September 2016

8-Hour Ozone 

State Implementation Plan Emission Inventory

Supplemental Documentation
September 2016

1

I. Introduction

This document describes the sources and methods used to develop California’s 

2012 summer emission inventory used in the 8-Hour Ozone State Implementation 

Plan (SIP or Plan) Emission Inventory Submittal (transmitted July 17, 2014). The 

Air Resources Board (ARB) works continuously with the local air districts to collect 

information and conduct research to improve California’s emission inventories. 

During development of this inventory submittal, ARB and district staff conducted a 

thorough review of the 2012 inventory to ensure that the emission estimates 

reflected accurate reports for point sources, and that estimates for area-wide and 

mobile sources were based on the latest available models and methodologies.

The United States Environmental Protection Agency (U.S. EPA) establishes 

requirements pertaining to emission inventories that must be included as part of the 

SIP submittal package. For an ozone plan, the regulations require that the emission 

inventory contain emissions data for the two precursors to ozone formation: nitrogen 

oxides (NOx) and volatile organic compounds (VOCs).

Emission Inventory Overview

An emission inventory is a critical tool in the evaluation of air pollution. In simple 

terms, an emission inventory is a systematic listing of the sources of air pollution 

along with the amount of pollution emitted from each source or category over a 

given time period. Source categories include stationary (point and area-wide), 

mobile (on- and off-road), and natural sources. Emission inventories are an 

estimate of the amount of air pollution that is released into the environment. 

They are not measurements of ambient concentrations. 

Emission inventories are fundamental components of an air quality plan. They 

serve as a primary input to air quality modeling used in attainment 

demonstrations, provide the emissions data used for developing control 

strategies, and serve as a means to track progress in meeting the emission 

reduction commitments.

Quality Assurance and Quality Control

ARB has established a quality assurance and quality control (QA/QC) process 

employed by ARB and air district staff to ensure the integrity and accuracy of the 

emission inventories used in the development of air quality plans. QA/QC occurs 

at the various stages of SIP emission inventory development. Base year 

emissions are assembled and maintained in the California Emission Inventory 

Development and Reporting System (CEIDARS). ARB inventory staff works with 

air districts, which are responsible for developing and reporting point source 

emission estimates, to verify these data are accurate. The locations of point 

sources, including stacks, are checked to ensure they are valid. Area-wide 

source emission estimates are developed by ARB staff as well as some air 

districts. The methodologies for estimating these are reviewed by ARB and 
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district staff before their inclusion in the emission inventory. Additionally, 

CEIDARS is designed with automatic system checks to prevent errors such as

double counting of emission sources. The system also makes various reports 

available to assist staff in their efforts to identify and reconcile anomalous 

emissions. Mobile categories are verified with ARB mobile source staff for 

consistency with the on-road and off-road emission models.

Base Year Selection 

The base year inventory is an essential element of an air quality plan that forms 

the basis for all future year projections and also establishes the emission levels 

against which progress in emission reductions will be measured. U.S. EPA 

regulations establish that an inventory base year should be comprehensive, 

accurate, and current for all actual emissions. U.S. EPA establishes guidance on 

which year to select as the base year. They would prefer that states use the 

2011 National Emissions Inventory (NEI), however, they allow a different year to 

be selected if justified by the state. At the time the base year inventory was 

required, ARB wanted a consistent inventory across the state. ARB worked with 

the local districts to come up with a base year inventory. The South Coast 

district typically aligns their base year inventory with their MATES data collection 

period. Since South Coast planned to use 2012 data consistent with MATES and 

ARB wanted consistency across the state, 2012 was selected as the base year.

Planning inventories typically include annual as well as seasonal (summer and 

winter) emission estimates. Annual emission inventories represent the total 

emissions over an entire year (tons per year), or the daily emissions produced on 

an average day (tons per day). Seasonal inventories account for temporal 

activity variations throughout the year, as determined by category-specific 

temporal profiles. Since ozone concentrations tend to be highest during the 

summer months, the emission inventory used in the Plan is based on the 

summer season (May through October).
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II. Emission Inventory Components

A summary of the components that make up the Ozone SIP base year emission 

inventory is presented in the following sections. These include mobile (on- and offroad) sources and stationary (point and area-wide) sources. Natural sources are not 

included in a SIP emission inventory.

Mobile Source Emissions

ARB develops the emission inventory for the mobile sources using various 

computer models. These models account for the effects of various adopted 

regulations, technology types, fleet turnover, and seasonal conditions on 

emissions. Mobile sources in the emission inventory are composed of both onroad and off-road sources, described in the sections below.

On-Road Mobile Source Emissions

On-road motor vehicle emissions from cars, light and heavy-duty trucks, 

motorcycles, buses, and motor homes in California are estimated using 

ARB’s Emission Factors (EMFAC) model. Emissions are calculated as 

the product of a population of vehicles, the number of miles each vehicle 

travels, and emission rates. Emission rates assume regional speed 

distributions, regional temperature and relative humidity profiles by hour of 

day, and category specific cumulative mileage accrual of the vehicle for a 

given calendar year.

Vehicle populations are estimated using registration data from the 

Department of Motor Vehicles (DMV). Registration data from the year 

2012 were used to update the populations in each vehicle class and 

geographic area.

The model contains default speed distributions and estimated vehicle 

miles traveled (VMT) as a function of vehicle population from DMV and 

mileage accrual rates from the Bureau of Automotive Repair Smog Check 

program. This methodology involves matching DMV registration 

information to Smog Check data from the Bureau of Automotive Repair 

and using vehicle identification number (VIN) decoders to interpret 

registration data.

The on-road mobile emissions inventory used in this submittal reflect 

recent updates to the EMFAC 2011 activity parameters. These updates 

include vehicle population and activity using 2012 DMV data, vehicle sales 

and survival rate estimates, fuel sales from Board of Equalization, and 

updates to mileage accrual rates using Smog Check data. The default 

VMT regional allocations have been adjusted using the 2012 National 

Transportation Atlas Database. 
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The model also reflects the emissions benefits of ARB’s recent 

rulemakings including ARB’s 2010 Truck and Bus Regulation, Pavley 

Clean Car Standards, and the Low Carbon Fuel standard.

Additional information regarding the EMFAC model is available at: 

http://www.arb.ca.gov/msei/msei.htm

Off-Road Mobile Source Emissions

Emissions from off-road sources such as locomotives, ships, industrial 

and construction equipment, and recreational vehicles were estimated 

using a suite of category-specific models. Many of these models were 

developed to support recent regulations, including in-use off-road 

equipment, ocean-going vessels and others. Where category-specific 

models were not yet developed, the OFFROAD2007 model was used. 

