2005 MEXICALI EMISSIONS 

INVENTORY 

Final Report

Prepared for:

Western Governors’ Association

Denver, Colorado

U.S. Environmental Protection Agency, Region 9

San Francisco, California

Secretaría de Protección al Ambiente de Baja California

Mexicali, Baja California, Mexico

February 27, 2009

Eastern Research Group, Inc.
ERG Project No: 3657.00.004.001

2005 MEXICALI EMISSIONS INVENTORY

Final Report

Prepared for:

Western Governors’ Association

Denver, Colorado

U.S. Environmental Protection Agency, Region 9

San Francisco, California

Secretaría de Protección al Ambiente de Baja California

Mexicali, Baja California, Mexico

Prepared by:

Eastern Research Group, Inc. (ERG)

Sacramento, California

with

Ingeniería en Control Ambiental y Riesgo Industrial, S. de R.L. (ICAR)

Mexicali, Baja California, Mexico

and

TransEngineering

El Paso, Texas

February 27, 2009
2005 Mexicali Emissions Inventory

Final, 2/27/09

i

TABLE OF CONTENTS

Section Page

ES.0 EXECUTIVE SUMMARY ...........................................................................................ES-1

ES.1 Methodology..................................................................................................... ES-1

ES.2 Summary of Results.......................................................................................... ES-2

1.0 INTRODUCTION ........................................................................................................... 1-1

1.1 Inventory Characteristics..................................................................................... 1-2

1.2 Data Management and Formatting....................................................................... 1-5

1.3 Data Quality Objectives....................................................................................... 1-5

1.4 Report Organization............................................................................................. 1-7

2.0 POINT SOURCES........................................................................................................... 2-1

2.1 Federal Jurisdiction Point Source Methodology.................................................. 2-1

2.2 State Jurisdiction Point Source Methodology...................................................... 2-4

2.3 Results.................................................................................................................. 2-7

2.4 Quality Assurance................................................................................................ 2-8

3.0 AREA SOURCES............................................................................................................ 3-1

3.1 Methodology........................................................................................................ 3-1

3.1.1 Fuel Combustion Categories.................................................................... 3-5

3.1.2 Evaporative VOC Categories................................................................... 3-5

3.1.3 Agricultural Categories............................................................................ 3-6

3.1.4 Ammonia Categories ............................................................................... 3-8

3.1.5 Paved Road Dust...................................................................................... 3-8

3.1.6 Unpaved Road Dust ............................................................................... 3-12

3.1.7 Miscellaneous Burning Categories........................................................ 3-13

3.1.8 Border Crossings.................................................................................... 3-13

3.1.9 Brick Kilns............................................................................................. 3-13

3.1.10 Charbroiling, Construction Dust, and Bakeries.................................... 3-14

3.1.11 Landfills................................................................................................ 3-14

3.1.12 Wastewater Treatment .......................................................................... 3-14

3.2 Results3-14

3.3 Quality Assurance.............................................................................................. 3-19

4.0 ON-ROAD MOBILE SOURCES.................................................................................... 4-1

4.1 Methodology........................................................................................................ 4-1

4.2 Results4-2

4.3 Quality Assurance................................................................................................ 4-4

5.0 NONROAD MOBILE SOURCES .................................................................................. 5-1

5.1 Methodology........................................................................................................ 5-1
2005 Mexicali Emissions Inventory

Final, 2/27/09

ii

TABLE OF CONTENTS (Continued)

Section Page

5.1.1 Aircraft..................................................................................................... 5-1

5.1.2 Locomotives............................................................................................. 5-2

5.1.3 Agricultural and Construction Equipment............................................... 5-2

5.2 Results.................................................................................................................. 5-3

5.3 Quality Assurance................................................................................................ 5-4

6.0 EMISSION INVENTORY RESULTS............................................................................ 6-1

7.0 REFERENCES ................................................................................................................ 7-1

APPENDIX A: AREA SOURCE CATEGORY FORMS

APPENDIX B: TECHNICAL REPORT (DRAFT), ESTIMATION OF TRAVEL DEMAND 

AND VEHICULAR TRAFFIC CONGESTION OF THE MEXICALI 

REGION

Tables Page

ES-1 2005 Mexicali Emissions Inventory Summary (Tons per Year) ...................................ES-3

1-1 2005 Mexicali Emissions Inventory Summary (Tons per Year) ..................................... 1-5

2-1 Listing of State Jurisdiction Point Sources...................................................................... 2-5

2-2 2005 Mexicali Federal Jurisdiction Point Source Emissions (Tons per Year)................ 2-9

2-3 2005 Mexicali State Jurisdiction Point Source Emissions (Tons per Year).................... 2-9

3-1 General Emission Estimation Methodologies for Area Sources in Mexicali .................. 3-2

3-2 2005 Mexicali Area Source Emissions (Tons per Year) ............................................... 3-15

4-1 2005 Mexicali On-Road Mobile Source Emissions (Tons per Year).............................. 4-4

4-2 2005 Imperial County and Mexicali On-Road Mobile Source Emissions

(Tons per Year)................................................................................................................ 4-6

5-1 2005 Mexicali Nonroad Mobile Source Emissions (Tons per Year)............................... 5-4

6-1 2005 Mexicali Emissions Inventory Summary (Tons per Year) ..................................... 6-1
2005 Mexicali Emissions Inventory

Final, 2/27/09

iii

Figures Page

1-1 State of Baja California and Five Municipalities............................................................. 1-3

1-2 Municipality and Mexicali and Most Populous Localities.............................................. 1-4

2-1 Location of Federal and State Jurisdiction Point Sources in the Urban Portion

of Mexicali....................................................................................................................... 2-3

3-1 Location of Paved and Unpaved Road Dust Sampling Sites........................................... 3-9

3-2 Pavement Coverage of Mexicali Roads......................................................................... 3-11

4-1 Mexicali Loaded Roadway Network Under Weekday Conditions.................................. 4-3

6-1 Mexicali NOx Emissions.................................................................................................. 6-2

6-2 Mexicali SO2 Emissions .................................................................................................. 6-2

6-3 Mexicali VOC Emissions ................................................................................................ 6-3

6-4 Mexicali CO Emissions................................................................................................... 6-3

6-5 Mexicali PM10 Emissions ................................................................................................ 6-4

6-6 Mexicali PM2.5 Emissions................................................................................................ 6-4

6-7 Mexicali NH3 Emissions.................................................................................................. 6-5

6-8 Mexicali CH4 Emissions.................................................................................................. 6-5
2005 Mexicali Emissions Inventory

Final, 2/27/09

iv

ACRONYMS

AGEB area geoestadístics básicas (basic geographic area)

ANAFAPYT Asociación Nacional de Fabricantes de Pinturas y Tintas (National Association 

of Paint and Dye Manufacturers)

ARB Air Resources Board, California

BC Baja California

CANALAVA Cámara Nacional de la Industria de Lavanderías (National Chamber of the Dry 

Cleaning Industry)

CFE Comisión Federal de Electricidad (Federal Electric Commission)

CH4 methane

CO carbon monoxide

COA Cédula de Operación Anual (Annual Operating Report)

DQOs data quality objectives

EIIP Emission Inventory Improvement Program

EIP Emission Inventory Plan

ERG Eastern Research Group, Inc.

FIFRA Federal Insecticide, Fungicide and Rodenticide Act

GIS geographical information system

HDDV heavy-duty diesel vehicle

HDGV heavy-duty gasoline vehicle

IC internal combustion

ICAO International Civil Aviation Organization

ICAR Ingeniería en Control Ambiental y Riesgo Industrial, S. de R.L.

ID identification number

INEGI Instituto Nacional de Estadística, Geografía e Informática (National Institute of 

Statistics, Geography, and Computing)

kg kilogram
2005 Mexicali Emissions Inventory

Final, 2/27/09

v

km kilometers

lb pound

lbs pounds

LDDT light-duty diesel truck

LDDV light-duty diesel vehicle

LDGT light-duty gasoline truck

LDGV light-duty gasoline vehicle

LPG liquefied petroleum gas

LTO landing and take-off

m

2

square meters

m

3

cubic meters

MC motorcycle

Mg megagram

mm Hg millimeters of mercury

mph miles per hour

NAICS North America Industry Classification System

NEI National Emissions Inventory

NH3 ammonia

NIF National Emissions Inventory Input Format

NOx nitrogen oxides

NPK nitrogen-phosphorus-potassium

PEMEX Petróleos Mexicanos

PM particulate matter

PM2.5 particulate matter less than 2.5 micrometers in equivalent aerodynamic 

diameter.

PM10 particulate matter less than 10 micrometers in equivalent aerodynamic diameter
2005 Mexicali Emissions Inventory

Final, 2/27/09

vi

PROAIRE Programa para Mejorar la Calidad del Aire (Program to Improve Air Quality)

QA quality assurance 

QAPP quality assurance project plan

QC quality control

s second

SAGARPA Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación 

(Secretariat of Agriculture, Livestock, Rural Development, Fisheries, and Food)

SCC source classification code

scf standard cubic feet

SEMARNAT Secretaría de Medio Ambiente y Recursos Naturales (Secretariat of the 

Environment and Natural Resources)

SENER Secretaría de Energía (Secretariat of Energy) 

SLRC San Luis Río Colorado, Sonora

SO2 sulfur dioxide

SPA Secretaría de Protección al Ambiente de Baja California (Secretary of 

Environmental Protection of Baja California)

TDM travel demand model

TIM time-in-mode

TSP total suspended particulate

U.S. EPA United States Environmental Protection Agency

VKT vehicle kilometers traveled

VMT vehicle miles traveled

VOC volatile organic compound

WGA Western Governors’ Association

WRAP Western Regional Air Partnership

yr year
2005 Mexicali Emissions Inventory

Final, 2/27/09

ES-1

ES.0EXECUTIVE SUMMARY

In response to requests from the Secretary of Environmental Protection of Baja California 

(Secretaría de Protección al Ambiente de Baja California – SPA) and the California Air 

Resources Board (ARB), the Western Governors’ Association (WGA), with funding from the 

U.S. Environmental Protection Agency (U.S. EPA), hired a contractor team to develop the 2005 

Mexicali inventory. The contractor team was led by Eastern Research Group, Inc. (ERG) and 

supported by two Mexico-based subcontractors (i.e., Ingeniería en Control Ambiental y Riesgo 

Industrial, S. de R.L. [ICAR] and TransEngineering). This 2005 Mexicali emissions inventory 

updates previous inventories developed for Mexicali, Baja California (BC), including Mexicali’s 

Programa para Mejorar la Calidad del Aire (PROAIRE) for a base year of 1996 (PROAIRE, 

1999) and the 1999 Mexico National Emissions Inventory (NEI) Program (ERG, 2006).

The 2005 Mexicali emissions inventory was developed for the entire municipality of 

Mexicali. Annual emissions (both tons per year and megagrams per year) were estimated for 

point sources, area sources, on-road mobile sources, and nonroad mobile sources. Emissions 

were estimated for the following pollutants: nitrogen oxides (NOx), sulfur dioxide (SO2), 

volatile organic compounds (VOC), carbon monoxide (CO), particulate matter (PM) less than 10 

micrometers (μm) in aerodynamic diameter (PM10), PM less than 2.5 μm in aerodynamic 

diameter (PM2.5), ammonia (NH3), and methane (CH4).

ES.1 Methodology

The point source emissions inventory was developed using existing emissions data 

provided by the Secretariat of Environment and Natural Resources (SEMARNAT) and the 

Secretary of Environmental Protection of Baja California (SPA). The area source and nonroad 

mobile source emissions inventory were developed using activity data collected from Mexicali 

government agencies and other local contacts. The on-road mobile source emission inventory 

was developed using vehicle activity data (i.e., vehicle kilometers traveled [VKT]) obtained from 

traffic and congestion modeling.
2005 Mexicali Emissions Inventory

Final, 2/27/09

ES-2

ES.2 Summary of Results

Table ES-1 provides a summary of the results of the 2005 Mexicali emissions inventory, 

by source type and pollutant. Table ES-1 shows that:

 Emissions from federal jurisdiction point sources are considerably larger than 

emissions from state jurisdiction point sources, even though the ratio of state-tofederal jurisdiction point sources is greater than 10-to-1.

 NOx and SO2 emissions are dominated by point sources.

 VOC emissions are emitted by area (i.e., mainly various evaporative source 

categories) and on-road mobile sources.

 On-road mobile sources are the predominant source of CO.

 Area sources are the largest contributors of PM10 and PM2.5 (i.e., due to unpaved and 

paved road dust), NH3 (i.e., from livestock ammonia and fertilizer application), and 

CH4 (i.e., from the landfill).

The final inventory was formatted to be compatible with U.S. EPA’s National Emissions 

Inventory Format (NIF), and SMOKE/IDA format (i.e., used for photochemical and other 

modeling). In addition, spatial surrogates for gridding area source emissions into a 4 km grid 

system for modeling were developed. Also, geographic information system (GIS)-based shape 

files obtained for Mexicali’s AGEBs (i.e., area geoestadístics básicas or basic geographic areas) 

which were used in the development of some area source category emissions, were provided 

along with the final inventory files for purposes of spatially distributing area source emissions 

over the inventory domain for purposes of air quality modeling.
2005 Mexicali Emissions Inventory

Final, 2/27/09

ES-3

Table ES-1. 2005 Mexicali Emissions Inventory Summary (Tons per Year)

Source Type NOx SO2 VOC CO PM10 PM2.5 NH3 CH4

Point –

Federal 13,931.7 3,650.9 659.3 3,636.2 1,537.7 128.4

Point – State 444.0 973.2 73.0 479.9 89.7

Area 1,205.5 131.1 15,301.5 18,854.0 50,879.3 6,753.5 9,015.2 6,033.3

On-Road 

Mobile 8,570.4 168.7 8,977.1 60,603.4 765.0 665.8 252.4 144.4

Nonroad 

Mobile 4,485.0 60.9 542.9 3,206.9 550.2 533.3 0.0 1.5

Total 28,636.5 4,984.8 25,553.8 86,780.4 53,821.8 8,081.0 9,267.6 6,179.2

Blanks indicate that pollutant emissions were not applicable or were not estimated due to a lack 

of data.
2005 Mexicali Emissions Inventory

Final, 2/27/09

1-1

1.0 INTRODUCTION

The first emissions inventory developed for Mexicali, Baja California (BC) was 

published as part of Mexicali’s Programa para Mejorar la Calidad del Aire (PROAIRE) for a 

base year of 1996 (PROAIRE, 1999). The next and most recent emissions inventory for 

Mexicali was developed and published as part of the 1999 Mexico National Emissions Inventory 

(NEI) Program; however, the industrial source emissions in the 1999 Mexico NEI for Mexicali 

were based on the previous 1996 PROAIRE inventory (ERG, 2006). 

The Secretary of Environmental Protection of Baja California (Secretaría de Protección al 

Ambiente de Baja California – SPA) has requested an update to the emissions inventory for the 

municipality of Mexicali for the year 2005. In addition, the California Air Resources Board 

(ARB) has requested an updated inventory for purposes of air quality modeling in the border 

area of Imperial County, California, and Mexicali. 

In response to these needs, the Western Governors’ Association (WGA), with funding 

from the U.S. Environmental Protection Agency (U.S. EPA), sponsored this project to update the 

Mexicali emissions inventory to 2005. The Contractor team, hired under Contract No. 30430-01, 

was led by Eastern Research Group, Inc. (ERG), and included Ingeniería en Control Ambiental y 

Riesgo Industrial, S. de R.L. (ICAR), and TransEngineering. ICAR was responsible for data 

collection related to area and point sources, and TransEngineering was responsible for estimating 

on-road motor vehicle activity data which were used to estimate mobile source emissions and to 

determine the distribution of vehicle activity over paved versus unpaved roads.

