050 – Industrial Natural Gas Combustion 

Page 1 of 17 Rev. Date: 13 June 2006 

IndustrialNG2006.doc Rev. By: K Thao

2006 Area Source Emissions Inventory Methodology 

050 – INDUSTRIAL NATURAL GAS COMBUSTION 

I. Purpose 

This document describes the Area Source Methodology used to estimate emissions 

of carbon monoxide (CO), nitrogen oxides (NOx), fine particulate matter less then 10 

microns (PM10), volatile organic compounds (VOC), and sulfur oxides (SOx) from the 

combustion of natural gas from industrial sources not reported through the District’s 

point source inventory. An area source is a collection of similar emission units within 

a geographic area (ie., a County). Area sources collectively represent individual 

sources that are small and numerous, and that may not have not been inventoried 

as specific point, mobile, or biogenic sources. The California Air Resources Board 

(CARB) has grouped these individual sources with other like sources into area 

source categories. These source categories are grouped in such a way that they can 

be estimated collectively using one methodology. 

II. Applicability 

The emission calculations from this Area Source Methodology apply to facilities that 

are identified by the following Category of Emission Source (CES) codes and 

Reconciliation Emission Inventory Codes (REIC): 

Table 1. Emission inventory codes. 

CES REIC Description 

66787 050-040-0110-0000 Industrial Stationary - I.C. Engines - Natural Gas 

47142 050-995-0110-0000 Industrial Natural Gas Combustion (Unspecified) 

III. Point Source Reconciliation 

Emissions from the area source inventory and point source inventory are reconciled 

against each other to prevent double counting. This is done using relationships 

created by the California Air Resources Board (ARB) between the area source REIC 

and the point sources’ Standard Industry Classification (SIC) code and emissions 

process Source Category Code (SCC) combinations. The area sources in this 

methodology reconcile against processes in our point source inventory with the 

SIC/SCC combinations listed in Appendix A. 

San Joaquin Valley

AIR POLLUTION CONTROL DISTRICT
050 – Industrial Natural Gas Combustion 

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IV. Methodology Description 

This area source methodology is a top down estimation of emissions from the 

combustion natural gas by the industrial sector in the San Joaquin Valley Air 

Pollution Control District. The industrial sector consumes natural gas for process 

uses (primarily heat), boiler fuel, space heat, electricity generation and feedstock. 

These end uses are divided into two categories: 1) stationary internal combustion 

engines - reciprocating engines and turbines, and 2) unspecified. The “unspecified” 

category includes external combustion sources such as heaters, boilers, and 

burners. The amount of natural gas delivered to industrial sources in each county 

within the District was obtained from the California Energy Commission (Gough, 

2007). From this, the amount of natural gas reported to the District’s point source 

inventory as consumed was subtracted. The difference between the amount of 

natural gas reported delivered and the amount reported consumed was considered 

the area source process rate. To estimate area source emissions, the area source 

process rate was assigned to end uses and then multiplied by emission factors. 

V. Activity Data 

Consumption. Total natural gas deliveries to the industrial sector for each county in 

the district in was obtained from the California Energy Commission (Gough, 2007) 

and is presented below. Industrial deliveries exclude companies whose primary 

function is to generate electricity or produce oil and gas as determined by their 

company SIC. Emissions from these industries are tabulated in other EICs. The 

District’s point source inventory of industrial natural gas combustion processes was 

then reconciled against the amount of natural gas reported delivered to industrial 

sources within the District. The area source consumption was calculated as the 

difference between the industrial natural gas deliveries and the industrial 

consumption reported through the point source inventory (Table 2). 

Table 2. 2006 industrial natural gas consumption (MMSCF). 

County Industrial Deliveries 

Reported by CEC 

Industrial Point 

Source Consumption 

Reconciled Area 

Source Consumption 

Fresno 8,868.32 5,691.36 3,176.96 

Kern 7,106.00 3,136.98 3,969.01 

Kings 3,163.25 2,435.93 727.31 

Madera 3,332.25 1,625.83 1,706.42 

Merced 7,529.53 5,683.38 1,846.15 

San Joaquin 7,231.04 5,861.54 1,369.50 

Stanislaus 7,279.97 5,569.08 1,710.89 

Tulare 6,960.05 5,521.34 1,438.70 

Total 51,470.41 35,525.48 15,944.93 
050 – Industrial Natural Gas Combustion 

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Categorization. To categorize industrial natural gas end use, we used a 1994 report 

prepared by the Energy Information Administration (EIA) entitled “How Changing 

Energy Markets Affects Manufacturing.” This study divided industrial natural gas 

consumption into the three main end use categories presented in Table 3. 