The following sections describe the off-road mobile source categories in 

more detail.

Aircraft

Aviation related emissions were reported for 2012 by the local air 

districts. Emission estimates span the landing and take-off cycle 

and are calculated using FAA’s EDMS model. Most aircraft 

emissions are reported as point sources but some districts have 

provided area source methodologies which are available at: 

http://www.arb.ca.gov/ei/areasrc/districtomobilsrcaircraft.htm 

Ocean Going Vessels

The Ocean-Going Vessel (OGV) inventory represents commercial 

vessels greater than or equal to 400 feet in length or 10,000 gross 

tons; or propelled by a marine compression ignition engine with a 

displacement of greater than or equal to 30 liters per cylinder. The 

ARB emission inventory includes all OGV emissions occurring 

within 100 nautical miles of the California coastline.

Vessel port calls were obtained from a database maintained by the 

California State Lands Commission (SLC) in 2007. This database 

includes vessel identification, port of arrival, previous port, next 

port, and date and time of arrival. The Lands Commission compiles 

this database from marine exchanges and port authorities 

statewide.

Vessel specific hoteling times and berth locations were obtained 

from port officials responsible for ship docking, or wharfingers, in 

Los Angeles, Long Beach, Oakland, San Diego, San Francisco and 

Hueneme. These data were reconciled with the port call data from 

the SLC.
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Emission factors for OGVs vary by pollutant, operating mode 

(transit, maneuvering, or hoteling), engine type (main engine/slow 

speed, main engine/medium speed, or auxiliary/medium speed), 

and fuel type (heavy fuel oil or marine distillate) for main and 

auxiliary engines using a methodology defined by Starcrest 

Consulting Group in 2007. Emission factors were updated for the 

2012 inventory to incorporate tier-weighted control factors.

The ocean going vessel inventory accounts for new information 

related to goods movement activity. This is based on growth 

projections from the Federal Highway Administrations Freight 

Analysis Framework model and supported by other forecasts done 

for the San Pedro Bay Ports.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/regact/2011/ogv11/ogv11appd.pdf

Commercial Harbor Craft

Commercial Harbor Craft (CHC) are grouped into nine vessel 

types, including ferry and excursion vessels, tow boats, tug boats, 

pilot vessels, work boats, crew and supply vessels, commercial 

fishing vessels, charter fishing vessels, and other. 

Vessel population data were collected from various sources, 

including the U.S. Coast Guard, the California Department of Fish 

and Game registration data, the ARB Harbor Craft Survey, and 

information from recent emission inventory estimates generated for 

the Port of Los Angeles. Vessel and engine profiles, including 

vessel and engine type, age, size, annual hours of operation, and 

annual fuel use were developed based on the ARB survey

Vessel and engine data were reported to ARB by vessel operators 

in compliance with ARB’s 2007 Commercial Harbor Craft 

Regulation. Staff updated the crew and supply vessel emissions 

inventory using 2009 reporting data and developed barge and 

dredge vessel emissions inventory using the 2009 survey 

information.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/regact/2010/chc10/appc.pdf

Recreational Boats

Recreational Boats is a broad category of marine vessels that 

includes gasoline powered spark-ignition marine watercraft and 

diesel-powered marine watercraft. The PC2014 model was 

developed by ARB to estimate emissions from recreational 
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watercraft. Population, activity, and emission factors were 

reassessed using surveys, registration information, and emissions 

testing.

In 2009, ARB funded a California State University Sacramento 

(CSUS) phone survey of over 1,123 respondents. Staff used the 

results of the survey to estimate the annual activity as well as the 

spatial allocations for operation and storage for recreational 

watercraft.

ARB updated exhaust emissions factors based on ARB marine 

engine certification data. Evaporative emissions factors were also 

updated based on actual ARB in-house testing. 

Additional information on this methodology is available at: 

http://www.arb.ca.gov/regact/2015/simw2015/simw15appj.pdf

Off-road Recreational Vehicles

Off-highway Recreational Vehicles (OHRVs) are integrated into a 

single regulatory category including off-road motorcycles (OMC), 

all-terrain vehicles (ATV), off-road sport vehicles, off-road utility 

vehicles, sand cars, and golf carts. ARB has developed an 

emissions inventory model, RV2013, to estimate emissions 

generated by OHRVs in each region of the State. This inventory 

revision builds on previous ARB assessments, and contains 

updates to vehicle population, activity (hours/year or miles/year), 

annual vehicle sales, emission factors, technology change from 

carbureted to fuel injected engines, as well as the change in the 

population split between two and four stroke engines. 

California Department of Motor Vehicle (DMV) registration data 

provided detailed information on the total population and model 

year distribution of that population for each calendar year. The 

database also allows estimates of vehicles that are actively used as 

well as vehicles in storage at households. Staff used the DMV 

registration data to reevaluate the projected lifecycle of each 

vehicle type, and to estimate the expected total life, half-life (or 

useful life), and year-to-year survival rate by vehicle type.

Activity was estimated from a 2009 ARB-funded CSUS phone 

survey. Staff corroborated the results of the survey with other data 

sources to develop estimates for OHRV use by age and vehicle 

type.

Staff developed emission factors based on certification data, 

vehicle testing, and other testing and analysis. Updates include 
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new evaporative emission factors based on evaporative test data 

for diurnal, resting, and hot soak emissions. 

Exhaust emission factors used in RV2013 are consistent with 

OFFROAD2007 and based on certification data and adopted 

exhaust emissions standards. In 2003, ARB contracted with 

Automotive Testing Laboratory for testing of evaporative emissions 

from OHRVs using a Sealed Housing for Evaporative 

Determination (SHED).

Additional information on this methodology is available at: 

http://www.arb.ca.gov/regact/2013/ohrv2013/ohrvattachc.pdf

Fuel Storage and Handling

In 2004, ARB staff contracted with the California State University, 

Sacramento to conduct two portable fuel container (PFC) surveys. 

The two surveys, Analysis of 2004 California Household Portable 

Fuel Container Survey (September 2004) and Analysis of the 2004 

California Commercial Portable Fuel Container Survey (January 

2005) estimated the number of PFCs and the penetration rate of 

compliant PFCs. In addition, ARB staff quantified the emissions 

that occur when the PFCs are vented prior to fueling. These data 

are included in the report Quantification of Vent Emissions from 

Portable Fuel Containers Prior to Fueling (May 2005). Details 

regarding the proposed emissions adjustments can be found in the 

report Revised California’s Portable Gasoline Container Emissions 

Inventory (May 2005).