The specific objectives of the 2005 Mexicali emissions inventory were to provide a 

current and accurate technical basis for air quality planning in the municipality of Mexicali. 

Also, the results of the 2005 Mexicali emissions inventory (for the non-methane pollutants) are 

formatted for use in air quality modeling to better understand the contribution of Mexicali 

emissions to concentrations of criteria pollutant levels in that region.
2005 Mexicali Emissions Inventory

Final, 2/27/09

1-2

1.1 Inventory Characteristics

The characteristics of the 2005 Mexicali emissions inventory are as follows:

 Base year: 2005.

 Temporal resolution: Annual emissions, in terms of megagrams per year (Mg/year) 

and tons per year (tons/year). Some intermediate activity data are presented in 

Imperial units. The inventory results are presented in Imperial units (i.e., tons per 

year) in the English version of the final report and in metric units (i.e., megagrams 

[Mg] per year) in the Spanish version of the final report.

 Geographic domain: Entire municipality of Mexicali. Figure 1-1 shows the entire 

state of Baja California and its five municipalities (i.e., Mexicali, Tijuana, Tecate, 

Playas de Rosarito, and Ensenada). Figure 1-2 shows the municipality of Mexicali 

and location of the most populous “localities” (e.g., cities, towns, communities, etc.) 

with population greater than 3,000.

 Geographic Resolution: In addition to total municipality-level emissions by pollutant 

and source type, emissions were estimated at various other levels of detail, including:

 Exact location (i.e., latitude/longitude) for point sources.

 Spatial surrogates at the level of basic geographic areas (area geoestadística 

básica – AGEB) are also provided. An AGEB is analogous to a census tract in 

the U.S. These surrogates provide the spatial allocation of emissions to 4 

kilometer (km) × 4 km grid cells within the ARB modeling domain (i.e., 

approximately 36 km to 50 km south of the California—BC border).

 Pollutants: 

 Nitrogen oxides (NOx)

 Sulfur dioxide (SO2)

 Volatile organic compounds (VOC)

 Carbon monoxide (CO)

 Particulate matter (PM) less than 10 micrometers (μm) in aerodynamic diameter 

(PM10)

 PM less than 2.5 μm in aerodynamic diameter (PM2.5)

 Ammonia (NH3)

 Methane (CH4).

 Source Types and Categories: Point sources, area sources, on-road mobile sources, 

and nonroad mobile sources. Each of these source types will be discussed in their 

individual sections.
2005 Mexicali Emissions Inventory

Final, 2/27/09

1-3

Figure 1-1. State of Baja California and Five Municipalities

Figure 2-2. Municipality of Mexicali and its Most Populous Localities

Figure 2-3. ARB Modeling Domain
2005 Mexicali Emissions Inventory

Final, 2/27/09

1-4

Figure 1-2. Municipality of Mexicali and its Most Populous Localities
2005 Mexicali Emissions Inventory

Final, 2/27/09

1-5

1.2 Data Management and Formatting

Development of the 2005 Mexicali emissions inventory required the compilation of 

considerable amounts of emissions and other related inventory data. Electronic spreadsheets 

were used to compile, calculate, and summarize emissions data. 

The final inventory was formatted to be compatible with U.S. EPA’s National Emissions 

Inventory Format (NIF), and SMOKE/IDA format (i.e., used for photochemical and other 

modeling). In addition, spatial surrogates for gridding the area source emissions into a 4 km grid 

system for modeling will be developed. Also, geographic information system (GIS)-based shape 

files of the obtained for Mexicali’s AGEBs, which were used in the development of some area 

source category emissions, will be provided along with the final inventory files for purposes of 

spatially distributing area source emissions over the inventory domain for purposes of air quality 

modeling.

1.3 Data Quality Objectives

The data quality objectives (DQOs) were established as part of the Emission Inventory 

Plan (EIP)/Quality Assurance Project Plan (QAPP) developed for this project. The specific 

DQOs, and criteria used to evaluate whether the DQOs are achieved for the 2005 Mexicali 

emissions inventory are as follows:

1. A comprehensive emissions inventory for all source types (i.e., point, area, on-road 

motor vehicle, and nonroad mobile sources) and all major categories within these 

source types. 

Acceptance criteria: The source types and major categories accounted for in the 

EIIP guidance documents are present in the Mexicali emissions inventory, and/or any 

differences are documented.

2. Identification of 80% of all federal jurisdiction and state jurisdiction point sources 

located within the municipality of Mexicali.

Acceptance criteria: A list of point sources under the federal (SEMARNAT 

Delegation), and state (SPA) jurisdictions compares to the emissions data, by source, 

provided by those agencies. 

3. Point sources: Emissions estimates with an accuracy of ± 25% for at least 10% of the 

facilities. 
2005 Mexicali Emissions Inventory

Final, 2/27/09

1-6

Acceptance criteria: Estimated emissions for 10% of the total facilities compare to 

measured emissions of all pollutants with ± 25% accuracy. The emissions data 

measurements will be obtained from subcontractor ICAR, and will be based on data 

collected over the past five years in Mexicali. 

4. Area, On-Road Motor Vehicle, and Nonroad Mobile Sources: Emissions estimates 

with an accuracy of ±50%. 

Acceptance criteria: Estimated emissions using emission factors/models compare to 

emissions estimated using a fuel-balance approach for all applicable pollutants. The 

fuel-balance approach will use national statistics, while the preferred inventory 

methodology will use PEMEX and local fuel distribution data. 

5. Documentation: All EI results are transparent and reproducible.

Acceptance criteria: Written and electronic inventory documentation provides 

detailed explanations of data collected, data measured/analyzed, values 

estimated/calculated, assumptions made, and emission factors used so that the results 

can be duplicated.

Most of these acceptance criteria have been met, and in some cases exceeded, in the 

development of the 2005 Mexicali emissions inventory. Instances where the acceptance criteria 

could not be met are documented (i.e., see Area Sources, Section 3.3). 

In general, the following quality assurance checks were performed to ensure the DQOs 

were achieved:

 Accuracy checks – Spreadsheets were developed to calculate emissions, and 100% of 

the formulas were checked for accuracy. 100% of the electronic calculations were 

checked (50% by hand), and any errors were corrected.

 Completeness checks – The list of pollutants and source categories for the 1999 

Mexico NEI was compared against all of the inventory files to ensure that emissions 

are estimated for the correct pollutants and source categories. Any errors were 

corrected.

 Representativeness – The emission factors and activity data were reviewed to ensure 

they are appropriate and current for the source categories for 100% of the source 

categories inventories. All adjustment factors (e.g., used to allocate national activity 

to a state- or municipality-level rate) were reviewed to ensure they are representative 

of actual conditions affecting emissions generated during the base year of 2005.

Specific quality assurance procedures followed during the estimation of emissions for 

each source type will be described in report Sections 2.0, 3.0, 4.0, and 5.0 for point sources, area 
2005 Mexicali Emissions Inventory

Final, 2/27/09

1-7

sources, on-road mobile sources, and nonroad mobile sources, respectively, as part of the final 

report.

1.4 Report Organization

The remainder of this report provides a complete and detailed description of all methods, 

assumptions, data, and calculations used to develop the emissions inventory, along with the 

results by source category. The report is organized as follows:

 Section 2.0 describes the point source estimation methodology and results.

 Section 3.0 describes the area source estimation methodology and results.

 Section 4.0 describes the on-road mobile source estimation methodology and results.

 Section 5.0 describes the nonroad mobile source methodology and results.

 Section 6.0 provides the overall 2005 Mexicali emissions inventory results.

 Section 7.0 lists all references used in the development of this emissions inventory.

 Appendix A contains the forms showing how each area source category’s emissions 

were calculated (i.e., method/emission factor/formula, reference, activity data, sample 

calculation).

 Appendix B contains a detailed explanation of the analysis conducted to estimate onroad mobile source activity data.
2005 Mexicali Emissions Inventory

Final, 2/27/09 2-1

2.0 POINT SOURCES

Point sources are stationary industrial sources that release emissions from fixed points 

(e.g., a stack or vent). In Mexico, point source emissions data are transmitted to the federal 

and/or state environmental agencies (depending upon sector-based jurisdiction) by means of the 

Annual Operating Certificate (Cédula de Operación Annual – COA). As a result, the 

development of point source emissions data for the 2005 Mexicali emissions inventory relied 

heavily on the cooperation of the government agencies that maintain emission registries – the 

Secretariat of Environment and Natural Resources (SEMARNAT) for federal jurisdiction point 

sources and the SPA for state jurisdiction point sources. The procedures used to compile 

emissions from the federal and state jurisdiction point sources are described below.

2.1 Federal Jurisdiction Point Source Methodology

There are 16 federal jurisdiction point sources located in the municipality of Mexicali, 

which was confirmed by SEMARNAT. These point sources are listed below with their 

sector/subsector, as applicable:

 CFE Campo y Centrales Geotermoeléctrico de Cerro Prieto (Electricity Generation)

 CFE Central Turbo Gas (Electricity Generation)

 Dafmex, S. de R.L. de C.V. (Metallurgical/Ferrous Metal Foundry)

 Energía Azteca X, S. de R.L. de C.V. (Electricity Generation)

 Energía de Baja California, S. de R.L. de C.V., Central Termoeléctrica (Electricity 

Generation)

 Fábrica de Papel San Francisco, S.A. de C.V. (Pulp and Paper/Paper Production)

 Fevisa Industrial, S.A. de C.V. (Glass/Container Glass Manufacture)

 Fundiciones San Martin o Felix Jesus del Valle Zamora (Metallurgical/Iron and Steel 

Foundry)

 Infra, S.A. de C.V., Sucursal Mexicali (Chemical/Industrial Gases)

 Kenworth Mexicana, S.A. de C.V. (Automotive/Truck Manufacture)

 Kyowa Mexicali, S.A. de C.V. (Plastic Parts Manufacturing)
2005 Mexicali Emissions Inventory

Final, 2/27/09 2-2

 Maquiladora San Diego, S.A. de C.V. (Metallurgical – Iron and Steel Foundry)

 Petróleos Mexicanos (PEMEX) Refinación Planta Mexicali (Petroleum/Petroleum 

Products Storage and Distribution

 Quimical, S.A. de C.V. (Chemical/Pesticides and Agricultural Chemicals)

 Termoeléctrica de Mexicali, S. de R.L. de C.V. (Electricity Generation)

 Vitro AFG, S.A. de C.V. (Glass/Plane Glass Manufacture)

The physical location of some of the federal jurisdiction (and state jurisdiction) point 

sources in the urban portion of Mexicali is illustrated in Figure 2-1. The federal jurisdiction 

point sources are shown as red dots (and the state jurisdiction point sources are shown as green 

dots). Some addition federal and state jurisdiction point sources located in the rural areas of 

Mexicali are not shown on Figure 2-1. 

ICAR made the initial data request to SEMARNAT for existing information regarding 

emissions for the year 2005 from Mexicali federal jurisdiction point sources. SEMARNAT 

provided two electronic files in Excel format: “Empresas Comp Federal (EMIS 230108).xls” 

and “DATGEN_MEXICALI_05.xls”. The “Empresas Comp Federal (EMIS 230108).xls” file 

provided a listing of all federal jurisdiction sources located in the state of Baja California, as well 

as those federal jurisdiction sources that reported 2005 emissions to SEMARNAT. The 

“DATGEN_MEXICALI_05.xls” file consisted of several sheets of which the following were 

most relevant for the compilation of emissions:

 Hoja1 – Complete facility description;

 EqComb – Emissions from combustion equipment;

 ActProc – Emissions from non-combustion equipment and processes;

 Chim – Stack parameters; and 

 EqCont – Description of control equipment.

In general, the information contained in the “DATGEN_MEXICALI_05.xls” file was 

fairly complete. However, much of the data contained in this file was represented in codes, 
2005 Mexicali Emissions Inventory

Final, 2/27/09 2-3

Figure 2-1. Location of Federal and State Jurisdiction Point Sources in the Urban 

Portion of Mexicali
2005 Mexicali Emissions Inventory

Final, 2/27/09 2-4

abbreviations, and acronyms. As a result, ICAR made a subsequent request to SEMARNAT to 

provide the relevant data dictionaries needed to decipher the file. Subsequently, SEMARNAT 

provided two data dictionary files associated with the “DATGEN_MEXICALI_05.xls” file: 

“Diccionario_Datos_Datgen.xls” and “Codigos_catalogo.xls”. The 

“Diccionario_Datos_Datgen.xls” file provided the data dictionary and formats used by the 

“DATGEN_MEXICALI_05.xls” file, while the “Codigos_catalogo.xls” file provided a key for 

all of the codes, abbreviations and acronyms.

Using the “Empresas Comp Federal (EMIS 230108).xls” and 

“DATGEN_MEXICALI_05.xls”, along with the data dictionary files, ICAR compiled emissions 

from the federal jurisdiction point sources.

2.2 State Jurisdiction Point Source Methodology

There are 173 state jurisdiction point sources located in the municipality of Mexicali. As 

seen in Figure 2-1, many of these state jurisdiction point sources are clustered in the city’s 

industrial parks, which was confirmed by SEMARNAT. The names for these facilities are listed 

in Table 2-1.

ICAR made an initial request to SPA for existing information regarding emissions for the 

year 2005 from Mexicali state jurisdiction point sources. SPA provided two electronic files: “2-

REGISTROS (2005).xls” and “SIARE.mdb”. The “2-REGISTROS (2005).xls” file provided a 

listing of all companies that submitted 2005 emission estimates to SPA and identified the paper 

file location within SPA offices of these emission submittals. The “SIARE.mdb” file is an 

Access database which contains such information as:

 Facility name

 File number

 Inventory year

 Type and number of process that generate emissions

 Emission controls (if any)

 Pollutant type (in units of kg/hr and kg/year)
2005 Mexicali Emissions Inventory

2-5

Final, 2/27/09

Table 2-1. Listing of State Jurisdiction Point Sources

Facility Name Facility Name Facility Name

Accuride International, S.A. de C.V. (Nelson 6) Cervecería de Baja California, S.A. de C.V. Expopartes, S.A. de C.V.

Accuride International, S.A. de C.V. (Pta-Oeste, Nelson-12) Chromalloy, S.A. de C.V. (Planta 1) Fabricaciones y Montajes Metálicos, S.A. de C.V.

Agribrands Purina México, S.A. de C.V. Chromalloy, S.A. de C.V. (Planta Ii) Fanosa, S.A. de C.V.

Alimentos y Frituras de Baja California, S.A. de C.V. Cias. Periodísticas del Sol de Pacífico, S.A. de C.V. Femsa, S. de R.L. de C.V.

American Meter de Mexico, S.A. de C.V. Compre Block Sucursal Criba Fetasa Culiacán, S.A. de C.V.

Amp Industrial Mexicana, S.A. de C.V. Compre Block, S.A. de C.V. Fetasa Industrial, S.A. de C.V

Arrendadora del Colorado del Norte, S.A. de C.V. Con Mex de Mexicali, S.A. Fetasa Mexicali, S.A. de C.V.

Ascotech, S.A. de C.V. Concretos Apasco, S.A. de C.V. Flexcel-Mexicali, S.A. de C.V.

Asociacion Rural de Interes Colectivo de Baja California  ́80 de 

R.I. Concretos Bajanor de Mexicali, S.A. de C.V. Frituras de Mexicali, S.A. de C.V.

Benq Mexicana, S.A. de C.V. Constructora Gallego, S.A. de C.V. (Planta 1) Fruvemex Mexicali, S.A. de C.V.