Table 3. Industrial natural gas consumption categories. 

REIC Category Description Combustion Process 

Industrial 

Natural Gas 

Consumption

050-040-0110-0000 Industrial Stationary - I.C. 

Engines - Natural Gas Turbines/Reciprocating Engines 6% 

050-995-0110-0000 Industrial Natural Gas 

Combustion (Unspecified) Heaters, Boilers, and Furnaces 84% 

Feedstock Non-combustion 

Processes 

Natural Gas used in the synthesis of 

other products 10% 

The Feedstock category does not involve natural gas combustion and will not be 

considered in this area source methodology. 

VI. Emission Factors 

CO, NOx, SOx, VOC and PM emission factors for reciprocating engines and 

“unspecified” industrial natural gas combustion were obtained from the EPA’s AP-42 

document (EPA, 1998 & 2000b). The SOx emission factor for all processes was 

obtained from San Joaquin Valley Air Pollution Control District Policy APR 1720. 

For internal combustion (IC) engines, the NOx, VOC, CO, and PM10 emission 

factors were taken from AP-42, section 3.2, table 3.2-2 (EPA, 2000b). The NOx and 

CO emission factors were used under the assumption that the IC engines are 4-

stroke lean-burn engines operating at normal conditions and less than 90% load. 

The Total Organic Gas (TOG) emission factor was speciated into a VOC emission 

factor using CARB’s speciation profile. The PM10 emission factor is also taken from 

the same table. In an effort to provide a more conservative estimate, the total PM 

(condensable) emission factor was speciated into PM10 emissions using CARB’s 

speciation profiles. 

For small boilers, the NOx, VOC, CO, and PM10 emission factors were taken from 

AP-42, section 1.4, tables 1.4-1 and 1.4-2 (EPA, 1998). The NOx and CO emission 

factors were taken under the assumption that these were small, uncontrolled boilers. 

The VOC emission factor was taken directly from AP-42 because it would be higher 

than the speciated TOC emission factor and therefore be a more conservative 

emission factor. The PM10 emission factor was obtained by applying the CARB 

speciation profile to the total PM emission factor.
050 – Industrial Natural Gas Combustion 

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Table 4. Industrial natural gas combustion emission factors. 

Emissions (pounds per million cubic feet) Combustion process NOx CO SOx VOC PM10

Reciprocating Engines 864 568 2.9 4.7 10.2 

Unspecified 100 84 2.9 5.5 7.6 

VII. Emissions Calculations 

A. Assumptions

1. Natural gas deliveries are accurately reported by the California Energy 

Commission. 

2. EIA’s study of the end-use consumption of natural gas within the 

manufacturing sector accurately describes the end-use consumption of 

natural gas by the industrial sector within the District. 

3. The AP-42 emission factors selected for reciprocating engines and 

unspecified devices are representative. 

4. All non-permitted natural gas powered internal combustion engines within the 

District are 4-stroke lean-burn engines. 

5. All non-permitted unspecified natural gas combustion devices within the 

District are uncontrolled small boilers. 

B. Sample Calculations:

The emissions for each criteria pollutant within this area source methodology can be 

calculated using the following equation: 

( ) 















































= × × ×

2000 lbs 

ton 1

MMSCF

lbs of Emissions

% End Use Emission Factor

yr

MMSCF

Fuel Consumptio n

yr

tons Emissions

For NOx emissions due to natural gas combustion in unspecified industrial sources 

in Fresno County: 

Given:

1. The reconciled area source consumption of natural gas by the industrial sector 

in Fresno County was 3,177 MMSCF (million std. cubic feet) in 2006. 

2. 84% of industrial end use was for unspecified sources. 
050 – Industrial Natural Gas Combustion 

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IndustrialNG2006.doc Rev. By: K Thao

3. The NOx emission factor for unspecified industrial natural gas combustion is 

100 pounds per million cubic feet of natural gas burned. 

