AIR POLLUTION CONTROL DISTRICT

Ambient Air Monitoring

Annual Network Plan

July 2013

Prepared by

APC PLANNING DIVISION

Monitoring Section

Jonathan Barroga

Reviewed by

APC Division Manager

Monica N. Soucier
150 S 9TH Street

El Centro, CA 92243

P 760.482.4606

F 760.353-9904

Table of Contents

Page

I Introduction........................................................................................ 6

II Air Monitoring Network Design Overview .......................................... 8

A Monitoring Objectives ............................................................. 10

B Spatial Scales ......................................................................... 9

C Purpose .................................................................................. 14

III Monitoring Requirements .................................................................. 18

A Ozone (O3).............................................................................. 19

B Carbon Monoxide (CO)........................................................... 20

C Nitrogen Dioxide (NO2) ........................................................... 20

D Sulfur Dioxide (SO2)................................................................ 21

E Particulate Matter (PM10) ........................................................ 21

F Particulate Matter (PM2.5)........................................................ 22

Spatial Averaging Approaches for PM2.5................................. 23

IV Sampling Frequency Review............................................................. 23

V Proposed Modifications to the Network Design ................................. 25

Calexico East..................................................................................... 25

Calexico Ethel.................................................................................... 25

Niland ................................................................................................ 26

Westmorland ..................................................................................... 26

VI Quality System Requirements ........................................................... 26

A Quality Management Plans (QMP) and

Quality Assurance Project Plan (QAPP) ................................. 26

B Data Review and Submittal..................................................... 26

VII Overall Summary of the Imperial County Ambient

Air Monitoring Network ...................................................................... 27

VIII Detailed Site Information ................................................................... 29

Niland Station .................................................................................... 29

Westmorland Station ......................................................................... 33

Brawley Station.................................................................................. 37

El Centro Station ............................................................................... 41

Calexico Ethel Station ....................................................................... 45

Appendix A Regulatory Language of 40 CFR §58.10 .................................. 50

Glossary of Acronyms .................................................................................. 52

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Annual Air Monitoring Network Plan 2013
150 S 9TH Street

El Centro, CA 92243

P 760.482.4606

F 760.353-9904

List of Figures

Page

Figure 1 Map of Ambient Air Monitoring Stations in

Imperial County....................................................................... 7

Figure 2. Map of Niland Monitoring Stations .......................................... 30

Figure 3. Map of Westmorland Monitoring Station................................. 34

Figure 4. Map of Brawley Monitoring Station ......................................... 38

Figure 5. Map of El Centro Monitoring Station ....................................... 42

Figure 6. Map of Calexico Ethel Monitoring Station ............................... 46

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List of Tables

Page

Table 1 Site Classifications Ozone and NO2........................................ 9

Table 2 Site Classifications CO and SO2 ............................................. 9

Table 3 Site Classifications PM10 and PM2.5 ........................................ 10

Table 4 Site Type Relationship to

Scales of Representativeness ................................................ 11

Table 5 Spatial Scales for Ozone and NO2.......................................... 11

Table 6 Spatial Scales for CO and SO2 ............................................... 12

Table 7 Spatial Scales for PM10 and PM2.5........................................... 13

Table 8 Network Monitoring Purpose

(Gaseous Criteria Pollutants) All............................................. 16

Table 9 Network Monitoring Purpose

(Particulate Pollutants-PM10) Brawley & Niland ...................... 17

Table 10 Network Monitoring Purpose

(Particulate Pollutants-PM10) El Centro, Calexico and

Westmorland........................................................................... 17

Table 11 Network Monitoring Purpose

(Particulate Pollutants –PM2.5) Brawley & El Centro ............... 17

Table 12 Network Monitoring Purpose

(Particulate Pollutants – PM2.5) Calexico ................................ 18

Table 13 SLAMS Minimum O3 Monitoring Requirements ...................... 19

Table 14 Summary of Minimum Monitoring Requirements Ozone......... 20

Table 15 Summary of Minimum Monitoring Requirements CO.............. 20

Table 16 Summary of Minimum Monitoring Requirements NO2 ............ 21

Table 17 Summary of Minimum Monitoring Requirements SO2............. 21

Table 18 PM10 Minimum Required Monitors per Concentration Level ... 22

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Table 19 Annual Max and Mean PM10 ................................................... 22

Table 20 Summary for Minimum Monitoring Requirements PM10.......... 22

Table 21 PM2.5 Minimum Monitoring Requirements............................... 23

Table 22 Summary for Minimum Monitoring Requirements PM2.5 ......... 23

Table 23 PM10 Sampling Frequency Calculations ................................. 24

Table 24 PM2.5 Sampling Frequency Calculations ............................... 25

Table 25 Ambient Air Quality Monitoring Site Locations 

Imperial County....................................................................... 27

Table 26 Pollutants and Parameter Monitored Per Site......................... 28

Table 27 Summary of Site type, Spatial Scale and Purpose ................. 28

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I INTRODUCTION

According to Title 40 of the Code of Federal Regulations (CFR) Part 58.10 (40 CFR 

58.10), states and where applicable local agencies are required to adopt and submit to 

the Regional Administrator of the United States Environmental Protection Agency (US 

EPA) an annual air monitoring network plan (Network Plan) which establishes and 

maintains an air quality surveillance system. By regulation an air quality surveillance 

system is composed of monitoring stations equipped with either, or a combination of 

Federal Reference Method (FRM), Federal Equivalent Method (FEM) or Approved 

Regional Method (ARM) monitors. These monitors measure ambient levels of gaseous 

and particulate (solid and liquid aerosol) air pollutants.

Depending on the purpose and air quality designation of an area the monitoring station 

may be one of many different types of stations. Here in Imperial County all monitoring 

stations are designated as state or local air monitoring stations (SLAMS). Per CFR all 

SLAMS networks are ambient air quality monitoring sites that are primarily needed for 

National Ambient Air Quality Standards (NAAQS) comparisons. The NAAQS is 

established by US EPA to protect the public health and the environment. There are two 

types of NAAQS that an Air District must consider; the primary standard which provides 

for the protection of the public health and the secondary standard which provides for 

protection of the public welfare which includes protection against decreased visibility 

and damage to animals, crops, vegetation and buildings.

SLAMS exclude special purpose monitor (SPM) stations but include national core 

multipollutant monitoring stations (NCore), photochemical assessment monitoring 

stations (PAMS) and all other State or locally operated stations that have not been 

designated as SPM stations.1

 Two Beta Attenuation Mass Monitors (BAM’s) for 

Particulate Matter of less than 10 microns (PM10) have been designated at SPM’s. One 

BAM is located in Brawley while the other is located in Niland. Currently, no NCore or 

PAMS are located in Imperial County.

In addition, 40 CFR Part 58 requires the identification of one and only one Primary 

Quality Assurance Organization (PQAO) for each criteria pollutant sampler/monitor

within a monitoring station. Currently, the identified PQAO for Imperial County for 

Ozone (O3), Carbon Monoxide (CO), Oxides of Nitrogen and PM10 is the California Air 

Resources Board (CARB). The PQAO for Particulate Matter of less than 2.5 microns 

(PM2.5) is the San Diego Air Pollution Control District (SDAPCD). While the Imperial 

County Air Pollution Control District (Air District) handles all the day to day operations 

for each criteria pollutant sampler/monitor the PQAO is the monitoring organization that 

is responsible for pooled data quality assessments.

The Network Plan, as mentioned above, is required by federal regulation. It requires 

the Air District to identify the purpose of each monitor within the SLAMS network and it 

requires evidence that the siting and operation of each monitor meets the requirements 

1 Code of Federal Regulations, Title 40 Part 58.1 Definitions of SLAMS

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of appendices A, C, D and E of 40 CFR Part 58. For clarity, “monitor” means an 

instrument, sampler, analyzer, or other device that measures or assists in the 

measurement of atmospheric air pollutants and which is acceptable for use in ambient 

air surveillance under the applicable provisions of appendix C of 40 CFR Part 58.2 

Overall, this Network Plan provides the results of a five year assessment broken down 

to reflect the annual outcome.

Figure 1 below depicts the current location of each monitoring station in Imperial 

County.

Figure 1

Ambient Air Monitoring Stations

Imperial County

*Calexico-East was closed in 2010

*Westmorland station experienced an electrical fire in 2012

2 Code of Federal Regulations, Title 40 Part 58, Appendix C

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II AIR MONITORING NETWORK DESIGN OVERVIEW

A Monitoring Objectives

The SLAMS network for Imperial County includes a total of five monitoring stations

located within the urban areas of Westmorland, Brawley, El Centro and Calexico and 

one station located in the rural area of Niland. The Air District operates four of the 

monitoring stations while the CARB operates the monitoring station in Calexico. All data 

and information concerning the Calexico monitoring station was obtained from CARB 

and is accurate to the best of our knowledge.

Specific criteria pollutants and meteorological parameters are monitored at each air 

monitoring station in Imperial County. For a list of the different measured pollutants and

parameters see page 28 Table 26 and section VIII Detailed site information. All data 

stemming from the network must abide by all applicable quality assurance requirements 

(40 CFR Part 58 Appendix A), ambient air quality monitoring methodology (40 CFR Part 

58 Appendix C), network design criteria (40 CFR Part 58 Appendix D) and must meet all 

applicable monitoring probe and path siting criteria (40 CFR Part 58 Appendix E). This 

allows for the proper management of a quality system that assures monitoring

information is produced in a systematic and organized way.

The intent of any air monitoring network should be to meet well defined needs, uses and 

purpose. In order to accomplish this, Appendix D of 40 CFR Part 58 requires all 

monitoring networks to be designed in such a way as to meet three basic monitoring 

objectives.

1. Provide air pollution data to the general public in a timely manner.

2. Support compliance with ambient air quality standards and emission strategy 

development.