Bi Technologies, S.A. de C.V. Constructora Gallego, S.A. de C.V. (Planta 2) Furukawa Mexico, S.A.de C.V.

Bimbo, S.A. de C.V. Constructora Gusa, S.A. de C.V. Grayline de México, S.A. de C.V.

Black & Decker Hhi México, S. de R.L. de C.V. (Pta-2) Controles de Mexicali, S. de R.L. Grupo Industrial Persal, S.A. de C.V.

Black & Decker Hhi México, S. de R.L. de C.V. K1 Dafmex, S. de R.L. de C.V. Guaycan Quimicos y Petroliferos, S.A. de C.V.

Black & Decker Hhi México, S. de R.L. de C.V. K2 Dataproducts Imaging Solution, S.A. de C.V. Harinera de Maíz de Mexicali, S.A. de C.V.

Black & Decker Hhi México, S. de R.L. de C.V. P1 Delivamex, S. de R.L. de C.V. Helados y Mezclas, S.A. de C.V.

Block Centinela, S.A. de C.V. Display Orion Mexicana, S.A. de C.V. Honeywell Aerospace de México, S.A. de C.V.

Bloquera Moderna, S.A. de C.V. Eco Constructora, S.A. de C.V.

Honeywell Productos Automotrices, S.A. de C.V. 

(Radiadores)

Blue Star, S.A. de C.V. Electronica Vanguard, S.A. de C.V.

Honeywell Productos Automotrices, S.A. de C.V. 

(Turbos)

Breg México, S. de R.L. de C.V. Embotelladora de Mexicali, S.A. de C.V. Hykam Electronica de Mexico, S.A. de C.V.

Cajas Agricolas, S.A. de C.V. Emermex, S.A de C.V. Ideas Y/O Enrique Hernández Santiago

Calidad Internacional de Pulido, S.A. de C.V. Emermex, S.A. de C.V. (Edif-3)

Iluminación Cooper de Las Californias, S. de R.L. de 

C.V.

Carley de México, S.A. de C.V. Empaques de Cartón Titán Impresora y Editorial, S.A. de C.V.

Cd Electrónica de Mexico, S.A de C.V. Empresas L.M., S. de R.L. de C.V. Industria de Refrescos del Noreste, S. de R.L. de C.V.

Cementos Químicos Industriales, S.A. de C.V. Energéticos y Grasas del Norte, S.A. de C.V.

Industrial Vallera de Mexicali, S.A. de C.V. (Coto 

Technologies)

Cemex Concretos, S.A. de C.V. Ensambladores Electrónicos de México, S.A.

Industrial Vallera de Mexicali, S.A. de C.V. (Div. 

Vishay)

Cemex México, S.A. de C.V. Ensambles de Mexicali, S.A. de C.V.

Industrial Vallera de Mexicali, S.A. de C.V. 

(Loveday)

Centro Camionero de Mexicali, S.A. de C.V. Ensambles de Silleria Mexicana, S.A. de C.V.

Industrial Vallera de Mexicali, S.A. de C.V. (Manik 

Motors)
Table 2-1. Continued

2005 Mexicali Emissions Inventory

2-6

Final, 2/27/09

Facility Name Facility Name Facility Name

Industrial Vallera de Mexicali, S.A. de C.V. (Martech-Mdi West) Mextearinas, S.A. de C.V. Sabritas, S. de R.L. de C.V.

Industrial Vallera de Mexicali, S.A. de C.V. (Másimo) Molinerea del Valle, S.A. de C.V.

Sánchez Quiñónez César (Servicios y Acabados 

Industriales)

Industrial Vallera de Mexicali, S.A. de C.V. (Merchants Metals) Muebles y Diseños El Bajio, S.A. de C.V. Sds de Mexico, S.A. de C.V.

Industrial Vallera de Mexicali, S.A. de C.V. (Taymar Plastics) Navarrete Rayos Noel Alejandro Service Container de Baja, S. de R.L. de C.V.

Industrias SL, S.A. de C.V. North Safety de Mexicali, S. de R.L. de C.V. Sigma Lapos, S.A. de C.V.

Industrias Zahori, S.A. de C.V. Novamex México, S.A. de C.V. Sigma Lapos, S.A. de C.V. (Sucursal)

Inovación en Concretos, S.A. de C.V. NSF Mexicali, S. de R.L. de C.V. Skyworks Solutions, S.A. de C.V.

International Assembly Specialists, S.A. de C.V. Nutricion Maxima de Baja California, S.A. de C.V.

Solís Meraza María de La Cruz (Transformadora de 

Maderas Satélite)

Isoclima de México, S.A. de C.V. Nutrimentos Mexicanos, S.A. de C.V. SPG de México, S.A. de C.V.

Isoclima de México, S.A. de C.V. Omega Industries, S.A. de C.V. Stone Container de México, S. de R.L. de C.V.

J. Cox de México, S.A. de C.V. Operaciones de Clase Mundial, S.A. de C.V. Strategic Materials Mexicana, S.A. de C.V.

Jean Charles Mexicali, S.A. de C.V. Orthodental, S.A. de C.V. Sukarne Produccion, S.A. de C.V.

Jumex Mexicali, S.A. de C.V. Panasonic Electric Works Mexicana, S.A. de C.V. Suntek Manufacturing Technologies, S.A. de C.V.

Kang Seo Mexicana, S.A. de C.V. Partes Remanufacturadas de México, S.A. de C.V. Super Muros, S.A. de C.V.

Kb Foam de Mexicali, S.A. de C.V. Pegamentos Industriales Galileo, S.A. de C.V. Technologies Solutions And Services, S.A. de C.V.

Kerns Beverages de México, S. de R.L. de C.V. Pims, S.A. de C.V.

Tecnologías Internacionales de Manufactura, S.A. de 

C.V.

Kwang Sung Electronics México, S.A. de C.V. (Pta-1) Placas Termodinámicas, S.A. de C.V. Tecnomex Industrial, S.A. de C.V.

Kyowa Mexicali, S.A. de C.V. Ponce Elizalde Armida (Transformadora de Maderas Tramex) Tecnomex Industrial, S.A. de C.V.

L.G. Innotek Mexicali, S.A. de C.V. Procesadora y Empacadora de Carnes del Norte, S.A. de C.V. Temcomex, S.A. de C.V.

Lam-Mex, S.A. Prodofi, S. de R.L. de C.V.

Teradyne Connection Systems de México, S.A. de 

C.V.

Lancer Orthodontics de México, S.A. de C.V. Productos de Acero de Baja, S.A. de C.V. Thomson

Lechera Mexicana, S.A. de C.V. Productos de Barro, S.A. de C.V. Tri-State de Mexico, S.A. de C.V.

LG Electronics Mexicali, S.A. de C.V. Productos Hola del Noroeste, S.A. de C.V. Tubos de Acero Internacional, S.A. de C.V.

L-N Safety Glass, S.A. de C.V. Productos Urólogos de Mexico, S.A de C.V. Valutech Out Sourcing, S.A. de C.V.

Lopez Cazares Rafael Promotora Industrial Per, S.A. de C.V. Veladoras del Pacifico, S.A. de C.V.

Lopez Cazares Rafael (Rancho) Pulidora de Baja California, S.A. de C.V. Vimifos, S.A. de C.V.

Maquiladora San Diego, S.A. de C.V. Pulidora Los Ángeles, S.A. de C.V. Wabash Technologies de México, S. de R.L. de C.V.

Marko de México, S. de R.L. de C.V. Puligamex, S.A. de C.V. Yiro Fabrica, S. de R.L. de C.V.

Masterwork Electronics de México, S.A. de C.V. Rheem Mexicali, S. de R.L. de C.V. Zahori, S.A. de C.V.

Megaplast, S.A. de C.V. Robert Bosch Tool de México, S.A. de C.V.
2005 Mexicali Emissions Inventory

Final, 2/27/09

2-7

 Type of fuel combusted

 Number of stacks

It should be noted that emissions were reported at the facility-level, but not at the process- or 

equipment-level. Also, stack parameters (i.e., stack coordinates, stack height, stack diameter, 

exit gas velocity, and exit gas temperature) were not included in the “SIARE.mdb” file. 

Based upon information contained in these two files, ICAR developed an Excel 

spreadsheet (“state_point_source_R0.xls”) that compiled the following data for each facility:

 Facility name

 Facility identification number (ID)

 Main activity

 Facility address

 Facility point of contact

 SCIAN code

 Emission quantification (kg/year)

 Type of control

 Facility latitude

 Facility longitude

 Emission points (i.e., the quantity and type of processes that generate emissions)

 Material type (i.e., type of fuel used)

 Basis of emissions estimate.

All of these data were based upon information obtained from the “SIARE.mdb” file.

2.3 Results

The federal jurisdiction point source emissions are shown in Table 2-2. Some 

conclusions that can be drawn from Table 2-2 are that the power plants are the largest sources of 

NOx, CO, and PM10. The PEMEX facility is the largest source of VOC emissions, while the 
2005 Mexicali Emissions Inventory

Final, 2/27/09

2-8

glass plants (i.e., Fevisa and Vitro AFG) and the paper plant (i.e., Fábrica de Papel San 

Francisco) are the three largest sources of SO2. It should be noted that there are no emissions 

reported from the Federal Electric Commission (Comisión Federal de Electricidad-CFE) 

geothermal power plant in Cerro Prieto. 

Emissions for the 173 state jurisdiction point sources are shown in Table 2-3, by industry 

group. From Table 2-3, it is clear that the Petroleum and Coal Products Manufacturing sector is 

the largest emitter of SO2 and a significant contributor of NOx. The Other Industrial 

Manufacturing sector has the largest NOx emissions. Computer, Communication, and Electronic 

Manufacturing is the largest emitter of VOC, while Food Manufacturing and Primary Metals are 

the primary contributors of CO emissions. Emissions for PM2.5, NH3, and CH4 are not included 

in Table 2-2 because emissions of these pollutants were not estimated by SPA. 

2.4 Quality Assurance

After compiling emissions for federal jurisdiction and state jurisdiction point sources, 

ICAR conducted quality assurance (QA) of these emissions. ICAR’s QA of the federal 

jurisdiction point sources used a QA checklist that focused on the following aspects:

 Facility information (i.e., North American Industry Classification System [NAICS] 

codes, address, latitude and longitude)

 Process/equipment information (i.e., process/equipment description, source 

classification code [SCC], stack assignment)

 Emissions (i.e., pollutant completeness, emissions contribution, particulate matter, 

hydrocarbons, emission units, emission reasonableness)

 Stack parameters (i.e., stack height, stack diameter, exit gas temperature, exit gas 

velocity, stack latitude and longitude)

 Operating schedule (i.e., days per week, hours per day)

 Controls (i.e., control device, control efficiency)

Overall, ICAR’s QA evaluation indicated fairly complete data for the federal jurisdiction 

point sources. However, a few specific data elements needed to satisfy the required 

characteristics of the Mexicali inventory were missing from some or all of the federal jurisdiction 
2005 Mexicali Emissions Inventory

Final, 2/27/09

2-9

Table 2-2. 2005 Mexicali Federal Jurisdiction Point Source Emissions (Tons per 

Year)

Facility Name NOx SO2 VOC CO PM10 PM2.5

CFE Central Turbo Gas Mexicali 27.4 11.8 1.9 2.4

CFE Campo y Centrales Geothermoeléctrico de Cerro 

Prieto

Dafmex, S. de R.L. de C.V. 0.4 0.1 0.0 0.3 0.0 0.0

Energía Azteca X, S. de R.L. de C.V. 5,757.9 7.5 12.4 1,433.2 548.4

Energía de Baja California, S. de R.L. de C.V. Central 

Termoeléctrica 2,385.5 3.1 5.1 593.8 227.2

Fevisa Industrial, S.A. de C.V. 277.4 2,500.2 0.5 29.0 140.2 91.6

Fábrica de Papel San Francisco, S.A. de C.V. 206.8 788.6 0.5 80.6 44.7 29.3

Infra, S.A. de C.V. Sucursal Mexicali 0.2

Kyowa Mexicali, S.A. de C.V. 0.1 0.0 76.3 0.1 0.0 0.0

Kenworth Mexicana, S.A. de C.V. 9.4 1.8 75.6 1.3 0.1 0.1

Maquiladora San Diego, S.A. de C.V. 0.9 0.4 0.2 30.0 2.4 2.2

PEMEX Refinación Planta Mexicali 458.9

Quimical, S.A. de C.V. 0.0 0.0 0.0 0.0 0.0 0.0

Termoeléctrica de Mexicali, S. de R.L. de C.V. 4,664.2 6.1 10.1 1,161.0 444.2

Vitro AFG, S.A. de C.V. 601.4 330.1 19.4 233.9 128.0 5.1

Fundiciones San Martin o Felix Jesus del Valle Zamora 0.2 1.1 0.1 71.1 0.0 0.0

Total 13,931.7 3,650.9 659.3 3,636.2 1,537.7 128.4

Table 2-3. 2005 Mexicali State Jurisdiction Point Source Emissions (Tons per Year)

3-Digit 

NAICS NAICS Description NOx SO2 VOC CO PM10

212 Mining (metallic and nonmetallic) 1.47 0.00 0.00 0.09 12.92

311 Food industry 70.11 60.84 0.00 243.61 22.53

312 Beverages/tobacco industry 1.80 0.00 0.00 0.23 0.00

321 Wood products industry 0.00 0.00 0.00 0.00 0.72

322 Paper industry 5.58 0.00 3.35 2.67 2.80

323 Publishing industry 0.00 0.00 0.14 0.00 0.00

324 Petroleum and coal products manufacturing 133.76 732.91 0.00 10.07 2.71

325 Chemical industry 0.31 0.00 0.00 0.03 0.00

326 Plastics and rubber industry 27.22 116.90 2.08 9.03 7.97

327 Nonmetallic materials manufacturing 11.04 0.12 4.48 7.06 3.27

331 Primary metals industry 11.31 19.95 0.00 121.58 0.24

332 Metal products manufacturing 4.81 0.00 7.64 16.05 6.89

333 Equipment and machinery manufacturing 5.94 0.00 2.36 7.48 0.48

334

Computer, communication, electronics 

manufacturing 2.13 0.19 33.98 16.09 9.45

335 Electricity generation equipment manufacturing 0.00 0.00 0.03 0.00 0.02

336 Transportation equipment manufacturing 0.71 0.00 1.42 12.90 12.28

337 Furniture manufacturing 1.99 0.00 14.53 6.06 1.28

339 Other industrial manufacturing 157.76 0.00 3.22 26.85 5.99

493 Storage service 8.02 42.27 0.00 0.08 0.00

Total 443.97 973.19 73.23 479.88 89.55
2005 Mexicali Emissions Inventory

Final, 2/27/09

2-10

point sources. The first data element was process/equipment SCC, which was missing from all 

sources; this was gap filled using engineering judgment based upon the specific process 

equipment description and fuel type. The stack latitude and longitude coordinates were also 

missing from a number of the sources. In most cases, these coordinates were for sources with a 

large number of processes that typically did not have well-defined stacks (e.g., vents, etc.). For 

these sources, the facility latitude and longitude coordinates were assigned to the stack(s).

The most significant data problem identified by ICAR’s QA evaluation of the state 

jurisdiction point sources was that none of the facilities had process- or stack-level emissions. 

