SEPA
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United States
Environmental Protection
Agency
Off ice of Air Quality
Planning and Standards
Research Triangle Park, NC 27711
EPA 456/R-98-001
January 1998
Air
Ambient Air Monitoring Plan
for Ciudad Acuna and Piedra
Negras, Coahuila, Mexico
c i c A
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EPA-456/R-98-001
Ambient Air Monitoring Plan
for Ciudad Acuna and Piedras Negras,
Coahuila, Mexico
U.S.-Mexico Border
Information Center on Air Pollution
CICA
Centra de Information sobre Contamination de Aire
Para la frontera de EE. UU.-Mexico
Sponsored by
Clean Air Technology Center (MD-12)
Information Transfer Group
Office of Air Quality and Standards
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th Floor
Chicago, IL 60604-3590
January 1998
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EPA-456/R-98-001
Ambient Air Monitoring Plan
for Ciudad Acuna and Piedra Negras,
Coahuila, Mexico
Prepared by
Jerry Winberry
Lance Henning
Richard Crume
Midwest Research Institute
401 Harrison Oaks Blvd., Suite 350
Gary, NC 27513
Under subcontract to
Randy Strait, Project Manager
E.H. Pechan & Associates, Inc.
3500 Westgate Drive, Suite 103
Durham, NC 27707
EPA Contract No. 68-D3-0035
Work Assignment No. 11-81
Project Manager
Dr. Nancy B. Pate
Information Transfer and Program Integration Division
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
Prepared for
U.S.-Mexico Border
Information Center on Air Pollution/
Centra de Information sobre Contamination de Aire
Para EE. UU. -Mexico (CICA)
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
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EPA REVIEW NOTICE
This report has been peer and administratively reviewed by the U.S. Environmental
Protection Agency, and approved for publication. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Information
Service, Springfield, Virginia 22161. Telephone (800) 553-6847.
111
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ACKNOWLEDGMENTS
The authors wish to express their appreciation to the following individuals for their
assistance and hospitality during the site visit to Mexico:
Gobierno del Estado de Coahuila
Rodolfo Garza Gutierrez
Sergio Martinez Alfaro
Jose Carlos Murguia Arizpe
CiudadAcuna Ciudad Piedras Negras
Emilio de Hoyos Cerna Ernest Vela del Campo
Jose Luis Coronado Rivera Juan A. Escandon Valdez
Francisco Muniz Hernandez Ruperto Roma Rangel
Andres Arejandro Tanaka Lopex
Jose Antonio Garga Carter
Without their support and enthusiasm, this study would not have been possible.
Additionally, the authors greatly appreciate the support provided by Maria Rodriguez,
Jim Menke, and Steve Neimer of the Texas Natural Resources Conservation Commission, who
provided valuable information, assistance, and advice throughout the project.
IV
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PREFACE
The U.S.-Mexico border Information Center on Air Pollution /Centra de Information
sobre Contamination de Aire (CICA), was established by the U.S. Environmental Protection
Agency (EPA), Office of Air Quality Planning and Standards (OAQPS) to provide technical
support and assistance in evaluating air pollution problems along the U.S.-Mexico Border. These
services and products are available at no cost to Federal, State and Local Agencies and
universities in Mexico. Others can use these services depending on available resources.
CICA provides ready access to EPA information and expertise. It draws on professional
staff from the EPA's OAQPS and Office of Research and Development (ORD). Private
contractors also are available when appropriate.
CICA SERVICES
The CICA provides five levels of assistance:
CICA'S LINES OF COMMUNICATIONS
CICA offers bilingual communication services (English & Spanish) to address air
pollution problems along the U. S. - Mexico Border.
Information lines
- Hotline Telephone: (919) 541-1800. Toll free from Mexico only (800) 304-1115
-Fax:(919)541-0242
Internet (WWW) Home Page
- http://www.epa.gov/ttn/catc/cica/
E-mail
Use CICA Home Page or send directly to: catcmail@epamail.epa.gov
ENGINEERING ASSISTANCE/TECHNICAL GUIDANCE
GUIDANCE DOCUMENTS AND COMPUTER SOFTWARE TOOLS
ON-LINE ASSISTANCE
CLEAN AIR TECHNOLOGY CENTER (CATC) WWW Services and Products
including its pollution prevention and control technology data base
(RACT/BACT/LAER Clearinghouse/RBLC) and access to other information and
services on EPA's Technology Transfer Network (TTN)
This CICA assistance project resulted from a request from the State of Coahuila, Mexico.
Coahuila was interested in improving ambient air quality monitoring capabilities in the two
cities, CiudadAcuna and Piedras Negras. To accomplish this, CICA was asked to help develop
and ambient air quality monitoring plan for these cities. This report is the result of that effort.
This report presents recommendations on implementing an ambient air quality monitoring
network for the two cities based the existing air quality monitoring equipment, emission sources
potentially affecting these cities, and the human resources needed to operate and maintain the
network.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY ES-1
1.0 INTRODUCTION 1-1
2.0 BACKGROUND 2-1
2.1 MEXICAN AND U.S. REGULATORY AUTHORITIES 2-1
2.2 CHARACTERISTICS OF CIUDAD ACUNA AND PffiDRAS
NEGRAS : 2-2
2.3 REVIEW OF HISTORICAL AIR QUALITY DATA 2-10
2.4 STUDY APPROACH 2-14
2.5 SITE VISIT ITINERARY 2-17
3.0 CRITERIA FOR DESIGNING AIR MONITORING NETWORK 3-1
3.1 INTRODUCTION 3-1
3.2 SITE SELECTION CRITERIA 3-1
3.3 PROBE PLACEMENT CRITERIA 3-4
3.4 MONITOR LOCATION PRIORITY 3-6
4.0 ' SITE VISIT APPROACH AND OBSERVATIONS 4-1
4.1 OVERVIEW OF APPROACH 4-1
4.2 SUMMARY OF OBSERVATIONS 4-2
5.0 RECOMMENDATIONS 5-1
5.1 CIUDAD ACUNA 5-1
5.2 PffiDRAS NEGRAS 5-13
5.3 STATE OF COAHUILA 5-24
APPENDICES
A. Windrose, Temperature, and Precipitation Data
B. Site Visit Contact List
Vll
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LIST OF TABLES
TABLE 2-1.
TABLE 2-2.
TABLE 2-3.
TABLE 2-4.
TABLE 2-5.
TABLE 2-6.
TABLE 2-7.
TABLE 3-1.
TABLE 3-2.
TABLE 3-3.
COMPARISON OF PRIMARY AMBIENT AIR QUALITY
STANDARDS BETWEEN MEXICO AND THE U.S
U.S. REFERENCE AND EQUIVALENT METHODS
CHARACTERISTICS OF CIUDAD ACUNA AND PEEDRAS
NEGRAS
MAQUILAS IN CIUDAD ACUNA AND PEEDRAS NEGRAS . .
AMBIENT AIR MONITORING IN CLOSE PROXIMITY TO
ACUNA AND PffiDRAS NEGRAS, YEAR . . . /
ANALYSIS OF HIGH-VOLUME FILTER FOR NONMETALS
AND METALS
ITINERARY FOR SITE VISIT
RELATIONSHIPS AMONG MONITORING OBJECTIVES AND
SCALES OF REPRESENTATIVENESS
MINIMUM TSP/PM10 SAMPLER SITING CRITERIA . . .
MINIMUM SEPARATION BETWEEN ROADWAYS AND
TSP/PMin STATIONS
4o
TABLE 5-1. SUMMARY OF RECOMMENDATIONS
Page
2-3
2-3
2-4
2-8
2-11
2-11
2-18
3-4
3-5
3-5
5-2
Vlll
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LIST OF FIGURES
Figure 2-1. Mexican states and cities containing Maquilas along the
Texas/Mexican border 2-6
Figure 2-2. Categories of Maquilas along the Texas/Mexican border 2-7
Figure 2-3. Typical lead concentrations for Ciudad Acuna 2-12
Figure 2-4. Typical lead concentrations for Piedras Negras 2-13
Figure 2-5. TSP concentrations for monitoring period 1974-84 for Ciudad
Acuna and Del Rio 2-15
Figure 2-6. TSP concentrations for monitoring period 1974-84 for Piedras
Negras and Eagle Pass 2-16
Figure 3-1. Siting checklist for air monitoring stations 3-18
Figure 3-2. Facilities and equipment checklist 3-11
Figure 3-3. Personnel resources checklist 3-12
Figure 3-4. Summary of process by which siting recommendations were
developed 3-13
Figure 5-1. Location of Station No. 1 on top of City Hall, Ciudad Acuna .... 5-4
Figure 5-2. -Location of Station No. 2 on roof of pump house, Ciudad Acuna . . 5-6
Figure 5-3. Location of Station No. 3 at General Electric in industrial
park, Ciudad Acuna 5-8
Figure 5-4. Location of Station No. 4 on top of two-story fire station, Ciudad
Acuna 5-11
Figure 5-5. Location of Station No. 1 on top of City Hall, Piedras Negras .... 5-16
Figure 5-6. Location of Station No. 2 on one-story building at General
Nicholas Bravo School, Piedras Negras 5-18
Figure 5-7. Location of Station No. 3 on top of junior high school building
(later moved 100 meters east), Piedras Negras . . .' 5-20
Figure 5-8. Location of Station No. 4 on one-story building at Conalep
Technical School, Piedras Negras 5-22
IX
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LIST OF PHOTOGRAPHS
Page
Photograph 5-1. Station No. 1 on top of City Hall, Ciudad Acuna 5-5
Photograph 5-2. Station No. 2 on roof of pump house, Ciudad Acuna 5-7
Photograph 5-3. Station No. 3 at General Electric in industrial park,
Ciudad Acuna 5-9
Photograph 5-4. Station No. 4 on top of two-story fire station (right),
Ciudad Acuna 5-12
Photograph 5-5. Station No. 1 on top of City Hall, Piedras Negras 5-17
Photograph 5-6. Station No. 2 on one-story building at General Nicholas Bravo
School, Piedras Negras 5-19
Photograph 5-7. Station No. 3 on top of junior high school building (later moved
100 meters east), Piedras Negras 5-21
Photograph 5-8. Station No. 4 on one-story building at Conalep Technical School,
Piedras Negras 5-23
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EXECUTIVE SUMMARY
During the week of June 17, 1996, two air quality monitoring specialists from
Midwest Research Institute (MRI) visited Ciudad Acuna and Piedras Negras in the State of
Coahuila, Mexico. The purpose of the visit was to assist the two cities in establishing an
ambient air quality monitoring network, using existing equipment to the extent possible.
Equipment and facilities in the two cities were inspected and discussions were held with city
officials. Additionally, existing monitoring station sites were toured and new sites were
identified for locating future monitoring stations.
As a result of this visit, a number of recommendations were developed. These
recommendations are summarized below.