3. Support for air pollution research studies.

All established air monitoring stations in Imperial County provide the three basic 

monitoring objectives mentioned above. Combined these three basic monitoring 

objectives directly relate to public exposure (PE). PE requires that decision making 

bodies be well informed about peak air pollution levels, typical levels in populated areas, 

the impact of transport either basin wide or internationally, and any source specific air 

pollution levels. The Air District analyzed all the monitoring sites to identify if the site 

classifies as either a highest concentration site, typical concentration site, a general 

background concentration site, a regional transport site (includes international 

transport), a site to determine the impact of significant sources or source categories or a 

site which measures impacts to visibility, vegetation damage, or other welfare based 

impact.

The following tables identify the site classifications for each monitor in Imperial County.

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TABLE 1

OZONE (44201) 8 HR MAX NO2 (42602) ANN 98%

YEAR

SITE 

LOCATION SITE TYPE PPM SITE TYPE PPB

2010 Calexico 

Ethel

Regional/Typical 

Concentrations (R/TC) 0.082 Highest Concentration 56.0 (HC)

El Centro Highest Concentration (HC) 0.082 Typical 

Concentration 41.9 (TC)

Niland General Background (GB) 0.075 No NO2 Monitoring N/A N/A

Westmorland Regional/Background (R/B) 0.077 No NO2 Monitoring N/A N/A

2011 Calexico 

Ethel

Regional/Typical 

Concentrations (R/TC) 0.076 Highest Concentration 63.0 (HC)

El Centro Highest Concentration (HC) 0.084 Typical 

Concentration 51.9 (TC)

Niland General Background (GB) 0.074 No NO2 Monitoring N/A N/A

Westmorland Regional/Background (R/B) 0.081 No NO2 Monitoring N/A N/A

2012 Calexico 

Ethel

Regional/Typical 

Concentrations (R/TC) 0.095 Highest Concentration 66.0 (HC)

El Centro Highest Concentration (HC) 0.091 Typical 

Concentration 49.8 (TC)

Niland General Background (GB) 0.076 No NO2 Monitoring N/A N/A

Westmorland Regional/Background (R/B) 0.074 No NO2 Monitoring N/A N/A

TABLE 2

CO (42101) 1 HR 

MAX

8 HR 

MAX SO2 (42401) 98% 3 HR

YEAR SITE

LOCATION SITE TYPE PPM PPM SITE TYPE PPB PPM

2010 Calexico 

Ethel

Typical 

Concentration (TC) 6.1 4.5 Typical Concentration 7 0.024 (TC)

El Centro Highest 

Concentration (HC) 19.6 5.6 No SO2 Monitoring N/A N/A N/A

2011 Calexico 

Ethel

Typical 

Concentration (TC) 7.7 6.1 Typical Concentration 8 0.025 (TC)

El Centro Highest 

Concentration (HC) 36.0 9.0 No SO2 Monitoring N/A N/A N/A

2012 Calexico 

Ethel

Typical 

Concentration (TC) 6.7 4.9 Typical Concentration 7 0.330 (TC)

El Centro Highest 

Concentration (HC) 25.1 7.4 No SO2 Monitoring N/A N/A N/A

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TABLE 3

PM10 (81102) 24 HR PM2.5 (88101) 24 HR ANN

YEAR

SITE 

LOCATION SITE TYPE μ/m3 SITE TYPE μ/m3 μ/m3

2010 Calexico 

Ethel Highest Concentrations (HC) 112 Highest Concentration 50.9 12.8 (HC)

El Centro Typical Concentrations (TC) 69 Typical Concentration 19.9 6.6 (TC)

Brawley Typical Concentrations (TC) 61 Background/Transport 16.2 6.2 (B/T)

Niland General Background (GB) 58 No PM2.5 Monitoring N/A N/A N/A

Westmorland Regional/Background (R/B) 86 No PM2.5 Monitoring N/A N/A N/A

2011 Calexico 

Ethel Highest Concentrations (HC) 80 Highest Concentration 80.3 13.5 (HC)

El Centro Highest Concentration (HC) 81 Typical Concentration 54.4 7.5 (TC)

Brawley Typical Concentrations (TC) 85 Background/Transport 37.0 7.1 (B/T)

Niland General Background (GB) 220 No PM2.5 Monitoring N/A N/A N/A

Westmorland Regional/Background (R/B) 74 No PM2.5 Monitoring N/A N/A N/A

2012 Calexico 

Ethel Highest Concentrations (HC) 406 Highest Concentration 64.7 14.4 (HC)

El Centro Highest Concentration (HC) 75 Typical Concentration 26.4 7.5 (TC)

Brawley Typical Concentrations (TC) 127 Background/Transport 25.9 8.1 (B/T)

Niland General Background (GB) 212 No PM2.5 Monitoring N/A N/A N/A

Westmorland Regional/Background (R/B) 109 No PM2.5 Monitoring N/A N/A N/A

B Spatial Scales

As mentioned above, PE is the basic monitoring objective for all air monitoring stations 

in Imperial County. In order to determine whether a monitor has been properly sited 

monitors must be represented by its spatial scale. The relationship between the 

monitoring objective, site type and the geographic location is understood or interpreted 

by the spatial scale of representativeness. In some cases, the physical location of a 

monitor is determined by considering the affect of identified emission patterns and not 

the spatial scale of representativeness. In these situations the spatial scale of 

representativeness is a result of the site location.

The spatial scale is described in the CFR as “...the physical dimensions of the air parcel 

nearest to a monitoring site throughout which actual pollutant concentrations are 

reasonably similar.”3

 Listed below are the general spatial scales identified as the most 

appropriate for the monitoring site types. Depending on the monitored pollutant the 

description may change slightly because of the behavior of the pollutant. Nonetheless, 

generally the spatial scales are as follows:

Microscale (MCS) – Defines the concentrations in air volumes associated with area 

dimensions ranging from several meters up to about 100 meters.

Middle Scale (MS) – Defines the concentration typical of areas up to several city blocks 

in size with dimensions ranging from about 100 meters to 0.5 kilometer.

3 Code of Federal Regulation Appendix D to Part 58 – Network Design Criteria for Ambient Air Quality Monitoring, 

section 1.2 Spatial Scales, subsection (b).

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Neighborhood Scale (NS) – Defines concentrations within some extended area of the city 

that has relatively uniform land use with dimensions in the 0.5 to 4.0 kilometer range. 

The neighborhood and urban scales have the potential to overlap in applications that 

concern secondarily formed or homogeneously distributed air pollutants.

Urban Scale (US) – Defines concentrations within an area of city-like dimensions, on the 

order of 4 to 50 kilometers. Within a city, the geographic placement of sources may 

result in there being no single site that can be said to represent air quality on an urban 

scale.

Regional Scale (RS) – Defines usually a rural area of reasonably homogeneous 

geography without large sources, and extends from tens to hundreds of kilometers.

National and Global Scales (NGS) – These measurement scales represent 

concentrations characterizing the nation and the globe as a whole. (There are no 

National or global scales monitoring stations in Imperial County.)

TABLE 4

SITE TYPE RELATIONSHIP TO SCALES OF REPRESENTATIVENESS

SITE TYPE APPROPRIATE SITING SCALES

1 Highest Concentration Micro, middle, neighborhood and sometimes 

urban or regional for secondarily formed 

pollutants

2 Population Oriented Neighborhood, urban

3 Source Impact Micro, middle, neighborhood

4 General/Background & regional 

transport

Urban, regional

5 Welfare-related Impacts Urban, regional

The following tables demonstrate the spatial scales for each monitor in Imperial County.

TABLE 5

OZONE (44201) 8 HR MAX NO2 (42602) ANN 98%

YEAR

SITE 

LOCATION SITE TYPE SCALE PPM SITE TYPE SCALE PPB

2010 Calexico 

Ethel R/TC Urban 0.082 HC Urban 56.0

El Centro HC Neighborhood 0.082 TC Neighborhood 41.9

Niland GB Regional 0.075 No NO2 Monitoring N/A N/A

Westmorland R/B Regional 0.077 No NO2 Monitoring N/A N/A

2011 Calexico 

Ethel R/TC Urban 0.076 HC Urban 63.0

El Centro HC Neighborhood 0.084 TC Neighborhood 51.9

Niland GB Regional 0.074 No NO2 Monitoring N/A N/A

Westmorland R/B Regional 0.081 No NO2 Monitoring N/A N/A

2012 Calexico 

Ethel R/TC Urban 0.095 HC Urban 66.0

El Centro HC Neighborhood 0.091 TC Neighborhood 49.8

Niland GB Regional 0.076 No NO2 Monitoring N/A N/A

Westmorland R/B Regional 0.074 No NO2 Monitoring N/A N/A

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The scale of representativeness for O3 monitoring would not occur under small but 

rather large volumes of air. Therefore, neighborhood, urban and regional spatial scales 

would be appropriate for O3. Data trends seem to indicate that the Calexico monitor 

meets the urban spatial scale while the El Centro monitor meets the neighborhood 

spatial scale. Both the Niland and Westmorland monitors meet the regional spatial 

scale. Although data indicates that both the Calexico and El Centro monitors measure

both regional and urban mixing the Calexico monitor measures downwind transport

concentrations from an international source. While the Niland and Westmorland 

monitors typically measure transported O3 from other air basins in California.

The El Centro monitor most closely meets the neighborhood spatial scale as the site is 

located away from immediate Nitrogen Dioxide (NO2) sources. The Calexico monitor 

however provides transport impact information for trend analysis. This is because the 

monitor is approximately 2.5 miles away from a major international port of entry, where 

high volumes of mobile source emissions are present. However, unlike a major 

roadway the majority of the mobile sources are idling for significant periods of time and 

little to no heavy duty vehicles are present. The Calexico monitor most closely meets 

the urban spatial scale.