After identifying this issue, ERG and ICAR focused on the seven most significant state 

jurisdiction point source emitters (i.e., Bimbo, Chromalloy, Sabritas, Sukarne, Temcomex, 

Thomson, and Zahori). ICAR searched the SPA paper files to obtain process- and stack-level 

emissions for these seven sources. Data obtained from the SPA paper files included the 

following:

 Number of sources

 Process/equipment description and codes

 Stack assignment

 Emission units

 Stack coordinates

 Stack height

 Stack diameter

 Exit gas velocity

 Exit gas temperature

 Operating schedule (days/year, hours/day)

 Controls (device and efficiency)

In addition to the detailed data collected for the seven most significant state jurisdiction 

point source emitters listed above, similar process- and stack-level data from the SPA files were 
2005 Mexicali Emissions Inventory

Final, 2/27/09

2-11

subsequently researched for another 85 state jurisdiction point sources. However, project 

constraints prevented similar data collection for the remaining 81 facilities.

Two of the five data quality objectives (DQOs) for the Mexicali inventory project are 

applicable to point source emissions. These are as follows:

1. Identification of 80% of all federal jurisdiction and state jurisdiction point sources 

located within the municipality of Mexicali.

Acceptance criteria: A list of point sources under the federal (SEMARNAT 

Delegation), and state (SPA) jurisdictions compares to the emissions data, by source, 

provided by those agencies. 

2. Point sources: Emissions estimates with an accuracy of ± 25% for at least 10% of the 

facilities.

Acceptance criteria: Estimated emissions for 10% of the total facilities compare to 

measured emissions of all pollutants with ± 25% accuracy. The emissions data 

measurements will be obtained from subcontractor ICAR, and will be based on data 

collected over the past five years in Mexicali.

Based on the federal jurisdiction and state jurisdiction point source methodologies and 

quality assurance used, both DQOs were met. With regard to DQO #1, all federal jurisdiction 

and state jurisdiction point sources were included. The lists of federal jurisdiction and state 

jurisdiction point sources were checked multiple times with SEMARNAT and SPA to ensure 

completeness. For DQO #2, ICAR checked process- and stack-level data obtained from 

SEMARNAT electronic files (for federal jurisdiction sources) and from SPA paper files (for 

state jurisdiction sources) against information they had previously obtained from their industrial 

clients (2 federal jurisdiction sources and 38 state jurisdiction sources). Overall, emissions data 

were within ± 25% accuracy.
2005 Mexicali Emissions Inventory

Final, 2/27/09 3-1

3.0 AREA SOURCES

Area sources are sources that are too numerous and dispersed to be effectively included 

in the point source inventory. Area sources include some commercial and/or industrial sources 

such as autobody shops and dry cleaners, fugitive sources such as paved and unpaved road dust, 

and fuel combustion in small boilers. The methodology used to estimate the 2005 Mexicali area 

source emissions is described below. 

3.1 Methodology

Wherever possible, local activity data were collected in Mexicali and used to estimate 

area source emissions. Local activity data collection was facilitated by ICAR, who are 

conveniently located in Mexicali. ICAR contacted some local sources of activity data directly 

(e.g., PEMEX, fire departments, etc.); in other situations, ICAR worked through SPA to reach 

these contacts (e.g., natural gas and LPG distributors, Department of Health, etc.).

If local activity data could not be collected from local contacts, then data from publicly 

available government agencies were used. In addition, some methodologies and data from the 

development of the 1999 Mexico NEI and recent emissions inventory work conducted in 2007 in 

San Luis Río Colorado, Sonora and the northeastern (agricultural) portion of Mexicali were also 

used (ERG, 2006; ENVIRON and ERG, 2008).

General estimation methodologies for related groups of area source categories are 

described below and summarized in Table 3-1. Detailed documentation for each area source 

category is provided through the Area Source Category Forms, which are located in Appendix A. 

The Area Source Category Forms succinctly summarize the following for each source category: 

category description, pollutants, method, activity data, emission factors, notes and assumptions, 

emission calculations, and spatial allocation surrogates. 
2005 Mexicali Emissions Inventory

3-2

Final, 2/27/09

Table 3-1. General Emission Estimation Methodologies for Area Sources in Mexicali

Source Category Pollutants Methodology Activity Data Spatial Allocation Notes

Industrial Fuel Combustion –

Distillate & Residual Fuel 

Oil, Natural Gas, LPG

NOx, SO2, VOC, CO, 

PM10, PM2.5, CH4 AP-42 emission factors Local use statistics

Employee data by 

sector

Reconciled with point 

sources.

Commercial/Institutional 

Fuel Combustion – Natural 

Gas & LPG

NOx, SO2, VOC, CO, 

PM10, PM2.5, CH4 AP-42 emission factors Local use statistics

Employee data by 

sector

Residential Fuel Combustion 

– Natural Gas & LPG

NOx, SO2, VOC, CO, 

PM10, PM2.5, CH4 AP-42 emission factrs Local use statistics Household data

Architectural Coating VOC

Mexico-specific per capita 

emission factors Population Population

Emissions estimated for 

solvent- and water-based 

coatings.

Industrial Surface Coating VOC

Mexico-specific per 

employee emission factors

Employment data 

by sector

Employee data by 

sector

Seven subcategories.

Reconciled with point 

sources.

Autobody Refinishing VOC

Mexico-specific per 

employee emission factors Employment data Employee data

Graphic Arts VOC

Mexico-specific per capita 

emission factors Population Population

Dry Cleaning VOC

Mexico-specific per 

employee emission factors Employment data Employee data

Petroleum-based solvents 

only; no perchloroethylene

Degreasing VOC

EIIP per employee emission 

factors

Employment data 

by sector Employee data

Four subcategories. 

Reconciled with point 

sources.

Consumer Solvents VOC

EIIP per capita emission 

factors (slightly adjusted) Population Population

U.S. emission factors –

household and automotive 

factors modified to 

represent Mexican 

conditions.

Traffic Markings VOC 1999 Mexico NEI results N/A

Paved road 

network

Local applied quantities 

were unavailable.

Used information from 

1999 Mexico NEI. 

Asphalt Application VOC 1999 Mexico NEI results N/A

Paved road 

network

Local applied quantities 

were unavailable.

Used information from 

1999 Mexico NEI. 
Table 3-1. Continued

2005 Mexicali Emissions Inventory

3-3

Final, 2/27/09

Source Category Pollutants Methodology Activity Data Spatial Allocation Notes

Petroleum Transport and

Distribution VOC EIIP emission factors

Local fuel 

throughput Population

Stage I controls 

(submerged with vapor 

balance; no Stage II 

controls)

Agricultural Burning

NOx, SO2, VOC, CO, 

PM10, PM2.5 ARB emission factors Burned acreage

Agricultural land 

use data

Burning limited to wheat, 

sorghum, and weeds in 

irrigation canals and 

ditchbanks.

Agricultural Tilling PM10, PM2.5 ARB emission factors Planted acreage

Agricultural land 

use data

Agricultural Harvesting PM10, PM2.5 ARB emission factors Harvested acreage

Agricultural land 

use data

Agricultural Pesticides VOC EIIP emission factors

Harvested acreage, 

type and quantity 

of pesticides 

applied

Agricultural land 

use data

Pesticide application rates 

limited to eight crop types

Beef Cattle Feedlots PM10 ARB emission factors

Number of 

slaughtered cattle

Agricultural land 

use data

Livestock VOC VOC ARB emission factors

Number of 

livestock head

Agricultural land 

use data

Livestock Ammonia NH3

WRAP NH3 model emission 

factors Number of head

Agricultural land 

use data

Fertilizer Application NH3

WRAP NH3 model emission 

factors

Planted acreage, 

type and quantity 

of fertilizers 

applied

Agricultural land 

use data

Fertilizer application rates 

limited to eight crop types

Paved Road Dust PM10, PM2.5

AP-42 emission factor 

equation

Local VKT, silt 

loading, vehicle 

speed, precipitation

Paved road 

network

VKT to be developed in 

conjunction with motor 

vehicle emissions/ 

consideration of silt 

loading samples

Unpaved Road Dust PM10, PM2.5

AP-42 emission factor 

equation

Local VKT, silt 

content, moisture 

content, vehicle 

weight and speed, 

precipitation

Unpaved road 

network

VKT to be developed in 

conjunction with motor 

vehicle emissions/ 

consideration of silt 

content and moisture 

content samples

Structural Fires

NOx, VOC, CO, PM10, 

PM2.5, CH4 EIIP emission factors

Number of houses 

burned Population
Table 3-1. Continued

2005 Mexicali Emissions Inventory

3-4

Final, 2/27/09

Source Category Pollutants Methodology Activity Data Spatial Allocation Notes

Border Crossing (idling 

vehicles from Mexicali to 

California)

NOx, SO2, VOC, CO, 

PM10, PM2.5, NH3

MOBILE6-Mexico 

emission factors

Local traffic 

counts, idling times Border crossing

Emission factors from 

MOBILE6-Mexico

Brick Kilns

NOx, SO2, VOC, CO, 

PM10, PM2.5

Utilization of previous 

inventory Not applicable Brick kiln locations

Charbroiling/Street Vendors

NOx, SO2, VOC, CO, 

PM10, PM2.5 1999 Mexico NEI results N/A Population

Local data were 

unavailable. Used 

information from 1999 

Mexico NEI grown based 

on population. 

Construction Dust PM10, PM2.5 1999 Mexico NEI results N/A Population

Local data were 

unavailable. Used 

information from 1999 

Mexico NEI grown based

on population. 

Landfills VOC, CH4 AP-42 emission factors

Annual quantity of 

waste landfilled, 

opening year Landfill location

Wastewater Treatment Plant VOC U.S. EPA emission factor

Wastewater flow 

rates Plant location

Local data unavailable to 

run model.
2005 Mexicali Emissions Inventory

Final, 2/27/09 3-5

3.1.1 Fuel Combustion Categories

Fuel combustion categories include industrial fuel combustion, commercial/institutional 

fuel combustion, and residential fuel combustion. Wherever possible, local collected data were 

used to estimate emissions. If local data were unavailable, publicly available government fuel 

statistics at the national- and regional-level were disaggregated down to the Mexicali 

municipality.

Industrial fuel combustion includes distillate fuel oil, residual fuel oil, liquefied 

petroleum gas (LPG), and natural gas while the commercial/institutional and residual fuel 

combustion source categories are limited to LPG and natural gas. Attempts were made by SPA 

and ICAR to contact all of the Mexicali fuel distributors. Natural gas statistics were obtained 

from Ecogas Mexico, S. de R.L. de C.V. (Vivo, 2008). Four LPG distributors were contacted; 

three of these distributors provided 2005 sales information (Álvarez Sánchez, 2008; Escalante, 

2008; Félix Robles, 2008). Sales information from the three LPG distributors that provided 

information were averaged together and then applied to the LPG distributor that did not provide 

information. 

The PEMEX terminal in Mexicali provided sales information regarding gasoline and 

distillate fuel (including motor vehicle, agricultural, and industrial uses), but did not respond to 

requests for information regarding residual fuel oils (Parra Armenta, 2008). Residual fuel oil 

information was obtained from the PEMEX terminal in Rosarito, which markets residual fuel oil 

in Mexicali (Miranda Palazuelos, 2008).

 Biomass combustion appears to be virtually nonexistent; most heating during the mild 

winters is electric heating (Martinez, 2007).

3.1.2 Evaporative VOC Categories

Evaporative VOC categories include the following area source categories: architectural 

surface coating, industrial surface coating, degreasing, graphic arts, traffic markings, dry 

cleaning, consumer products, asphalt application, and gasoline distribution.

The development of Mexico-specific emission factors as part of the 1999 Mexico NEI for 

architectural surface coating, industrial surface coating, graphic arts, and dry cleaning was a 
2005 Mexicali Emissions Inventory

Final, 2/27/09 3-6

significant advance. These emission factors were based upon data from the National Association 

of Paint and Dye Manufacturers (Asociación Nacional de Fabricantes de Pinturas y Tintas –

ANAFAPYT) and the National Chamber of the Dry Cleaning Industry (Cámara Nacional de la 

Industria de Lavanderías – CANALAVA) (ANAFAPYT, 2003; ANAFAPYT, 2004; 

CANALAVA, 2002). These Mexico-specific emission factors were combined with Mexicali 

population and sector-specific employee counts. The industrial surface coating emissions were 

also reconciled with emissions from point source industrial surface coating operations

Because Mexico-specific emission factors were not developed for degreasing and 

consumer products, per capita and per employee emission factors were obtained from the 

Emission Inventory Improvement Program (EIIP) guidance documents (EIIP, 1996; EIIP, 1997). 

However, recent health survey data collected in San Luis Río Colorado, Sonora indicate lower 

usage of household products corresponding to increased usage of bleach and a virtual absence of 

windshield fluid (Fierro and O’Rourke, 2007; Fierro, 2007; Gonzalez-Ayala, 2007); the EIIP 

emission factors were adjusted to account for these findings. The degreasing emissions were 

also reconciled with emissions from point source degreasing operations.

Traffic markings and asphalt application quantities were requested from the Mexicali 

Public Works Department; however, these quantities were not available (Reynoso Ambriz, 

2008). As a result, the emission estimates for traffic markings and asphalt application from the 

1999 Mexico NEI were used for the municipality of Mexicali.

Gasoline sales statistics were obtained from PEMEX (Parra Armenta, 2008), while 

gasoline distribution emission factors were obtained from EIIP guidance (EIIP, 2001a).

3.1.3 Agricultural Categories

The northeast portion of Mexicali has significant agricultural activity. Activity data for 

four specific agricultural categories (i.e., pesticides, burning, tilling, and harvesting) were 

requested from both the state and federal agricultural agencies. These four agricultural 

categories were previously estimated for the 2005 San Luis Río Colorado and northeastern 

Mexicali inventory (ENVIRON and ERG, 2008). Originally, it was anticipated that improved 

information could be collected from the state and federal agricultural agencies for Mexicali; 

however, the only useful agricultural information that could be obtained was estimates of 
2005 Mexicali Emissions Inventory

Final, 2/27/09 3-7

burning of wheat residues, sorghum residues, and weeds in irrigation canals and drainages 

(Rodríguez Hernández, 2008; López Bojorques, 2008). Agricultural burning methodologies 

from the California Air Resources Board (ARB) were used to estimate emissions (ARB, 2005).

Crop acreage information was provided for the agricultural tilling and harvesting source 

categories; however, this information had previously been obtained from a government database 

(SAGARPA, 2007a). For the previous inventory work in San Luis Río Colorado and 

northeastern Mexicali, municipality-level emissions for agricultural tilling and harvesting were 

spatially allocated in order to estimate the portion of emissions that were contained within that 

project’s modeling domain (ENVIRON and ERG, 2008). For the 2005 Mexicali inventory, the 

previously estimated municipality-level emissions were simply used without the modeling 

domain spatial allocation. The previous agricultural tilling and harvesting estimates were based 

upon ARB methodologies (ARB, 2003a; ARB, 2003b).

Emissions from agricultural pesticides were estimated by applying pesticide-specific 

emission factors to the quantities of pesticides applied. Typical crop-specific pesticide 

application rates were obtained from state-specific cost production estimates (SAGARPA, 

2007b). However, the application rates were only available for a limited number of crops (i.e., 

garlic, green alfalfa, cotton, broccoli, asparagus, tomatoes [green and red], and wheat). These 

pesticide application rates were applied to the crop-specific planted acres. specific pesticide 

application rates. Pesticide emission factors were obtained from EIIP guidance (EIIP, 2001b). 

Active ingredients were identified based upon Mexico’s Registry of Authorized Pesticides 

(COFEPRIS, 2007). Formulation types were also assumed based upon the predominant 

formulation types listed in the Registry. Active and inactive ingredient fractions, as well as inert 

ingredient VOC fractions, were obtained from the EIIP guidance. Pesticide information (i.e., 

density, % active ingredient, and vapor pressure) was obtained from various databases 

maintained by California’s Department of Pesticide Regulation (DPR, 2007).