1. Both cities have existing PM10 monitors that represent the latest technology and
are fully functional. The number of PM10 monitors available to each city (i.e., four each) is
adequate. However, several monitors have not been placed at monitoring station locations,
and none of the monitors are currently being operated. The existing monitor locations were
determined to be appropriate, and locations for the remaining monitors are identified in this
report. In evaluating existing monitor locations and selecting new locations, the objective
was to allow air contaminant concentrations in residential and industrial areas to be evaluated
and to measure concentrations both upwind and downwind of the cities.
2. To begin operation of the PM10 monitors, both cities need to be supplied with
quartz fiber filters that have been conditioned, labeled and stored according to established
protocols. In addition, operating manuals, standard operating procedures, data quality
objectives, log books, calibration kits, and a variety of auxiliary equipment are also needed.
Access to the existing monitoring stations needs to be improved. Additionally, facilities for
calibrating and maintaining equipment and meteorological monitoring stations are needed in
ES-1
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each city. The level of training provided to operating personnel by the National Institute of
Ecology is adequate, although Ciudad Acuna should identify and train a second operator as a
back up to the first operator. The number of trained operators in Piedras Negras (i.e., two)
is adequate.
3. As a second priority, it is recommended that both cities monitor SC>2, lead, and
possibly ozone at the same locations as the PM10 monitors, which will require purchasing
monitors and associated equipment and training operators. (An alternative lead monitor
location is discussed in the report.) While additional operators would not be required to
operate this equipment, the total amount of time both operators devote daily to operating and
maintaining the network and to analyzing data would increase, possibly to as much as 8
hours per day. The monitoring of SC>2 is important due to the proximity of the Carbon I and
n electric power plants. The monitoring of lead is important due to the presence of many
older automobiles not having emissions controls and the potential use of unleaded gasoline.
(Lead emissions may also be associated with local steel mill and trash dump burning
operations.) The monitoring of ozone, while not a crucial need, is desirable due to the
presence of ozone precursors (i.e., nitrogen oxides from the power plants and volatile
organic compounds from local factories). An existing SC^ monitor and data logger in
Piedras Negras need repair and associated supplies.
4. The State of Coahuila can play an important role in ensuring successful operation
of the air monitoring networks in Ciudad Acuna and Piedras Negras. In particular, it is
recommended that Coahuila establish a comprehensive quality assurance oversight program
and provide periodic operator training. There may also be some advantage to having
Coahuila coordinate the purchase, preparation, and handling of all monitoring supplies and
equipment and the conditioning and analysis of particulate filters. Finally, it is recommended
that Coahuila be responsible for all coordination with the National Institute of Ecology in
Mexico City. These oversight activities could be conducted by a state air quality
coordinator.
ES-2
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1.0 INTRODUCTION
The Cities of Ciudad Acuna and Piedras Negras and the State of Coahuila in Mexico
are interested in improving ambient air quality monitoring capabilities in the two cities
through the establishment of a network of ambient air monitors. The purpose of the
networks is to characterize population exposure to potentially harmful air contaminants,
possibly including sulfur dioxide (802), nitrogen oxides (NOX), ozone (03), carbon
monoxide (CO), total suspended particulate matter (TSP), paniculate matter with
aerodynamic diameter less than 10 /xm (PM10), and lead. The networks are not intended to
assess other ambient air quality issues, such as toxic air contaminant concentrations or
regional transport phenomena.
This report presents the results of an evaluation of existing air quality monitoring
equipment and facilities in Ciudad Acuna and Piedras Negras. Additionally, the report
presents recommendations for developing an air quality monitoring network for PM10, SO2,
lead, and ozone in these cities, using a combination of both new and existing equipment.
The human resources currently available and ultimately needed to operate and maintain the
network are also discussed.
The report presents background information on the study in Section 2, a discussion of
criteria used to select potential monitoring station locations and equipment in Section 3, site
visit approach and observations in Section 4, and recommendations in Section 5.
Additionally, the Appendix contains information used in support of the study.
1-1
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2.0 BACKGROUND
The Mexico-U.S. border region is typically defined as the region within 100 km of
either side of the 3,200 km international boundary between Mexico and the United States.
Fourteen pairs of twin Mexican/U.S. cities share common airsheds along the border region.
Ciudad Acuna and Piedras Negras are both located within this border region.
Formal cooperation between Mexican and U.S. environmental authorities was
established in 1983 with the La Paz Agreement. In 1992, the Integrated Environmental Plan
for the Mexican-U.S. border area (IBEP) established goals for border environmental quality,
and a follow-up agreement addressing long range plans for border environmental quality is
currently being developed.
The remainder of this section provides a brief description of Mexican and U.S.
regulatory authorities, characteristics of Ciudad Acuna and Piedras Negras, a review of
historical air quality data, the study approach, and the site visit itinerary.
2.1 MEXICAN AND U.S. REGULATORY AUTHORITIES
Environmental protection and restoration in Mexico has been mandated by
constitutional provisions under a General Law of Ecological Equilibrium and Environmental
Protection. The law is implemented following six titles, as follows: Title I-General
Provisions, Title H-Protected Natural Areas, Title IE-Rational Use of Natural Elements, Title
IV-Environmental Protection, Title V-Public Participation, and Title VI-Measures for
Control, Safety, and Sanctions.
Title I-General Provisions regulates authority among local, state, and federal
governments. The Secretaria de Desarrollo Social (SEDESOL) has been charged with
responsibility for federal environmental enforcement as of May 25, 1992. Two main
agencies constitute SEDESOL: (1) the Institute Nacional de Ecologia (INE), which is
2-1
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responsible for establishing environmental policy and administering regulations and (2) the
Procuraduria Federal de Proteccion al Ambiente, which is responsible for enforcing
environmental regulations.
Title IV-Environmental Protection regulates seven general categories of environmental
protection. Air pollution is covered in the first category, which prescribes the control of air
pollution and the classification of static and dynamic emission sources. State and local
governments have jurisdiction over air emissions, and regulations governing air pollution
control require industries planning to release emissions to the atmosphere to obtain an
operational license. The development of air quality standards is under the authorization of
the Federal Law of Measurement and Standards, dated July 1, 1992. INE's Bureau of
Environmental Standards develops air quality standards and provides regulatory guidance for
the sampling and analytical methodology necessary to carry out air monitoring.
The U. S. Environmental Protection Agency (EPA), under authorization of the Clean
Air Act and its amendments, has promulgated primary and secondary national ambient air
quality standards (NAAQS). (Whereas primary standards are intended to provide for the
immediate protection of public health, secondary standards provide for public welfare.)
Primary standards for the United States are presented in Table 2-1 and compared with the
similar Mexican standards.
Air quality monitoring data in the United States are used to determine if an area
attains the NAAQS and to evaluate air pollution control strategies. Consequently, the
NAAQS and associated ambient air monitoring networks provide a means of assessing and
evaluating compliance with regulatory limits within a defined geographical area. Reference
methods have been prescribed to monitor NAAQS pollutants using uniform sampling and
analytical techniques. Table 2-2 identifies the reference and equivalent methods for the six
NAAQS pollutants listed in Table 2-1.
2.2 CHARACTEPJSTICS OF CIUDAD ACUNA AND PDEDRAS NEGRAS
Characteristics of Ciudad Acuna and Piedras Negras are summarized in Table 2-3.
Both cities are moderately sized, and while neither city has any large industries, both have a
number of small- to medium-sized factories and shops. Additionally, both cities are subject
2-2
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TABLE 2-1. COMPARISON OF PRIMARY AMBIENT AIR QUALITY
STANDARDS BETWEEN MEXICO AND THE U.S.
Pollutant
PM10
TSP
SO2
0,
NO2
CO
Pb
Mexico
Standard
150 /ig/m3
50 jig/m3
260 /ig/m3
75 jig/m3
0.13 ppm
0.03
0.11 ppm
0.21 ppm
11 ppm
~
j
1.5 /xg/mj
Average
24 hr
Annual arithmetic
mean
24 hr
Annual arithmetic
mean
24 hr
Annual arithmetic
mean
Ihr
1 hr
-
8hr
3 month
United States
Standard
150 /ig/m3
50 /tg/m3
0.14 ppm
0.03 ppm
0.12 ppm
0.25 ppm
0.053 ppm
9 ppm
35 ppm
1.5Mg/m3
Average
24 hr
Annual arithmetic
mean
24 hr
Annual arithmetic
mean
1 hr
1 hr
Annual arithmetic
mean
8hr
1 hr
3 month
TABLE 2-2. U.S. REFERENCE AND EQUIVALENT METHODS
Pollutant
TSP
PM10
Lead
S02
0,
NO9
CO
Method
High-volume sampler (manual)
High-volume sampler (manual)
Beta-gauge microbalances (automated)
High-volume sampler with atomic absorption (manual)
Pararosaniline method (manual)
Fluorescence spectroscopy (automated)
Chemiluminescence with ethylene (automated)
Chemiluminescence with ozone (automated)
Nondispersive infrared spectroscopy (automated)
2-3
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TABLE 2-3. CHARACTERISTICS OF CIUDAD ACUNA AND PEEDRAS NEGRAS
City
Location
Population
Industry
Major sources
and pollutants
Prevailing winds
Land Use
Other facts
Ciudad Acuna
In the State of Coahuila, near the U.S.
border, about 2 km south of Del Rio,
Texas
87,000
Automobile wiring, seat covers, water
bottling, and fishing lures
No major sources; however, a number of
smaller industries are believed to emit
VOC's; considerable fugitive dust from
unpaved roads and dry lands surrounding
the city; local dump burns trash and tires
Generally from the S to ESE; occasion-
ally from the N to NNE; winds are calm
about 8% of the time
Housing: 53 %
Industry: 22%
Agriculture: 21%
Roads: 4%
Area: 26 km2 (10 mi2)
Avg. temp.: 21.5°C(71CF)
Avg. rainfall 51.5 mm (2")
per month:
Elevation: 220 meters
No. of vehicles: 12,000
Piedras Negras
In the State of Coahuila, near the U.S.
border, about 5 km south of Eagle
Pass, Texas
98,185
Recycling steel mill, small motor
manufacturing, electrical components
Steel recycling mill with large storage
piles; large electric utility power plants
located 30 km south of the city;
considerable fugitive dust from unpaved
roads and dry lands surrounding the
city
Generally from the S to ESE;
occasionally from the N to NNE; winds
are calm about 8 % of the time; winds
reportedly from the SE at night
Housing: 50%
Industry: 7%
Agriculture: 16%
Roads: 13%
Other: 14%
Area: 36 km2 (14 mi2)
Avg. temp.: 21.5°C (71°F)
Avg. rainfall 51.5 mm (2")
per month:
Elevation: 250 meters
No. of vehicles: 20,000
2-4
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to periodic episodes of wind-blown dust, originating from unpaved roads and dry lands
surrounding the cities.