TABLE 6

CO (42101) 1 HR MAX 8 HR MAX SO2 (42401) 98% 3 HR

YEAR

SITE 

LOCATION SITE TYPE SCALE PPM PPM SITE TYPE SCALE PPB PPM

2010 Calexico 

Ethel TC Middle 6.1 4.5 TC Urban 7 0.024

El Centro HC Neighborhood 19.6 5.6 No SO2 Monitoring N/A N/A N/A

2011 Calexico 

Ethel TC Middle 7.7 6.1 TC Urban 8 0.025

El Centro HC Neighborhood 36.0 9.0 No SO2 Monitoring N/A N/A N/A

2012 Calexico 

Ethel TC Middle 6.7 4.9 TC Urban 7 0.330

El Centro HC Neighborhood 25.1 7.4 No SO2 Monitoring N/A N/A N/A

Because CO is primarily occurring in areas near major roadways and intersections with 

high traffic density the El Centro and Calexico monitors meet the neighborhood and 

middle spatial scales, respectively. It may be argued that the Calexico Ethel monitor 

may also fit the neighborhood scale because of the proximity of international roadway 

emissions. This assessment is still under review and requires further evaluation.

The most appropriate spatial scale for the Sulfur Dioxide (SO2) monitor in Calexico is 

the urban spatial scale. The Calexico monitor is located away from stationary point and 

area sources of SO2 however, this site is unique in that it is located just north of a major 

international metropolitan and as such is ideal for identifying trends and background 

concentrations.

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TABLE 7

PM10 (81102) 24 HR PM2.5 (88101) 24 HR ANN

YEAR

SITE 

LOCATION SITE TYPE SCALE μ/m3 SITE TYPE SCALE μ/m3 μ/m3

2010 Calexico 

Ethel HC Neighborhood 112 HC Neighborhood 50.9 12.8

El Centro TC Neighborhood 69 TC Neighborhood 19.9 6.6

Brawley TC Neighborhood 61 B/T Neighborhood 16.2 6.2

Niland GB Middle 58 No PM2.5 Monitoring N/A N/A N/A

Westmorland R/B Middle 86 No PM2.5 Monitoring N/A N/A N/A

2011 Calexico 

Ethel HC Neighborhood 80 HC Neighborhood 80.3 13.5

El Centro TC Neighborhood 81 TC Neighborhood 54.4 7.5

Brawley TC Neighborhood 85 B/T Neighborhood 37.0 7.1

Niland GB Middle 220 No PM2.5 Monitoring N/A N/A N/A

Westmorland R/B Middle 74 No PM2.5 Monitoring N/A N/A N/A

2012 Calexico 

Ethel HC Neighborhood 406 HC Neighborhood 64.7 14.4

El Centro TC Neighborhood 75 TC Neighborhood 26.4 7.5

Brawley TC Neighborhood 127 B/T Neighborhood 25.9 8.1

Niland GB Middle 212 No PM2.5 Monitoring N/A N/A N/A

Westmorland R/B Middle 109 No PM2.5 Monitoring N/A N/A N/A

In Imperial County size selective inlet high volume samplers are operated at 5 sites 

Brawley, Calexico, El Centro, Niland and Westmorland. Three of the monitors for PM10

sampling in Imperial County can be categorized as neighborhood scale, while two can 

be categorized as middle scale. Both the particulate matter concentrations and the land 

use and land surface characteristics can be said to be homogeneous among all the 

monitoring stations albeit in their own unique way. The Brawley, Calexico and El Centro 

monitors can be said to represent conditions where people commonly live and work for 

extended periods and provide comparisons between cities. The Niland and 

Westmorland monitors help provide short-term exposure to public health effects as 

these monitors tend to provide PM10 emissions on outlaying rural areas.

In addition to the high volume samplers two designated SPM PM10 BAM units are 

operated in Niland and Brawley. These BAM units are utilized primarily for research and 

public advisory purposes.

US EPA approved FRM PM2.5 monitors operate within the cities of Brawley, Calexico 

and EI Centro. The Brawley and El Centro PM2.5 monitors (which are not collocated) 

represent a reasonably homogeneous urban sub-region with similar land use and land 

surface characteristics. These sites provide information about trends and compliance 

with the NAAQS. The Calexico site includes collocated FRM PM2.5 monitors and 

collocated SPM non FEM continuous PM2.5 analyzers combined these monitors are 

intended to capture those characteristic concentrations associated with heavy mobile 

emissions and their exposure to the general public. Because of the close proximity of 

the international port of entry the Calexico PM2.5 monitors combined are appropriate for 

the evaluation of possible short-term PE, population exposure, trends and compliance 

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with the NAAQS. Finally, the Calexico monitors consistently record the highest 

concentrations for PM2.5 within the Imperial County air monitoring network. Therefore, 

the most appropriate spatial scale for Brawley, Calexico and El Centro is the 

neighborhood scale.

C Purpose

As mentioned above, the intent of any air monitoring network should be to meet well

defined needs, uses and purpose. A properly established monitoring station should 

target the key data collection need identified by the monitoring objective and spatial 

scale of the site. Nationally, there are several different types of monitoring stations 

varying in technical sophistication. Locally, all the monitoring stations in Imperial 

County measure the levels of concentrations affecting the general public or public 

exposure. As such all the air monitoring stations meet the three basic monitoring 

objectives that relate to public exposure. Below is the list of the basic monitoring 

objectives and an explanation of how the data is utilized to meet those objectives.

1. Provide air pollution data to the general public in a timely manner.

a Utilizing the CARB sponsored Air Quality and Meteorological Information 

System (AQMIS) http://www.arb.ca.gov/aqmis2/aqmis2.php. To do this, the 

Air District provides hourly data via a transmission control protocol (TCP) over 

the World Wide Web. Data transmitted in this format is “real time” data 

subject to change upon undergoing verification protocol.

b Utilizing the Air Quality Index (AQI) format, the Air District provides AQI 

notifications and information to the general public via the 

www.imperialvalleyair.org webpage. This site allows the public or any 

interested party to subscribe to instant messaging via e-mail or text for 

notifications concerning levels of PM10 and/or seasonal forecast for Ozone. 

The Imperial Valley Air webpage also supports an independent school 

program in Calexico, Heber, El Centro and Brawley designed to help 

minimize impacts to students during unusually high particulate days.

c Finally, the Air District posts daily meteorological conditions and advisories, 

such as wind advisories, on the Imperial County Air Pollution Control District 

webpage for use by the general public. Such information is designed as a 

guide for members of the public, industry and governments when making 

decisions on the type of activity they intend to commit to during any one given 

day.

2. Provide compliance and emission strategy development and support.

Currently, all SLAMS data is utilized in the development of attainment and 

maintenance plans. The Air District, along with the CARB, continually review 

existing data for trends, peaks and seasonal variations that allow for proper regional 

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air quality modeling. Regional air Quality modeling is used to develop emissions 

strategies and to identify the impact of control measures, either as improving air 

quality or as an identification of where improvement is needed. 

On August 11, 2009 the Imperial County Board of Directors adopted the 2009 PM10

State Implementation Plan (SIP) and on July 13, 2010 the same board adopted the 

2009 8-Hour Ozone Air Quality Management Plan. The newest SIP development is 

that of the PM2.5 SIP.

3. Provide support for air pollution research studies.

The CARB is the lead agency for working on research studies related to health effect 

assessments, atmospheric processes and for monitoring methods development. 

CARB issues its “State and Local Air Monitoring Network Plan” which covers the 

monitoring networks throughout the state. In addition, the CARB maintains a 

comprehensive webpage, with information concerning the “Air Quality Monitoring 

Network” activities, studies, and research conducted for the entire state. 

http://www.arb.ca.gov/aqd/aqmoninca.htm

The pollutants of primary interest here in Imperial County are listed in detail under 

section VI Overall Summary of the Imperial County Ambient Air Monitoring Network. 

The following tables describe the monitoring purpose per monitor in Imperial County.

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TABLE 8

NETWORK MONITORING PURPOSE (GASEOUS CRITERIA POLLUTANTS)

Name El Centro Brawley Westmorland Niland Calexico

Address 15O S. 9th St. 220 Main St. 570 Cook St. 7711 English Rd. 1020 Belcher St.

Lat/Long. N 32.79215 

W -115.56299

N 32.97831 

W -115.53904

N 33.03239 

W -115.62362

N 33.21383 

W -115.54448

N 32.67618 

W -115.48307

AQS ID 06 025 1003 06 025 0007 06 025 4003 06 025 4004 06 025 0005

ARB ID 13694 13701 13697 13997 13698

Operator ICAPCD ICAPCD ICAPCD ICAPCD CARB

O3

Monitor 

Designation SLAMS SLAMS SLAMS SLAMS SLAMS

Sampling 

Method API T400 44201 API 400A 44201 API 400A 44201 API 400E 44201

Spatial Scale NEIGHBORHOOD REGIONAL REGIONAL URBAN

Monitor 

Objective

PUBLIC 

EXPOSURE

PUBLIC 

EXPOSURE

PUBLIC 

EXPOSURE

PUBLIC 

EXPOSURE

CO

Monitor 

Designation SLAMS SLAMS SLAMS SLAMS SLAMS

Sampling 

Method API T300 42101 DASIBI 3008 42101

Spatial Scale NEIGHBORHOOD MIDDLE

Monitor 

Objective

PUBLIC 

EXPOSURE

PUBLIC 

EXPOSURE

NO2

Monitor 

Designation SLAMS SLAMS SLAMS SLAMS SLAMS

Sampling 

Method API 200A 42602 API 200E

Spatial Scale NEIGHBORHOOD URBAN

Monitor 

Objective

PUBLIC 

EXPOSURE

PUBLIC 

EXPOSURE

SO2

Monitor 

Designation SLAMS SLAMS SLAMS SLAMS SLAMS

Sampling 

Method TECO 43

Spatial Scale URBAN

Monitor 

Objective

PUBLIC 

EXPOSURE

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TABLE 9

NETWORK MONITORING PURPOSE

(PARTICULATE POLLUTANTS)

Name Brawley Niland

Address 220 Main St. 7711 English Rd.