Additional information on this methodology is available at: 

http://www.arb.ca.gov/regact/pfc/2005/isor.pdf

Farm Equipment

The agricultural equipment inventory includes a wide variety of farm 

equipment including tractors, harvesters, loaders, and cotton 

pickers. In 2009, the California State University, Fresno 

Foundation conducted a voluntary survey of agricultural operations 

throughout California in order to update the emission inventory for 

off-road mobile agricultural equipment. This survey collected data 

on population, operational characteristics, and activity of off-road 

mobile agricultural equipment. The survey also included questions 

about the types and amounts of commodities produced. 

Off-road farm equipment emissions were updated as part of the InUse Off-Road Diesel Fueled Fleets regulation development 

process. The updated inventory relies on newly available 

information from statewide surveys, economic assessments and 
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fuel analyses. The survey analysis resulted in an update to the age 

distribution of the statewide fleet. 

The detailed data on California farm practices was combined with 

statewide data on agricultural fuel use from the California State 

Board of Equalization and United States Department of Agriculture 

data on farm equipment to revise equipment populations, activity, 

load factors, and turnover practices.

The In-Use Mobile Agricultural Equipment Regulation Survey is 

available at http://www.arb.ca.gov/ag/agtractor/agsurvey.htm

Off-road Equipment 

ARB’s off road equipment category spans a wide range of 

equipment types, including transportation refrigeration units, 

construction and mining equipment, airport ground support 

equipment, oil drilling and workover rigs, and cargo handling 

equipment.

ARB updated this inventory in 2010 to support the analysis for 

amendments to the In-Use Off-Road Diesel Fueled Fleets 

Regulation. 

Transport Refrigeration Units 

Transport refrigeration units (TRUs) are diesel-powered 

refrigeration units that are installed on vehicles used in 

transporting produce, meat, dairy products, and other 

perishable goods. TRUs are found on refrigerated vans, 

trucks, trailers, railroad cars and containers. 

The original inventory was completed in 2003 to support 

ARB’s TRU Airborne Toxic Control Measure (ATCM) which 

was adopted in February 2004. Under the TRU ATCM, 

owners of TRUs based within California are required to 

report to ARB’s Equipment Registration Reporting (ARBER) 

Database. Data from ARBER were used as a primary input 

for the population and age distribution of the TRUs

This inventory relies on emission factors and deterioration 

rates from OFFROAD2007.

The inventory also reflects updates to activity, population, 

growth and turn-over data, and emission factors developed 

to support the 2011 amendments to the Airborne Toxic 

Control Measure for In-Use Diesel-Fueled Transport 

Refrigeration Units.
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Additional information on this methodology is available at: 

http://www.arb.ca.gov/regact/2011/tru2011/truisor.pdf

Drill Rigs

Oil Drilling and Workover Rig emissions are estimated by 

several equipment types and horsepower categories. These 

emissions are estimated using ARB’s OFFROAD2007 

model. OFFROAD2007 uses average horsepower and 

engine load factors obtained from the Power Systems 

Research (1996) database along with equipment population, 

activity, and useful life based on data from ARB’s Off-Road 

Diesel Equipment Survey in 2005.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/regact/2010/offroadlsi10/offroadappd.

pdf

Cargo Handling Equipment

This category estimates emissions from diesel-fueled cargo 

handling equipment (CHE) at California's ports and 

intermodal rail yards. Cargo handling equipment is used to 

transfer goods or perform maintenance and repair activities 

and includes equipment such as forklifts, yard trucks, 

cranes, top and side handlers, and loaders.

As part of ARB’s 2006 Cargo Handling Equipment 

Regulation, fleet owners and operators of CHE are required 

to submit information to ARB regarding equipment 

populations and hours of use. In 2006 and 2009, the 

Starcrest Consulting Group conducted a study on engine 

load for yard trucks cranes operating at the Ports of Los 

Angeles and Long Beach, and San Diego. ENVIRON 

conducted a similar study resulting in an emissions inventory 

for the Port of Oakland in 2005

As part of the rail yard emission reduction program, health 

risk assessments were initiated in 2005 to determine the 

relative risk of exposure to diesel particulate matter in the 

proximity of 17 intermodal rail yards. As part of the 

assessment, activity data were collected for over 400 pieces 

of cargo handling equipment.

The CHE inventory relies on emission factors and 

deterioration rates from OFFROAD2007. These emission 

factors are composed of zero-hour emission rates, 

deterioration rates and useful life assumptions.
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The growth factors used to estimate cargo handling 

equipment emissions in future years was based on growth 

factors from ARB’s Ocean-Going Vessel inventory for 

container, bulk, general and reefers vessels. 

Additional information on this methodology is available at: 

http://www.arb.ca.gov/regact/2011/cargo11/cargoappb.pdf

Trains

The methodology and assumptions used for estimating locomotive 

emissions is based on the Booz-Allen Hamilton’s Locomotive 

Emission Study report in 1992. Emission factors reflecting 

locomotive operations in California were developed by Southwest 

Research Institute along with various engine manufacturers such 

as General Electric (GE) and Electro-Motive Diesel (EMD). 

Locomotive fleet and operation profiles were obtained from the 

Atchison Topeka Santa Fe and Union Pacific railroad companies 

using Train Performance Calculation data and actual event 

recorder data.

The Booz-Allen Hamilton analysis projected future rail traffic as a 

function of population and economic growth in the state. This 

includes industrial production and railroad statistics from the 

Association of American Railroads. Staff also reflected the effects 

of the goods movement from ports in California on locomotive traffic 

levels as well as emission controls resulting from the existing 

memorandum of understanding. The locomotive inventories also 

reflect the 2008 U.S.EPA locomotive regulations and adjustments 

due to economic activity.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/msei/categories.htm#loco_category
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Stationary Sources

The following reflects methods for developing ARB’s stationary source inventory. 

The stationary source inventory is composed of point sources and area-wide 

sources. Point source estimates are reported annually by the local air districts, 

which are responsible for working with facility operators to compile estimates. 

These methods include source testing, direct measurement by continuous 

emissions monitoring systems, or engineering calculations.