Beef cattle feedlots are a source of fugitive dust caused by cattle movement over dusty 

ground. Slaughter statistics were used to estimate the number of cattle in feedlots. There are 

approximately 11 feedlots in Mexicali, all located outside of the urban area (Rodríguez 

Hernández, 2008). It has been estimated that cattle stay in the feedlots for approximately 90 
2005 Mexicali Emissions Inventory

Final, 2/27/09 3-8

days prior to being slaughtered (Sukarne, 2008). The beef cattle feedlot emission factor was 

obtained from ARB (ARB, 2004).

VOC emissions from livestock (i.e., beef cattle, dairy cattle, swine, sheep, and goats were 

also estimated. State- and district-level livestock headcounts were obtained from a SAGARPA 

database and then allocated to the municipality-level based on slaughter statistics (SAGARPA, 

2007c). The livestock VOC emission factors were obtained from ARB (ARB, 2004). 

3.1.4 Ammonia Categories

Two important ammonia area source categories in a regional inventory are typically 

livestock ammonia and agricultural fertilizers. State- and district-level livestock headcounts 

were obtained from a SAGARPA database and then allocated to the municipality-level based on 

slaughter statistics (SAGARPA, 2007c). The livestock ammonia emission factors were based on 

information gathered from literature reviews that is currently being implemented in the latest 

Western Regional Air Partnership (WRAP) NH3 modeling (Chinkin et al., 2003).

Emissions from agricultural fertilizers were estimated by applying fertilizer-specific 

emission factors to the quantities of fertilizer applied. Similar to agricultural pesticides, typical 

crop-specific fertilizer application rates were obtained from state-specific cost production 

estimates (SAGARPA, 2007b). As with the pesticides, application rates were only available for 

a limited number of crops (i.e., garlic, green alfalfa, cotton, broccoli, asparagus, tomatoes [green 

and red], and wheat). Ammonia emission estimates from fertilizer application were developed 

using emission factors from the European Environment Agency (EEA, 2002) as recommended in 

the development and application of the WRAP NH3 model. 

3.1.5 Paved Road Dust

Paved road dust emissions were estimated using the most recent emission factor equation 

presented in the U.S. EPA Compilation of Air Pollutant Emission Factors (AP-42), Section 

13.2.1 (revised November 2006) (U.S. EPA, 1995). Silt samples were collected at 10 locations 

in Mexicali by ICAR in July 2008. The 10 locations are shown in Figure 3-1 (numbered 1 

through 10) and are as follows:

 1 – Calzada Lázaro Cárdenas between Calzada Benito Juárez and Calzada Venustiano 

Carranza
2005 Mexicali Emissions Inventory

3-9

Final, 2/27/09

Figure 3-1. Location of Paved and Unpaved Road Dust Sampling Sites
2005 Mexicali Emissions Inventory

Final, 2/27/09 3-10

 2 – Calzada Independencia between Boulevard Adolfo López Mateos and Calle Río 

Culiacán

 3 – Calzada Industrial Palaco between Calzada M. Gómez Morin and Calzada Lázaro 

Cárdenas

 4 – Francisco I. Madero between Calle Justo Sierra and Calle “F”

 5 – Calzada Anahuac between Avenida Torino and Avenida Gobernador

 6 – Avenida Oaxaca between Calle Uxmal and Heroico Colegio Militar

 7 – Calle Río Mocorito between Calzada Cuauhtémoc and Avenida F. Montes de Oca

 8 – Calzada Laguna de Xochimilco between Calzada Anahuac and Granada

 9 – Avenida Río Verde between Calle Cuarta and Calle Novena

 10 – Avenida Centauro del Norte between Calzada Lázaro Cárdenas and Calzada 

Héctor Terán Terán

All samples were collected according to the sampling procedures presented in Appendix 

C.1 of AP-42 (U.S. EPA, 1995). The samples were analyzed by a laboratory in Tijuana, 

Laboratorio de Muestreo y Análisis, S.A. de C.V., according to the analytical procedures 

presented in Appendix C.2 of AP-42 (LMA, 2008a). The paved road dust emission factors 

(PM10 and PM2.5) were calculated using the AP-42 methodology; emission factors were 

calculated for each sampling site and then averaged together. A precipitation adjustment factor 

of 0.98562 corresponding to 21 “wet” days was also used (NWS, 2005).

The vehicle kilometers traveled (VKT) estimate used to estimate paved road dust 

emissions was developed in conjunction with the on-road mobile source VKT development (see 

Section 4.0 of this report for details). Figure 3-2 demonstrates a portion of the analysis to 

determine the split of paved and unpaved analysis; further details are located in Appendix B, 

Section VI, of this report. The estimated paved road dust emission factors were then combined 

with the link-level paved road VKT to obtain link-level paved road dust emissions (GonzalezAyala, 2008a).
2005 Mexicali Emissions Inventory

Final, 2/27/09 3-11

Figure 3-2. Pavement Coverage of Mexicali Roads

Pavement coverage detail for 

urban Mexicali
2005 Mexicali Emissions Inventory

Final, 2/27/09 3-12

3.1.6 Unpaved Road Dust

Unpaved road dust emissions were estimated using the most recent emission factor 

equation presented in AP-42, Section 13.2.2 (revised November 2006) (U.S. EPA, 1995). Silt 

samples were collected at 10 locations in Mexicali by ICAR in July 2008. The 10 locations are 

shown in Figure 3-1 (marked with letters A through J) and are as follows:

 A – Calle Caoba between Calle Mauto and Calle Olivo

 B – Calle Mérida between Avenida Nayarit and Avenida Puebla

 C – Avenida Río Atoyac between Calle Onceava and Calle Terceava

 D – Avenida Camino Real between Avenida Campestre and Avenida Valle Verde

 E – Calle Texcoco between Calzada Laguna de Xochimilco and Avenida Acolman

 F – General Jesus M. Garza at Calle Federación

 G – Avenida Ricardo Flores Magón between Calle Bernardo Reyes and Calle 

Filomeno Mata

 H – Calle de las Delicias between Avenida de los Insurgentes and Avenida Juan 

Álvarez

 I – Calle Venustiano Carranza between Avenida Nuevo León and Avenida Querétaro

 J – Carretera Relleno Sanitario (on the road to Hipolito Landfill; location in Figure 3-

1 is not to scale)

All samples were collected according to the sampling procedures presented in Appendix 

C.1 of AP-42. The samples were analyzed by Laboratorio de Muestreo y Análisis, S.A. de C.V. 

in Tijuana according to the analytical procedures presented in Appendix C.2 of AP-42 (LMA, 

2008b). The unpaved road dust emission factors were calculated using the AP-42 methodology. 

Three different emission factors were calculated at each sampling site using different vehicle 

speeds: urban (11 miles per hour [mph]), suburban (18 mph), and rural (25 mph). Three average 

emission factors (i.e., urban, suburban, and rural) were then calculated by averaging together the 

emission factors over all of the sites. A precipitation adjustment factor of 0.94247 corresponding 

to 21 “wet” days was also used (NWS, 2005).
2005 Mexicali Emissions Inventory

Final, 2/27/09 3-13

Three different sets of unpaved emission factors (PM10 and PM2.5) were estimated for 

urban, suburban, and rural unpaved roads. The estimated unpaved road dust emission factors 

were then combined with the link-level unpaved road VKT to obtain link-level unpaved road 

dust emissions (Gonzalez-Ayala, 2008b).

The VKT estimate used for estimating paved road dust emissions was developed in 

conjunction with the on-road mobile source VKT development (see Section 4.0 of this report). 

Figure 3-2 demonstrates a portion of the analysis to determine the split of paved and unpaved 

analysis; further details are located in Appendix B, Section VI, of this report.

3.1.7 Miscellaneous Burning Categories

Area source inventories can potentially have a number of miscellaneous burning 

categories. These include wildfires, prescribed fires, on-site incineration, open burning, and 

structural fires. Based on site visits and interviews, the only miscellaneous burning activity that 

occurs in Mexicali is structural fires. The number of structural fires was obtained from the 

Mexicali fire department (Ruiz Burgueño, 2008), while the appropriate emission factors were 

obtained from EIIP guidance (EIIP, 2001a). 

3.1.8 Border Crossings

Emissions from idling vehicles queued to enter the United States were estimated as an 

area source, and were not included in the on-road mobile sources estimates. There are three 

border crossings in Mexicali: Calexico and Calexico East (both across from urban Mexicali) and 

Andrade (across from Algodones). Vehicle count and queue waiting times were obtained from 

the Bureau of Transportation Statistics (BTS, 2008). Emission factors were estimated using the 

MOBILE6-Mexico emission factor model (ERG, 2003).

3.1.9 Brick Kilns

The municipality of Mexicali has two distinct brick kiln areas. The first area is in 

Colonia Campestre and the second area is in Algodones (i.e., northeast Mexicali). Emissions 

from the Algodones brick kiln area were previously estimated as part of the 2007 inventory work 

in San Luis Río Colorado and northeastern Mexicali (ENVIRON and ERG, 2008); these 

emissions were re-used for the Mexicali inventory. Accurate activity data could not be collected 

at Colonia Campestre, therefore emission estimates from the smaller San Luis Río Colorado 
2005 Mexicali Emissions Inventory

Final, 2/27/09 3-14

brick kiln area (i.e., Colonia La Grullita) were assumed to be representative of the Colonia 

Campestre brick kiln emissions.

3.1.10 Charbroiling, Construction Dust, and Bakeries

Detailed Mexicali-specific activity data for charbroiling (restaurants and street vendors), 

construction dust, and bakeries could not be obtained. Emissions for these area source categories 

were extrapolated from the 1999 Mexico NEI (ERG, 2006). Construction dust emissions were 

disaggregated into two categories: residential construction and industrial/commercial 

construction.

3.1.11 Landfills

The municipality of Mexicali has one landfill (Hipolito landfill) which is located south of 

the urban area. Emissions were estimated using U.S. EPA’s theoretic first order kinetic model of 

methane production (U.S. EPA, 1995). Many of the site-specific data needed to make an 

accurate estimation of emissions (e.g., methane generation potential, methane generation rate 

constant, temperature, etc.) were not available. The only information that was obtained 

regarding the landfill was the year it opened and the daily quantity of waste landfilled (Villegas 

Ibarra, 2008). Default values were used for all other necessary parameter variables.

3.1.12 Wastewater Treatment

The municipality of Mexicali has eight wastewater treatment facilities: four in Mexicali 

and single facilities in Ciudad Morelos (Cuervos), Guadalupe Victoria (Km. 43), Vicente 

Guerrero (Algodones), and San Felipe. These facilities have a combined installed capacity of 

2.964 cubic meters per second (m3/s) with an actual treatment rate of 1.8494 m3/s (CNA, 2007). 

This treatment rate translates to an annual flow of 58,322,678,400 liters. The VOC emission 

factor for wastewater treatment was then applied to this annual flow (U.S. EPA, 1991). 

3.2 Results

The 2005 Mexicali area source emissions inventory is presented in Table 3-2. 

Examination of Table 3-2 indicates the following regarding area source emissions in Mexicali in 

2005:

 Agricultural field burning is the largest source of NOx followed by industrial natural 

gas combustion and residential LPG combustion.
2005 Mexicali Emissions Inventory

3-15

Final, 2/27/09

Table 3-2. 2005 Mexicali Area Source Emissions (Tons per Year)

Source Category NOx SO2 VOC CO PM10 PM2.5 NH3 CH4

Industrial Distillate 

Combustion 66.47 2.29 0.67 0.00 3.27 0.82 0.00 0.17

Industrial Residual 

Combustion 0.00 0.00 1.58 0.00 11.06 10.45 0.00 5.64

Industrial Natural Gas 

Combustion 279.79 0.00 6.30 0.00 8.40 8.73 4.45

Commercial Natural 

Gas Combustion 2.58 0.02 0.14 2.17 0.20 0.20 0.06

Residential Natural Gas 

Combustion 7.33 0.05 0.43 3.12 0.59 0.59 0.18

Industrial LPG 

Combustion 56.33 0.16 3.43 32.09 3.02 3.02 0.82

Commercial LPG 

Combustion 23.63 0.07 1.44 13.46 1.27 1.27 0.34

Residential LPG 

Combustion 102.97 0.29 6.27 58.65 5.52 5.52 1.49

Paved Road Dust 4,609.79 422.18

Unpaved Road Dust 42,331.35 4,209.66

Charbroiling/Street 

Vendors 2.77 9.69 150.18 75.44 60.21

Bakeries 117.94

Construction Activities 

– Residential 16.77 3.49

Construction Activities 

– Industrial/Commercial 118.59 24.65

Architectural Surface 

Coating (Solvent-based) 311.48

Architectural Surface 

Coating (Water-based) 167.27

Autobody Refinishing 78.74

Traffic Markings 57.06

Industrial Surface 

Coating - Wood 

Furniture 64.78

Industrial Surface 

Coating - Other Metallic 

Products 1,007.07
Table 3

-2. Continued

2005 Mexicali Emissions Inventory 3-16Final, 2/27/09

Source Category NO

x SO2 VOC CO PM10 PM2.5 NH3 CH4

Industrial Surface 

Coating – Electronics 32.47

Industrial Surface 

Coating – Automotive 1,281.22

Industrial Surface 

Coating - Other 

Transportation 327.24

Industrial Surface 

Coating - Other 

Manufacturing 1,262.62

Industrial Surface 

Coating - Industrial 

Maintenance 433.48

Degreasing (Vapor and 

In-line cleaning - Other) 323.47

Degreasing (Vapor and 

In-line cleaning –

Electronics 284.68

Degreasing (Cold 

Cleaning – Other) 744.18

Degreasing (Cold 

Cleaning - Automotive 

Repair) 565.11

Dry Cleaning 145.74

Graphic Arts 346.90

Consumer Solvents -

Personal Care 993.18

Consumer Solvents –

Household 84.62

Consumer Solvents -

Automotive Aftermarket 67.61

Consumer Solvents –

Coatings 242.98

Consumer Solvents -

Adhesives and Sealants 761.13

Consumer Solvents -

Federal Insecticide, 

Fungicide and 409.59
Table 3

-2. Continued

2005 Mexicali Emissions Inventory 3-17Final, 2/27/09

Source Category NO

x SO2 VOC CO PM10 PM2.5 NH3 CH4

Rodenticide Act 

(FIFRA) Products

Consumer Solvents -

Miscellaneous 29.58

Asphalt Application 145.97

Agricultural Pesticides 216.60

Gasoline Distribution –

Stage I 12.72

Gasoline Distribution –

Stage II 419.88

Gasoline Distribution -

Spillage 25.45

Underground Tank 

Breathing 38.17

Tank Truck Transit 4.45

Landfills 235.46 6,019.90

Wastewater Treatment 835.76

Agricultural Tilling 929.76 206.13

Agricultural Harvesting 767.74 170.21

Agricultural Field 

Burning 621.30 126.57 1,078.07 17,384.11 1,596.17 1,521.23

Fertilizer application –

Anhydrous ammonia 660.75

Fertilizer application –

Urea 4,878.75

Fertilizer application –

N-P-K 436.84

Fertilizer application –

Calcium nitrate 2.69

Fertilizer application –

Diammonium phosphate 1.38

Beef cattle feedlots 290.72

Livestock – Dairy Cattle 

(NH

3 and VOC) 322.77 1,389.78

Livestock –Beef Cattle 

(NH

3 and VOC) 1,025.42 1,589.51

Livestock – Swine 

(NH

3 and VOC) 10.92 36.65
Table 3-2. Continued

2005 Mexicali Emissions Inventory

3-18

Final, 2/27/09

Source Category NOx SO2 VOC CO PM10 PM2.5 NH3 CH4

Livestock – Sheep 

(NH3 and VOC) 4.43 13.63

Livestock – Goats (NH3

and VOC) 2.77 3.70

Structure Fires 0.11 0.85 4.64 0.82 0.76 0.22

Border Crossing 20.65 0.41 46.86 428.04 2.28 1.91 1.56

Brick Kilns 21.55 1.23 704.91 777.55 106.51 102.50

Total 1,205.48 131.09 15,301.55 18,854.02 50,879.89 6,753.65 9,015.23 6,033.28

Blanks indicate pollutant(s) are not applicable; 0.00 indicates pollutant emissions are insignificant.
2005 Mexicali Emissions Inventory

Final, 2/27/09

3-19

 Agricultural field burning is also the largest source of SO2. Typically, there would be 

high SO2 emissions from industrial residual combustion, but reconciliation with the 

point source inventory reduced the area source industrial residual combustion 

emissions to zero. In fact, the estimated SO2 emissions from industrial residual 

combustion were 3,275 tons.