Both cities contain numerous "Maquilas," otherwise known as the "Maquiladoras," or
"Twin Plants." These industrial facilities were originally established by the Mexican
government in 1966 under the Border Industrialization Program. This program was
commissioned in Mexico to assist in providing employment for Mexican workers along the
U.S. border, thereby alleviating the unemployment resulting from termination of the Bracero
Program and international competition from Asian manufacturing. In the early 1980's, the
Mexican government provided special economic opportunities and incentives for foreign
companies to establish facilities along the Mexico-U.S. Border region; Ciudad Acuna and
Piedras Negras participated in this program.
The total number of foreign owned plants in the region grew steadily from the early
1980's to an estimated 2,000 facilities by 1996 in the States of Chihuahua, Coahuila, Nuevo
Leon, and Tamaulipas, as illustrated in Figure 2-1. Maquila activities are as diverse as the
two countries that participate in the program, ranging from assembly of finished products to
the production of feedstocks and parts for the automobile industry. As illustrated in
Figure 2-2, over 30 percent of the facilities assemble, rebuild, or construct materials
associated with electronic components. These facilities have the potential to emit a wide
range of substances, both organic and inorganic, that can affect air quality locally as well as
regionally. Table 2-4 lists the major Maquilas with employment greater than 100 workers
and their associated air pollutant category for both Ciudad Acuna and Piedras Negras.
Sources of emissions for the two cities are summarized below, by pollutant type.
SC*2. Results largely from coal and oil combustion sources, refineries, pulp and
paper mills, and nonferrous smelters. Ciudad Acuna and Piedras Negras lack major
stationary emission points as sources of SC^. Additionally, home heating is minimum, with
few combustion furnaces. The only major SC^ point sources in the region are the Carbon I
and n power plants. Carbon I and n comprise a complex of coal-fired electric generating
stations approximately 30 km south of Piedras Negras on Highway 57. These power plants
are considered "mine-mouth" operations because they are located at the site of Mexico's only
known commercial coal deposits. Carbon I, a 1,200 megawatt (Mw) power plant consisting
2-5
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GULF OF MEXICO
LEGEND:
1. El paso (C'rty)/Juarez
2. El Paso (County)
3. Fort Davis
4. Alpine
5. Del Rio/Acuna
6. Eagle Pass/Piedras Negras
7. Laredo/Nuevo Laredo
8. Hidalgo County
9. McAllen/Reynosa
10. Weslaco
11. Santa Maria
12. Harlingen
13. SanBenrto
14. Brownsfille/Matamoros
Figure 2-1. Mexican states and cities containing Maquilas along the Texas/Mexican border.
2-6
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Categories of Maquilas on the
Texas-Mexico Border
CATEGORY (% of facilities)
II (16.3)
111(19.1)
1(3.3)
XII (13.6)
XI (8.4)
IV (10.1)
V (4.4)
VI (3.3)
""t.r
VII (1.1)
X(7.9)
VIII (10.6)
IX (19.1)
I. Electronic material accessories
II. Assembly of electrical electronic machinery, equipment, & goods
III. Construction, rebuilding, assembly of transport equipment and accessories
(V. Textiles and wearing apparel
V. Assembly of metalic & wooden furniture accessories
VI. Services
VII. Toys and sporting goods
VIII. Assembly of equipment tools and parts (non-electrical)
IX. Shoes and leather goods
X. Food processing
XI. Chemical products
XII. Other manufacturing and assembly products
Figure 2-2. Categories of Maquilas along the Texas/Mexican border.
2-7
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TABLE 2-4. MAQUILAS IN CIUDAD ACUNA AND PIEDRAS NEGRAS
Industry
Product
Potential air
pollutants
CIUDAD ACUNA/DEL RIO
1. A. D. Smith Electrical
2. ALCOA Fujikura
3. Allied Signal Automotive
4. Border Opportunity Saver Systems
5. Carolina Coupon
6. Douglas & Lomason
7. Eagle Picher Construction
8. Gateway Safety Systems
9. General Electric
10. Irvin Automotive Products
11. N.S.C. Electronics
12. SASofDelRio
13. Sunbeam Products
Hermetic motors
Wiess harnesses
Compressors, dryers
Diapers, cotton balls
Commercial coupons
Automotive seat covers
Welded steel parts
Seatbelts
Wiring devices
Trim products
Test equipment
Shoes
Blenders
VOCs
VOCs
VOCs
PM10/VOCs
VOCs
VOCs
PM,0/VOCs
PM10/VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
PIEDRAS NEGRAS/EAGLE PASS
1. Alamo Lumber
2. Eagle Broom
3. Maverick Arms
4. Newell Recycling
5. Texas Apparel
6. Williamson-Dickie Company
Building materials
Brooms
Pump shotguns
Metal recycling
Work apparel
Jeans
PM10
PMIO
VOCs
PMIO
PM10 -"
VOCs/PMjo
2-8
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of four separate 300 Mw units, has been generating electricity since the early 1980's, with
the fourth unit coming on line in late 1986. Carbon n is a 1,400 Mw plant consisting of
four 350 Mw units, with only two of the four units currently on-line. Carbon I and n
represent approximately 9 percent of Mexico's power generating capacity, with a total coal
consumption of 8 million tons annually. Both plants have paniculate emission control
devices on the operating units, but lack SC>2 emission controls. Prevailing winds in the
region from the southeast have the potential to transport Carbon I and n SC>2 emissions in
the general direction of Ciudad Acuna and Piedras Negras.
CO. A colorless, odorless, and toxic gas produced by incomplete burning of carbon
in fuels. Nearly two-thirds of all emissions of CO are from transportation sources.
Consequently, the highest concentrations often occur along busy roads. Ciudad Acuna and
Piedras Negras have a number of automobiles operating in relatively small geographical
areas. Also, many of the automobiles are older models that are generally less efficient
combustors, thereby creating greater CO emissions than new models.
NOX. Emitted almost entirely from fuel combustion sources; only a limited number
of industrial processes emit NOX. A small fraction of total NOX emissions consist of NC^,
and most of the N©2 found in the atmosphere results from atmospheric oxidation of NO to
NO2- (When ozone is present, the oxidation of NO to N02 proceeds rapidly.) Major NOX
sources are not present in either Ciudad Acuna or Piedras Negras. However, NOX transport
into the cities from the Carbon I and n plants is a possibility.
Oj. Not directly emitted into the atmosphere, but results from a complex
photochemical reaction involving organic compounds, NOX, and sunlight. The buildup of
ozone oxidants tends to be rather slow and occurs over relatively large areas. Peak'bzbne
concentrations normally occur several kilometers downwind of industrial areas. Ozone
concentrations are expected to be relatively low within the city limits of both Ciudad Acuna
and Piedras Negras due to constant winds, low NOX emissions, and the occurrence of
organic compound emissions from manufacturing facilities generally sited near city
perimeters. While ozone may be present in the two cities, no ozone monitoring data
currently exist.
2-9
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TSP/PM10. Paniculate matter is a broad class of airborne liquid and solid substances
that varies greatly in chemical and physical properties. There are two distinct types of
particulate emissions: coarse and fine particles. Coarse particles (2.5 microns to 10 microns
in diameter) generally make up most of the total particulate mass and include particles
formed by anthropogenic processes and reentrained surface dust. Fine particles (less than
2.5 microns) usually result from combustion processes, including the condensation and
atmospheric transformation of exhaust gases to particles. Pollutants that contribute to fine
particle formation include sulfates, nitrates, condensable organics, ammonium, and lead.
Because Ciudad Acuna and Piedras Negras are located in dry areas with minimal rainfall,
wind-entrained dust can be problem. Local industries and automobiles also contribute to
particulate concentrations in the atmosphere.
Pb. A major source of lead is the use of unleaded gasolke in automobiles. Unleaded
gasoline has been phased out in Piedras Negras, but may still be used in Ciudad Acuna.
Industrial sources of lead also may be present in the two cities (e.g., the burning of city
dump trash in Ciudad Acuna and a steel recycling mill in Piedras Negras), although
emissions from these sources may be minor.
2.3 REVIEW OF HISTORICAL AIR QUALITY DATA
Various ambient air monitoring studies have been conducted over the past 25 years in
both Ciudad Acuna and Piedras Negras, although the majority of the data have been
validated only during the last 17 years. Sources for these data include the Texas Natural
Resource Conservation Commission (TNRCC), the El Paso City-County Health Department,
the State Government of Coahuila, and the EPA.
The first ambient air monitoring performed along the boarder was conducted by the
U.S. Public Health Service (PHS), starting in 1954, as part of their National Air Sampling
Network. In 1957, the El Paso City-County Health Department began monitoring for TSP,
and later in 1957, the TNRCC (then called Texas Air Control Board) began a sampling
program along its 1,600 km boarder. Most collected data involve monitoring for TSP and
metals and continuous monitoring for S02- However, as identified in Table 2-5, other
analytes also have been monitored in close proximity to Ciudad Acuna and Piedras Negras
over the past 25 years using a variety of methodologies. The quality of these data varies
2-10
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from excellent for TSP to fair for SC^. Early data suffered from lack of quality control
procedures, which where not initiated until the mid-70's.
TABLE 2-5. AMBIENT AIR MONITORING IN CLOSE PROXIMITY TO
ACUNA AND PffiDRAS NEGRAS, YEAR
Ambient Air Monitoring
Location
1. Del Rio, -DC
(near Ciudad Acuna)
2. Eagle Pass, TX
(near Piedras Negras)
Pollutant
TSP S04= N03'
Other,
Including
Pb Metals
Year
1975-1984 1975 1975
1971-1984 1973-1976 1973-1976
1975-1984 1975-1984
1973-1976 1973-1976
As identified in Table 2-6, monitoring often involved TSP evaluation with subsequent
analysis for metals and nonmetals captured on the high volume filter. However, review of
the data indicates that, except for Pb, metals were generally not detected during the
monitoring periods identified in Table 2-5.
TABLE 2-6. ANALYSIS OF HIGH-VOLUME FILTER FOR
NONMETALS AND METALS
Nonmetals
TSP, SQ4> NO3> benzene soluble organics (BSO)
Metals
NAAQS Metal: Pb
Other Priority Metals: As, Cd, Cr
Intermediate Metals: Co, Hg, Mn, Ni, Sb, Sn
Rare Earth Metals: Be, La, Sr, V, Co, Mo, Ti, Ge, Rb, Tl
Naturally Occurring Metals: Al, Cu, Ba, Si, Fe, Se, Br, I, Ca, K, Zn, Cl, P
Figures 2-3 and 2-4 illustrate lead concentrations for Ciudad Acuna and Piedras
Negras, respectively, for the 1976-77 monitoring period. The Mexico air quality standard
for lead is 1.5 micrograms per cubic meter for a 3-month average. With respect to TSP
2-11
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1976-77 Lead Data for Acuna
NJ
H-l
K)
CO
1.6-
1.5-
1.4-
1.3-
1.2-
1.1-
1-
0.9-
0.8-
0.7-
0.6-
0.5-
0.4-
0.3-
0.2-
0.1-
0-
INE Standard
3 5 7'9
2468
Month
i Figure 2-3. Typical lead concentrations for Ciudad Acuna.