Operator ICAPCD ICAPCD

PM10

Monitor 

Designation SLAMS SPM SLAMS SPM

Sampling 

Method

GMW/SA 1200 

81102

MET ONE 

BAM1020 85101

GMW/SA 

1200 81102

MET ONE 

BAM1020 

85101

Spatial 

Scale NEIGHBORHOOD MIDDLE

Monitor 

Objective 

PUBLIC 

EXPOSURE SUPPORT PUBLIC EXPOSURE SUPPORT

Sampling 

Frequency 1-6 CONTINUOUS 1-6 CONTINUOUS

TABLE 10

NETWORK MONITORING PURPOSE

(PARTICULATE POLLUTANTS)

Name El Centro Calexico Westmorland

Address 150 S. 9th St. 1020 Belcher St. 570 Cook St.

Operator ICAPCD CARB ICAPCD

PM10

Monitor 

Designation SLAMS SLAMS SLAMS

Sampling 

Method

GMW/SA 1200 

81102

GMW/SA 1200 

81102 GMW/SA 1200 81102

Spatial 

Scale NEIGHBORHOOD NEIGHBORHOOD NEIGHBORHOOD

Monitor 

Objective 

PUBLIC 

EXPOSURE

PUBLIC 

EXPOSURE PUBLIC EXPOSURE

Sampling 

Frequency

1-6 1-6 1-6

TABLE 11

NETWORK MONITORING PURPOSE

(PARTICULATE POLLUTANTS)

Name Brawley El Centro

Address 220 Main St. 15O S. 9th St.

Operator ICAPCD ICAPCD

PM2.5

Monitor 

Designation SLAMS SLAMS

Sampling 

Method R&P 2025 (WINS) 88101 R&P 2025 (WINS) 88101

Spatial Scale NEIGHBORHOOD NEIGHBORHOOD

Monitor 

Objective PUBLIC EXPOSURE PUBLIC EXPOSURE

Sampling 

Frequency 1-3 1-3

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Annual Air Monitoring Network Plan 2013
TABLE 12

NETWORK MONITORING PURPOSE

(PARTICULATE POLLUTANTS)

Name Calexico

Address 1020 Belcher St.

Operator CARB

PM2.5

Monitor 

Designation SLAMS SLAMS SPM SPM

Sampling 

Method

R&P 2025 (VSCC) 

88101 POC1

R&P 2025 (VSCC) 

88101 POC2

MET ONE 

BAM 1020 

88501 POC3

MET ONE 

BAM 1020 

88501 POC4

Spatial 

Scale NEIGHBORHOOD NEIGHBORHOOD

Monitor 

Objective

PUBLIC 

EXPOSURE

PUBLIC 

EXPOSURE SUPPORT SUPPORT

Sampling 

Frequency 1-3 1-6 CONTINUOUS CONTINUOUS

III MONITORING REQUIREMENTS

As mentioned in the introduction, there are no NCore or PAMS located in Imperial 

County. Because there are no NCore stations there is no coarse particulate matter 

(PM10-2.5) monitoring or lead (Pb) monitoring. In addition, the Imperial County Airport 

was not one of the 15 airports selected by the US EPA for study, nor are there any 

stationary sources in Imperial County meeting the 0.5 tons per year (tpy) threshold 

established by US EPA. There is however, lead monitoring used for State and local 

purposes only at the Calexico Ethel site that is not required under any federal 

monitoring requirement.

Federal regulation requires a minimum number of monitors per pollutant and grants 

discretionary authority to the Regional Administrator, under certain conditions, to require 

additional monitors above and beyond that required by the minimum standards. To 

determine the total minimum number of required monitor’s specific consideration is 

given to the pollutant of interest, purpose and population. To address population the 

CFR utilizes a statistical-based definition of a metropolitan area provided by the Office 

of Management and Budget and the Census Bureau. Pertinent to Imperial County is the 

metropolitan statistical area (MSA) which has been defined as a Core Based Statistical 

Area (CBSA) associated with at least one urbanized area with a population of 50,000 or 

more. Imperial County is part of the EI Centro MSA, referenced as 20940. It covers the 

major cities in our county and has a population count of 174,528 (2010 U.S. Census 

Bureau information).

Overall, Imperial County meets or exceeds US EPA's minimum requirements. 

Depending on the monitoring objective, state and local agencies will operate more 

monitors than are required by law. Typically, additional monitors are used to fulfill state 

and local purposes for monitoring that are in addition to federal purposes. California air 

quality standards are more stringent than federal standards and require more ambient 

Imperial County Air Pollution Control District Page 18 of 53

Annual Air Monitoring Network Plan 2013
air monitoring to show compliance with the state standards. Monitors are also used to 

keep the public informed of the actual air quality conditions where they live and work.

For O3, PM2.5 and PM10, the required minimum number of monitoring sites is based on 

area size (in terms of population and geographic characteristics) and typical peak 

concentrations, either below or near the NAAQS. For other pollutants, no monitoring is 

required unless an area exceeds or is close to exceeding a NAAQS. 

A Ozone (O3)

Currently, under federal regulation there are two Ozone NAAQS to be met. Although 

the US EPA determined, on December 3, 2009, that the Imperial County "moderate" 8-

hour ozone non-attainment area attained the 1997 8-hour Ozone standard the Imperial 

County is classified by US EPA as a "moderate" non-attainment area. For the new 

2008 8-hour ozone standard Imperial County has been classified as a “marginal” nonattainment area.

In designing an O3 monitoring network factors such as geographic size, population 

density, complexity of terrain, meteorology and air pollution transport must be 

considered.

Up until November of 2012, four (4) ozone monitors functioned in Imperial County. 

Because of an electrical fire, the Westmorland ozone monitor was placed out of 

commission. Monitoring for O3 in Imperial County is year round with forecasting 

capabilities during the “ozone season”. For the three year period 2010-2012 El Centro 

recorded the highest concentration among all sites within the monitoring network. El 

Centro’s 8 hour design value is 0.081ppm4

. Although El Centro is considered the 

highest concentration site all sites are used to keep the public informed of air quality 

utilizing the Air Quality Index (AQI) reporting framework and air quality mapping.

4

 In 2012 Calexico had the highest daily concentration, 0.095 vs. El Centro concentration of 0.091 however the design value of El 

Centro remained the highest of the four stations.

TABLE 13

SLAMS MINIMUM O3 MONITORING REQUIREMENTS

MSA

MOST RECENT 3-YEAR DESIGN 

VALUE

MOST RECENT 3-YEAR DESIGN 

VALUE

POPULATION CONCENTRATION ≥85% OF ANY 

O3 NAAQS

CONCENTRATIONS <85% OF 

ANY O3 NAAQS

> 10 million 4 2

4-10 million 3 1

350,000-<4 million 2 1

50,000-<350,000 1 0

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Annual Air Monitoring Network Plan 2013

 
TABLE 14

Summary of Minimum Monitoring Requirements Ozone

MSA County Population 

(year 2010)

8-hr design 

value (years)

Min # of 

monitors 

required

Number of 

active 

monitors

Monitors 

needed

20940 

El Centro Imperial 174,528 0.081 ppm 

2010 2012 1 4* 0

MSA

20940

El Centro

Monitor

Site

8-hr design 

value(years)

2010 2012

≥85% of 

2008 O3

NAAQS

(.075 ppm)

Min # of 

monitors 

required

Number of 

active 

monitors

Monitors 

needed

Population 

(year 2010)

174,528

El Centro

Calexico

Westmorland

Niland

0.081 ppm

0.075 ppm

0.071ppm

0.070 ppm

YES

YES

NO

NO

1 4* 0

*The Westmorland Station experienced an electrical fire November of 2012. Currently, the station does not monitor for Ozone.

B Carbon Monoxide (CO)

Population density is the significant trigger for CO monitoring. High population densities 

of 1 million and above trigger the requirement of a single CO monitor along with a nearroad NO2 monitor. Imperial County does not meet the population requirement under the 

CFR for required CO monitoring. However, continued operation of existing SLAMS CO 

sites using FRM or FEM is required until discontinuation is approved by the US EPA 

Regional Administrator. There are two SLAMS CO monitors operating within the 

Imperial County monitoring network. For 2012, the maximum 1-hour CO concentration 

for El Centro was 25.1 ppm, and for Calexico Ethel 6.7 ppm.

TABLE 15

Summary of Minimum Monitoring Requirements CO

MSA County Population 

(year 2010)

8-hr max 

value (years)

Min # of 

monitors 

required

Number of 

active 

monitors

Monitors 

needed

20940 

El Centro Imperial 174,528 7.5 ppm 

2010 2012 0 2 0

C Nitrogen Dioxide (NO2)

Regulation requires the establishment of one microscale near-road NO2 monitoring 

station within CBSA’s with a population of 500,000 or more. Regulation further requires 

that there be one NO2 monitoring station within CBSA’s with a population of 1,000,000 

or more. The Imperial County does not meet either requirement. Nevertheless, 

continued operation of existing SLAMS NO2 sites is required until discontinuation is 

approved by the US EPA Regional Administrator. There are two SLAMS NO2 monitors 

operating within the Imperial County monitoring network. The highest concentration site 

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Annual Air Monitoring Network Plan 2013
is the Calexico Ethel site with an 8 hour design value of 62 ppb (2010 2012 data) and 

the 2012 98th percentile of 66 ppb. For 2012 the maximum 1-hr concentration of 91 ppb

was recorded at the Calexico Ethel monitoring station.