 There are a number of VOC sources that emit approximately 1,000 tons per year: 

agricultural field burning, several types of industrial surface coating, several types of 

consumer solvents, wastewater treatment, and dairy cattle. However, if some of these 

subcategories are aggregated together, then overall, industrial surface coating and 

consumer solvents are the most significant area source emitters of VOC.

 Paved and unpaved road dust are the most important PM10 and PM2.5 sources, while 

agricultural field burning is also an important source of PM2.5.

 Fertilizer application and livestock ammonia are the predominant NH3 sources, while 

the landfill is the largest CH4 source.

3.3 Quality Assurance

Several general quality assurance checks were conducted for the entire Mexicali 

inventory. These checks (including hand calculations, completeness checks against the 1999 

Mexico NEI, emission factor checks, etc.) were conducted for all area source categories. In 

addition, two of the overall five DQOs for the Mexicali inventory project are applicable to area 

source emissions:

1. A comprehensive emissions inventory for all source types (i.e., point, area, on-road 

motor vehicle, and nonroad mobile sources) and all major categories within these 

source types. 

Acceptance criteria: The source types and major categories accounted for in the 

EIIP guidance documents are present in the Mexicali emissions inventory, and/or any 

differences are documented.

2. Area, On-Road Motor Vehicle, and Nonroad Mobile Sources: Emissions estimates 

with an accuracy of ±50%. 

Acceptance criteria: Estimated emissions using emission factors/models compare to 

emissions estimated using a fuel-balance approach for all applicable pollutants. The 

fuel-balance approach will use national statistics, while the preferred inventory 

methodology will use PEMEX and local fuel distribution data. 

The Mexicali area source inventory meets DQO #1. The area source inventory categories 

were based upon the area source categories previously inventoried in the 1999 Mexico NEI. The 
2005 Mexicali Emissions Inventory

Final, 2/27/09

3-20

1999 Mexico NEI area source categories were selected by reviewing all source categories 

included in Emission Inventory Improvement Program (EIIP) and other U.S. EPA guidance 

documents; Mexican federal environmental staff then identified those categories that either did 

not exist in Mexico or could be considered to be insignificant. Based upon comments to the draft 

inventory report, one area source category was added (i.e., VOC from beef cattle feedlots) and 

one area source category was disaggregated into two (i.e., construction activities into residential 

construction activities and industrial/commercial construction activities).

With regard to DQO #2, most area source fuel combustion emissions could not be 

assessed using a fuel-balance approach due to the lack of specific fuel usage data. However, the 

accuracy of the border crossing emission estimates was evaluated. Border crossing emissions 

(i.e., idling emissions) are typically not estimated in the U.S. since the wait times resulting in 

increased emissions generally occur on the Mexican side of the border. The preferred estimation 

methodology is to obtain queue waiting times and then calculate the distance based upon the 

lowest allowable vehicle speed in the MOBILE6 emission factor model (i.e., 2.5 miles per hour 

or 4 kilometers per hour). This calculated distance is then multiplied by the emission factor 

corresponding to the lowest allowable vehicle speed (Brzezinski, 2009). This methodology was 

used to estimate border crossing emissions in Mexicali. All inputs to the model and all 

subsequent post-model emission calculations were rechecked and no errors were found.

Besides the methodology used to estimate border crossing emissions, accurate idling 

emissions data are relatively unavailable (Brzezinski, 2009). Only one somewhat relevant source 

of data (i.e., a guidance document related to “long duration idling” for heavy-duty diesel 

vehicles) was identified (U.S. EPA, 2004). The typical hourly idling emission factors for heavyduty diesel vehicles identified from this guidance document were 135 g NOx/hour, and 3.68 g 

PM10/hour and g PM2.5/hour. The heavy-duty diesel vehicle emission factors used in the 

Mexicali emission estimates were 15.96 g NOx/mile, 1.27 g PM10/mile, and 1.14 g PM2.5/mile. 

At 2.5 miles per hour, these emission factors translate to 39.9 g NOx/hour, 3.18 g PM10/hour, and 

2.85 g PM2.5/hour. Although the PM10 and PM2.5 emission factors are comparable with those in 

the guidance document, the NOx emission factor differs by a factor of over 3.
2005 Mexicali Emissions Inventory

Final, 2/27/09

3-21

However, discussions with U.S. EPA staff familiar with idling emissions indicated that 

long duration idling does not correspond with border crossing idling. Long duration idling 

involves engine idling of long-haul heavy-duty diesel trucks during mandated rest periods (i.e., 

typically overnight or 10 hours rest for every 14 hours of driving) to operate air conditioning, 

heat, or on-board appliances (e.g., televisions, computers, microwaves, etc.). This type of idling 

occurs with higher engine loads and is fundamentally different than idling that occurs at border 

crossings (Brzezinski, 2009). In addition, queue waiting times for the three Mexicali border 

crossings were considerably shorter than the overnight (or long duration) idling (BTS, 2008). 

Thus, it is not unexpected that the NOx emissions during long duration idling would be 

substantially greater than emissions from idling at border crossings. Given these findings, the 

border crossing emissions were not adjusted.
2005 Mexicali Emissions Inventory

Final, 2/27/09

4-1

4.0 ON-ROAD MOBILE SOURCES

On-road mobile sources include all motor vehicles that are allowed to operate on public 

roadways (e.g., cars, trucks, buses, motorcycles). On-road mobile source emissions include 

exhaust emissions, as well as various types of evaporative emission processes. Several other 

types of emissions are caused by on-road mobile sources, including paved and unpaved road 

dust, Stage II vehicle refueling, and emissions from vehicles idling at the border crossings; these 

source categories are estimated as area sources and are addressed in Section 3.0 of this report.

Based upon previous experience from developing the 1999 Mexico NEI, availability of 

the VKT data needed to estimate emissions from on-road motor vehicles at the municipalitylevel is very limited in Mexico (with the exception of Mexico City, Guadalajara, and other large 

metropolitan areas). Therefore, traffic and congestion modeling were used to estimate VKT by 

road segment (i.e., link) for the municipality of Mexicali. The link-level VKT estimates were 

combined with emission factors generated by the MOBILE6-Mexico model (i.e., a Mexicospecific version of the MOBILE6 emission factor model) to estimate on-road motor vehicle 

emissions (ERG, 2003). The methodology is described below, and a more detailed explanation 

of the methodology is presented in Appendix B.

4.1 Methodology

The traffic volume and congestion modeling used a simplified road network, which 

included freeways, main arterials, collector roads, and “connectors” (i.e., artificial links that 

modeled local traffic flows). Although the road network was simplified, the road network 

consisted of 3,603 individual links. In general, the road network is primarily concentrated in the 

Mexicali urban area, but Federal Highway 2 (connecting Mexicali to Tijuana and San Luis Río 

Colorado), Federal Highway 5 (connecting Mexicali to Ensenada and San Felipe), as well as 

rural roads in the agricultural areas in the northeast and rural areas in the south, are also modeled.

The traffic modeling relied upon known Mexican trip generation rates combined with 

demographic and socio-economic information (i.e., population, household size, income, and 

employment) for each AGEB (i.e., Mexican equivalent of a census tract). The traffic modeling 

resulted in daily VKT estimates for daily traffic volumes for each link in the roadway network. 
2005 Mexicali Emissions Inventory

Final, 2/27/09

4-2

Link-level VKT was then estimated by multiplying each link’s daily traffic volume by its length 

in kilometers. Figure 4-1 shows the Mexicali roadway network and traffic volume intensity 

during a typical week day.

The traffic volumes for individual roadway network links were assigned to corresponding 

link-specific congested speed emissions factors from MOBILE6-Mexico in order to estimate 

daily link-level emissions. Several sets of emission factors were developed to account for 

different congested speeds (i.e., from 3 to 65 miles per hour [mph]), variations in ambient 

temperature, and seasonality. Overall emissions were estimated by summing the link-level 

emissions over the entire Mexicali road network.

Emissions were estimated for the following seven vehicle classifications:

 Light-Duty Gasoline Vehicles (LDGV)

 Light-Duty Gasoline Trucks (LDGT)

 Heavy-Duty Gasoline Vehicles (HDGV)

 Light-Duty Diesel Vehicles (LDDV)

 Light-Duty Diesel Trucks (LDDT)

 Heavy-Duty Diesel Vehicles (HDDV)

 Motorcycles (MC)

4.2 Results

The annual on-road mobile source emissions are presented in Table 4-1. Examination of 

Table 4-1 indicates the following regarding on-road mobile source emissions in Mexicali in 

2005:

 Light-duty gas vehicle and trucks are the primary sources of VOC, CO, NH3, and 

CH4.

 Heavy-duty diesel vehicles are the major sources of NOx, SO2, PM10, and PM2.5.

 Light-duty diesel vehicles and trucks, as well as motorcycles are relatively 

insignificant contributors of all pollutants - primarily due to their comparatively small 

fraction of the overall VKT.
2005 Mexicali Emissions Inventory

Final, 2/27/09

4-3

Figure 4-1. Mexicali Loaded Roadway Network Under Weekday Conditions

Detail of loaded roadway network 

for urban SLRC

Detail of roadway loaded network 

for urban Mexicali

Daily vehicle flow
2005 Mexicali Emissions Inventory

Final, 2/27/09

4-4

Table 4-1. 2005 Mexicali On-Road Mobile Source Emissions (Tons per Year)

NOx SO2 VOC CO PM10 PM2.5 NH3 CH4

LDGV 1,151.9 25.4 4,550.3 29,441.3 143.3 117.9 124.6 58.4

LDGT 1,523.4 33.1 3,594.6 26,650.3 184.1 155.4 113.5 61.7

HDGV 374.8 4.4 393.5 2,475.8 8.8 6.6 3.3 6.6

LDDV 12.1 0.0 9.9 18.7 2.2 2.2 0.0 0.0

LDDT 7.7 0.0 5.5 11.0 1.1 1.1 0.0 0.0

HDDV 5,463.0 105.8 340.6 1,574.1 424.4 382.5 11.0 13.2

MC 37.5 0.0 82.7 432.1 1.1 0.0 0.0 4.4

Total 8,570.4 168.7 8,977.1 60,603.4 765.0 665.8 252.4 144.4

4.3 Quality Assurance 

As discussed in Section 1.3, a number of general quality assurance checks were 

conducted for the entire Mexicali inventory. These checks (including hand calculations, 

completeness checks against the 1999 Mexico NEI, emission factor checks, etc.) were conducted 

for all on-road mobile source categories. In addition, two of the five data quality objectives 

(DQOs) for the Mexicali inventory project are applicable to on-road mobile source emissions:

1. A comprehensive emissions inventory for all source types (i.e., point, area, on-road 

motor vehicle, and nonroad mobile sources) and all major categories within these 

source types. 

Acceptance criteria: The source types and major categories accounted for in the 

EIIP guidance documents are present in the Mexicali emissions inventory, and/or any 

differences are documented.

2. Area, On-Road Motor Vehicle, and Nonroad Mobile Sources: Emissions estimates 

with an accuracy of ±50%. 

Acceptance criteria: Estimated emissions using emission factors/models compare to 

emissions estimated using a fuel-balance approach for all applicable pollutants. The 

fuel-balance approach will use national statistics, while the preferred inventory 

methodology will use PEMEX and local fuel distribution data. 

The Mexicali on-road mobile source inventory meets DQO #1. Emissions were 

estimated for seven on-road mobile source categories: light-duty gasoline vehicles (LDGV), 

light-duty gasoline trucks (LDGT), heavy-duty gasoline vehicles (HDGV), light-duty diesel 

vehicles (LDDV), light-duty diesel trucks (LDDT), heavy-duty diesel vehicles (HDDV), and 

motorcycles (MC). The MOBILE6-Mexico emission factor does provide emission factors for 28 
2005 Mexicali Emissions Inventory

Final, 2/27/09

4-5

disaggregated categories; however, the use of 7 categories is consistent with the 1999 Mexico 

NEI and provides easier reporting.

Also, the Mexicali on-road mobile source inventory also meets DQO #2. The on-road 

mobile source quality assurance took two forms: comparison of inventory VMT estimates with 

fuel-based VMT estimates and comparison of inventory motor vehicle activity data with Imperial 

County motor vehicle activity data.

The first quality assurance step was to compare the Mexicali VMT estimates derived 

using traffic and congestion modeling with fuel-based VMT estimates; VMT estimates were 

used instead of VKT estimates for ease of comparison. As part of the Mexicali traffic and 

congestion modeling, weekday VMT was estimated to be 7,876,541 miles (Appendix B, Table 

11) and weekend day VMT was estimated to be 5,496,411 miles (Appendix B, Table 12). 

Assuming 52 weeks per year consisting of 5 weekdays and 2 weekend days, then annual VMT 

was estimated to be 2.63 × 109 miles. As described in the area source fuel combustion and 

evaporative VOC methodology sections of this report (Sections 3.1.1 and 3.1.2), 2005 fuel sales 

statistics were provided by the PEMEX Mexicali bulk terminal. Additional research conducted 

as part of this QA procedure indicated that a significant portion of the fuels sold by the PEMEX 

Mexicali bulk terminal was sold and transported for consumption in Sonora (e.g., San Luis Río 

Colorado, Puerto Peñasco, Sonoyta, etc.) and other parts of Baja California (i.e., Tecate and 

Ensenada). Therefore, PEMEX staff provided revised fuel sales statistics of the fuel actually 

sold in the municipality of Mexicali (i.e., 224,800,401 liters of Magna gasoline, 63,773,310 liters 

of premium gasoline, and 84,678,057 liters of diesel) (Parra Armenta, 2009). Based on a 

PEMEX assumption that 60 percent of the diesel is used in motor vehicles, there is a total of 

89,664,609 gallons of motor vehicle fuel used in Mexicali. The new vehicle fuel economy for 

Mexico light-duty vehicles and trucks has been estimated to be 20.5 miles per gallon (mpg) (An 

and Blumberg, 2005); this value is likely overestimated for the overall in-use vehicle fleet, but 

fuel economy statistics for the overall Mexico in-use vehicle fleet could not be identified. 

Multiplying the motor vehicle fuel statistics by the fuel economy resulted in an annual VMT 

estimate of 1.84 × 109 miles. The fuel-based VMT estimate is approximately 70 percent of the 

VMT estimate developed using traffic and congestion modeling. Given that the Mexicali VMT 

estimate developed using traffic and congestion modeling has an approximate uncertainty of ±20 
2005 Mexicali Emissions Inventory

Final, 2/27/09

4-6

percent (Gonzalez-Ayala, 2008c), then the VMT estimate based on traffic and congestion 

modeling could potentially be overestimated slightly. This is within the 50 percent uncertainty 

specified by DQO #4.