11
10 12
(torn: ShMdi. 1991
-------
to
1.6-
1.5-
1.4-
1.3-
1.2-
1.1-
1-
co
t
0.7-
0.6-
0.5-
0.4-
0.3-
0.2-
0.1-
o-
1976-77 Lead Data for Piedras Negras
INE Standard
2468
Month
' Figure 2-4. Typical lead concentrations for Piedras Negras.
11
10 12
from: Shhtdi. 1991
-------
concentrations, Figures 2-5 and 2-6 illustrate a 10-year period of monitoring in Ciudad
Acuna and Piedras Negras. The national TSP standard for that period was 75 micrograms
per cubic meter based on an annual geometric mean and 150 micrograms per cubic meter
based on a maximum 24-hour concentration, not to be exceeded more than once per year.
Both Ciudad Acuna and Piedras Negras are located near the southwest Texas border.
Elevations are near 220 to 250 meters, the climate is semi-arid continental, and annual
precipitation is insufficient for dry farming, averaging 19.6 inches per year. Over 80 percent
of the average annual precipitation occurs from April through October. During this period,
rainfall is chiefly in the form of showers and thunderstorms. The small amount of
precipitation occurring in November through March usually falls as steady light rain.
Temperature averages indicate mild winters and hot summers. Cold periods in winter
are ushered in by strong, dry, dusty north and northwest winds known as northers. During
the summer, winds are generally out of the southeast, as illustrated by the windrose in
Appendix A for San Antonio, Texas, for 1992 and wind data from Del Rio, Texas, from
1969 to 1984. Hot weather persists from late May to mid-September, and temperatures
above 100°F (38°C) have been recorded as early as March and as late as October. The
mean early-morning humidity is about 79 percent, and the mean afternoon humidity is near
44 percent. Clear to partly cloudy skies predominate, and even during the more cloudy
winter months, the mean number of cloudy days is less than the mean number of clear days.
2.4 STUDY APPROACH
The first step in conducting the study was to review available information about the
two cities, including maps, emission inventories, and meteorological and air quality data.
Based on this initial review, preliminary decisions were made about potential monitor
locations.
The second step was to review all relevant technical references for information
regarding the procedures and criteria for selecting monitor locations for the pollutants of
interest. As part of this review, three checklists were prepared to help evaluate facilities and
2-14
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1974-84 TSP Data
for Acuna & Del Rio
---Acuna -*- Del Rio ** «*o«
Figure 2-5. TSP concentrations for monitoring period 1974-84 for Ciudad Acuna and Del Rio.
-------
to
300-
280-
260-
240-
220-
200-
180-
160-
140-
120-
100-
80-
60-
40-
20-
0-
i
74
1974-84 TSP Data
for Piedras Negras & Eagle Pass
INE Standard
i
76
75
i
77
i
78
80
79
Year
~r~
81
82
i
83
r~
84
-«- Piedras Negras -Ar Eagle Pass >rom: SWeW»-1991
Figure 2-6. TSP concentrations for monitoring period 1974-84 for Piedras Negras and Eagle Pass.
-------
equipment, assess the availability of the human resources required to operate and maintain a
monitoring network, and guide the evaluation of specific candidate monitor locations.
Finally, a 5-day site visit to Ciudad Acuna and Piedras Negras was conducted by two
senior air quality specialists. The purpose of the site visit was to evaluate existing equipment
and procedures, assess human resource needs, and develop recommendations for improving
existing monitoring stations and the siting of new stations. During the visit, considerable
time was spent meeting with local officials; studying topographical, meteorological, and
population data; evaluating existing equipment; and touring existing and potential monitoring
sites. Detailed discussions were held with local officials regarding their air monitoring needs
and associated human resource requirements.
Upon returning from Ciudad Acuna and Piedras Negras, the recommendations
presented in Section 5.0 were developed for improving existing equipment and procedures
and for establishing the air quality monitoring networks. In developing these
recommendations, the authors were guided by the following objectives:
Existing equipment and monitor locations should be used to the extent practicable.
The purchase of new equipment, although probably necessary, should be limited.
Only those pollutants believed to contribute to air quality degradation need be
monitored.
The level of training and availability of staff for operating and maintaining the
networks and analyzing data need to be considered.
Based upon these considerations, recommendations were formulated that allow for the
assessment of air quality within the cities while minimizing any unnecessary costs.
2.5 SITE VISIT ITINERARY
The site visit was conducted from June 17 through 21, 1996, by two air quality
monitoring specialists from Midwest Research Institute (MRI): Messers. Lance Henning and
Jerry Winberry. The itinerary for the visit is summarized in Table 2-7, and a list of
Mexican officials participating in the study, including their addresses and telephone numbers,
is provided in Appendix B.
Messrs. Henning and Winberry first traveled to Ciudad Acuna, where they met with
officials from the City and the State of Coahuila. Additionally, they were accompanied
2-17
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TABLE 2-7. ITINERARY FOR SITE VISIT
Date
Activity
June 17 (Monday)
Noon arrival at Del Rio, Texas, airport
Meeting with representatives of Coahuila and Ciudad
Acuna at airport; drive over border to Ciudad Acuna
Tour of Ciudad Acuna and investigation of potential
monitoring sites
June 18 (Tuesday)
Meeting with Ciudad Acuna administrative officials and
technical staff
Acquire additional data associated with emission
inventories, meteorological and topographical
information, and human resources
Continue investigation of potential monitoring sites
June 19 (Wednesday)
Morning: Conclusion of survey of potential Ciudad
Acuna monitoring sites and travel to Piedras Negras
Afternoon: Meeting with Piedras Negras administrative
and technical staff
June 20 (Thursday)
Investigation of potential monitoring sites in Piedras
Negras
Acquire additional data associated with emission
inventories, meteorological and topographical
information, and human resources
June 21 (Friday)
Conclusion of potential monitoring sites survey in Piedras
Negras
Return to Del Rio for mid-afternoon departure
2-18
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during part of the trip by Ms. Maria Rodriguez of the TNRCC. Over the 2'/2-day period in
Ciudad Acuna, Messrs. Henning and Winberry conducted several meetings, visited two
existing PM10 monitoring sites, inspected two uninstalled PM10 monitors and meteorological
equipment, and visited potential sites for locating additional monitors. Additionally, they
met with the Mayor to discuss the objectives of the study.
During the remainder of the week, Messrs. Henning and Winberry traveled to Piedras
Negras, where they met with the Mayor and other officials from the City and the State of
Coahuila and Ms. Rodriguez of the TNRCC. Activities included visits to four existing PM10
monitoring sites, inspection of a data logger and S02 monitor, and review of a recent
government report containing particulate monitoring data and an emissions inventory for the
city.
2-19
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3.0 CRITERIA FOR DESIGNING AIR MONITORING NETWORK
3.1 INTRODUCTION
Before decisions could be made regarding recommended monitoring station locations,
it was necessary to develop a clear understanding among all parties of the purpose of the
network. The primary objectives for establishing air quality monitoring networks in the
cities of Piedras Negras and Ciudad Acuna were to characterize urban air contaminant
concentration, and to do so in a cost-effective manner, using available monitoring equipment
to the extent practicable. The data collected by the networks will be useful for assessing
exposure levels for residents and workers, trends in city-wide air quality, and the
effectiveness of any future air pollution control strategies.
It is important to note that the air monitoring networks are not intended to
characterize localized neighborhood concentrations, concentrations in close proximity to
major point-sources, mobile source impacts, urban plumes, regional concentrations, air
toxics, or ozone precursor concentrations, or to define the extent to which urban
concentrations can be attributed to regional transport phenomena. However, depending on
the locations ultimately selected for siting the monitoring stations, some characterization of
the above phenomena may still be feasible.
3.2 SITE SELECTION CRITERIA
Once the purpose of the networks was defined, the next step was to develop the
general criteria for siting the monitors. Although final locations necessarily depend upon
observations made during the site visit, priorities for monitor siting were determined
beforehand to serve as guidance during the site visit.
3-1
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Selecting the appropriate site is one of the most important tasks associated with
monitoring network design, as it must be the most representative location to monitor air
quality conditions. General siting requirements are identified in Appendix D of the U.S.
Code of Federal Regulations (40 CFR 58). These requirements help classify sites by their
intended objective and spacial scale of representativeness. More specific guidelines are
delineated in the following EPA documents:
Site Selection for the Monitoring of Photochemical Air Pollutants, USEPA, Office
of Air Quality Planning and Standards, Research Triangle Park, NC,
EPA-600/7-88-022.
Ambient Monitoring Guidelines for Prevention of Significant Deterioration (PSD),
USEPA, Office of Air Quality Planning and Standards, Research Triangle Park,
NC, EPA-450/2-77-010.
Network Design and Optimum Site Exposure Criteria for Paniculate Matter,
USEPA, Office of Air Quality Planning and Standards, Research Triangle Park,
NC, 1983.
Network Design for State and Local Air Monitoring Stations (SLAMS) and
National Air Monitoring Stations (NAMS), USEPA, Office of Air Quality
Planning and Standards, Research Triangle Park, NC, Code of Federal
Regulations, Title 40, Part 58, Appendix D, 1990.
Network Design and Site Exposure Criteria for Nonmethane Organic
Hydrocarbons, USEPA, Office of Air Quality Planning and Standards, Research
Triangle Park, NC, SYSAPP-89/138, 1989.
The basis for monitor site selection is to match each site-specific monitoring objective
to an appropriate scale of spatial representation and then to choose a monitoring location that
is characteristic of that spatial scale. Six spatial scales are commonly applied to siting-air
pollution monitoring systems: microscale, middle scale, neighborhood scale, urban scale,
regional scale, and global scale. To better understand the spatial scale setting and its
relationship to network design, a brief description of each of the scales is provided below.
Microscale Scale. Ambient air volumes with dimensions ranging from several
meters to approximately 100 meters are associated with this scale (e.g., ozone,
CO, and NOX). For gaseous monitors, this scale is used to evaluate the
distribution of the gas within the plume either over flat or complex terrain or
within building wake cavities. For total suspended paniculate (TSP) and PMj0
monitoring, this scale is used to characterize emissions from close proximity
point sources. This type of scale might also be used to define health effects for
3-2
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certain individuals, such as policemen, who remain near a fixed location for
extended periods.
Middle Scale. This scale represents dimensions from about 100 meters to 0.5
kilometers and characterizes air quality in areas up to several city blocks in size.
Some data uses associated with middle scale measurements for both gaseous and
TSP/PMi0 include assessing the effects of control strategies to reduce urban
concentrations and monitoring air pollution episodes.