The remaining area-wide sources, including aggregated point sources, are 

estimated using various models and methodologies. Emissions for these 

categories are estimated by both ARB and the local districts. Area-wide sources 

include categories where emissions take place over a wide geographic area, 

such as consumer products. Area-wide sources also include smaller point 

sources, such as gasoline dispensing facilities and residential water heaters that 

are not inventoried individually, but are estimated as a group and reported as a 

single source category. The area-wide emission inventory categories are 

described below.

Point Source Emissions

Food and Agricultural Processing

Emissions from the Food and Agricultural Processing category 

include emissions from stationary fuel combustion sources in the 

agricultural and food processing sectors. Most of these emissions 

are reported as point sources; however, the exhaust emissions 

from agricultural irrigation pumps are estimated from a model 

developed by ARB staff. Air districts with significant irrigated 

agricultural acreage provided estimates of the population and 

emissions from stationary and mobile diesel-fueled agricultural 

irrigation pumps. These data were reconciled with equipment 

population estimates from the 2003 US Department of Agriculture 

Farm and Ranch Irrigation Survey (FRIS). The inventory also 

reflects the number of pumps that have been replaced to date 

under the Carl Moyer Program.

Estimation of the population and emissions from agricultural 

engines is described in an April 30, 2003 California Air Resources

Board (ARB) memorandum entitled “Updated Statewide Population 

and Emission Inventory for Diesel-Fueled Agricultural Irrigation 

Pumps”. The stationary diesel engine inventory is based upon 

reconciliation of district permit data for selected districts and Power 

Systems Research (PSR) data for all districts.

Emission factors are taken from ARB’s OFFROAD model and are 
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based on actual source tests of agricultural irrigation pump engines.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/regact/agen06/attach2.pdf

Other Fuel Combustion

Non-agricultural stationary diesel engines fall under the Other Fuel 

Combustion category. These equipment types include air 

compressors, prime and backup generators, prime and backup 

pumps, and other miscellaneous stationary diesel engines. 

Stationary non-agricultural diesel engines are assumed to be 

engines that remain at a facility for at least 12 months.

The stationary non-agricultural diesel engine population was based 

on population estimates from ARB’s OFFROAD model database of 

non-road mobile diesel engines. The OFFROAD population 

estimates were developed from nationwide engine sales data 

provided by PSR in 1996 and the ARB Stationary Source Division 

(SSD) Portable Equipment Database.

Emission factors were obtained from Appendix A of the ARB’s 

OFFROAD Model Documentation. They are based on the U.S. 

EPA’s adopted diesel standards and reflect California regulations.

The year 2002 engine populations provided in this methodology 

were grown to the 2012 base year using the OFFROAD2007 

model. The growth surrogates used in the OFFROAD model were 

obtained from a 1994 study by California State University -

Fullerton (CSUF) entitled “A Study to Develop Projected Activity for 

Non-Road Mobile Categories in California, 1970-2020”.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/FULLPDF/FULL1-2.pdf

Laundering

The Laundering category includes VOC emissions from 

perchloroethylene dry cleaning establishments. 

Activity information is taken from national consumption rates for the 

year 2001 cited in the Solvents Update July/August 2002 report 

compiled by the Halogenated Solvents Industry Alliance. 

The emission factors were obtained by applying a 25 percent 

recovery rate to perchloroethylene's density of 13.5 pounds per 

gallon. This recovery rate was based on data in the CAPCOA Air 

Toxic "Hot Spots" Program Perchloroethylene Dry Cleaners 
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Industry-wide Risk Assessment Guidelines (June 20, 2000).

Emissions were grown from the original 2001 estimates to 2012 

using population data from the California Department of Finance 

(2013).

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/onehtm/one3-1.htm

Degreasing

These categories include VOC emissions resulting from the use of 

solvents in degreasing operations in the manufacturing and 

maintenance industries. The emission estimates from this source 

category are based on the E.H. Pechan and Associates, Inc. 

(Pechan) report titled, "Solvent Cleaning/Degreasing Source 

Category Emission Inventory." (1996)

To estimate degreasing emissions, Pechan collected activity data 

by surveying solvent users in two major groups: manufacturing and 

maintenance. Emissions were estimated for 32 equipment and 

solvent pairs. For the manufacturer's survey, the emission factor 

for pure solvents is the density of the particular 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 with no exhaust controls.

The 1993 emissions estimates were grown to 2012 based on 

manufacturing output data (SIC codes 20-39) developed by 

Pechan.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/onehtm/one3-2.htm

Food and Agriculture

The Food and Agriculture category includes estimates of 

evaporative VOC emissions from processes in the agricultural and 

food processing industries. Wine fermentation and wine aging are 

among the largest contributors of these emissions.

Wine fermentation volumes in California are reported by the U.S. 

Alcohol and Tobacco Tax and Trade Bureau. ARB staff derived the 

emission factors from a computer model developed by Williams and 

Boulton. The model simulates the effects of temperature and the 

sugar concentration on the amount of evaporative ethanol loss 
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during isothermal batch fermentation. Emissions were initially 

estimated for 2002 and grown to later years using Beverages 

(Alcoholic & Non-Alcoholic) economic output.

The wine aging category also includes evaporative ethanol 

emissions from the aging of wine in oak barrels to produce brandy. 

The 1990 grape production in each county is taken from the Annual 

Crop and Livestock Report (Annual Crop Report) prepared by each

County Agricultural Commissioner. The amount of grapes produced 

was determined from the California Department of Food and 

Agriculture (CDFA) along with the Annual Crop Report. The amount 

of grapes crushed in the grape growing districts is from the CDFA 

report, "Final Grape Crush Report, 1990 Crop."

An emission factor for brandy was derived by Hugh Cook of the 

Wine Institute. Emissions were initially estimated for 1992 then 

grown to subsequent base years using Dollar Output for Food 

Manufacturing (SIC 20).

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/arbindprofandag.htm

Petroleum Marketing

The Petroleum Marketing category includes activities associated 

with the distribution of petroleum base products, including fuel 

loading and unloading, gasoline dispensing facilities, and gasoline 

storage tanks.

Marine Petroleum Loading

These categories are used to inventory 1987 hydrocarbon 

emissions associated with loading crude oil, residual oil, 

gasoline, and jet fuel into marine tankers and gasoline into 

barges. Emissions result from the displacement of vapors 

existing in the tank before loading and those generated as 

new product is loaded.