Calculate Emissions:

( )

Year

266,868 lbs of NOx

MMSCF

100 lb of NOx 84.0

Year

,3 177 MMSCFt NOx Emissions  =











 × ×











=

Year

133 4. tons of NOx

,2 000 lbs

1 ton

Year

266,868 lbs of NOx NOx Emissions =















 ×











=

VIII. Temporal Variation 

The following section outlines the daily, weekly, and monthly consumption of natural 

gas within the San Joaquin Valley for each end use category due to temporal 

variations. 

A. Daily

ARB Code 24. 24 hours per day - uniform activity during the day 

B. Weekly

ARB Code 7. 7 days per week - uniform activity every day of the week 

C. Monthly

Monthly activity in California is relatively uniform as illustrated by 2006 industrial 

natural gas consumption data from the U.S. Department of Energy’s Energy 

Information Administration presented below: 

Table 5. California industrial natural gas consumption. 

Month 

(2006) 

Natural Gas Consumption 

(million cubic feet) 

Activity Level 

(% of annual) 

January 60,043 8.20% 

February 59,659 8.15% 

March 61,924 8.46% 

April 60,888 8.32% 

May 58,174 7.95% 

June 57,333 7.83% 

July 59,573 8.14% 

August 62,997 8.61% 

September 64,032 8.75% 

October 63,729 8.71% 

November 60,995 8.33% 

December 62,708 8.57% 

Total 732,055 100.00% 
050 – Industrial Natural Gas Combustion 

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IX. Spatial Variation 

Industrial natural gas deliveries in 2006 for each county in the SJVAPCD were 

provided by the California Energy Commission (Gough, 2007) and were presented 

previously in Section V. Within each county, activity can be assigned to parcels 

zoned for industrial activity. 

X. Growth Factor 

Growth factors are developed by either the District’s Planning Department or CARB 

for each EIC. These factors are used to estimate emissions in future years. The 

growth factors associated with this emissions category may be obtained from the Air 

Quality Analysis Section of the District’s Planning Department. 

XI. Control Level 

Emission units within this area source category may be subject to the following 

District Rules: 

Table 6. District rules applicable to REIC 050-040-0110-0000 and 050-995-0110-0000. 

Rule No. Rule Description 

4701 Internal Combustion Engines - Phase 1 

4702 Internal Combustion Engines - Phase 2 

4703 Stationary Gas Turbines 

4305 Boilers, Steam Generators, and Process Heaters - Phase 2 

4306 Boilers, Steam Generators, and Process Heaters - Phase 3 

4307 Boilers, Steam Generators, and Process Heaters - 2.0 MMBtu/hr to 5.0 MMBtu/hr 

4308 Boilers, Steam Generators, and Process Heaters (0.075 MMBtu/hr to 2.0 MMBtu/hr) 

4309 Dryers, Dehydrators and Ovens 

4311 Flares 

4313 Lime Kilns 

4351 Boilers, Steam Generators, and Process Heaters - Phase 1 

Control levels associated with this emissions category may be obtained from the Air 

Quality Analysis Section of the District’s Planning Department. 

XII. ARB Chemical Speciation 

CARB has developed organic gas profiles in order to calculate reactive organic 

gasses (ROG), volatile organic compounds (VOC) or total organic gas (TOG) given 

any one of the three values. For each speciation profile, the fraction of TOG that is 

ROG and VOC is given. The organic gas profile codes can also be used to lookup 

associated toxics. CARB’s speciation profiles for industrial natural gas combustion 

processes are presented in Table 7. Organic gas profile #719 is applied to REIC 

050-040-0110-0000 (Industrial stationary IC engines, natural gas). Organic gas 
050 – Industrial Natural Gas Combustion 

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profile #3 is applied to REIC 050-995-0110-0000 (Industrial natural gas combustion, 

unspecified). 

CARB has developed particulate matter speciation profiles in order to calculate 

particulate matter (PM), particulate matter with a diameter less than or equal to 10 

microns (PM10) or particulate matter with a diameter less than or equal to 2.5 

microns (PM2.5) given any one of the three values. For each speciation profile, the 

fraction of PM that is PM10 and PM2.5 is given. The particulate matter profile codes 

can also be used to lookup associated toxics. CARB’s speciation profiles for 

industrial natural gas combustion processes are presented in Table 8. Particulate 

matter profile #123 is applied to REIC 050-040-0110-0000 (Industrial stationary IC 

engines, natural gas). Particulate matter profile #120 is applied to REIC 050-995-

0110-0000 (Industrial natural gas combustion, unspecified). 