Neighborhood Scale. Neighborhood scale measurements characterize conditions
over areas with dimensions of 0.5 km to 4 km. This scale applies in areas where
the gaseous and TSP/PM10 concentration gradient is relatively flat (i.e., mainly
suburban areas surrounding the urban center) and in large sections of small cities
and towns. In general, these areas are homogeneous in terms of concentration
profile. Neighborhood scale measurements may be associated with baseline
concentrations in areas of projected growth and in studies of population responses
to exposure to pollutants (i.e., health effects). Also, concentration maxima
associated with air pollution episodes may be reasonably uniformly distributed
over areas of neighborhood scale, and measurements taken within such areas
represent neighborhood as well as middle scale concentrations. Finally, this scale
is used for intemeighborhood comparisons within or between cities. This scale
also meets most of the objectives of city and regional planners and decision-
makers.
Urban Scale. Urban scale measurements characterize conditions over an entire
metropolitan area. Such measurements are useful for assessing trends in city-
wide air quality, and hence, the effectiveness of larger-scale pollution control
strategies. Measurements that represent city-wide areas also serve as a valid
basis for comparisons among different cities.
Regional Scale. Conditions over areas with dimensions of as much as hundreds
of kilometers are represented by regional scale measurements. These
measurements are applicable mainly to large homogeneous areas, particularly
those sparsely populated. Such measurements provide information on background
air quality and interregional pollution transport.
Global Scale. This measurement scale represents concentrations characterizing
the globe as a whole. Such data are useful in determining pollutant trends,
studying international and global transport processes, and assessing the effects of
control policies on global scale.
With any monitoring network design, each spatial scale is designed to meet specific
monitoring objectives. The specific objectives for most air monitoring network designs are
to determine (1) the highest concentrations expected to occur in the area covered by the
3-3
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network, (2) the representative concentrations in areas of high population density, (3) the
impact on ambient pollutant levels of significant sources or source categories, and (4) the
general background concentration levels. The goal in siting air monitoring stations is to
correctly match the spatial scale most appropriate for the monitoring objective of that station.
Table 3-1 illustrates the relationship between these four basic monitoring objectives and the
scales of representativeness that are generally most appropriate for that objective.
TABLE 3-1. RELATIONSHIPS AMONG MONITORING OBJECTIVES AND
SCALES OF REPRESENTATIVENESS
Monitoring Objective Appropriate Siting Scales
Highest Concentration Micro, Middle, and Neighborhood (sometimes
Urban)
Population Neighborhood, Urban
Source Impact Micro, Middle, and Neighborhood
General Background Neighborhood
3.3 PROBE PLACEMENT CRITERIA
Once the monitoring objectives of the sites have been well defined, the placement of
the monitors at the sites must be determined based on specific probe siting criteria.
Guidelines are given in 40 CFR 58, Appendix E, for probe siting after the general station
location has been selected. Adherence to the siting criteria is necessary to ensure the
uniform collection of compatible and comparable air quality data. As summarized in
Tables 3-2 and 3-3, the probe siting criteria address horizontal and vertical probe placement
and spacing from obstructions, trees, and roadways. Tables 3-2 and 3-3 are specific-to-
TSP/PM10 sampling. However, more general guidelines for all pollutants are summarized
below.
Vertical and Horizontal Probe Placement. The height of the inlet probe or
monitor should be as close as possible to the breathing zone and 3 to 15 meters
above ground level. A minimum separation distance of 2 meters between the
inlet probe or monitor and any walls, parapets, penthouses, etc. is required for
probes located on roofs or other structures. In addition, probes or monitors
should be located far from any furnace or incineration flues.
3-4
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TABLE 3-2. MINIMUM TSP/PM10 SAMPLER SITING CRITERIA
Scale
Micro
Middle, neighborhood, urban, and regional
scale
Height Above
Ground, meters
2 to 7
2 to 15
Distance From Supporting
Structure, meters
Vertical
~
Horizontal8
>2
>2
Other Spacing Criteria
1. Should be >20 meters from trees.
2. Distance from sampler to obstacle, such buildings, must be twice the height the obstacle protrudes
above the sampler.
3. Must have unrestricted airflow 270° around the sampler inlet.
4. No furnace or incineration flues should be nearby.
5. Spacing from roads varies with traffic (see Table 3-3 and 40 CFR 58, Appendix E).
6. Sampler inlet should be at least 2 m but not greater than 4 m from any collocated PM10 sampler
(see 40 CFR 58, Appendix A).
aWhen inlet is located on rooftop, this separation distance is in reference te> walls, parapets, or penthouses
located on the roof.
TABLE 3-3. MINIMUM SEPARATION BETWEEN
ROADWAYS AND TSP/PM10 STATIONS
Average Daily Traffic
(vehicles/day)
Minimum Separation
Distance
(meters)
< 10,000
15,000
20,000
40,000
70,000
>110,000
20
30
50
100
>250
3-5
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Spacing from Obstructions. The probe or monitor must be located away from
obstacles and buildings such that the distance between any obstacle and the inlet
probe or monitor is at least twice the height that the obstacle protrudes above the
sampler. An unrestricted airflow in an arc of at least 270° must exist around the
inlet probe or monitor. If the probe is located on the side of a building, a 180°
clearance is required.
Spacing from Roads. Motor vehicle emissions constitute a major source of
paniculate, lead, and volatile organics emissions. Therefore, a minimum
separation distance between roadways and monitoring sites must be maintained so
valid data can be acquired. Table 3-3 provides the required minimum separation
distances from roadways for various traffic volumes when monitoring for
TSP/PM10. The minimum separation distance also must be maintained between
the sampling station and other areas of automotive traffic, such as parking lots.
Spacing from Trees. Trees can provide surfaces for adsorption and/or reactions
and can affect normal wind flow patterns. To limit these effects, probe inlets or
monitors should be placed at least 20 meters from the dripline of any trees.
Similar to pollutant monitors, meteorological stations collocated with paniculate
and/or gaseous monitors should be located so that the measurement data are representative of
the meteorological conditions that affect pollutant transport and dispersion within the
monitoring site area. Meteorological stations should meet the same siting criteria as the
pollutant monitors and should be located away from the immediate influence of trees,
buildings, steep slopes, ridges, cliffs, and hollows on wind patterns.
3.4 MONITOR LOCATION PRIORITY
Based on the guidelines in 40 CFR 58, Appendix D, the first priority for siting
monitors in Ciudad Acuna and Piedras Negras was to locate at least one station in a
residential area, where many individuals receive 24-hour exposure and where sensitive
populations (e.g., children and the elderly) and schools are located. The second priority was
to establish a monitoring station in an industrial and/or business area, where exposure levels
are probably higher than in residential areas, but where worker exposure to these higher
levels occur for fewer hours per day. The third priority was to locate a monitor near the drv
center to characterize combined emissions from all sources on a city-wide air quality basis.
The final priority was to site a monitoring station upwind (i.e., in the southeast) of each city,
thereby allowing background concentrations to be measured.
3-6
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During the site visit, the above siting criteria were used in combination with other
site-specific information to develop recommendations about specific monitoring sites.
Background information related to factors such as climate, topography, and population
distribution was evaluated. Additionally, to guide the collection and evaluation of site-
specific information, a number of technical references on monitor siting and operation were
reviewed, as identified in Section 3.2. Checklists were then prepared to facilitate the site
inspections.
The first checklist was designed to assist in the evaluation of potential monitoring site
locations by highlighting factors that are crucial to monitoring siting decisions, including:
If the location will allow a representative sample to be collected, including
average or typical concentrations in the areas of interest.
If the site is subject to potential monitoring interferences or unusual
micrometeorological conditions.
If there is adequate road access, electric power, and accessibility to the monitors.
If inlet orientation and placement criteria can be met with regard to separation
from nearby obstacles and roadways, unrestricted airflow, distance above ground
level and from tree driplines, distance above the instrument shelter, and ground
elevation.
If the site can be made secure from vandalism.
This checklist is presented in Figure 3-1.
The second checklist, presented in Figure 3-2, was designed to assist with inspection
of the monitoring equipment and any laboratory facilities and to determine the availability of
required equipment and materials. Example items include:
Which instruments are in operating condition or require repair?
Are operating instructions, calibration procedures, and associated monitoring
supplies, materials, and equipment available?
Is laboratory space available for equipment set-up, calibration, and maintenance?
And if so, what supplies and facilities are included in the laboratory?
The third checklist (see Figure 3-3) was designed to assist with the assessment of
personnel resources available to operate and maintain the equipment and analyze the data.
3-7
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SITING CHECKLIST FOR AIR MONITORING STATIONS
D Measurements to be made at this site (NOX, S02, 03, CO, Pb, PM10/2.5,
meteorological parameters)
D Description of site (e.g., surface material, surrounding terrain, nearby
obstructions, road access, and any unusual features)
D Is the general location representative of a priority exposure scenario? For
example:
D Residential areas, schools, sensitive populations
D Business or industrial areas
D Downwind location near city limits (especially for ozone measurements)
D Upwind location near city limits (for background measurements)
D Is the site sufficiently distant from emissions sources having the potential to cause
bias or interference? For example:
D Point sources:
D Manufacturing facilities
D Refineries
D Power plants
D Other
D Area sources:
D Fugitive dust
D Agricultural chemical application
D Roadways (criteria for locating monitors away from roadways is
attached; also see Table 3-3).
Figure 3-1. Siting checklist for air monitoring stations.
3-8
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D Is there any reason to believe that unusual micrometeorological conditions could
bias results (especially for particulates)?
D Is the site appropriate for determining average or typical concentration levels for
the required averaging period? For example:
D Gases (NOX> SO2, CO)
D Ozone (taking into account time of day and wind direction when
photochemical reactivity is greatest)
D Paniculate (PM10/2.5 and lead)
D Is road access adequate?
D Are electric power and data transmission lines available?
D Can the location be made secure with respect to vandalism?
D Are there any nearby buildings, trees, terrain features, or other obstructions that
would alter flow patterns or serve as sinks or reactive surfaces? For example:
D Can the inlet locations be separated from nearby obstacles by 2 to 3 times the
height of the obstacle above the inlet?
D Can unrestricted airflow (at least 270°) be provided around the inlet probe?
D For ozone measurements, can the monitor be located on a small hill to
minimize surface destructive processes? Can low-lying areas be avoided?
D For particulate measurements, is the site at least 20 meters away from the
dripline of trees?
D Can the inlets be located 3 to 15 meters above ground level (ideally as close as
possible to the breathing zone, but high enough to discourage vandalism)? (For
particulate, specified level is 2 to 15 meters.)
D Can the inlets be positioned 1 to 2 meters above the instrument shelter (at least
2 meters for particulate measurements)? Can inlets that protrude from the shelter
walls be avoided?