The amounts of crude oil, gasoline, jet fuel, and residual oil 

shipped off from California ports was obtained from an 

United States Army Corps of Engineers report "Waterborne 

Commerce of the United States, Calendar Year 1986, Part 

4”

The emission factor for crude oil loading into tankers was 

obtained from the report "Hydrocarbon Emissions During 

Marine Loading of Crude Oils" from Western Oil and Gas 

Association (1977). The gasoline emission factors for 
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loading into tankers and barges and jet fuel into tankers 

were obtained from ARB’s "Report to the Legislature on Air 

Pollutant Emissions from Marine Vessels" (1984). The 

emission factor for residual oil loading into tankers was 

obtained from the "Inventory of Emissions from Marine 

Operations within California Coastal Waters, Preliminary 

Draft" report by Scott Environmental Technology, Inc. 

(1980). 

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/arbpetprodmarkpm.htm

Marine Petroleum Unloading

These categories are used to estimate hydrocarbon 

emissions associated with lightering crude oil and ballasting 

marine vessels after unloading crude oil or gasoline. 

The amounts of crude oil and gasoline unloaded at California 

ports were obtained from the United States Army Corps of 

Engineers report "Waterborne Commerce of the United 

States, Calendar Year 1986" Part 4.

Crude oil lightering data was obtained from the Bay Area Air 

Quality Management District (AQMD) for 1987. Crude oil 

and gasoline ballasting data for San Luis Obispo for 1987 

was obtained from the Army Corps of Engineers. The 

volume of water used for ballasting following a cargo 

discharge was obtained from ARB’s "Report to the 

Legislature on Air Pollutant Emissions from Marine Vessels" 

(1984). 

The crude oil lightering emission factor was obtained from 

"Hydrocarbon Emissions During Marine Loading of Crude 

Oils," Western Oil and Gas Association (1977). 

Ballasting crude oil and gasoline vessels emission factors 

were obtained from "Inventory of Emissions from Marine 

Operations within the California Coastal waters," by Scott 

Environmental Technology, Inc. (1981) 

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/arbpetprodmarkpm.htm

Gasoline Dispensing Facilities

These categories include estimates of organic gas emissions 

resulting from the storage and transfer operations at 
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gasoline dispensing facilities. Gasoline dispensing facilities 

consist of gasoline retail outlets and private dispensing 

facilities. Emissions from these operations include the 

working losses and breathing losses from underground 

tanks, vapors displaced through vehicle refueling, and 

spillage. 

The total gasoline sales for service stations in the California 

by county were taken from the 1997 Annual Report from the 

California State Board of Equalization. County level 

emissions were estimated using taxable sales, population, 

vehicle miles of travel, and the number of registered vehicles

by county from the California Department of Transportation. 

Emissions were grown to 2012 based on fuel consumption 

estimates from EMFAC. 

Emission factors are based on the CAPCOA Air Toxics "Hot 

Spots" Program Gasoline Service Station Industrywide Risk 

Assessment Guidelines Document.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/arbpetprodmarkpm.htm

Bulk Gasoline Storage

This Bulk Gasoline Storage category estimates VOC 

emissions from gasoline cargo tanks. Pressure-related 

fugitive emissions occur during gasoline storage by leaking 

from fittings, valves and other connecting points in the vapor 

collection system on a cargo tank. Emissions are developed 

by both ARB and local air districts. The following sections 

describe ARB’s methodology.

The total highway gasoline sales cited in the Caltrans report, 

"Travel and Related Factors in California" (1997) represents 

all gasoline transported by gasoline cargo tankers in 

California. The emission factors are derived from the data in 

the report, "Emissions from Gasoline Cargo Tanks, First 

Edition," published by the Air and Waste Management 

Association in 2002. 

The initial emission estimates for 1997 were grown to 2012 

using a growth parameter developed by Pechan based on 

gasoline and oil expenditures data.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/arbpetprodmarkpm.htm
September 2016

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Oil and Gas Production

Oil and Gas Production categories are related to fugitive emissions 

from sumps, pits, valves, fittings, pumps, wells and storage tanks 

during oil and gas exploration and extraction. The following 

describes each of the categories in detail.

Fugitive Losses - Sumps and Pits

These categories include VOC emissions associated with 

the operation of sumps and pits used in oil production 

processes. A sump is defined as an excavated lined or 

unlined pit in the ground that is used to separate oil, water, 

and sand for oil and gas production operations. 

The amounts of sump emissions were estimated by ARB 

from the districts that reported sump usage in their 

jurisdiction in 1991. The data gathered were sump surface 

area, the type of sump, and the API gravity of the sump 

liquid.

TOG emission factors for light crude sumps were based on 

test data collected by Rockwell in a report prepared for the 

American Petroleum Institute entitled "Fugitive Hydrocarbon 

Emissions from Petroleum Production Operations," 1980. 

The VOC emission factors for heavy crude were obtained 

from ARB tests conducted between 1983 and 1986. From 

the Rockwell TOG emission factors, ARB derived 

corresponding emission factors for VOC by using speciation 

profiles provided by Rockwell.

Emissions were grown to the 2012 base year using is dollar

output for oil and gas extraction (SIC 13).

The San Joaquin Valley Air Pollution Control District (APCD) 

supplied an updated methodology for the Sump and Pits 

category in 2007. The number and surface area of active 

sumps and well cellars was determined from an industry 

survey of oil production facilities within the District. Emission 

factors are taken from ARB’s Technical Guidance Document 

for the Emission Inventory Criteria and Guidelines 

Regulation for AB 2588. Emissions in the San Joaquin 

Valley were grown from 2007 to 2012 using annual oil 

production data from DOGGR.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/onehtm/one4-1.htm
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Fugitive losses - Valves and Fittings 

These categories include the fugitive emissions from valves 

and fittings (threaded and flanged connections) associated 

with oil production operations.

The activity data are based on 1987 lease data from the 

California Department of Conservation Division of Oil, Gas 

and Geothermal Resources (DOGGR). These data were 

used to determine the number of wells on each lease and 

the gas to oil ratios for these wells. 

The emission factors were derived from two sources. 

General oil and gas production emission factors were 

obtained from Rockwell International's report "Fugitive 

Hydrocarbon Emissions from Petroleum Production 

Operations" (March 1980). KVB Incorporated, in its report 

"Emission Characteristics of Crude Oil Production 

Operations in California" (January 1983), based its 

composite emission factors for valves and fittings on a 1979-

80 field study of California oil production operations. 