Table 8. CARB chemical speciation profiles for 050-040-0110-0000, 050-995-0110-0000. 

Fractions Profile Description ARB PM 

Profile# PM10 PM2.5 

Stationary I.C. Engine - Natural Gas 123 0.994 0.992 

Gaseous Material Combustion 120 1 1 

XIII. Assessment Of Methodology 

This area source estimate relies on point source and total District consumption of 

natural gas to determine area source consumption. It is important that both 

inventories be accurate and complete. 

Although all internal combustion engines less than 50 horsepower are assumed to 

be reciprocating engines, there are proposals for microturbines within the District for 

use in the future. However, these microturbines are not expected to make a 

significant impact on the area source estimation. 

The manner by which the EIA broke down the natural gas usage in the 

manufacturing sector (EIA, 1994) is used as a surrogate for the assignment of 

industrial natural gas consumption to devices. This is based on a national study 

performed in 1994 and representing the manufacturing sector only. Future research 

or studies could lead to a more accurate and up-to-date depiction of the natural gas 

consumption in the industrial sector. 

Table 7. CARB chemical speciation profiles for 050-040-0110-0000, 050-995-0110-0000.

Fractions Profile Description ARB Organic 

Gas Profile# ROG VOC 

Internal Combustion Engines - 

Reciprocating - Natural Gas 719 0.091428 0.091428 

External Combustion Boiler - Natural Gas 3 0.422181 0.422181 
050 – Industrial Natural Gas Combustion 

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XIV. Emissions 

Following is the 2006 area source emissions inventory for REIC 050-040-0110-0000 

(Industrial Stationary - I.C. Engines - Natural Gas) and 050-995-0110-0000 

(Industrial Natural Gas Combustion - Unspecified) estimated by this methodology. 

Emissions are reported for each county in the District. 

Table 9. Area source emissions for industrial natural gas combustion. 

Emissions (tons/year) County NOx CO SOx VOC(1)

 PM10

(2)

INDUSTRIAL STATIONARY - I.C. ENGINES - NATURAL GAS 

Fresno 82.35 54.14 0.28 0.45 0.97

Kern(3) 102.88 67.63 0.35 0.56 1.21

Kings 18.85 12.39 0.06 0.10 0.22

Madera 44.23 29.08 0.15 0.24 0.52

Merced 47.85 31.46 0.16 0.26 0.56

San Joaquin 35.50 23.34 0.12 0.19 0.42

Stanislaus 44.35 29.15 0.15 0.24 0.52

Tulare 37.29 24.52 0.13 0.20 0.44

TOTAL 413.3 271.71 1.4 2.24 4.86

INDUSTRIAL NATURAL GAS COMBUSTION (UNSPECIFIED) 

Fresno 133.43 112.08 0.80 7.34 6.14

Kern(3) 166.70 140.03 1.00 9.17 7.67

Kings 30.55 25.66 0.18 1.68 1.41

Madera 71.67 60.20 0.43 3.94 3.30

Merced 77.54 65.13 0.47 4.26 3.57

San Joaquin 57.52 48.32 0.35 3.16 2.65

Stanislaus 71.86 60.36 0.43 3.95 3.31

Tulare 60.43 50.76 0.36 3.32 2.78

TOTAL 669.7 562.54 4.02 36.82 30.83

(1) The District only reports ROG to ARB. As noted in Section XII, ROG is the 

same as VOC. 

(2) At this time, the District does not calculate PM2.5 emissions. PM2.5 emissions 

can be estimated using the speciation profiles found in Section XII. 

(3) Includes both the Valley and non-Valley portions of Kern County. 
050 – Industrial Natural Gas Combustion 

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Following is the 2006 point source emissions inventory for REIC 050-040-0110-0000 

(Industrial Stationary - I.C. Engines - Natural Gas) and 050-995-0110-0000 

(Industrial Natural Gas Combustion - Unspecified) estimated by this methodology. 

Emissions are reported for each county in the District. 

Table 10. Point source emissions for industrial natural gas combustion. 