Figure 3-1. (continued)
3-9
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D Are the following criteria for minimum distance from roadway to monitor
location met:
Roadway average daily
traffic (vehicles per
day)
^.10,000
15,000
20,000
30,000
40,000
50,000
_>60,000
70,000
>_l 10,000
Minimum distance between roadway and monitoring
station (meters)
CO
MO
25
45
80
115
135
.>150
°3
.>io
20
30
50
100
X250
NO2
^.10
20
30
50
100
^250
Monitor Height (meters)
2
5
10
15
Minimum Distance Between
Roadway and Monitoring
Station (meters)
TSP/PM10
25
20
13
5
Figure 3-1. (continued)
3-10
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FACILITIES AND EQUIPMENT CHECKLIST
D Is an inventory of monitoring equipment available?
D Which instruments are in operating condition?
D Which instruments are not in operating condition; why?
D Are operating instructions and calibration procedures available for each
instrument?
D Are associated air monitoring materials, supplies, and equipment available, such
as:
D Operation and maintenance supplies (e.g., spare parts, fuses, and filters)?
D Calibration standards and equipment (calibration gases, dilution systems, and
flowmeters)?
D Meteorological measurement equipment?
D Data transmission equipment (e.g., computer download capabilities)?
D Are meteorological data available from local airports?
D Is laboratory space available? If so, is the following provided?
D Well-ventilated or air conditioned work space?
D Adequate electric power and lighting?
D Benchtop areas for testing and repairing equipment and processing samples?
D Hand tools and electrical testing equipment?
D Storage space for reagents, glassware, etc.?
D Laboratory sink with running water?
D Filter conditioning room or desiccator?
D Exhaust hood?
D Analytical balance?
D Light box or light table?
D Atomic adsorption spectrophotometer (lead analyses)?
D Ultrasonic waterbath?
D Source of distilled or deionized water?
D Drying oven and refrigerator?
D Communications equipment for field work?
D Chemistry and engineering reference texts?
D Safety apparatus (e.g., fire extinguisher)?
Figure 3-2. Facilities and equipment checklist.
3-11
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PERSONNEL RESOURCES CHECKLIST
D Is an organizational chart showing agency staff and reporting relationships
available?
D Are staff are available to operate and service the monitoring stations, provide
laboratory support, and analyze data; what are their names and home office
locations?
D What percent of their normal working hours are available to support the air
monitoring network project?
D Are the available staff trained and/or experienced in any of the following areas:
D Air quality monitoring?
D Meteorological station operation?
D Laboratory analysis/chemistry?
D Data analysis/personal computer operation?
Figure 3-3. Personnel resources checklist.
This checklist includes questions related to staff availability, experience, education, skill
level, and location.
Using the generalized siting criteria and checklist information, various site inspections
were conducted and recommendations for candidate sites were developed. In several
instances, the sites recommended in Section 5.0 represent existing monitor locations; in other
cases, entirely new sites are recommended. The entire process by which siting
recommendations were developed is summarized in Figure 3-4.
3-12
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DEVELOP CLEAR UNDERSTANDING OF MONITORING NETWORK
PURPOSE
Characterize population exposure to urban air contaminant concentrations
Develop cost-effective network plan, using available equipment where
practicable
IDENTIFY GENERALIZED AREAS WHERE MONITORS ARE TO BE
LOCATED
>- Residential areas, schools, sensitive populations
> Business and industrial areas
>- Downwind location near dty limits (especially for ozone measurements)
>- Upwind location near city limits (for background measurements)
REVIEW BACKGROUND INFORMATION
»- Climatological and meteorological
data
*- Topographical maps
» Emission inventories
» Dispersion modeling resufts
* Traffic and land use patterns
> Population distribution
*- Existing monitoring data
DEVELOP CHECKLISTS FOR TECHNICAL CRITERIA
> How well the air quality impact scenarios of interest are
represented
> Distance of site from potential interferences/biases
Large point or areas source
Agricultural chemical applications
- Roadways
-Wind-blown dust
> Inlet height and orientation requirements
* Availability of electric power
»- Availability of data transmission lines
*- Absence of nearby buildings, trees, and other obstacles
> Averaging period/time of day measurements made
>- Accessibility and security
CONDUCT SITE INSPECTION OF EACH AREA AND
SELECT CANDIDATE SITES
DEVELOP FINAL SITE SELECTION RECOMMENDATIONS
Figure 3-4. Summary of process by which siting recommendations were developed.
3-13
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4.0 SITE VISIT APPROACH AND OBSERVATIONS
4.1 OVERVIEW OF APPROACH
The initial step in preparing for the site visit was to review and evaluate background
materials and emissions data for the two cities. MRI worked with the EPA, TNRCC, and
State of Coahuila to acquire all relevant information, including terrain and land-use data for
prospective monitor siting areas, the distribution of point and area sources, the location of
appropriate airport meteorological stations from which weather data can be obtained, and
population distribution and density for each city. Examples of specific items reviewed
include:
Isopleth maps of pollutant concentrations from previous studies.
Emission inventories.
Regional meteorological data and wind roses (see Appendix A).
Topographic, population, and land-use maps.
After reviewing this informatiion, MRI worked with EPA, Texas, and Coahuila to
define project data quality objectives (DQOs). DQOs are useful in ensuring that the
information collected and observations made during a field study are of the right type,
quality, and quantity to support their intended use. The DQOs for this project were as
follows:
Lay the groundwork for establishing ambient air monitoring networks in Ciudad
Acuna and Piedras Negras for pollutants of concern to city and state officials.
Provide for the measurement of urban concentrations of pollutants in residential
and industrial areas.
4-1
-------
Incorporate the measurement of upwind and downwind concentrations to provide a
better understanding of background concentrations and regional transport
phenomena.
Develop realistic network designs within the constraints of available administrative,
technical, and financial resources, using existing equipment and personnel to the
greatest extent possible.
Guided by these DQOs, two MRI air monitoring specialists conducted the site visit to
Ciudad Acufia and Piedras Negras and collected the information used to develop the
recommendations in Section 5.0. The site visit included meetings with administrative and
technical staff of the two cities and the State of Coahuila, visits to potential monitoring
locations, acquisition of additional data associated with local emission inventories and
meteorological/topographical characteristics, and evaluation of the human resources needed
and available to operate the networks. MRI also evaluated existing equipment for its
potential use in the proposed air monitoring networks.
The site selection process itself was an elimination process: the recommended sites
were chosen from prospective sites selected from general siting areas. The underlying logic
in this process was to determine the general locations of the monitoring sites; refine the
locations to minimize undue influences from nearby sources, including meteorological
effects; and ultimately place the monitor inlets according to established siting criteria so that
defensible data could be acquired throughout this process. Careful attention was paid to the
siting criteria presented in the checklists in Section 3.0.
4.2 SUMMARY OF OBSERVATIONS
During the visit to Ciudad Acufia, the MRI staff observed that the city has four
operational EPA reference PM10 monitors manufactured by Wedding and Associates. This
equipment is of the latest design and appropriate for its intended purpose of collecting PM10
data at multiple locations with the city. Two of the monitors are already located at specific
sites within the city limits (Stations 1 and 3), while the remaining two monitors are stored in
the offices of the Director of Ecology (i.e., the responsible official for air monitoring). The
municipality does not have a working meteorological station, a PM10 monitor calibration kit,
or other facilities to support the continued operation and maintenance of the monitors.
Logbooks and operating manuals were also not available.
4-2
-------
Ciudad Acuna's Department of Ecology has one person trained in the operation of
PM10 monitors. The NEE had previously calibrated the monitors and provided operator
training, including instructions on changing and handling filters and operation of the
monitors. However, follow-up training addressing the detailed steps involved in receiving,
loading, unloading, packaging, and shipping filters to an analytical laboratory had not been
conducted. Troubleshooting and maintenance training also had not been conducted.
During the visit to Piedras Negras, it was observed that the city has an inventory of
four operating PM10 monitors manufactured by Wedding and Associates. As with Ciudad
Acuna, these monitors are appropriate for use in the city. All four PM10 monitors are
already located at specific sites within the city limits. In addition, Piedras Negras has
one SC>2 analyzer manufactured by Measurement Control Corporation and an associated data
logger system by Odessa. Neither the SC>2 analyzer nor the data logger are operational, and
the support equipment needed for future operation was not present. The municipality does
not have a working meteorological station, PM10 calibration kit, or other facilities to support
the continued operation and maintenance of the PM10 monitors. However, the city does have
operating manuals for the PM10 monitors, which have been translated from English into
Spanish.
Piedras Negras's Department of Ecology has two people trained by the INE to operate
the PM10 monitors. Additionally, the INE had previously calibrated the PM10 monitors.
Training included instructions on changing and handling filters and operating the monitors,
but excluded detailed instructions addressing the receiving, loading, unloading, packaging,
and shipping of filters and troubleshooting and maintaining equipment.
4-3
-------
5.0 RECOMMENDATIONS
Recommendations are presented below for implementing improved ambient air quality
monitoring networks in Ciudad Acuna and Piedras Negras. Additionally, steps that can be
taken by the State of Coahuila to improve data quality and ensure measurement consistency
between the two cities are recommended. All of the recommendations are summarized in
Table 5-1.
5.1 CIUDAD ACUNA
Ciudad Acuna currently has four operational PM10 monitors, two of which are located
at monitoring sites within the city limits, and the other two are stored at the office of the
Director of Ecology. Because these monitors are immediately available to the city, and
because two the monitors are already sited, it is recommended that siting of the other two
monitors and operation of all four monitors be the city's highest priority.
The two monitors that have already been located at monitoring sites are considered
appropriately sited, and the relocation of these monitors is not recommended. While
improvements to these locations could be suggested, it is doubtful that these improvements
would significantly improve the quality of data collected. Recommendations for the locations
of all four monitors are summarized below, and the locations are illustrated in Map 5-1.
Station 1 fEastl: Existing location on top of City Hall (see Figure 5-1 and
Photograph 5-1); provides measurements in vicinity of highly populated residential
area.
Station 2 (Southeast1): New location on top of one-story building at water pumping
station (see Figure 5-2 and Photograph 5-2); provides measurements of upwind
background concentrations.
Station 3 fNorthwestl: New location on top of one-story building at General
Electric facility in local industrial park (see Figure 5-3 and Photograph 5-3);
provides measurements downwind of industrial area (e.g., numerous maquilas).
5-1
-------
TABLE 5-1. SUMMARY OF RECOMMENDATIONS
CIUDAD ACUNA
Locate two remaining PM10 monitors and begin operation of all four monitors as highest priority.
Establish additional SC^, lead, and possibly ozone monitors at each PM10 location as second
priority.
Install meteorological monitoring station.
Obtain operating manuals, log books, and required auxiliary equipment such as calibration kits and
inventory of spare parts.
Establish support facility for set-up, calibration, and maintenance of equipment.
* Develop SOPs; data reduction, validation, and reporting procedures; and DQOs.