Emissions from 1987 were grown to 2012 using dollar output 

for oil and gas extraction (SIC 13) and annual oil production 

in the San Joaquin Valley.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/onehtm/one4-2.htm

Fugitive losses - Pumps, Compressors and Well Heads 

These categories include the fugitive VOC emissions from 

pumps, compressors, and well heads associated with active 

wells. The activity data for these sources are from the 

California Division of Oil and Gas and represent 1987. The 

emission factors are from a report by KVB, Inc., "Emission 

Characteristics of Crude Oil Production Operations in 

California" (January 1983). Emissions were grown to the 

2012 base year using dollar output for oil and gas extraction 

(SIC 13) or annual oil production in the San Joaquin Valley.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/onehtm/one4-3.htm

Tertiary Oil Production - Steam Drive and Cyclic Wells 

These categories include the VOC emissions associated 

with steam drive wells and cyclic wells. In oil production 
September 2016

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fields, steam is injected in two ways: continuously through an 

injection well (steam drive) and periodically into the oil 

production well itself (cyclic injection). These sources of 

emissions are only found in Kern County in the San Joaquin 

Valley Air Basin.

The activity data is based on the total number of steam drive 

and cyclic wells. Both steam drive and cyclic wells were 

surveyed by the ARB in 1985. 

The emission factors are obtained from an ARB report, "A 

Suggested Control Measure for Emissions of 

Photochemically Reactive Organic Compounds from Vents 

of Steam Drive Oil Production Wells" (January 1982), and a 

report by KVB, Inc., "Emission Characteristics of Crude Oil 

Production Operations in California" (January 1983).

Emission estimates for 1985 were grown to 2012 using 

annual oil production.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/onehtm/one4-5.htm

Tertiary Oil Production – Pseudo Cyclic Wells

This methodology estimates VOC emissions from pseudo 

cyclic wells. The activity is based on the number of steam 

drive wells and injection wells. The emission factor for 

steam drive wells is obtained from a report by KVB, Inc., 

"Emission Characteristics of Crude Oil Production 

Operations in California" (January 1983). An injection well 

has an emission factor of zero.

Emissions from 1987 were grown to 2012 using dollar output 

for oil and gas extraction (SIC 13) or annual oil production in 

the San Joaquin Valley.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/onehtm/one4-4.htm

Gas Stripping 

These categories include the VOC emissions associated 

with natural gas processing. Natural gas obtained from gas 

wells contains impurities such as water, carbon dioxide, and 

sulfur compounds. Natural gas must be processed to 

remove these impurities. The sources of fugitive emissions 

during gas stripping originate from leaks in compressor 
September 2016

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seals, pump seals, valves, and fittings.

The activity data for the amounts of natural gas produced in 

each county in California were obtained from a report by the 

California Division of Oil and Gas, "73rd Annual Report of 

the State Oil and Gas Supervisor, 1987."

The emission factor for natural gas stripping was taken from 

a report by the U.S.EPA "Revision of Evaporative 

Hydrocarbon Emission Factors" (1976). 

Emissions from 1987 were grown to 2012 using dollar output 

for oil and gas extraction (SIC 13) or annual oil production in 

the San Joaquin Valley.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/onehtm/one4-6.htm

Oil Production Tanks

This category includes the VOC emissions from both open 

top and fixed roof tanks associated with oil production 

operations. The two major sources of tank emissions are 

breathing losses and working losses. 

The activity data are obtained from the Oil Production Tank 

Survey conducted in 1984. This survey was developed by 

representatives from the oil production industry, air pollution 

control districts, and ARB. Data obtained from this survey 

includes tank throughputs.

The emission factors to calculate breathing and working loss 

emissions are from the U.S.EPA's AP-42, Section 4.3 (4th 

edition). Control factors added to each equation to account 

for any California-specific control measures that are installed 

on the tanks. 

Emissions from 1987 were grown to 2012 using dollar output 

for oil and gas extraction (SIC 13) or barrels of oil in the San 

Joaquin Valley.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/onehtm/one4-7.htm
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Area-Wide Source Emissions

Managed Burning and Disposal

The Managed Burning and Disposal includes emissions from 

agricultural and forest management burns, also known as 

prescribed burns. A prescribed burn is a fire ignited by a planned 

management action, most often administered by a public land 

management agency.

Agricultural burn activity is updated annually with emissions data 

reported by the local air districts. The 2012 base year inventory 

uses burn activity reported for the year 2012. Emissions are 

calculated using crop specific emission factors and fuel loadings. 

Monthly burn activity provides seasonal emission estimates.

Prescribed burn emissions are calculated using the Emission 

Estimation System (EES) developed by UC Berkeley's Center for 

the Assessment and Monitoring of Forest and Environmental 

Resources (CAMFER). The EES implements the First Order Fire 

Effects Model (FOFEM 6.0) developed by the U.S. Forest Service 

(USFS) Fire Sciences Laboratory. Known fire perimeters are 

overlaid on the USFS Fuel Characterization Classification System 

land cover vegetation layer establishing the acres of specific 

vegetation burned in each fire. Fuel loading characteristics and 

moisture factors are assigned to each vegetation type using the 

USFS Wildland Fire Assessment System. The EES then calculates 

the tons of fuel consumed in each vegetation type and applies the 

appropriate emission factor to estimate emissions per burn event. 

Emission factors are contained in the FOFEM documentation. The 

emission factors are characterized by ten different fuel components 

that comprise a vegetation type, including duff, litter, wood of 

varying diameters, herbaceous vegetation, understory vegetation, 

branch and canopy fuels. 

Statewide interagency prescribed wild land burn data were

retrieved from the California Department of Forestry and Fire 

Protection (CDF), Fire and Resources Assessment Program 

(FRAP) fire perimeters geodatabase.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/see/see.htm. 

Pesticides

This category includes estimates of VOC emissions resulting from 

the application of agricultural and structural pesticides. Emissions 
September 2016

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were calculated by applying Emission Potential (EP) values to the 

amount of reported pesticide application in the Pesticides Use 

Report (PUR) dataset. Each pesticide has a specific EP value 

assigned.

The California Department of Pesticide Regulation (DPR) requires 

reporting of all agricultural and structural pesticide applications. 

DPR develops month-specific emission estimates from this 

reported information. Each calendar year, DPR updates the 

inventory based on the PUR that provides updated information from 

1990 to the most current data year available. This includes 

estimates for the 2012 calendar year. 

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/fullpdf/full6-4.pdf

Consumer Products

The Consumer Products category was updated to reflect the three 

most recent Consumer Products Surveys conducted by ARB for the 

years 2003, 2006, and 2008. Together these surveys collected 

updated product and ingredient information for approximately 350 

consumer product categories. ARB staff determined the total sales 

and total VOC emissions for the various product categories based 

on the survey data. In 2011 the Consumer Products inventory 

categorization was expanded to provide more detail, and in 2014 

the 2010 inventory was updated for 11 product categories. 