TABLE 16

Summary of Minimum Monitoring Requirements NO2

MSA County Population 

(year 2010)

8-hr design 

value (years)

Min # of 

monitors 

required

Number of 

active 

monitors

Monitors 

needed

20940 

El Centro Imperial 174,528 62 ppb 

2010 2012 0 2 0

D Sulfur Dioxide (SO2)

Regulation requires States for each CBSA to calculate the Population Weighted 

Emissions Index (PWEI) in millions persons-tons per year of SO2. Thresholds for the 

SO2 monitoring requirements begin at a PWEI of 1,000,000 down to 5,000. At a PWEI 

equal to or greater than 5,000 but less than 100,000 a minimum of one SO2 monitor is 

required. At a PWEI equal to or greater than 100,000 but less than 1,000,000 a 

minimum of two SO2 monitors are required. The only SO2 monitor operating within the 

Imperial County is located in Calexico. For 2012, the maximum concentration for 

Calexico Ethel for 1-hr was 15 ppb the 99th percentile is 7 ppb (2010 2012). PEWI

calculated using 2008 emission inventory data for Sulfur Oxide (SOX) result in a value of 

0.07 million persons-tons/yr.

E Particulate Matter (PM10)

According to regulation the number of PM10 stations must range between 2 and 10 

stations in areas where MSA populations exceed 1,000,000. Low population urban 

areas are not required to have more than two (2) PM10 stations. Regulation further 

assesses the minimum monitoring requirement for PM10 according to levels of 

concentration. For those areas with a MSA population equal to or less than 250,000 but 

greater than 100,000 the minimum required number of PM10 monitors is summarized 

below.

TABLE 17

Summary of Minimum Monitoring Requirements SO2

MSA County Population 

(year 2010)

Min # of 

monitors 

required

Number of 

active 

monitors

Monitors 

needed

20940 

El Centro Imperial 174,528 1 1 0

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Annual Air Monitoring Network Plan 2013
TABLE 18

PM10 MINIMUM REQUIRED MONITORS PER CONCENTRATION LEVEL

HIGH MEDIUM LOW

CONCENTRATION CONCENTRATION CONCENTRATION

1-2 0-1 0

High concentration areas are those areas in which the ambient PM10 concentrations 

exceed the PM10 NAAQS by 20 percent or more (180μ/m3). Medium concentration 

areas are those areas where ambient PM10 concentrations exceed 80% percent of the 

PM10 NAAQS (>127.5μ/m3). Low concentration areas are those areas where ambient 

PM10 concentrations are less than 80% of the PM10 NAAQS (<127.5μ/m3). Because 

each area has its own unique sources of pollutants and controls the number of stations 

is ultimately determined jointly by US EPA and the State.

Imperial County is classified by US EPA as a “serious” non-attainment area for PM10. All 

PM10 monitors operate on a one in six day schedule. On annual average, Brawley and 

Calexico record the highest concentrations within the monitoring network. Calexico’s

annual measurement is 63.6μ/m3 while Brawley’s annual measurement is 37.9μ/m3.

TABLE 19

2012 Calexico Brawley El Centro Westmorland Niland

Annual Max. 406 127 75 109 212 μg/m3

Annual Mean 63.6 37.9 32.9 35.9 37.8 μg/m3

TABLE 20

Summary for Minimum Monitoring Requirements PM10

MSA

20940 

El Centro

County

Imperial

Population (year 

2010)

174,528

Min # of 

monitors 

required

Number of 

active 

monitors

Monitors needed

SITE

Calexico

Niland

Brawley

Westmorland

El Centro

Max 

406

212

127

109

75

Avg.Mean

63.3

37.8

37.9

35.9

32.9

2 5 0

F Particulate Matter (PM2.5)

Federal regulation requires that all State, and where applicable, local agencies operate 

the minimum number of required PM2.5 monitoring sites. The minimum required PM2.5

monitoring sites is determined by MSA population and the most recent 3-year design 

value. See Table 9 for a summary below. 

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Annual Air Monitoring Network Plan 2013
TABLE 21

PM2.5 MINIMUM MONITORING REQUIREMENTS

MSA

MOST RECENT 3-YEAR DESIGN 

VALUE

MOST RECENT 3-YEAR DESIGN 

VALUE

POPULATION CONCENTRATION ≥85% OF ANY 

PM2.5 NAAQS

CONCENTRATIONS <85% OF ANY 

PM2.5 NAAQS

> 1 million 3 2

500,000 - 1 million 2 1

50,000 - <500,000 1 0

Regulation further requires all required monitoring sites to be sited to represent 

community-wide air quality. The community-wide site must be located in a populationoriented area of expected maximum concentration. In addition, the regulation requires 

State, or where appropriate, local agencies to operate continuous PM2.5 analyzers equal 

to at least one-half (round up) the minimum required monitoring sites. On this point, the 

regulation further explains that at least one required continuous analyzer in each MSA 

must be collocated with one of the required FRM/FEM/ARM monitors unless the monitor 

is itself a continuous FEM or ARM monitor in which case no collocation requirement 

applies. Finally, the regulation requires States to establish PM2.5 background and 

transport sites, as well as conduct PM2.5 chemical speciation utilizing Speciation Trends 

Network (STN).

TABLE 22

Summary for Minimum Monitoring Requirements PM2.5

MSA County Population 

(year 2010)

8-hr design value 

(2010-2012)

Min # of 

monitors 

required

Number of 

active 

monitors

Monitors 

needed

20940 

El Centro Imperial 174,528 32μ/m3 1 3 0

SPATIAL AVERAGING APPROACHES FOR PM2.5

The PM2.5 NAAQS as specified in 40 CFR part 50 allows State and local air monitoring 

agencies to spatially average PM2.5 air quality data for comparison to the annual PM2.5

NAAQS. This approach is not however comparable with the daily PM2.5 NAAQS and is 

directly related to epidemiological studies. The Air District has not opted to use spatial 

averaging nor has the State included spatial averaging in Calexico. Consultation with 

CARB and US EPA will occur should circumstances change such that the Air District 

would consider spatial averaging as necessary in the future.

COLLOCATION REQUIREMENTS

Appendix A of 40 CFR 58 includes requirements for collocation of samplers as part of 

quality checks for the PM2.5 continuous PM2.5, PM10 and Pb monitoring networks. The 

requirements are to be met by each PQAO. Currently, there are four PQAO’s in 

California, San Francisco Bay Area AQMD, San Diego County APCD, South Coast 

AQMD and CARB. The respective requirements for collocation PM2.5 is discussed by 

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Annual Air Monitoring Network Plan 2013
each PQAO in their respective Network Plans. CARB’s 2013 Annual Monitoring 

Network Report for Small Districts in California contains information regarding the 

collocation requirements on pages 34 through 37.

IV SAMPLING FREQUENCY REVIEW

The PM10 five year assessment resulted in no changes to current sampling frequencies 

for PM10 in Imperial County.

TABLE 23

PM10 Sampling Frequency Calculations

CALEXICO 0005 BRAWLEY 0007

1/6 Schedule 2008 2009 2010 2011 2012 2008 2009 2010 2011 2012

Design conc. = Highest 110 275 112 80 406 137 196 61 85 127

Ratio to Standard --> 0.7 1.8 0.7 0.5 2.7 0.9 1.3 0.4 0.6 0.8

EL CENTRO 1003 WESTMORLAND 4003

2008 2009 2010 2011 2012 2008 2009 2010 2011 2012

88 243 69 81 75 136 161 86 74 109

Ratio to Standard --> 0.6 1.6 0.5 0.5 0.5 0.9 1.1 0.6 0.5 0.7

NILAND 4004

2008 2009 2010 2011 2012

121 202 58 220 212

Ratio to Standard --> 0.8 1.3 0.4 1.5 1.4

Methodology: Highest value of each month/each year.

The results of the PM2.5 five year assessment indicates that the Calexico Ethel station 

triggered the requirement for everyday sampling during the 2006-2008, 2007-2009 and 

2009-2011 design values (all based on the 24-hr design values within ±5% of the 

NAAQS). Discussions with US EPA indicate that everyday sampling should have been 

commenced as early as January 1, 2010 for a minimum of 3 years. US EPA’s position 

is that regulatory actions that include data that has not been meeting historical sampling 

frequency requirements cannot move forward unless the required sampling frequency is 

implemented. This is true even when the most current design value does not fall within 

the ±5% of the NAAQS. Therefore, the Calexico Ethel site is required to go to everyday 

sampling no later than October 1, 2013.

.

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Annual Air Monitoring Network Plan 2013
TABLE 24

PM2.5 Sampling Frequency Calculations

STATION YEAR 24 hour Annual

24 Hour 

Std

Annual 

Std

Within -/+ 5% of 

Std?

Daily 

sampling

Design 

Value

Design 

Value 35 12 24 hour Annual Required?

Calexico 2012 32 14 8.57 16.67 NO NO NO

Brawley 2012 18 7 48.57 41.67 NO NO NO

El Centro 2012 20 7 42.86 41.67 NO NO NO

Calexico 2011 35 14 0.00 16.67 YES NO YES

Brawley 2011 19 7 45.71 41.67 NO NO NO

El Centro 2011 20 7 42.86 41.67 NO NO NO

Calexico 2010 32 13 8.57 8.33 NO NO NO

Brawley 2010 19 8 45.71 33.33 NO NO NO

El Centro 2010 16 8 54.29 33.33 NO NO NO

Calexico 2009 34 13 2.86 8.33 YES NO YES

Brawley 2009 21 8 40.00 33.33 NO NO NO

El Centro 2009 18 8 48.57 33.33 NO NO NO

Calexico 2008 36 12 2.86 0.00 YES YES YES

Brawley 2008 19 8 45.71 33.33 NO NO NO

El Centro 2008 21 8 40.00 33.33 NO NO NO

References: AQS AMP480 Design Value Report (05.20.2013)

40 CFR 58.12(d)(iii) Required SLAMS whose measurements determine the design value for their area and that are 

within plus or minus 5 percent of the daily PM2.5 NAAQS must have an FRM or FEM operate on a daily schedule. A 

continuously operating FER or ARM PM2.5 monitor satisfies this requirement.