Improve accessibility to existing stations.
Provide at least one additional trained employee for operating and maintaining air monitoring
network.
PIEDR AS NEGR AS
Begin operation of all four PMIO monitors at existing sites as highest priority.
Repair and set up existing SO? monitor and associated data logger as second priority; locate monitor
at Station 2 (i.e., upwind, in the direction of the power plant).
Establish additional SO2, lead, and possibly ozone monitors at each PM,0 location as third priority.
Install meteorological monitoring station.
Obtain log books and required auxiliary equipment such as calibration kits and inventory of spare
parts.
Establish support facility for set-up, calibration, and maintenance of equipment.
Develop SOPs; data reduction, validation, and reporting procedures; and DQOs.
Improve accessibility to existing stations.
STATE OF COAHUILA
Establish comprehensive quality assurance program, providing for: (1) periodic inspection and
performance audits of monitoring sites; (2) preparation of written operating, data analysis, and report
procedures; (3) DQOs, including limits for precision, accuracy, and completeness; and (4)
certification requirements for analytical laboratories.
Provide periodic training for air quality monitor operators.
Coordinate purchase, preparation, and handling of all monitor supplies and equipment and
conditioning and analysis of particulate filters.
Assume responsibility for all coordination with National Institute of Ecology.
Consider hiring an air quality coordinator.
5-2
-------
OJ
AmbJad .
To Amistad Dam Industrial Sl» t3 - Industrial Complax
p,rX (General Electric)
Site (M - Oe Station
Site fZ-Waler Pump
Station
Map 5-1. Illustration of monitoring station locations in Ciudad Acuna.
-------
CITY HALL-ACUNA
PM 10 MONITOR #1
NORTH
PARKING LOT
t
STREET
-150'
PM10 MONITOR
27'
BUILDING ROOF IS APPROXIMATELY 30' HIGH
ANTENNA ON ROOF IS POSSIBLE SITE OF METEORLOGICAL STATION
ACCESS TO ROOF (LADDER) REQUIRED
STREET
o
3)
O
to
Figure 5-1. Location of Station No. 1 on top of City Hall, Ciudad Acuna.
5-4
-------
Photograph 5-1. Station No. 1 on top of City Hall, Ciudad Acuna.
5-5
-------
WATER PUMP STATION - ANUNA
PM10 MONITOR SITE #2
NORTH
1
L
2
CD
I
33
§
1
I
0
£
a
1
?v
^ FENC
;E-6'HIG
6C
PUMPS
A
Tc^' CD/tll CCM^C TO
H ^
BUILDING
*
1 m- V m1
I 10 x 18
4
~7
5'
£_
12'
7
2^
/_
r-
ROAD
* POSSIBLE SITE FOR PM10 MONITOR ON ROOF OF BUILDING
BUILDING HAS ELECTRIC SERVICE AND STANDS -T OFF THE GROUND
Figure 5-2. Location of Station No. 2 on roof of pump house, Ciudad Acuna.
5-6
-------
Photograph 5-2. Proposed Station No. 2 on roof of pump house, Ciudad Acuna.
5-7
-------
GENERAL ELECTRIC
PM10 MONITOR SITE #3
SECOND
BUILDING
3
z
INDUSTRIAL PARK
NORTH
FENCELINE
BASKETBALL COURT
WATER TANKS
-165'
MAIN
BUILDING
CASA DE BOMBAS
SOCCER FIELD
POSSIBLE SITE FOR PM10 MONITOR ROOF OF BUILDING, -8' HIGH
-300'
420'
201
MAIN ROAD
Figure 5-3. Proposed location of Station No. 3 at General Electric in industrial park,
Ciudad Acuna.
5-8
-------
f< f:'-v V^A^14^^^£~ - *
JrwBM^.,-. ***>»'- ^w«>. . » .
-------
Station 4 (North'): Existing location on top of two-story fire station (see Figure 5-4
and Photograph 5-4); measurements represent city-wide air quality associated with
the urban/neighborhood scale.
We believe that a total of four monitor locations is sufficient for a city the size of Ciudad
Acuna, and that additional monitors are not needed.
Once these monitoring stations are operational, we recommend that the city establish
additional monitors at each location for SC>2, Pb, and possibly Oy While there are no
monitoring data or other evidence that these contaminants represent a concern for the city,
monitoring for these contaminants is recommended for the following reasons:
SO_2: As discussed previously, the Carbon I and n electric power plants are
located to the southeast, and wind rose data indicate that winds from the southeast
are common. Because this facility does not employ SC>2 emission controls, the
potential exists for significant levels of SC^ to be transported in the direction of
the cities.
Pb: Ciudad Acuna has many older cars without emission control devices. Because
leaded gasoline may be used in the city, and because other sources of Pb emissions
may be present, the potential exists for significant lead exposure, especially in the
vicinity of major roadways. As an alternative to locating Pb monitors at all four
previously identified stations, a single micro-scale lead monitor could be located
beside the busiest roadway.
0.3: Because Ciudad Acuna is a relatively small city and because there is no
strong evidence for the regional transport of ozone from the U.S. border region
(e.g., prevailing winds are from a different direction), the monitoring of O^ may
not be critical. Nevertheless, the many uncontrolled automobiles in the city and
the numerous small industrial facilities probably contribute significant volatile
organic compounds (VOCs), and the Carbon I and n plants emit NOX emissions.
Because these precursor compounds can lead to the formation of ozone, ozone
monitoring may be appropriate. However, we recommend that the monitoring of
this contaminant be given lower priority than the monitoring of the other
compounds.
If monitoring for SC>2, lead, and possibly ozone is to be conducted, the city would need to
purchase the monitors and associated equipment and provide operator training. The monitors
can be co-located with the PM10 monitors, with the possible exception of lead, as noted
above.
To operate the existing PM10 stations, a meteorological station and calibration kit will
be required. Support facilities for setting up, calibrating, and maintaining equipment also are
5-10
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FIRE STATION
PM10 MONITOR #4
u_
o
o
o:
UJ
o
z
0.
O
_j
CO
J
^
/ I/
A '
1 L
PM10 MONITOR
FLAT CONCRETE ROOF
/
lx
r ~i^ ^
PLAN VIEW
-7
6*
25
M
.^ PHAH fcp
NORTH
PM10
UNIT
STAND-*-
10'
3'
\ ^
FLOOR
SECOND
FLOOR
FIRST
FLOOR
Figure 5-4. Location of Station No. 4 on top of two-story fire station, Ciudad Acuna.
5-11
-------
Photograph 5-4. Station No. 4 on top of two-story fire station (right), Ciudad Acuna.
5-12
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needed, as are log books and operating manuals. Similar equipment and facilities are needed
for operation of the SC^, Pb, and 63 monitors.
Ciudad Acuna currently has one employee who is trained in the operation of PM10
monitors. At least one additional trained employee should be provided so that a minimum of
two individuals are familiar with monitor operation and maintenance (i.e., one employee wifl
serve as a backup to the other). If monitoring is conducted for other contaminants, two
trained personnel will probably still be sufficient. However, with more monitors in
operation, one of these two employees may need to devote his/her entire workday to
operation, maintenance, data reduction, and reporting activities.
In addition to the above recommendations, a number of operational details that need
to be addressed are listed below.
Site-specific standard operating procedures (SOPs), including procedures for
monitor operation, preventive maintenance, and corrective action, are needed for
each monitor. Procedures for data reduction, validation, and reporting also are
needed.
Data quality objectives (DQOs), especially for precision, accuracy, and
completeness, should be established.
Accessibility to the existing monitoring stations needs to be improved (e.g.,
platforms are needed to facilitate routine operation and maintenance) and electrical
connections need to be weatherized.
A spare parts inventory should be established, which includes items such as a
PM10 gasket kit, motor brushes, motors, filter holders, and timers.
5.2 PffiDRAS NEGRAS
Piedras Negras currently has four operational PM10 monitors and one inoperable S02
monitor and associated data logger. The four PM10 monitors are located at monitoring sites
within the city limits. Because these monitors are already on hand, the operation of these
monitors should be the city's highest priority.
We recommend that the four PM10 monitors be operated at their current locations.
While improved locations probably could be identified, we doubt that the quality of data
collected could be significantly improved. Given the expense associated with relocating the
monitors and the difficulty likely to be experienced in locating suitable sites that provide
adequate security, we recommend that all four monitors be left at their current locations.
5-13
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These recommended locations are summarized below, and the locations are illustrated in
Map 5-2.
Station 1 (North): Existing location on top of City Hall (see Figure 5-5 and
Photograph 5-5); measurements represent city-wide air quality associated with the
urban/neighborhood scale.
Station 2 (Southeast*): Existing location on top of one-story school (see Figure 5-6
and Photograph 5-6); provides measurements of upwind background
concentrations.
Station 3 (South'): Existing location at junior high school building (see Figure 5-7
and Photograph 5-7); provides measurements in vicinity of highly populated
residential area. (Note that the figure and photograph represent the original
location of the monitoring station, on top of a one-story school building.
However, based on recommendations of the MRI site visit team, the monitoring
station has been relocated about 100 meters east to a ground level location where
potential interferences from surrounding trees can be avoided.)
Station 4 (West): Existing location on top of a one-story technical college building
within local industrial park (see Figure 5-8 and Photograph 5-8); provides
measurements in vicinity of industrial area (e.g., numerous maquUas).
As with Ciudad Acuna, we believe that a total of four monitor locations is sufficient for a
city the size of Piedras Negras, and that additional monitors are not needed.
Once these monitoring stations are operational, we recommend that the city establish
additional monitors at each location for SC^, Pb, and possibly 63. As with Ciudad Acuna,
there are no monitoring data or other evidence that these contaminants represent a concern
for the city. However, given the nearby electric power plants, number of uncontrolled older
cars, and numerous sources of VOCs, significant concentrations of SC^, Pb, and possibly 63
may be present.
If monitoring for SC^, Pb, and possibly 0)3 is conducted, the city would need to
purchase the monitors and associated equipment and provide operator training. The monitors
can be co-located with the PM10 monitors, with the possible exception of Pb, as discussed
Section 5.1. Because an SC^ monitor and associated data logger currently are available to
the city, we recommend that this equipment be set up and operated as a second priority. The
best location for this monitoring equipment would be at Station 2 (i.e., upwind, in the
direction of the power plant).
5-14
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Site #1 - City Had
To Eagle Pass, Texas
OUMHT&S7.73M WOO WEED (KNOTS)
Site #4-Condon
Technics^ School
Site «2 - General Nicholas
Bravo School
PopUadon Density
Site #3 - Able Herrera Radolfo
Junior High School
Map 5-2. Illustration of monitoring station locations in Piedras Negras.
5-15
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PIEDRAS NEGRAS, MEXICO
SITE #1 - CITY HALL .