Emissions (tons/year) County NOx CO SOx VOC(1) PM10

(2)

INDUSTRIAL STATIONARY I.C. ENGINES NG (050-040-0110-0000) 

Fresno 0.47 0.28 0.23 0.42 0.50 

Kern(3) 0.05 1.14 0.00 0.08 0.01 

Kings 0.00 0.00 0.00 0.00 0.00

Madera 0.03 0.02 0.00 0.00 0.00 

Merced 0.00 0.01 0.00 0.00 0.00 

San Joaquin 0.14 0.65 0.00 0.16 0.00 

Stanislaus 0.00 0.00 0.00 0.00 0.00

Tulare 0.30 1.64 0.12 0.55 0.32 

TOTAL 0.99 3.74 0.35 1.21 0.83

INDUSTRIAL NG COMBUSTION (UNSPECIFIED) (050-995-0110-0000) 

Fresno 106.03 133.03 11.44 22.75 23.24

Kern(3) 86.07 70.67 3.54 9.27 12.25

Kings 47.13 57.01 4.46 10.29 13.29

Madera 162.46 41.47 7.71 10.34 10.82

Merced 96.05 166.34 6.76 15.32 16.51

San Joaquin 78.88 91.45 2.84 13.17 12.55

Stanislaus 118.50 74.32 7.06 8.71 20.24

Tulare 83.40 137.49 12.35 13.43 16.72

TOTAL 778.52 771.78 56.16 103.28 125.62

(1) The District only reports ROG to ARB. As noted in Section XII, ROG is the same 

as VOC. 

(2) At this time, the District does not calculate PM2.5 emissions. PM2.5 emissions 

can be estimated using the speciation profiles found in Section XII. 

(3) Includes only the Valley portion of Kern County. 
050 – Industrial Natural Gas Combustion 

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IndustrialNG2006.doc Rev. By: K Thao

Following is the 2006 total unreconciled (point source plus area source) emissions 

inventory for REIC 050-040-0110-0000 (Industrial Stationary - I.C. Engines - Natural 

Gas) and 050-995-0110-0000 (Industrial Natural Gas Combustion - Unspecified) 

estimated by this methodology. Emissions are reported for each county in the 

District. 

Table 11. Total emissions for industrial natural gas combustion. 

Emissions (tons/year) County NOx CO SOx VOC(1) PM10

(2)

INDUSTRIAL STATIONARY I.C. ENGINES NG (050-040-0110-0000) 

Fresno 82.82 54.42 0.51 0.87 1.47

Kern(3) 102.93 68.77 0.35 0.64 1.22

Kings 18.85 12.39 0.06 0.10 0.22

Madera 44.26 29.10 0.15 0.24 0.52

Merced 47.85 31.46 0.16 0.26 0.57

San Joaquin 35.64 23.99 0.12 0.35 0.42

Stanislaus 44.35 29.15 0.15 0.24 0.52

Tulare 37.59 26.16 0.25 0.75 0.76

TOTAL 414.29 275.44 1.75 3.45 5.7

INDUSTRIAL NG COMBUSTION (UNSPECIFIED) (050-995-0110-0000) 

Fresno 239.46 245.11 12.24 30.09 29.38

Kern(3) 252.77 210.70 4.54 18.44 19.92

Kings 77.68 82.67 4.64 11.97 14.70

Madera 234.13 101.67 8.14 14.28 14.12

Merced 173.59 231.47 7.23 19.58 20.08

San Joaquin 136.40 139.77 3.19 16.33 15.20

Stanislaus 190.36 134.68 7.49 12.66 23.55

Tulare 143.83 188.25 12.71 16.75 19.50

TOTAL 1,448.22 1,334.32 60.18 140.1 156.45

(1) The District only reports ROG to ARB. As noted in Section XII, ROG is the same 

as VOC. 

(2) At this time, the District does not calculate PM2.5 emissions. PM2.5 emissions 

can be estimated using the speciation profiles found in Section XII. 

(3) Includes both the Valley and non-Valley portions of Kern County. 
050 – Industrial Natural Gas Combustion 

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Following is the net change in total unreconciled emissions between this update 

(2006 inventory year) and the previous update (2005 inventory year) for REIC 050-

040-0110-0000 (Industrial Stationary - I.C. Engines - Natural Gas) and 050-995-

0110-0000 (Industrial Natural Gas Combustion - Unspecified) estimated by this 

methodology. The change in emissions are reported for each county in the District. 

Table 12. Net emissions change for industrial natural gas combustion 

(2006-2005). 