Final Network Plan memo (Region IX; May 08, 2012); Attachment E: % formula used – 24 hour standard ABS((35-

x)/(35)*100) Annual Standard ABS ((12-y)/(12)*100)

V PROPOSED MODIFICATIONS TO THE NETWORK DESIGN

Calexico East

CARB has discontinued monitoring activities at the Calexico East site since July 2010. 

US EPA formally approved the closure of Calexico East site April 2013.

Calexico Ethel

Both the Air District and CARB are currently evaluating the relocation of the Calexico

Ethel site. The current site has been overrun by development and tree growth. The 

proposed relocation is within a 1 mile perimeter from the current location. CARB and 

Air District staff concluded the physical aspect of the evaluation however the data 

review is still ongoing. No actual changes will occur until US EPA formally approves the 

newly proposed site. Review and discussions are ongoing.

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Annual Air Monitoring Network Plan 2013
Niland

Evaluation of the station shelter has resulted in the determination to replace the current 

shelter. 

Westmorland

An electrical fire resulted in the determination that the current shelter is in need of 

replacement. Damage from the fire resulted in the loss of the data logger and ozone 

monitor. A proper assessment of the station is pending. On finalization the Air District 

will submit the information to US EPA and CARB for discussion and approval.

VI QUALITY SYSTEM REQUIREMENTS

A Quality Management Plans (QMP) and Quality Assurance Project Plans (QAPP)

Federal regulation requires all organizations to develop a quality system which allows 

for the proper management of monitoring information in a systematic and organized 

manner. The quality system, when well developed, provides a framework for planning, 

implementing, assessing, reporting and for carrying out required quality assurance and 

quality control activities. Developing a Quality management plan (QMP) and a quality 

assurance project plan (QAPP) assures that monitoring results are well-defined for 

need, use, purpose, monitoring objective, as well as, compliance with applicable 

standards and statutory requirements. 

The QMP describes the quality system in terms of the organizational structure, 

functional responsibilities of management and staff, lines of authority, and required 

interfaces for those planning, implementing, assessing and reporting activities involving 

environmental data operations. The QMP must be approved by the Regional 

Administrator. The QAPP is a formal document describing the quality system in such a 

manner as to assure that the results of work performed will satisfy the stated objectives. 

Ultimately, the monitoring quality system must have a demonstration of adequate 

resources both in personnel and funding.

Currently, the Air District is developing its QMP and QAPP and expects to have a draft 

version of both by fall for review by CARB and US EPA. In addition, all Standard 

Operating Procedures, station site visit logs, troubleshooting and check logs have been 

updated and are in use by field technicians and reviewers.

B DATA REVIEW AND SUBMITTAL

Currently, all quality control and assurance procedures are in place, despite the fact that 

the QMP and QAPP have not been finalized. In practice, field technicians review and 

document all checks, flows, visits and troubleshooting evidence onto logs which are 

maintained at each station. All data is reviewed and all instrument systems are verified 

in working order on a daily basis. In order to maintain quality control prior to submitting 

certified data to CARB all data is reviewed by staff that is not tied to the data generation 

activity. Once all data points are checked and verified then staff submits the data in a 

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Annual Air Monitoring Network Plan 2013
formalized manner as certified data to CARB. In addition to certified data the Air District 

remits raw uncertified data for Air Quality Index advisories and forecasts.

Certified data submitted to CARB includes, all 1 hour ozone concentrations, all 1 hour 

NO, NO2 and NOx concentrations, all CO 1 hour concentrations, all PM10 continuous 1 

hour concentrations, all precision and accuracy data and all 1 hour meteorological 

concentrations. In addition, the Air District remits all PM10 filter samples to CARB, via a 

chain of custody protocol and PM2.5 filter samples to the San Diego Air Pollution Control 

District (SDAPCD) utilizing the accepted chain of custody protocol for PM2.5. All data is 

submitted either by CARB or SDAPCD on to the US EPA Air Quality System (AQS) 

after certification by the appropriate agency. Once in AQS US EPA will then affirm 

completeness and accuracy on an annual basis.

VII OVERALL SUMMARY OF THE IMPERIAL COUNTY AMBIENT AIR 

MONITORING NETWORK

The following tables and figures summarize the content of information provided within 

the descriptive sections of the Network Plan. Figure 1 on page 7 is a map listing the 

current operating ambient air monitoring stations in Imperial County. Table 25 is a list of 

all the Air Quality Monitoring Site locations. Table 26 lists the pollutants and other 

parameters monitored by site. Table 27 lists the criteria pollutant spatial scale and 

monitoring objective. All of the monitors operating in Imperial County are part of the 

SLAMS network.

The tables in this section give detailed information relating to the sites and monitors. 

They are presented to show compliance with the monitoring requirements found in 40 

CFR58.10.

TABLE 25

Ambient Air Quality Monitoring site locations in Imperial County

Location Address ARB 

No. AIRS No. Latitude Longitude

Niland 7711 English Road, Niland, CA 

92257 13997 060254004 33°12'49" 115°32'43"

Westmorland 570 Cook St., Westmorland, CA 

92281 13697 060254003 33°01'57" 115°37'25"

Brawley 220 Main St., Brawley, CA 92227 13701 060250007 32°58'42" 115°32'21"

El Centro 150 S. 9th St., El Centro, CA 92243 13694 060251003 32°47'32" 115°33'47"

Calexico 

Ethel

1029 Belcher St., Calexico, CA 

922231 13698 060250005 32°40'34" 115°28'59"

Imperial County Air Pollution Control District Page 27 of 53

Annual Air Monitoring Network Plan 2013
TABLE 26

Pollutants and Parameter Monitored per site

Location Pollutants Monitored Parameters Monitored

Niland O3, PM10 OT, RH, WD, HWS, BP

Westmorland O3, PM10 OT, RH, WD, HWS, BP

Brawley PM10, PM2.5 OT, BP

El Centro CO, NO2, O3, PM10, PM2.5 OT, WD, HWS, BP

Calexico Ethel CO, SO2, NO2, PM10, PM2.5 OT, RH, WD, HWS, BP, SR

Pollutant Parameter

O3 Ozone OT Outside Temperature

PM10 Particulate Matter <10 microns RH Relative Humidity

PM2.5 Particulate Matter <2.5 microns WD Wind Direction

NO2 Nitrogen Dioxide HWS Horizontal Wind Speed

CO Carbon Monoxide BP Barometric Pressure

SO2 Sulfur Dioxide SR- Solar Radiation

TABLE 27

Summary of Site Types, Spatial Scales and Purpose

Location CO NO2 SO2 O3 PM10 PM2.5

Niland G/B/RS/PE GB/MS/PE

Westmorland R/B/RS/PE R/B/MS/PE

Brawley TC/NS/PE B/T/NS/PE

El Centro HC/NS/PE TC/NS/PE HC/NS/PE TC/NS/PE TC/NS/PE

Calexico Ethel TC/MS/PE HC/US/PE TC/US/PE R/TC/US/PE HC/NS/PE HC/NS/PE

Site Type Spatial Scale Monitoring Purpose

R/TC Regional/Typical Concentrations US Urban Scale PE Public Exposure

HC Highest Concentrations NS Neighborhood Scale

GB General Background RS Regional Scale

R/B Regional/Background MS Middle Scale

TC Typical Concentrations

B/T Background/Transport

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Annual Air Monitoring Network Plan 2013
VIII DETAILED SITE INFORMATION

The following tables and figures were downloaded from the CARB Monitoring Network 

webpage. The detailed information is a product of State assessment and does not 

necessarily reflect the findings within this document. In any event, this section provides 

evidence in addition to the previous pages that all established monitoring sites meet 

minimum federal requirements.

Niland Monitoring Station Details

Site Name Niland 

AQS ID 60254004

GIS Coordinates Lat 33° 12' 49" Long 115° 32' 43" 

Location Located in remote setting near the community of Niland 

Address 7711 English Road, Niland, CA 92257 

County Imperial County 

Dist. to road 20 meters 

Traffic count 50 vehicles per day 

Ground Cover Dirt 

Representative area MSA (EI Centro) 

Pollutant O3 PM10 PM10 

Sampling Method 

APl/Teledyne 

400A Anderson 1200 

Met One 

BAM1020 

Analysis Method N/A 

Weighed by 

ARB N/A 

Start Date 6/1/1996 6/1/1996 1/7/2009

Operation Schedule Continuous 1in 6day Continuous 

Sampling Season All year All year AIl year 

Probe height 4.5m 4.5 m 5.0m 

Dist. from supporting structure 1. 5m 1.5 m 1.5 m 

Dist. from obstructions on roof None None None 

Distance from trees None None None 

Unrestricted airflow 360° 360° 360° 

Probe Material Glass & Teflon N/A N/A 

Residence Time 4.7 sec N/A N/A 

Is it suitable for comparison against the annual PM2.5? N/A No No 

Frequency of flow rate verification for manual PM 

samplers audit N/A Monthly N/A 

Frequency of flow rate verification for automated PM 

analyzers audit N/A N/A Monthly 

Frequency of 1-point QC check (gaseous) Bi-Weekly N/A NIA 

Last annual performance evaluation (gaseous) 1/30/2013 N/A NIA 

Last two semi-annual flow rate audits for PM monitors N/A 8/21/12-1/30/13 8/21/12-1/30/13

Imperial County Air Pollution Control District Page 29 of 53

Annual Air Monitoring Network Plan 2013
Site Information for Niland-English Road

AIRS 

Number ARB Number Site Start Date Reporting Agency and Agency Code

060254004 13997 6/1/96 Imperial County APCD (009)

Site Address County Air Basin Latitude (N) Longitude (W) Elevation 

(m)

7711 English 

Road, Niland CA 

92257

Imperial Salton Sea 33.21383 -115.54448 -57

Pollutants Monitored (click on parameter link for real-time data)

Note: multiple monitors may be available through the AQMIS query tool.