5
PAVED
PARKING
LOT
-V
54'
PM10 MONITOR
NORTH
125'
RAISED 20' ABOVE GROUND
y- 90'
* PENTHOUSE »15' HIGHER THAN ROOF
Q
g
or
ANTENNA TOWER SUITABLE
FOR MET TOWER
Figure 5-5. Location of Station No. 1 on top of City Hall, Piedras Negras.
5-16
-------
Photograph 5-5. Station No. 1 on top of City Hall, Piedras Negras.
5-17
-------
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Photograph 5-6. Station No. 2 on one-story building at General Nicholas Bravo
School, Piedras Negras.
5-19
-------
PIEDRAS NEGRAS, MEXICO
SITE #3 - ABLE HERRERA RADOLFO JUNIOR SCHOOL
NORTH
TREES
.30' HIGH
WATER TANK
HOUSE
«.8' HIGH
/
/ 3D1
2
\
12' .
3
y
£
Ac'
4S /
y ^~
TREES
«30' HIGH
ROOF «15'HIGH
1001
- RECOMMEND MOVING PM10 MONITOR
TO FARTHEST MOST NORTH BUILDING
- 2 BUILDINGS OVER WITH SCIENCE ROOM
- A LOT OF UNPAVED ROADS IN AREA
ROAD-PAVED-
Figure 5-7. Location of Station No. 3 on top of junior high school building
(later moved 100 meters east), Piedras Negras.
5-20
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' w$vf*v&eif,&^ 5 ^"s1 ^.^V>V^ ^ ?x^%%j^*S*^ * % A?"''
Photograph 5-1. Station No. 3 on top of junior high school building
(later moved 100 meters east), Piedras Negras.
5-21
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PIEDRAS NEGRAS. MEXICO
SITE #4 - CONALEP TECHNICAL SCHOOL
PM-10 MONITORS
PORCH =10'HIGH
NORTH
»- *
9'
12'
BUILDING ROOF -6' HIGHER
THAN ROOF OF INSTRUMENT
PORCH ROOF «=3' HIGHER
THAN ROOF OF INSTRUMENT
O
O
o:
<
m
GRASS
AREA
54'
81'X81'
METAL BUILDING
=30' HIGH
Figure 5-8. Location of Station No. 4 on one-story building at
Conalep Technical School, Piedras Negras.
5-22
-------
Photograph 5-8. Station No. 4 on one-story building at Conalep Technical School,
Piedras Negras.
5-23
-------
To operate the existing PM10 stations, a meteorological station and calibration kit is
required. Additionally, log books and support facilities for setting up, calibrating, and
maintaining equipment are needed. (Spanish language operating manuals are already
available.) Similar equipment and facilities are needed to operate the SC>2, Pb, and 63
monitors.
Piedras Negras currently has two employees who are trained in the operation of PM10
monitors. This number of trained employees is sufficient for operating and maintaining the
four PM10 stations (i.e., one employee will serve as a backup for the other). If monitoring
is ultimately conducted for other contaminants, two trained personnel is still probably
sufficient. However, with more monitors in operation, one or the other of these two
employees may need to devote his/her entire workday to operation, maintenance, data
reduction, and reporting activities.
In addition to the above recommendations, a number of operational details need to be
addressed, as discussed in Section 5.2. Also, the inoperable SC^ monitor and associated
data logger need repair and auxiliary equipment (tubing, connectors, etc.) must be provided.
5.3 STATE OF COAHUILA
The State of Coahuila plays an important role in ensuring successful operation of the
air monitoring networks in Ciudad Acuna and Piedras Negras. In particular, we recommend
that Coahuila establish a comprehensive quality assurance (QA) program that includes:
Periodic inspections and performance audits of monitoring sites.
The preparation of written operating, data analysis, and reporting procedures for
the two cities.
DQOs, including limits for precision, accuracy, and completeness.
Certification requirements for analytical laboratories.
Additionally, we recommend that Coahuila provide periodic training for the air
quality monitor operators. We believe there would be some advantage to having Coahuila
coordinate the purchase, preparation, and handling of all monitor supplies and equipment and
the conditioning and analysis of paniculate filters. We also recommend that Coahuila take
responsibility for all coordination with the INE. Finally, we recommend that Coahuila
consider hiring an air quality coordination to provide oversight for all of the above activities.
5-24
-------
APPENDIX A.
WIND, TEMPERATURE, AND PRECIPITATION DATA
-------
San Antonio, TX 1992
January 1-December 31; Midnight-11 PM
16%
CALM WINDS 7.72%
WIND SPEED (KNOTS)
11-16
NOTE: Frequencies indicate direction from which the wind is blowing.
A-l
-------
Lat=29.2N Lon=100.5W Elevation=1092 feet
Number of years available from 1961 to 1990: 27
Del Rio, TX, 1961 -1990 Monthly Means
January maximum temperature
72-
70
$6
«6$
S 62
160
5$
54
52-j
50
"62:2
'M«ar
!
-------
O O 0)
3 o> °
^ "^
to 0)_ (D
5 S'~^
O) (D
-J. x O
Precip. in hundredths of
inches snow in tenths
Degrees Fahrenheit
Degrees Fahrenheit
z'
-n
(D
r
"n-
c.
i_-
r
t.
ri
3
9
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s
r|~i . : ;"~J'
"V i .
' '*~~2C '">'
sf, . . .
lv ' = ; : i 1
......^.TT,...
. ,^i» ' ' ;
. ^_. "f?^. . .
r^i? ! ' * *
*£'
^-"-"^^^
. :::..:
» i_J
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gfif:T|
a S Sv I
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01
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-55
-* c"
- 1
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-»
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10
-sj
-------
Lat=29.2N Lon=100.5W Elevation=1092 feet
Annual average chance of precipitation: 16.9%
Annual average wind speed: -999.0 mph
Annual average percent of available sun: -999.0
Daily chance of precipitation, Del Rio, TX
JAN FEE MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1000.
Year
A-4
-------
APPENDIX B.
SITE VISIT CONTACT LIST
-------
State Government of Coahuila, Mexico
Dr. Rodolfo Garza Gutierrez - El Director General
Secretaria de Desarrollo Social
Direccion General de Ecologia
Victoria 406, ler, Piso
Saltillo, Coahuila
Office Phone: (84) 12-5622 & 14-9213
Fax: (84) 12-5678 - Need to call first
Ing. Sergio Marinez Alfaro - Subdirector of Prevention and Control
Secretaria de Desarrollo Social
Direccion General de Ecologia
Victoria 406, ler, Piso
Saltillo, Coahuila
Office Phone: (84) 12-5622 & 14-9213
Fax: (84) 12-5678 - Need to call first
Ing. Jose Carlos Murguia Arizpe - Jefe de Verification
Secretaria de Desarrollo Social
Direccion General de Ecologia
Allende 202 Pte, 60, Piso
Saltillo, Coahuila
Office Phone: (84) 14-9213
Fax: (84) 14-43-20 - Need to call first
Municipality of Ciudad Acuna, Coahuila
Lie. Emilio de Hoyos Cema
Presidente Municipal de Acuna (Mayor)
B-l
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Ciudad Acuna, Coahuila
Prof. Jose Luis Coronado Rivera
Director de Ecologia Municipal de Acuna
Andador Tayasol 1848, Col. Fouissste
Ciudad Acuna, Coahuila
Phone: (877)2-35-11
Fax: (877) 2-44-99
Francisco Muniz Hernandez
Direccion de Ecologia Municipal de Acuna
Mina 249, Sur. Col. Centre.
Ciudad Acuna, Coahuila
Phone: (877)2-35-11
Fax: (877) 2-44-99
B-2
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Municipality of Acuna, Coahuila, Cont.
Andres Arejandro Tanaka Lopex
Direccion de Ecologia Municipal de Acuna
Anador Xamantun No 364, Col Fouissste
Ciudad Acuna, Coahuila
Phone: (877)2-35-11
Fax: (877) 2-44-99
Jose Antonio Garga Corter
Director of Water Works (SIMAS)
Ciudad, Acuna, Coahuila
Municipality of Piedras Negras, Coahuila
Lie. Ernesto Vela del Campo (Mayor)
Presidente Municipal
Ave. 16 de Septiembre y Monterrey
Piedras Negras, Coahuila
Phone: (878) 2-51-08
Fax: (878) 2-31-91
Dr. Juan A. Escandon Valdez
Director de Ecologia Municipal de Piedras Negras
Ave. 16 de Septiembre y Monterrey
Piedras Negras, Coahuila
Phone: (878) 2-01-49
Fax: (878) 2-22-02
Ruperto Roma Rangel
B-3
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Direction de Ecologia Municipal de Piedras Negras
Ave. 16 de Septiembre y Monterrey
Piedras Negras, Coahuila
Phone: (878) 2-01-49
Fax: (878) 2-22-02
B-4
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Texas Natural Resource Conservation Commission
Maria M. Rodriguez
Border Outreach - San Antonio Region
Region 13 - San Antonio
140 Heimer Rd. #360
San Antonio, Texas 78232-5042
Phone: (210) 490-3096 Ext. 341
Fax: (210) 545-4329
Jim Menke
Region 13 - San Antonio
140 Heimer Rd.
San Antonio, Texas 78232-5042
Phone: (210) 490-3096
Fax: (210) 545-4329
Steve Neimer
Texas Natural Resource Conservation Commission
6330 Highway 290 East
Austin, Texas Office
Phone: (512)239-3605
B-5
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TECHNICAL REPORT DATA
1. REPORT NO.
EPA-456/R-98-001
4. TITLE AND SUBTITLE
Ambient Air Monitoring Plan for
Coahuila, Mexico
2.
Ciudad Acuna and Piedra Negras,
7. AUTHOR(S)
William T. Wmberry
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Midwest Research Institute
Suite 350
Hamson Oaks Boulevard
Gary, NC 27513
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. -Mexico Information Center on Air Pollution (CICA)
Office of Information Transfer and Program Integration Division
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
January 1998
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT
NO.
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D30035, WA 11-81
13. TYPE OF REPORT AND PERIOD
COVERED
Final
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This report presents the results of an evaluation of existing air quality monitoring equipment and facilities in Ciudad Acuna and Piedras
Negras, Coahuila, Mexico. Additionally, the report presents recommendations for developing an air quality monitoring network for air
pollutants in these cities, using a combination of both new and existing equipment. The human resources currently available and ultimately
need to operate and maintain the network are also discussed.
17.
a. DESCRIPTORS
Mexico Air Pollution
Mexico Air Pollution Monitoring
18. DISTRIBUTION
STATEMENT
Unlimited
KEY WORDS AND DOCUMENT ANALYSIS
b. IDENTIFIERS/OPEN ENDED TERMS
Mexico Air Pollution Monitoring
19. SECURITY CLASS (This Report)
Unclassified
20. SECURITY CLASS (This page)
Unclassified
c. COASTI Field/GroupO
13B
21. NO. OF PAGES
48
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE
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