The second quality assurance step was to compare Mexicali motor vehicle activity data 

with Imperial County motor vehicle activity data for reasonableness based upon comments 

regarding the draft report. Overall Imperial County and Mexicali on-road mobile source 

emissions data are compared in Table 4-2.

Table 4-2. 2005 Imperial County and Mexicali On-Road Mobile Source Emissions 

(Tons per Year)

Imperial County 

(tons/day)

Imperial County 

(tons/year)

Mexicali 

(tons/year)

Ratio 

(Mexicali/Imperial)

NOx 19.59 7,150.4 8,570.4 1.199

SO2 0.14 51.1 168.7 3.301

VOC 6.41 2,339.7 8,977.1 3.837

CO 56.52 20,629.8 60,603.4 2.938

PM10 0.86 313.9 765.0 2.437

PM2.5 0.71 259.2 665.8 2.569

Imperial County emissions data were obtained from ARB’s Almanac Emission Projection 

Data (ARB, 2007). As can be seen in the ratios in Table 4-2, the Mexicali on-road mobile source 

emissions exceed the Imperial County emissions by a factor of 1.2 to 3.8. 

As described in the area source methodology (Section 3.0 and Appendix A), the 2005 

population of the municipality of Mexicali was 855,962 people. The 2005 population of 

Imperial County was estimated to be 153,857 people (U.S. Census, 2008). The ratio of Mexicali 

population to Imperial County population is 5.563. If on-road mobile source emissions were 

proportional to population, then the Mexicali on-road mobile source emissions would exceed the 

Imperial County emissions by a similar factor of 5.563.

One potential reason why the Mexicali/Imperial County emission ratios are lower (i.e., 

1.2 to 3.8) than the population ratio (i.e., 5.563) is that there is a significantly higher level of 

vehicle ownership in Imperial County compared to the municipality of Mexicali. Chapter 4 of 

the Imperial County Air Quality Management Plan (AQMP) provides a count of 121,707 

vehicles for the year 2002 and an estimate of 161,231 vehicles for the year 2009 (Imperial, 

2008); linear interpolation between these two data points resulted in an estimate of 138,646 
2005 Mexicali Emissions Inventory

Final, 2/27/09

4-7

vehicles for the year 2005. This results in an estimated vehicle ownership rate of 0.901 vehicles 

per person. Vehicle registration statistics for the municipality of Mexicali obtained from INEGI 

indicate a total of 422,357 vehicles registered in 2005 (INEGI, 2008), which corresponds to an 

estimated vehicle ownership rate of 0.493 vehicles per person. Therefore, Imperial County 

vehicle ownership rates are significantly higher than in Mexicali. 

Chapter 4 of the Imperial County AQMP also provide estimated daily VMT for 2002 and 

2009 (4.780 × 106 miles and 6.277 × 106 miles, respectively) (Imperial, 2008); linear 

interpolation between these two data points resulted in an estimate of 5,421,571 daily VMT in 

2005, which corresponds to an annual VMT estimate of 1.98 × 109 miles. Overall Mexicali 

VMT is higher than overall Imperial County VMT by a factor of 1.33. Perceptions of even 

higher levels of vehicle activity in Mexicali compared to Imperial County are potentially due to 

Mexicali vehicle activity being concentrated in the urban portion of Mexicali, compared to 

Imperial County vehicle activity being spread among a number communities located throughout 

the county (e.g., El Centro, Brawley, Holtville, Calipatria, Westmorland, etc.).

Based upon these QA analyses, it was felt that the Mexicali on-road mobile source 

emission estimates were reasonably accurate and that additional adjustments were not needed.
2005 Mexicali Emissions Inventory

Final, 2/27/09

5-1

5.0 NONROAD MOBILE SOURCES

Nonroad mobile sources include all equipment that move under their own power, or that 

are portable, and are not allowed to operate on public roadways. For the 2005 Mexicali 

emissions inventory, nonroad mobile sources include aircraft and airport ground support 

equipment and auxiliary power units, locomotives, and agricultural and construction equipment. 

Another nonroad source type is commercial marine vessels; however, no major ports with 

significant commercial marine vessel activity exist in Mexicali. Initially, it was thought that 

there might be some fishing vessels in some of the communities located on the Gulf of 

California. However, fishing vessel activity data were not available. Some fishing occurs out of 

San Felipe, but this appears to consist of tourist fishing, rather than commercial fishing. Due to 

the lack of data and apparent insignificance of these emissions, emissions for commercial marine 

vessels were not estimated.

5.1 Methodology

The methodologies used to estimate emissions for the various nonroad mobile source 

types operating in Mexicali are described below. 

5.1.1 Aircraft

There are two airports located in the municipality of Mexicali: General Rodolfo Sánchez 

Taboada International Airport (east of the Mexicali urban area) and San Felipe International 

Airport (located in the southern portion of the municipality). Operator-specific landing and 

takeoff (LTO) statistics and aircraft fleet composition data were obtained from local airport 

officials (Sanchez Resendiz, 2008). These data included information for both the Mexicali and 

San Felipe airports; however, the data were not associated with a particular airport. Therefore, it 

was assumed that all flight data were associated with the General Rodolfo Sánchez Taboada 

International Airport airport because it is much larger than San Felipe International Airport. 

Because of the large amount of agricultural activity in Mexicali, crop dusting (or aerial spraying) 

is a significant activity in the area. Crop dusting activity data (including LTO data, flight 

lengths, and fuel usage) were provided by staff from the Mexicali crop dusting industry 

association (Tamayo Moreno, 2008). There were also numerous other general aviation landing 
2005 Mexicali Emissions Inventory

Final, 2/27/09

5-2

strips located throughout Baja California, but these were not included in the inventory because 

LTO data for these landing strips were not available.

The aircraft operations information was input into the latest version of the Emissions and 

Dispersion Modeling System (EDMS 5.0.2, release June 29, 2007) model. The EDMS model 

was developed by the Federal Aviation Administration and is recommended for use by U.S. 

EPA. The model contains the latest emission factors from the International Civil Aviation 

Organization’s (ICAO) Engine Exhaust Emissions Data Bank. The default time-in modes for 

taxi out, take off, climb out, approach, and taxi in were used to run the model. The model output 

included emissions by aircraft type and total emissions, including emissions for aircraft, ground 

support equipment, and auxiliary power units. Emissions from other airport-related activities 

(e.g., parking lots, roadways, stationary sources within airport boundaries, etc.) were not 

included in the estimates because these sources addressed within other emission inventory 

categories.

5.1.2 Locomotives

A railway line extends from Mexicali to Puerto Peñasco, Sonora. In order to estimate 

emissions for locomotives operating within the municipality of Mexicali (i.e., in the locomotive 

yard and from line haul activities), local locomotive fuel consumption data are needed; however, 

these data were not available. Visual observations ERG staff indicated that there is very limited 

locomotive activity in the municipality. Due to the lack of data needed to estimate these 

emissions for Mexicali, the emissions calculated for the 1999 Mexico NEI were used without 

adjustment. These are felt to be appropriate because of the observed limited locomotive activity.

5.1.3 Agricultural and Construction Equipment

As part of the 1999 Mexico NEI project, a Mexico-specific version of the U.S. EPA’s 

NONROAD emissions model was developed (i.e., NONROAD-Mexico), which provided a 

streamlined way to estimate emissions from agricultural and construction equipment (ERG, 

2005). To develop a Mexico-specific version of this model, various parameters were adjusted to 

better reflect conditions in Mexico, including: average annual temperature, altitude, and diesel 

sulfur content. Also, Mexican state-level agricultural and construction equipment populations 

were incorporated into the model. Although other nonroad equipment types (lawn and garden, 
2005 Mexicali Emissions Inventory

Final, 2/27/09

5-3

logging, etc.) exist in Mexico, agricultural and construction equipment were given highest 

priority during the development of the NONROAD-Mexico model because it was believed that 

they emitted the most emissions as compared to the other equipment types. 

Because the NONROAD-Mexico model contained data which would generate emissions 

for 1999, only, it was desirable to update the equipment population and operation files to 2005 in 

order to estimate 2005 emissions for the municipality of Mexicali. However, sufficient recent 

data were not available.

Due to the lack of data needed to update the NONROAD-Mexico model, the 

municipality-level nonroad equipment emissions from the 1999 Mexico NEI generated using the 

NONROAD-Mexico model were extrapolated using 2005 population for Mexicali. This 

extrapolation method was previously used to estimate nonroad source emissions in the San Luis 

Río Colorado emission inventory, which included the northeast portion of the municipality of 

Mexicali (ENVIRON and ERG, 2008). First, for agricultural equipment, it was assumed that 

agricultural land area would be fairly stable over time. As a result, the agricultural equipment 

population would likely not grow significantly between 1999 and 2005. For construction 

equipment, it was assumed that equipment population growth was proportional to population 

growth. The population of the municipality of Mexicali grew from 764,602 to 855,962 over the 

same time period; this corresponds to a growth rate of 1.1195 (INEGI, 2000; INEGI, 2006). This 

growth factor was applied to the 1999 municipality-level emissions estimated using 

NONROAD-Mexico to obtain 2005 emissions for agricultural and construction equipment.

5.2 Results

The annual nonroad mobile source emissions are presented in Table 5-1; NH3 and CH4

emissions were not estimated for nonroad mobile sources. As seen in the table, the largest 

emissions are from construction and agricultural equipment. The construction and agricultural 

equipment are dominated by diesel-powered equipment which will cause relatively high NOx, 

PM10, and PM2.5 emissions. Locomotives have infrequent activity and the portion of aircraft 

flight durations that occur in the inventory domain are comparatively short relative to the length 

of an entire flight, with the exception of cropdusters.
2005 Mexicali Emissions Inventory

Final, 2/27/09

5-4

Table 5-1. 2005 Mexicali Nonroad Mobile Source Emissions (Tons per Year)

Source Category NOx SO2 VOC CO PM10 PM2.5

Aircraft – Commercial 15.2 1.9 6.8 31.7 0.3 0.3

Airport Auxiliary Power Units 3.7 0.3 1.1 32.4 0.1 0.1

Airport Ground Support 

Equipment 0.6 0.1 0.0 0.4 0.0 0.0

Locomotives 206.2 1.8 7.8 20.4 5.1 4.6

Construction Equipment 3,100.2 41.6 320.4 1,552.3 348.9 338.5

Agricultural Equipment 1,158.5 14.6 195.7 785.3 195.7 189.8

Aircraft – Cropdusters 

(General) 0.5 0.6 11.1 784.4 0.0 0.0

Total 4,485.0 60.9 542.9 3,206.9 550.2 533.3

5.3 Quality Assurance

As discussed in Section 1.3, a number of general quality assurance checks were 

conducted for the entire Mexicali inventory. These checks (including hand calculations, 

completeness checks against the 1999 Mexico NEI, emission factor checks, etc.) were conducted 

for all area source categories. In addition, two of the five DQOs for the Mexicali inventory 

project are applicable to nonroad mobile source emissions:

1. A comprehensive emissions inventory for all source types (i.e., point, area, on-road 

motor vehicle, and nonroad mobile sources) and all major categories within these 

source types. 

Acceptance criteria: The source types and major categories accounted for in the 

EIIP guidance documents are present in the Mexicali emissions inventory, and/or any 

differences are documented.

2. Area, On-Road Motor Vehicle, and Nonroad Mobile Sources: Emissions estimates 

with an accuracy of ±50%. 

Acceptance criteria: Estimated emissions using emission factors/models compare to 

emissions estimated using a fuel-balance approach for all applicable pollutants. The 

fuel-balance approach will use national statistics, while the preferred inventory 

methodology will use PEMEX and local fuel distribution data. 

The Mexicali nonroad mobile source inventory meets DQO #1. The nonroad mobile 

source inventory categories were based upon the nonroad mobile source categories previously 

inventoried in the 1999 Mexico NEI. The 1999 Mexico NEI nonroad mobile source categories 

were selected by reviewing all source categories included in Emission Inventory Improvement 

Program (EIIP) and other U.S. EPA guidance documents; Mexican federal environmental staff
2005 Mexicali Emissions Inventory

Final, 2/27/09

5-5

then identified those categories that either did not exist in Mexico or could be considered to be 

insignificant. Some U.S.-specific nonroad mobile source categories typically inventoried were 

excluded in Mexico (e.g., lawn and garden equipment, logging equipment, recreational vehicles, 

etc.). It should also be noted that the aircraft and locomotive categories were included as area 

sources in the 1999 Mexico NEI, but were classified as nonroad mobile sources for the Mexicali 

inventory. Also, two nonroad mobile source categories not previously inventoried in the 1999 

Mexico NEI were included in the Mexico inventory (i.e., airport auxiliary power units and 

airport ground support equipment). Finally, based upon comments to the draft inventory report, 

one additional nonroad mobile source category was added (i.e., cropdusting aircraft).

With regard to DQO #2, there were insufficient fuel usage data to assess the nonroad 

mobile source emissions using a fuel balance approach.
2005 Mexicali Emissions Inventory

Final, 2/27/09

6-1

6.0 EMISSION INVENTORY RESULTS

The overall 2005 Mexicali emissions inventory results are shown in Table 6-1. The 

results are presented by source type and pollutant. Figures 6-1 through 6-8 show the distribution 

of emissions by source type for each pollutant. The table and figures show that:

 Emissions from federal jurisdiction point sources are considerably larger than 

emissions from state jurisdiction point sources, even though the ratio of state-tofederal jurisdiction point sources is greater than 10-to-1.

 NOx and SO2 emissions are primarily emitted by point sources.

 VOC emissions are emitted by area (i.e., mainly various evaporative source 

categories) and on-road mobile sources.

 On-road mobile sources are the predominant source of CO.

 Area sources are the largest sources of PM10 and PM2.5 (i.e., due to unpaved and 

paved road dust), as well as NH3 (i.e., from livestock ammonia and fertilizer 

application) and CH4 (i.e., from the landfill).