Emissions (tons/year) County NOx CO SOx VOC PM10

INDUSTRIAL STATIONARY I.C. ENGINES NG (050-040-0110-0000) 

Fresno 59.98 39.57 0.42 0.73 1.20

Kern 11.07 8.37 0.04 0.13 0.14

Kings 18.85 12.39 0.06 0.10 0.22

Madera -0.18 -0.07 -0.00 -0.00 -0.00

Merced 47.85 31.46 0.16 0.26 0.57

San Joaquin 35.39 23.74 0.09 0.31 0.34

Stanislaus 38.93 25.59 0.13 0.21 0.46

Tulare -23.59 -14.23 0.03 0.40 0.04

TOTAL 188.3 126.82 0.93 2.14 2.97

INDUSTRIAL NG COMBUSTION (UNSPECIFIED) (050-995-0110-0000) 

Fresno 88.79 102.73 4.09 12.86 9.51

Kern 19.28 -28.79 0.92 3.51 -0.45

Kings 40.94 34.69 2.10 5.82 7.38

Madera 14.78 5.86 1.22 2.64 -0.08

Merced 95.56 59.11 3.23 12.96 9.58

San Joaquin -384.71 64.72 -263.70 6.91 3.86

Stanislaus 69.23 26.71 0.39 4.73 5.11

Tulare -23.92 -22.19 4.11 0.60 -0.85

TOTAL -80.05 242.84 -247.64 50.03 34.06

XV. Revision History 

2006. The methodology was reformatted to the new District standard, and process 

rates were updated. A correction was made to the IC engine emission factors 

which resulted in an increase in emissions for this source category. The 

reduction in industrial unspecified natural gas combustion emissions in San 

Joaquin county is due to moving glass furnace emissions to the Glass 

Manufacturing source category . 

2005. This is a new District methodology based upon one developed by Sonoma 

Technology as part of the Central California Ozone Study. 
050 – Industrial Natural Gas Combustion 

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XVI. Update Schedule 

In an effort to provide inventory information to ARB and other District programs and 

maximize limited resources, the District has developed an update cycle based on 

emissions within the source category as shown in Table 13. 

Table 13. Area source update frequency criteria. 

Total Emissions 

(Tons/Day) 

Update Cycle 

(Years) 

<1 4 

>1 and <= 2.5 3 

>2.5 and <=5 2 

>5 1 

Since NOx emissions exceed 5 tons per day, these area source estimates will be 

updated every year. 

Table 14. Industrial natural gas combustion methodology update frequency. 

EIC Frequency 

(In years) 

Source of Emissions 

(Point Source Inventory / Data 

Gathering) 

050-040-0110-0000 1 Point Source Inventory / Data Gathering 

050-995-0110-0000 1 Point Source Inventory / Data Gathering 

XVII. References 

1. E.H. Pechan and Associates. 2005. Appendix A: Industrial fuel combustion, 

Natural gas. In: Documentation for the draft 2002 nonpoint source national 

emission inventory for criteria and hazardous air pollutants (March 2005 version). 

Prepared for the Emissions Inventory Group (D205-01), U.S. Environmental 

Protection Agency. Pages A88-A90. 

2. Energy Information Administration. 1994. How changing energy markets affect 

manufacturing. 

<http://www.eia.doe.gov/emeu/mecs/mecs94/special_topics/restructuring_mecs9

4.htm> 

3. Gough, A., 2007. E-mailed 2006 natural gas delivery data from the California 

Energy Commission, Sacramento, CA to Yu Vu, San Joaquin Valley Unified 

APCD. (May 30, 2007). 

4. Sonoma Technology, Inc. 2002. Central California ozone study, Attachment A: 

Natural gas combustion. <http://www.arb.ca.gov/ei/areasrc/ccosmethods.html> 
050 – Industrial Natural Gas Combustion 

Page 13 of 17 Rev. Date: 13 June 2006 

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5. United States Environmental Protection Agency (1998). AP 42 Section 1.4: 

Natural gas combustion. U.S. GPO, Washington D.C. 

<http://www.epa.gov/ttn/chief/ap42/ch01/final/c01s04.pdf> 

6. United States Environmental Protection Agency (2000a). AP 42 Section 3.1: 

Stationary Gas Turbines. U.S. GPO, Washington D.C. 

<http://www.epa.gov/ttn/chief/ap42/ch03/final/c03s01.pdf> 

7. United States Environmental Protection Agency (2000b). AP 42 Section 3.2: 

Natural gas-fired reciprocating engines. U.S. GPO, Washington D.C. 

