of any pollutant and are reported by the Air Pollution Control Districts, are subtracted from these total emissions.

TEMPORAL DATA: The annual activity is uniform throughout the year. The weekly activity is uniform on weekdays, with minimal activity on weekends. Most daily activity occurs during the daylight working hours from 7:00 a.m. to 6:00 p.m.

CHANGES IN METHOD AND EMISSION ESTIMATES: The major change from the previous methodology is that emissions are now estimated for 32 equipment and solvent categories representing a process oriented approach. The previous five categories were based on the place where emissions occur and general solvent type. Another major change is that the current methodology is based on a survey of solvent end users (a bottom-up approach), whereas the previous methodology is based primarily on solvent production data (a top-down approach).

DATE OF THE LAST UPDATE: March 2000

GROWTH PARAMETER: The growth parameters were developed by Pechan and are based on manufacturing output data (SIC codes 20-39).



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

CES No.	TOG	CO	NOX	SOX	PM
Cold Cleaning (11 codes)	110.55	0.00	0.00	0.00	0.00
Vapor Degreasing (7 codes)	19.14	0.00	0.00	0.00	0.00
Handwiping (14 codes)	65.73	0.00	0.00	0.00	0.00
Total	195.42	0.00	0.00	0.00	0.00

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This page last revised on May 31, 2006

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