Emissions are grown to the 2012 base year using population data 

from the California Department of Finance (2013)

Additional information on this methodology is available at:

http://www.arb.ca.gov/consprod/survey/survey.htm

Cooking 

Commercial Cooking emission estimates are based on 

methodologies developed by the local air districts. The 2012 base 

year inventory includes an update for the San Joaquin Valley based 

on 2008 activity data that includes the number of restaurants, the 

number and type of cooking equipment, the food type, and 

emission factors from US EPA’s 2002 NEI. Emissions for this 

category were grown to 2012 based on population projections 

provided by the California Department of Finance (2013). 

Additional information on this methodology is available at:

http://www.arb.ca.gov/ei/areasrc/distmiscproccook.htm
September 2016

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Architectural Coatings

Architectural coatings are surface coatings applied to stationary 

structures and their accessories such as mobile homes, 

pavements, or curbs as protection from environmental conditions. 

VOC emissions result from the application of these oil-based and 

water-based coatings and the associated use of thinning and 

cleanup solvents and additives. 

Annual average VOC emission estimates for the year 2004 were 

derived from data obtained through a survey of manufacturers of 

architectural and industrial maintenance coatings conducted by 

ARB’s Stationary Source Division in 2005. The results of the 

survey provided the number of gallons of coatings sold in California 

in 2004 as well as the percentage that was oil versus water-based.

Emission factors were developed through the ARB sponsored a 

research project “Improvement of Emissions Inventories for 

Industrial Coatings and Thinning and Cleanup Solvents” in 2004.

Chemical composition data obtained from the survey report were 

used to inform the fractions of VOCs for water-based and oil-based 

coatings as well as for thinning and cleanup solvents and additives. 

The emission estimates include benefits of the 2003 and 2007 ARB 

Suggested Control Measure for Architectural Coatings.

Growth to the 2012 base year was based on DOF estimates of 

occupied housing units (December 2013).

Additional information on this methodology is available at:

http://www.arb.ca.gov/coatings/arch/survey/2005/2005survey.htm

Residential Fuel Combustion

The Residential Fuel Combustion category includes emission 

estimates for wood combustion from fireplaces and wood stoves 

and natural gas combustion for space heating, water heating, and 

cooking. The following sections describe the categories in more 

detail.

Residential Wood Combustion

This category represents emission estimates from woodburning fireplaces and wood stoves including fireplace 

inserts and pellet stoves 

ARB staff updated the Residential Wood Combustion 

methodology in 2011 to reflect recent survey data on types 
September 2016

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of wood burning devices and wood consumption rates, 

updates to the 2002 U.S. EPA National Emission Inventory 

(NEI) emission factors, and improved calculation 

approaches. The update reflects wood combustion surveys 

conducted by several districts including Bay Area AQMD in 

2007, South Coast AQMD in 2003 and 2006, Placer County 

APCD in 2007, San Joaquin Valley APCD in 2008, and 

Sacramento Metropolitan AQMD in 2007. This update also 

accounts for lower emissions resulting from various district 

curtailment programs

Emissions from fireplaces were initially estimated in 2005 

then grown to subsequent base years using Housing Unit 

data from the California Department of Finance, fireplace

data from the U.S. Census Bureau “American Housing 

Surveys”, and Regional Economic Models Inc. (REMI) 

population data. Emissions from wood stoves were initially 

estimated in 2005 then grown to subsequent base years 

using Housing unit data from California Department of 

Finance and Department of Energy 1998 Annual Energy 

Outlook (AEO) Renewables data.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/arbmiscprocresfuelcom.htm

Residential Natural Gas Combustion

Combustion of natural gas in the residential sector is broken 

down into four categories: space heating, water heating, 

cooking, and unspecified. The unspecified category includes 

the combustion of natural gas in appliances such as clothes 

dryers, barbecues, and water heaters used for pools, spas 

and hot tubs. 

The amount of natural gas consumed in the residential 

sector for each county was obtained from the California 

Energy Commission report, "Quarterly Fuel and Energy 

Report, 1997 Residential Natural Gas Consumption." The 

amount of natural gas was apportioned into the four 

categories described above based on percentages from the 

California Energy Commission report, "Breakdown of 

California Natural Gas Usage by Appliance and by Utility 

Company for All Housing Types Combined." The emission 

factors for residential natural gas combustion were obtained 

from EPA's AP-42 5

th Edition (1995).

Emissions were initially calculated for 1998 then grown to 
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subsequent base years. The growth parameters were 

developed by Pechan and Associates (Pechan) as 

documented in their report, "Development of Emission 

Growth Surrogates and Activity Projections Used in 

Forecasting Point and Area Source Emissions, Final 

Report," February 26, 2001. For cooking and unspecified, 

data on housing units were adjusted by Pechan using the 

Department of Energy's Annual Energy Outlook residential 

natural gas consumption projections. 

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/ONEHTM/ONE7-2.HTM

Residential Distillate Oil and Liquefied Petroleum Gas

The residential distillate oil/liquefied petroleum gas (LPG) 

category includes emissions occurring in the residential 

sector. Distillate oil for heating is used only in older homes 

and remote areas where natural gas lines are not available. 

Activity is based on the number of housing units, population, 

and LPG and distillate oil capacities. The 1991 Fuels Report 

Working Paper published by the California Energy 

Commission was used to determine energy demand by fuel 

type in terms of the number of houses heated by a specific 

fuel in a particular area. Heating degree days (HDD) are 

used to estimate how many heating days are likely to occur 

in a particular area. 

This category uses emission factors from U.S. EPA's AP-42. 

The emissions were initially calculated in 1993 then grown to 

subsequent base years using Housing Unit data from the 

California Department of Finance (2013)

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/ONEHTM/ONE7-3.HTM

Asphalt Paving

Asphalt paving estimates are based on various methodologies used 

by the local air districts. As an example of a typical methodology, 

the San Joaquin Valley APCD used emission factors taken from 

two studies: KVB’s “Control of Hydrocarbon Emissions from 

Stationary Sources in the California South Coast Air Basin” (1978) 

and “Central California Ozone Study, Attachment C: Asphalt Paving 

and Roofing.” by Sonoma Technology, Inc. (2003)

Emissions for this category are grown to the 2012 base year using 
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construction employment from the REMI model.