O3, PM10, BAMPM10, Outdoor Temperature, Relative Humidity, Wind Direction, Horizontal 

Wind Speed, Barometric Pressure

Imperial County Air Pollution Control District Page 30 of 53

Annual Air Monitoring Network Plan 2013
Niland Site Survey Report

Siting Information

Site Name: Niland-English Road Audit Date: 2013-01-30 ARB Number: 13997 AIRS Number: 060254004

Address: 7711 English Road

 Niland, CA 92257

Latitude: N 33.21383 Longitude: W -115.54448 Elevation (m): -57

Auditors: Leena Khangura

 Alvin Danque Site Technician: Michael Green Site Phone:

Operating Agency: Imperial County APCD Site Report: Yes Site Photos: Yes

General Siting Conditions

Station Temperature Traffic Topography Predominant Wind Direction: West

 Controlled: Yes Description: Remote Site: Level Arc Air Flow (Deg): 360 Degrees

 Recorded: Yes Distance: 20 meters Region: Valley Probe Clean: Yes

 Inside Temp: 23 Degrees Celsius Count (Veh/Day): 50 QA Manual Manifold Clean: N/A

Meteorology Non-vehicular

Local Sources Approved: Yes Cleaning Schedule: As Needed

 Located With Instruments: Yes Description: Agriculture Agency: Imperial County APCD Autocalibrator Type: API 400A IZS

 Shadowing: No Distance: 50 meters Urbanization: Remote Site Survey Complete: Yes

 Boom Orientation (Deg): 349

 Temp(Motor/Natural): Natural

 Direction: 360 Ground Cover: Gravel Logbook Up To Date: Yes

Action Items

Comments

Imperial County Air Pollution Control District Page 31 of 53

Annual Air Monitoring Network Plan 2013
Niland Site Survey Report (Cont.)

Monitor Type Ozone PM10-SSI BAM Outdoor Temperature

Manufacturer/Model API/Teledyne 400 Anderson 1200 Met One BAM 1020 MET ONE 064-2

Serial Number 30333 7377 20005420 X4805

POC 1 1 1 1

Data For Record? Yes Yes Yes Yes

Purpose SLAMS SLAMS SPM SLAMS

Objective

POPULATION 

EXPOSURE/TRANSPORT

POPULATION 

EXPOSURE/TRANSPORT SUPPORT -

Scale REGIONAL MIDDLE -

Height Above Ground 4.6 4.5 5.2 4.2

Height Above Platform 1.6 1.5 2.2 1.2

Sampler Spacing N/A N/A

Current Manual Available? Yes Yes Yes Yes

Instrument Log Up-to-date? Yes Yes Yes Yes

In-line Filter Change Date 2013-01-29 N/A N/A N/A

Cal. Gas Cert. Date N/A N/A N/A N/A

Calibration Current? Yes Yes Yes Yes

Calibration Date 5/26/2011 1/26/2011 1/9/2012 2013-01-10

Cal. Equipment Cert. Date 3/24/2011 12/21/2010 3/16/2011 2012/04/23

Obstacle Description None None None None

Distance to Obstacle - - - -

Obs. Height Above Inlet - - - -

Distance to Walls, etc. - - - -

Distance to Dripline - - - -

Dominant Influence Agriculture Agriculture Agriculture -

Residence Time (sec) 4.7 N/A N/A N/A

Monitor Type Wind Direction Horizontal Wind Speed

Manufacturer/Model MET ONE 020-C MET ONE 010-C

Serial Number X4362 X4245

POC 1 1

Data For Record? Yes Yes

Purpose SLAMS SLAMS

Objective - -

Scale - -

Height Above Ground 8.5 8.5

Height Above Platform

Sampler Spacing N/A N/A

Current Manual Available? Yes Yes

Instrument Log Up-to-date? Yes Yes

In-line Filter Change Date N/A N/A

Cal. Gas Cert. Date N/A N/A

Calibration Current? Yes Yes

Calibration Date 2012-11-26 2012-11-27

Cal. Equipment Cert. Date N/A 2012-10-31

Obstacle Description None None

Distance to Obstacle - -

Obs. Height Above Inlet - -

Distance to Walls, etc. - -

Distance to Dripline - -

Dominant Influence - -

Residence Time (sec) N/A N/A

Imperial County Air Pollution Control District Page 32 of 53

Annual Air Monitoring Network Plan 2013
Westmorland Monitoring Station Details

Site Name Westmoreland 

AQS ID 060254003 

GIS Coordinates Lat 33° 01' 57" Long 115° 37' 25" 

Location Located in suburban setting in the City of Westmoreland 

Address 570 Cook St., Westmoreland, CA 92281 

County Imperial County 

Dist. to road 20 meters 

Traffic count 100 vehicles per day 

Ground Cover Dirt 

Representative area MSA (EI Centro) 

Pollutant O3 PM10 

Sampling Method APl/Teledyne 400 Anderson 1200 

Analysis Method N/A Weighed by ARB 

Start Date 4/1/93 4/1/93 

Operation Schedule Continuous 1in 6day 

Sampling Season All year All year 

Probe height 5m 5m 

Dist. from supporting structure 1.3 m 1.5 

Disl. from obstructions on roof None None 

Distance from trees None None 

Unrestricted airflow 360° 360°

Probe Material Glass & Teflon N/A 

Residence Time 6.5 sec N/A 

Is it suitable for comparison against the annual PM2.5? N/A No 

Frequency of flow rate verification for manual PM samplers 

audit N/A Monthly 

Frequency of flow rate verification for automated PM analyzers 

audit N/A N/A 

Frequency of 1-point QC check (gaseous) Bi-Weekly N/A 

Last annual performance evaluation (gaseous) 01/31/12 N/A 

Last two semi-annual flow rate audits for PM monitors N/A 08/21/12 01/30/13

Imperial County Air Pollution Control District Page 33 of 53

Annual Air Monitoring Network Plan 2013
SITE INFORMATION FOR WESTMORLAND

AIRS Number ARB Number Site Start 

Date Reporting Agency and Agency Code

060254003 13697 4/1/93 Imperial County APCD (009)

Site Address County Air Basin Latitude (N) Longitude 

(W)

Elevation 

(m)

570 Cook St., 

Westmorland CA 

92281

Imperial Salton Sea 33.03239 -115.62362 -43

Pollutants Monitored (click on parameter link for real-time data)

Note: multiple monitors may be available through the AQMIS query tool.

O3, PM10, Outdoor Temperature, Relative Humidity, Wind Direction, Horizontal Wind 

Speed, Barometric Pressure

Imperial County Air Pollution Control District Page 34 of 53

Annual Air Monitoring Network Plan 2013
Westmorland Site Survey Report

Siting Information

Site Name: Westmorland Audit Date: 2013-01-30 ARB Number: 13697 AIRS Number: 060254003

Address: 570 Cook St.

 Westmorland, CA 92281

Latitude: N 33.03239 Longitude: W -115.62362 Elevation (m): -43

Auditors: Leena Khangura

 Alvin Danque Site Technician: Michael Green Site Phone:

Operating Agency: Imperial County APCD Site Report: Yes Site Photos: Yes

General Siting Conditions

Station Temperature Traffic Topography Predominant Wind Direction: West

 Controlled: Yes Description: Rural Site: Level Arc Air Flow (Deg): 360 Degrees

 Recorded: Yes Distance: 20 meters Region: Level Probe Clean: Yes

 Inside Temp: 25 Degrees Celsius Count (Veh/Day): 100 QA Manual Manifold Clean: N/A

Meteorology Non-vehicular

Local Sources Approved: Yes Cleaning Schedule: As Needed

 Located With Instruments: Yes Description: None Agency: Imperial County APCD Autocalibrator Type: API 400A IZS

 Shadowing: No Distance: N/A Urbanization: Rural Site Survey Complete: Yes

 Boom Orientation (Deg): 347

 Temp(Motor/Natural): Natural

 Direction: N/A Ground Cover: Gravel Logbook Up To Date: Yes

Action Items

Comments

Imperial County Air Pollution Control District Page 35 of 53

Annual Air Monitoring Network Plan 2013
Westmorland Site Survey Report (Cont.)

Monitor Type Ozone PM10-SSI Outdoor Temperature

Manufacturer/Model API/Teledyne 400 Anderson 1200 MET ONE 064-2

Serial Number 30331 P1770 X4808

POC 1 1 1

Data For Record? Yes Yes Yes

Purpose SLAMS SLAMS SLAMS

Objective

PUBLIC 

EXPOSURE/TRANSPORT

PUBLIC 

EXPOSURE/TRANSPORT -

Scale REGIONAL MIDDLE -

Height Above Ground 4.3 4.6 4

Height Above Platform 1.2 1.5 0.9

Sampler Spacing N/A N/A

Current Manual Available? Yes Yes Yes

Instrument Log Up-to-date? Yes Yes Yes

In-line Filter Change Date 1/27/2012 N/A N/A

Cal. Gas Cert. Date N/A N/A N/A

Calibration Current? No Yes No

Calibration Date 3/3/2011 1/26/2011 1/26/2011

Cal. Equipment Cert. Date 12/15/2010 12/21/2010 1/11/2011

Obstacle Description None None None

Distance to Obstacle - - -

Obs. Height Above Inlet - - -

Distance to Walls, etc. - - -

Distance to Dripline - - -

Dominant Influence Vehicular Vehicular -

Residence Time (sec) 6.5 N/A N/A

Monitor Type Horizontal Wind Speed

Manufacturer/Model MET ONE 010-C

Serial Number X4246

POC 1

Data For Record? Yes

Purpose SLAMS

Objective -

Scale -

Height Above Ground 8.5

Height Above Platform

Sampler Spacing N/A

Current Manual Available? Yes

Instrument Log Up-to-date? Yes

In-line Filter Change Date N/A

Cal. Gas Cert. Date N/A

Calibration Current? Yes

Calibration Date 11/30/2011

Cal. Equipment Cert. Date 12/28/2010

Obstacle Description None

Distance to Obstacle -

Obs. Height Above Inlet -

Distance to Walls, etc. -

Distance to Dripline -

Dominant Influence -

Residence Time (sec) N/A

Imperial County Air Pollution Control District Page 36 of 53

Annual Air Monitoring Network Plan 2013
Brawley Monitoring Station Details

Site Name Brawley

ADS 10 060250007 

GIS Coordinates Lat 32° 58' 42" Long 115° 32' 21" 