Table 6-1. 2005 Mexicali Emissions Inventory Summary (Tons per Year)

Source Type NOx SO2 VOC CO PM10 PM2.5 NH3 CH4

Point –

Federal 13,931.7 3,650.9 659.3 3,636.2 1,537.7 128.4

Point – State 444.0 973.2 73.0 479.9 89.7

Area 1,205.5 131.1 15,301.5 18,854.0 50,879.3 6,753.5 9,015.2 6,033.3

On-Road 

Mobile 8,570.4 168.7 8,977.1 60,603.4 765.0 665.8 252.4 144.4

Nonroad 

Mobile 4,485.0 60.9 542.9 3,206.9 550.2 533.3 0.0 1.5

Total 28,636.5 4,984.8 25,553.8 86,780.4 53,821.8 8,081.0 9,267.6 6,179.2

Blanks indicate that pollutant emissions were not applicable or were not estimated due to a lack 

of data.
2005 Mexicali Emissions Inventory

Final, 2/27/09

6-2

Figure ES-1. Mexicali NOx Emissions

Point - Federal

48.7%

Point - State

1.6%

Area

4.2%

On-Road Mobile

29.9%

Non-Road Mobile

15.7%

Figure 6-1. Mexicali NOx Emissions

Figures ES-2. Mexicali SO2 Emissions

Point - Federal

73.2%

Point - State

19.5%

Area

2.6%

On-Road Mobile

3.4%

Non-Road Mobile

1.2%

Figure 6-2. Mexicali SO2 Emissions
2005 Mexicali Emissions Inventory

Final, 2/27/09

6-3

Figure ES-3. Mexicali VOC Emissions

Area

59.9%

On-Road Mobile

35.1%

Point - Federal

2.6%

Point - State

0.3%

Non-Road Mobile

2.1%

Figure 6-3. Mexicali VOC Emissions

Figure ES-4 Mexicali CO Emissions

Area

21.7%

On-Road Mobile

69.8%

Point - Federal

4.2% Point - State

0.6%

Non-Road Mobile

3.7%

Figure 6-4. Mexicali CO Emissions
2005 Mexicali Emissions Inventory

Final, 2/27/09

6-4

Figure ES-5. Mexicali PM10 Emissions

Area

94.5%

Point - State

0.2%

Point - Federal

Non-Road Mobile 2.9%

1.0%

On-Road Mobile

1.4%

Figure 6-5. Mexicali PM10 Emissions

Figure ES-6. Mexicali PM2.5 Emissions

Area

83.6%

On-Road Mobile

8.2%

Non-Road Mobile

6.6%

Point - Federal

1.6%

Point - State

0.0%

Figure 6-6. Mexicali PM2.5 Emissions
2005 Mexicali Emissions Inventory

Final, 2/27/09

6-5

Figure ES-7. Mexicali NH3 Emissions

Area

97.3%

Point - Federal

0.0%

Non-Road Mobile

0.0%

Point - State

0.0%

On-Road Mobile

2.7%

Figure 6-7. Mexicali NH3 Emissions

Figure ES-8. Mexicali CH4 Emissions

Area

97.6%

Point - Federal

0.0%

Non-Road Mobile

0.0% Point - State

0.0%

On-Road Mobile

2.3%

Figure 6-8. Mexicali CH4 Emissions
2005 Mexicali Emissions Inventory

Final, 2/27/09

7-1

7.0 REFERENCES

Álvarez Sánchez, 2008. LPG statistics provided by I. Álvarez Sánchez, Gas Silza S.A. de C.V., 

Mexicali, Baja California. August 22.

An and Blumberg, 2005. “The Case for Mexico to Improve Vehicle Fuel Efficiency”, 

presentation by F. An and K. Blumberg at Workshop on Sustainable Transport in Latin America: 

From Theory to Practice. Washington D.C., January 9. 

ANAFAPYT, 2003. National paint sales provided by the National Association of Paint and Ink 

Manufacturers (Asociación Nacional de Fabricantes de Pinturas y Tintas).

ANAFAPYT, 2004. National ink sales provided by the National Association of Paint and Ink 

Manufacturers (Asociación Nacional de Fabricantes de Pinturas y Tintas).

ARB, 2002. California Emission Inventory Development and Reporting System (CEIDARS) 

Particulate Matter (PM) Speciation Profiles. Updated September 26, 2002. California Air 

Resources Board, Sacramento, California.

ARB, 2003a. Area Sources Methods – Section 7.4 (Agricultural Land Preparation). California 

Air Resources Board, Sacramento, California.

ARB, 2003b. Area Sources Methods – Section 7.5 (Agricultural Harvest Operations). 

California Air Resources Board, Sacramento, California.

ARB, 2004. Area Sources Methods – Section 7.6 (Livestock Husbandry). California Air 

Resources Board, Sacramento, California. May. 

ARB, 2005. Area Sources Methods – Section 7.17 (Agricultural Burning and Other Burning 

Methodology). California Air Resources Board, Sacramento, California. June.

ARB, 2007. Almanac Emission Projection Data. California Air Resources Board, Sacramento, 

California.

Brzezinski, 2009. Personal communication with D. Brzezinski, U.S. Environmental Protection 

Agency, National Vehicle and Fuel Emissions Laboratory, Ann Arbor, Michigan. January 13.

BTS, 2007. National Transportation Statistics 2007 (Table 1-32 – U.S. Vehicle-Miles). Bureau 

of Transportation Statistics, U.S. Department of Transportation. 

BTS, 2008. Border crossing vehicle counts and queue waiting times provided by the Bureau of 

Transportation Statistics.

CANALAVA, 2002. National dry cleaning solvent statistics provided by the National Chamber 

of the Dry Cleaning Industry (Cámara Nacional de la Industria de Lavanderías).
2005 Mexicali Emissions Inventory

Final, 2/27/09

7-2

Chinkin, L.R., P.A. Ryan, and D.L. Coe. 2003. “Recommended Improvements to the CMU 

Ammonia Emission Inventory Model for Use by LADCO”. Prepared for the Lake Michigan Air 

Directors Consortium.

CNA, 2007. Inventario Nacional de Plantas Municipales de Potabilización y de Tratamiento de 

Aguas Residuales en Operación – Diciembre de 2007. Prepared by the National Commission on 

Water (Comisión Nacional del Agua).

COFEPRIS, 2007. Registros de Plaguicidas Autorizados por Categoría Toxicológica. Prepared 

by the Federal Commission for Sanitary Risk Protection (Comisión Federal de Protección Contra 

Riesgos Sanitarios).

DPR, 2007. Pesticide databases. California Department of Pesticide Regulation, 

http://www.cdpr.ca.gov/dprdatabase.htm

EEA, 2002. Joint EMEP/CORINAIR Atmospheric Emission Inventory Guidebook, Third 

Edition. European Environment Agency, Copenhagen, Denmark

EIIP, 1996. Consumer and Commercial Solvent Use. Volume III, Chapter 5. Emission 

Inventory Improvement Program. August.

EIIP, 1997. Solvent Cleaning, Volume III: Chapter 6. Emission Inventory Improvement 

Program, Area Sources Committee. September.

EIIP, 2001a. Gasoline Marketing (Stage I and Stage II). Volume III. Chapter 11. Emission 

Inventory Improvement Program, Area Sources Committee. January.

EIIP, 2001b. Pesticides – Agricultural and Nonagricultural. Volume III, Chapter 9. Emission 

Inventory Improvement Program, Area Sources Committee. June.

EIIP, 2001c. Structure Fires. Volume III, Chapter 18. Emission Inventory Improvement 

Program. January.

EIIP, 2001d. Asphalt Paving. Volume III, Chapter 17. Emission Inventory Improvement 

Program. April.

ENVIRON and ERG, 2007. Development of Air Emissions Inventory for the Western Arizona 

Sonora Border Air Quality Study (WASBAQS) – Emission Inventory Project Report. Prepared 

for the Arizona Department of Environmental Quality by ENVIRON International Corporation 

and Eastern Research Group, Inc., June.

ERG, 2003. MOBILE6-Mexico. Prepared for the Western Governors’ Association by Eastern 

Research Group, Inc. (ERG), Austin, Texas. June 27.

ERG, 2005. NONROAD-Mexico: A Tool for Estimating Emissions from Agricultural and 

Construction Equipment in Mexico. Prepared for the Western Governors’ Association and the 

Binational Advisory Committee. Prepared by Eastern Research Group, Inc., Austin, Texas. July 27.
2005 Mexicali Emissions Inventory

Final, 2/27/09

7-3

ERG, 2006. Mexico National Emissions Inventory, 1999 – Final. Prepared for the Secretariat of 

the Environment and Natural Resources and the National Institute of Ecology of Mexico by 

Eastern Research Group, Inc. with sponsorship of the U.S. EPA, Western Governors’ Association, 

and the North American Commission for Environmental Cooperation. October 11, 2006.

Escalante, 2008. LPG statistics provided by E. Escalante, Kino Gas del Noroeste, S.A. de C.V., 

Mexicali, Baja California. August 7. 

Félix Robles, 2008. LPG statistics provided by C.R. Félix Robles, Hidrocarburos del Noroeste, 

S.A. de C.V., Mexicali, Baja California. August 13.

Fierro, 2007. Personal communication with Marian Fierro (Arizona College of Public Health, 

University of Arizona, Tucson, Arizona) regarding bleach use in SLRC. May 4.

Fierro, M.A. and M.K. O’Rourke, 2007. Binational Household Product Survey. Prepared by 

Marian A. Fierro and Mary Kay O’Rourke, College of Public Health, University of Arizona, 

Tucson, Arizona. 

Gonzalez-Ayala, 2007. Per capita San Luis Río Colorado, Sonora VMT estimates provided by 

S. Gonzalez-Ayala, TransEngineering, Ciudad Juárez, Chihuahua. December.

Gonzalez-Ayala, 2008a. Link-level paved road dust emission estimates provided by S. 

Gonzalez-Ayala, TransEngineering, Ciudad Juárez, Chihuahua. September.

Gonzalez-Ayala, 2008b. Link-level unpaved road dust emission estimates provided by S. 

Gonzalez-Ayala, TransEngineering, Ciudad Juárez, Chihuahua. September.

Gonzalez-Ayala, 2008c. Estimates of Mexicali travel demand modeling uncertainty provided by 

S. Gonzalez-Ayala, TransEngineering, Ciudad Juárez, Chihuahua. December 22.

Imperial, 2008. Imperial County Air Quality Management Plan, Chapter 4 – Emissions 

Inventory. Imperial County Air Pollution Control District, El Centro, California. April 9.

INEGI, 2000. XII Censo General de Población y Vivienda, 2000. Prepared by the National 

Institute of Statistics, Geography, and Information (Instituto Nacional de Estadística, Geografía e 

Informática).

INEGI, 2005. Censos Económicos 2004 medianto el Sistema Automatizado de Información 

Censal (SAIC), version 5.0. Prepared by the National Institute of Statistics, Geography, and 

Information (Instituto Nacional de Estadística, Geografía e Informática).

INEGI, 2006. II Conteo de Población y Vivienda, 2005. Prepared by the National Institute of 

Statistics, Geography, and Information (Instituto Nacional de Estadística, Geografía e 

Informática).

INEGI, 2008. Vehículos de Motor Registrados en Circulación. Prepared by the National 

Institute of Statistics, Geography, and Information (Instituto Nacional de Estadística, Geografía e 

Informática). 
2005 Mexicali Emissions Inventory

Final, 2/27/09

7-4

LMA, 2008a. Laboratory analysis results of Mexicali paved road dust samples provided by 

Laboratorio de Muestro y Analisis, S.A. de C.V., Tijuana, Baja California. July 24.

LMA, 2008b. Laboratory analysis results of Mexicali unpaved road dust samples provided by 

Laboratorio de Muestro y Analisis, S.A. de C.V., Tijuana, Baja California. July 24.

López Bojorques, 2008. Personal communication with G. López Bojorques, Secretaría de 

Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación (SAGARPA), Mexicali, Baja 

California. August 13. 

Martinez, 2007. Personal communication with K. Martinez, Urban Development and Ecology 

Office, San Luis Río Colorado, Sonora. January.

Miranda Palazuelos, 2008. Residual fuel oil statistics provided by F.H. Miranda Palazuelos, 

PEMEX – Rosarito Terminal, Rosarito, Baja California. October 2.

NWS, 2005. “Record of River and Climatological Observations – Calexico 2NE ”, January 2005 

through December 2005. U.S. Weather Service.

Parra Armenta, 2008. Gasoline and distillate fuel oil statistics provided by F. Parra Armenta, 

PEMEX – Mexicali Terminal, Mexicali, Baja California. May 19.

Parra Armenta, 2009. Revised gasoline and distillate fuel oil statistics provided by F. Parra 

Armenta, PEMEX – Mexicali Terminal, Mexicali, Baja California. January 6.

PROAIRE, 1999. Programa para Mejorar la Calidad del Aire de Mexicali, 2000-2005. 

Prepared by the Gobierno del Estado de Baja California, Gobierno Municipality de Mexicali, 

Secretaría de Medio Ambiente, Recursos Naturales y Pesca, Secretaría de Salud, and Delegación 

Federal SEMARNAP, Baja California. December.

Reynoso Ambriz, 2008. Personal communication with F. Reynoso Ambriz, Obras Públicas del 

Ayuntamiento de Mexicali, Mexicali, Baja California. August 13.

Rodríguez Hernández, 2008. Agricultural burning information provided by A. Rodríguez 

Hernández, Secretario de Fomento Agropecuario, Mexicali, Baja California. May 19.

Ruiz Burgueño, 2008. Fire statistics provided by M.A. Ruiz Burgueño, Dirección del Heroico 

Cuerpo de Bomberos, Mexicali, Baja California. May 6. 

Ruiz Méndez, 2003. PEMEX municipality-level gasoline station information provided by A. 

Ruiz Méndez, PEMEX, Mexico City, Mexico. July 30.

SAGARPA, 2007a. Anuario Estadístico de la Produccíon Agrícola. Prepared by the Secretariat 

of Agriculture, Livestock, Rural Development, Fisheries, and Food (Secretaría de Agricultura, 

Ganadería, Desarrollo Rural, Pesca y Alimentación). 

SAGARPA, 2007b. Vínculo Informático para la Obtención de Costos de Producción (VIOCS), 

Estructuras de Costos de Producción (ECP), Versión 2.0. Prepared by the Secretariat of 
2005 Mexicali Emissions Inventory

Final, 2/27/09

7-5

Agriculture, Livestock, Rural Development, Fisheries, and Food (Secretaría de Agricultura, 

Ganadería, Desarrollo Rural, Pesca y Alimentación). 

SAGARPA, 2007c. Servicio de Información Agroalimentaria y Pesquera (SIAP). Prepared by 

the Secretariat of Agriculture, Livestock, Rural Development, Fisheries, and Food (Secretaría de 

Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación). 

Sanchez Resendiz, 2008. Mexicali airport landing-and-takeoff (LTO) statistics provided by C. 

Sanchez Resendiz, Dirección de Aeropuerto. May 15.

Sukarne, 2008. Beef cattle residence time estimates provided by Sukarne Produccion, S.A. de 

C.V., Mexicali, Baja California. September.

Tamayo Moreno, 2008. Crop dusting activity data provided by A. Tamayo Moreno, Asociación 

de Pilotos Privados Aplicadores de Plaguicida. October 31.

U.S. Census Bureau, 2007. Annual Estimates of the Population for the United States, Population 

Division, U.S. Census Bureau, Washington, D.C.

U.S. Census Bureau, 2008. Annual Estimates of Population Change for Counties of California 

and County Rankings: April 1, 2000 to July 1, 2007. Population Division, U.S. Census Bureau, 

Washington, D.C.

U.S. EPA, 1991. Procedures for the Preparation of Emission Inventories for Carbon Monoxide

and Precursors of Ozone. Volume I: General Guidance for Stationary Sources. EPA-450/4/91-

016. U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, 

Research Triangle Park, North Carolina.

U.S. EPA, 1995. Compilation of Air Pollution Emission Factors (AP-42) – Volume I: 

Stationary Point and Area Sources, Fifth Edition. Various sections. U.S. Environmental 

Protection Agency, Office of Air Quality Planning and Standards, Research Triangle Park, North 

Carolina. January.

U.S. EPA, 2004. Guidance for Quantifying and Using Long Duration Truck Idling Emission 

Reductions in State Implementation Plans and Transportation Conformity. EPA420-B-04-001. 

U.S. Environmental Protection Agency, Office of Transportation and Air Quality. January.

Valdes Cantu, 2003. PEMEX fuel sulfur contents (diesel, combustoleo, marine diesel, and 

Intermedio 15) provided by N. Valdes Cantu, PEMEX, Mexico City, Mexico. December 11.

Villegas Ibarra, 2008. Landfill statistics provided by E. Villegas Ibarra, Dirección de Ecología 

de Mexicali. May 14.

Vivo, 2008. Natural gas statistics provided by A.R. Vivo, Ecogas Mexico S. de R.L. de C.V., 

Mexicali, Baja California. August 26.