Additional information on the San Joaquin Valley APCD

methodology is available at: 

http://www.valleyair.org/Air_Quality_Plans/EmissionsMethods/Meth

odForms/Current/AsphaltPaving2008.pdf

Coatings and Related Process Solvents

The Coatings and Related Process Solvents category includes 

VOC emissions from auto refinishing, surface coatings, and 

thinning and cleaning solvents.

Auto Refinishing 

VOC emissions from auto refinishing operations are related 

to solvents contained in products such as auto refinishing 

paints, enamels and lacquers, refinish primers and 

undercoatings. Emissions are developed by both ARB and 

local air districts. The following sections describe ARB’s 

methodology.

Emissions from automotive coatings are estimated from the 

Automotive Coatings Survey conducted by the ARB 

Stationary Source Division (SSD) in 2002. A total of 17 

companies provided data. The survey collected data on the 

VOC ingredients of products, which were then used to 

estimate emissions from these specific automotive coatings. 

The survey also collected information on speciation of 

VOCs. The 2001 emission estimates were grown to 2012 

using Pechan’s auto refinishing growth parameter from 2002 

based on jobs in the automobile services industry. For 

Southern California, growth was based on employment in 

automobile services including car rental and miscellaneous 

repair. (SIC 75 and 76).

Additional information on this methodology is available at: 

http://www.arb.ca.gov/coatings/autorefin/scm/sreport/scmsta

ffreport.htm

Surface Coatings

The Surface Coatings categories estimate VOC emissions 

from the application of surface coatings in the manufacturing 

and industrial sectors. These include coatings for marine, 

paper, fabric, metal, and industrial products. Emissions are 

developed by both ARB and local air districts. The following 
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sections describe ARB’s methodologies. 

For marine coatings, the activity data were obtained from 

national production data from the Bureau of the Census 

1984 report entitled "1982 Census of Manufacturers, Paint 

and Allied Products". For paper and fabric coatings, 

estimated use in California is based on SSD's 1977 survey 

data and an annual growth factor of 1.68 taken from ARB’s 

"Consideration of Proposed Rule for Control of VOCs from 

Paper and Fabric Coating Operations" (1978). The emission 

factors were obtained from developed composites for each 

category from data in the 1977 survey.

Emissions were initially estimated for 1983, then grown to 

subsequent base years using employment in the 

manufacturing of transportation equipment (SIC 37), dollar 

output from manufacturing of paper and allied products (SIC 

26), manufacturing of textiles (SIC 22), manufacturing of 

furniture (SIC 25), and the total manufacturing industry (SICs 

20-39)

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/arbcleancoatreproc.htm

Thinning and Cleaning Solvents

This category includes the VOC emissions from thinning 

solvents used with industrial surface coatings. This solvent 

category includes the use of thinners used for dopes, 

lacquers, and oleoresinous thinners. Emissions are 

developed by both ARB and local air districts. The following 

section describes ARB’s methodology.

The Thinning and Cleaning Solvents category was updated 

using data from the Census Bureau’s report “Current 

Industrial Reports, Paint & Allied Products” (2002). U.S. 

consumption of each coating type within each category was 

apportioned to California using employment data specific to 

the coating type. 

Emission estimates are grown to the 2012 base year using 

the manufacturing output parameter developed by Pechan.

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/arbcleancoatreproc.htm
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Adhesives and Sealants

This category includes VOC emissions from solvents 

contained in adhesives and sealants used for the 

construction, transportation and other industries. The 

emissions are broken down into two subcategories: solventbased and water-based.

The activity data for adhesives and sealants used nationally 

in 1983 for construction, transportation and other industries 

were obtained from the report "Outlook for the U.S. 

Adhesives and Sealants Industry," by Decision Resources. 

California's percent use of the national production was based 

on a ratio of California to national use, from the Science 

Applications International Corporation (SAIC) report titled 

"Development and Improvement of Organic Compound 

Emissions Inventory for California," published in 1985.

The emission factors for solvent-based adhesive and 

sealants for the transportation and other industries 

categories were based on data from the SAIC report. The 

emission factor for solvent-based adhesive and sealants for 

the construction industry was based on data from an U.S. 

EPA report titled "Preliminary Draft of Industry Classification, 

Estimates of Adhesives Consumed, and Solvent Emissions." 

The emission factor for all water-based adhesives and 

sealants was based on data from Decision Resources.

The emissions from 1983 were grown to 2012 using dollar 

output for manufacturing industries (SICs 20-39). 

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/arbcleanadhseal.htm

Farming Operations

This category provides estimates of the VOC emissions produced 

by dairy cattle, range cattle, poultry, swine, sheep, goats, and 

horses. Emissions are calculated by multiplying a per animal

emission factor by the population of each animal type. 

The dairy, feedlot, and range cattle emission estimates reflect 

livestock population data from the U.S. Department of Agriculture’s 

(USDA) 2012 Census of Agriculture (2007). The emission 

estimates for other livestock categories are based on the USDA 

2007 Census of Agriculture.
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Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/arbmiscprocresfarmop.htm

Fires

This category is used to estimate the combustion emissions from 

structure, mobile home, and automobile fires. The Structure Fires 

category includes both residential and commercial structures.

Estimates of building, mobile home, and automobile fires are based 

on data from a 1996 report by the California Fire Incident Reporting 

System (CFIRS), California State Fire Marshall's Office. 

Structure fire emission factors were obtained from the report, "Fires 

Dynamics of Model Wood Buildings," Fire and Flammability, Vol. 3, 

p. 336 (October 1972). The emission factor for NOx is assumed to 

be similar to the factor for municipal refuse listed in AP-42, Sections 

2.2 and 2.4. This amount, representing both structural loss and 

content loss, was calculated using data from the California State 

Fire Marshall Office, the Census Bureau, the National Association 

of Home Builders, and the National Bureau of Standards. 

For automobile fires, composite emission factors have been 

calculated as a weighted average of the emission factors listed in 

AP-42 Table 2.2-1 (uncontrolled auto body incineration) and Table 

2.4-1 (open burning of automobile components including 

upholstery, belts, hoses, and tires burned in common). 

Emissions were initially calculated for 1999, and then grown to 

subsequent base years using the following growth factors. For 

structure fires, the growth parameters were developed by Pechan 

and are based on occupied housing units. For automobile fires, the 

growth parameters are based on population from the Department of 

Finance (2013). 

Additional information on this methodology is available at: 

http://www.arb.ca.gov/ei/areasrc/ONEHTM/ONE7-14.HTM