<http://www.epa.gov/ttn/chief/ap42/ch03/final/c03s02.pdf> 

XVIII. Appendices 

Appendix A. Inventory Reconciliation Codes 
050 – Industrial Natural Gas Combustion 

Page 14 of 17 Rev. Date: 13 June 2006 IndustrialNG2006.doc Rev. By: K Thao

XIX. Appendix A. Inventory Reconciliation Codes 

Table 15. EIC, SCC and SIC codes in the District’s 2006 point source inventory that reconciled to REIC 050-040-0110-000. 

EIC SCC Point Source Type SIC 

50-040-0110-0000 20200202 INTERNLCOMBUSTION - INDUSTRIAL - NATURAL GAS - RECIPROCATING 3069, 3086, 3221, 3471, 3511, 3999 50-045-0110-0000 20200201 INTERNLCOMBUSTION - INDUSTRIAL - NATURAL GAS - TURBINE 3061 52-040-0110-0000 20200202 INTERNLCOMBUSTION - INDUSTRIAL - NATURAL GAS - RECIPROCATING 2022, 2033, 2037, 2099 

Table 16. EIC, SCC and SIC codes in the District’s 2006 point source inventory that reconciled to REIC 050-995-0110-000. 

EIC SCC Point Source Type SIC 

10200601 EXTCOMB BOILER - INDUSTRIAL - NATURAL GAS - >100MMBTU/HR 1389, 1442, 2951, 3561 10200602 EXTCOMB BOILER - INDUSTRIAL - NATURAL GAS - 10-100MMBTU/HR 

2273, 2499, 2621, 2631, 2653, 2656, 2759, 2819, 2869, 2873, 2879, 2951, 2952, 3061, 3086, 3089, 3111, 3221, 3273, 3295, 3296, 3479, 3713, 7694 

50-005-0110-0000 

10200603 EXTCOMB BOILER - INDUSTRIAL - NATURAL GAS - <10MMBTU/HR 

2599, 2621, 2653, 2759, 2819, 2851, 2875, 2879, 2952, 3061, 3069, 3086, 3089, 3211, 3272, 3273, 3296, 3315, 3321, 3325, 3369, 3411, 3442, 3471, 3479, 3483, 3537, 3561, 3613, 3663, 3679, 3713, 3714, 3728, 3842, 6331 

50-005-0240-0000 10201201 EXTCOMB BOILER - INDUSTRIAL - SLD WASTE-SPECIFY - SPEC MAT COMM FLD 8733 
050 – Industrial Natural Gas Combustion 

Page 15 of 17 Rev. Date: 13 June 2006 IndustrialNG2006.doc Rev. By: K Thao

EIC SCC Point Source Type SIC 

30190003 CHEMICAL MFG - FUEL-FIRED EQPMNT - PROCESS HEATERS - NAT GAS 723, 2023, 2816, 2819, 3089, 7694 30390003 PRIMARY METALS - FUEL-FIRED EQPMNT - PROCESS HEATERS - NAT GAS 3499 30390023 PRIMARY METALS - FUEL-FIRED EQPMNT - FLARES - NAT GAS 1311 30490003 SECONDARY METALS - FUEL-FIRED EQPMNT - PROCESS HEATERS - NAT GAS 3325, 3411, 3441, 3442, 3444, 3479, 3724 30500206 PETROLEUM INDRY - ASPHALT CONCRETE - ASPHALT HEATER - NATURAL GAS 2951, 2952 30590003 MINERAL PRODUCTS - FUEL-FIRED EQPMNT - PROCESS HEATERS - NAT GAS 2759, 2951, 3295 30790003 WOOD PRODUCTS - FUEL FIRED EQPMNT - PROCESS HEATERS - NAT GAS 2431, 2434 30890003 RUBBER/PLASTICS - FUEL FIRED EQPMNT - PROCESS HEATERS - NAT GAS 3086 30990003 FABRICATED METALS - FUEL FIRED EQPMNT - PROCESS HEATERS - NAT GAS 3448 39900601 INDUSTRIAL PROCES - MIS IND-FUEL EQPT - PROCESS HTER/FURNACE - NATURAL GAS 2657, 3411, 3495 

50-010-0110-0000 

39990003 INDUSTRIAL PROCES - MIS IND-FUEL EQPT - PROCESS HEATERS - NAT GAS 1459, 2657, 2679, 2813, 2952, 3089, 3411, 3479, 3679 

50-012-0110-0000 40201001 ORGANIC SOLVENT - SURFACE COATING - OVEN HEATER - NATURAL GAS 

2431, 2656, 2674, 2732, 3088, 3312, 3354, 3399, 3411, 3441, 3442, 3444, 3479, 3493, 3495, 3499, 3585, 3621, 3663, 3713, 3728 

39000689 INDUSTRIAL PROCES - INPROCESS FUEL - NATURAL GAS - NOT CLASSIFIED 2099, 3221, 3411, 3479, 3949 39000699 INDUSTRIAL PROCES - INPROCESS FUEL - NATURAL GAS - NOT CLASSIFIED 1459, 2951, 3211, 3296, 3555 50-070-0110-0000 

39092050 INDUSTRIAL PROCES - INPROCESS FUEL - NATURAL GAS - WITHDRAWAL LOSS 1321 
050 – Industrial Natural Gas Combustion 

Page 16 of 17 Rev. Date: 13 June 2006 IndustrialNG2006.doc Rev. By: K Thao

EIC SCC Point Source Type SIC 

30490033 SECONDARY METALS - FUEL-FIRED EQPMNT - FURNACES - NAT GAS 2952, 3363, 3364 50-995-0110-0000 

30505020 MINERAL PRODUCTS - NONMETALLIC MINRL - ASPHALT HEATER - NATURAL GAS 1442 

10200601 EXTCOMB BOILER - INDUSTRIAL - NATURAL GAS - >100MMBTU/HR 723, 2023, 2032, 2033, 2034, 2063, 2084, 7694 10200602 EXTCOMB BOILER - INDUSTRIAL - NATURAL GAS - 10-100MMBTU/HR 

179, 241, 2011, 2015, 2022, 2023, 2024, 2026, 2032, 2033, 2034, 2037, 2038, 2041, 2043, 2044, 2046, 2047, 2048, 2061, 2063, 2066, 2068, 2076, 2077, 2079, 2084, 2086, 2096, 2099 

52-005-0110-0000 

10200603 EXTCOMB BOILER - INDUSTRIAL - NATURAL GAS - <10MMBTU/HR 

179, 2011, 2015, 2023, 2024, 2026, 2032, 2033, 2034, 2037, 2041, 2043, 2047, 2048, 2051, 2068, 2076, 2077, 2084, 2087, 2098, 2099, 2874 

30290003 FOOD/AGRICULTURE - FUEL-FIRED EQPMNT - PROCESS HEATERS - NAT GAS 

191, 723, 724, 2011, 2015, 2022, 2023, 2026, 2033, 2034, 2041, 2043, 2044, 2048, 2051, 2066, 2068, 2077, 2095, 2096, 2099, 5143 

52-010-0110-0000 

30291001 FOOD/AGRICULTURE - FUEL-FIRED EQPMNT - BROILING FOOD - NATURAL GAS 2013 

52-020-0110-0000 10500206 EXTCOMB BOILER - SPACE HEATER - COMMERCL-INSTUTNL - NATURAL GAS 2099 

39000689 INDUSTRIAL PROCES - INPROCESS FUEL - NATURAL GAS - NOT CLASSIFIED 2051, 2063 52-070-0110-0000 

39000699 INDUSTRIAL PROCES - INPROCESS FUEL - NATURAL GAS - NOT CLASSIFIED 2022, 2043 
050 – Industrial Natural Gas Combustion 

Page 17 of 17 Rev. Date: 13 June 2006 IndustrialNG2006.doc Rev. By: K Thao

EIC SCC Point Source Type SIC 

30490013 SECONDARY METALS - FUEL-FIRED EQPMNT - INCINERATORS - NAT GAS 3411, 7694 30790013 WOOD PRODUCTS - FUEL FIRED EQPMNT - INCINERATORS - NAT GAS 9223 30890013 RUBBER/PLASTICS - FUEL FIRED EQPMNT - INCINERATORS - NAT GAS 3086, 3089 30990013 FABRICATED METALS - FUEL FIRED EQPMNT - INCINERATORS - NAT GAS 4612 

130-130-0110-0000 

40290013 ORGANIC SOLVENT - SURFACE COATING - INCIN./AFTERBURNER - NAT GAS 2752, 3411 

130-132-0110-0000 39990023 INDUSTRIAL PROCES - MIS IND-FUEL EQPT - FLARES - NAT GAS 2869