Location Located in city center setting in the City of Brawley 

Address 220 Main St., Brawley, CA 92227 

County Imperial County 

Dist. to road 30 meters 

Traffic count 5000 vehicles per day 

Ground Cover Roof 

Representative area MSA (EI Centro) 

Pollutant PM 2.5 PM10 PM10 

Sampling Method R&P seq. WINS Anderson 1200 BAM 1020 

Analysis Method Weighed by 

SDAPCD

Weighed by 

ARB N/A 

Start Date 01/01/04 01/01/04 01/07/09 

Operation Schedule 1 in 3 day 1 in 6 day Continuous 

Sampling Season All year All year All year 

Probe height 10.0 m 10.0m 10.0 m 

Dist. from supporting structure 1.5 m 1.5 m 1.5 m 

Dist. from obstructions on roof No ne None None 

Distance from trees None None None 

Unrestricted airflow 360° 360° 360°

Probe Material N/A N/A N/A 

Residence Time N/A N/A N/A 

Is it suitable for comparison against the annual PM2.5? Yes No No 

Frequency of flow rate verification for manual PM samplers audit Monthly Monthly N/A 

Frequency of flow rate verification for automated PM analyzers audit N/A N/A Monthly 

Frequency of 1-point QC check (gaseous) N/A N/A N/A 

Last annual performance evaluation (gaseous) N/A N/A N/A 

Last two semi-annual flow rate audits for PM monitors 08/21/12 

01/31/13

08/21/12 

01/31/13

08/21/12 

01/31/13

Imperial County Air Pollution Control District Page 37 of 53

Annual Air Monitoring Network Plan 2013
Site Information for Brawley-Main Street

AIRS Number ARB Number Site Start Date Reporting Agency and Agency Code

060250007 13701 1/1/04 Imperial County APCD (009)

Site Address County Air Basin Latitude (N) Longitude (W) Elevation 

220 Main St., Brawley 

CA 92227 Imperial Salton Sea 32o 58' 42" 115o 32' 21" -13

Pollutants Monitored (click on parameter link for real-time data)

PM10, BAMPM10, PM2.5, Outdoor Temperature

Imperial County Air Pollution Control District Page 38 of 53

Annual Air Monitoring Network Plan 2013
Brawley Site Survey Report

Siting Information

Site Name: Brawley-Main Street #2 Audit Date: 01/31/13 ARB Number: 13701 AIRS Number: 060250007

Address: 220 Main St.

 Brawley, CA 92227

Latitude: N 32.97831 Longitude: W -115.53904 Elevation (m): -15

Auditors: Leena Khangura

 Alvin Danque Site Technician: Mike Green Site Phone:

Operating Agency: Imperial County APCD Site Report: Yes Site Photos: Yes

General Siting Conditions

Station Temperature Traffic Topography Predominant Wind Direction: South

 Controlled: Yes Description: Commercial Site: Level Arc Air Flow (Deg): 360 Degrees

 Recorded: Yes Distance: 30 meters Region: Level Probe Clean: N/A

 Inside Temp: 25 Degrees Celsius Count (Veh/Day): 5000 QA Manual Manifold Clean: N/A

Meteorology Non-vehicular

Local Sources Approved: Yes Cleaning Schedule: N/A

 Located With Instruments: Yes Description: None Agency: Imperial County APCD Autocalibrator Type: N/A

 Shadowing: No Distance: N/A Urbanization: City Center Site Survey Complete: Yes

 Boom Orientation (Deg): N/A

 Temp(Motor/Natural):

 Direction: N/A Ground Cover: Roof Logbook Up To Date: Yes

Action Items

Comments

Imperial County Air Pollution Control District Page 39 of 53

Annual Air Monitoring Network Plan 2013
Brawley Site Survey Report (Cont.)

Monitor Type PM10-SSI BAM PM2.5 Outdoor Temperature

Manufacturer/Model GMW 1200 Met One BAM 1020 R&P 2025 MET ONE 064-2

Serial Number 7346 20021472 20020954 B1681

POC 1 1 1 1

Data For Record? Yes Yes Yes Yes

Purpose SLAMS SPM SLAMS SLAMS

Objective POPULATION EXPOSURE SUPPORT POPULATION EXPOSURE -

Scale NEIGHBORHOOD NEIGHBORHOOD -

Height Above Ground 10 10 10 10

Height Above Platform 1.7 2.4 1.5 1

Sampler Spacing N/A

Current Manual Available? No No No No

Instrument Log Up-to-date? Yes Yes Yes Yes

In-line Filter Change Date N/A N/A N/A N/A

Cal. Gas Cert. Date N/A N/A N/A N/A

Calibration Current? Yes Yes Yes Yes

Calibration Date 1/25/2011 1/9/2012 1/9/2012 1/25/2011

Cal. Equipment Cert. Date 12/21/2010 3/16/2011 3/16/2011 1/11/2011

Obstacle Description None None None None

Distance to Obstacle - - - -

Obs. Height Above Inlet - - - -

Distance to Walls, etc. - - - -

Distance to Dripline - - - -

Dominant Influence Vehicular Vehicular Vehicular -

Residence Time (sec) N/A N/A N/A N/A

Imperial County Air Pollution Control District Page 40 of 53

Annual Air Monitoring Network Plan 2013
El Centro Monitoring Station Details

Site Name EI Centro 

AQS ID 06025 1003 

GIS Coordinates Lat 32° 47' 32" Long 115° 33' 47" 

Location Located in city center setting in the City of EI Centro 

Add ress 150 S. 9th St., EI Centro, CA 92243 

County Imperial County 

Dist. to road 30 meters 

Traffic count 2500 vehicles per day 

Ground Cover Roof 

Representative area MSA (EI Centro) 

Pollutant NO2 O3 CO PM2.5 PM10 

Sampling Method API 200A APl/Teledyne T400 API T300 R&P seq. WINS Anderson 1200 

Analysis Method N/A N/A N/A Weighed by 

SDAPCD Weighed by ARB 

Start Dale 2/1/88 2/1/88 2/1/88 2/1/88 2/1/88 

Operation Schedule Continuous Continuous Continuous 1 in 3 day 1 in 6 day 

Sampling Season All year All year All year All year All year 

Probe height 9.2 m 9.2 m 9.2 10.0 m 10.0 m 

Dist. from supporting structure 1.8 m 1.8m 1.8 m 1.5 m 1.5m 

Dist. from obstructions on roof None None Non e None None 

Distance from trees None None None None None 

Unrestricted airflow 360° 360° 360° 360° 360°

Probe Material Glass & 

Teflon 

Glass & Teflon Glass & 

Teflon 

N/A N/A 

Residence Time 8.6 sec 8.1 sec 8.8 sec N/A N/A 

Is it suitable for comparison 

against the annual PM2.5? N/A N/A N/A Yes No 

Frequency of flow rate 

verification for manual PM 

samplers audit 

N/A N/A N/A Monthly Monthly 

Frequency of flow rate 

verification for automated PM 

analyzers audit 

N/A N/A N/A N/A N/A 

Frequency of 1-point QC 

check (gaseous) Bi-Weekly Bi-Weekly Bi-Weekly N/A N/A 

Last annual performance 

evaluation (gaseous) 01/25/12 01/25/12 01/25/12 N/A N/A 

Last two semi-annual flow rate 

audits for PM monitors 

N/A N/A N/A 08/21/12 

02/05/13

08/21/12 

02/05/13

Imperial County Air Pollution Control District Page 41 of 53

Annual Air Monitoring Network Plan 2013
Site Information for El Centro-9th Street

AIRS 

Number ARB Number Site Start Date Reporting Agency and Agency Code

060251003 13694 2/1/88 Imperial County APCD (009)

Site Address County Air Basin Latitude (N) Longitude 

(W) Elevation (m)

150 9th St, El Centro 

CA 92243 Imperial Salton Sea 32.79215 -115.56299 9

Pollutants Monitored (click on parameter link for real-time data)

Note: multiple monitors may be available through the AQMIS query tool.

CO, NO2, O3, PM10, PM2.5, Outdoor Temperature, Wind Direction, Horizontal Wind Speed, 

Barometric Pressure

Imperial County Air Pollution Control District Page 42 of 53

Annual Air Monitoring Network Plan 2013
El Centro Site Survey Report

Siting Information

Site Name: El Centro-9th Street Audit Date 2013-02-05 ARB Number: 13694 AIRS Number: 060251003

Address: 150 9th St

 El Centro, CA 92243

Latitude: N 32.79215 Longitude: W -115.56299 Elevation (m): 9

Auditors: Leena Khangura

 Harnek Nijjar Site Technician: Mike Green Site Phone:

Operating Agency: Imperial County APCD Site Report: Yes Site Photos: Yes

General Siting Conditions

Station Temperature Traffic Topography Predominant Wind Direction: South

 Controlled: Yes Description: Residential Site: Level Arc Air Flow (Deg): 360 Degrees

 Recorded: Yes Distance: 30 meters Region: Level Probe Clean: Yes

 Inside Temp: 22 Degrees Celsius Count (Veh/Day): 2500 QA Manual Manifold Clean: Yes

Meteorology Non-vehicular

Local Sources Approved: Yes Cleaning Schedule: As Needed

 Located With Instruments: Yes Description: None Agency: Imperial County APCD Autocalibrator Type: Environics 9100

 Shadowing: No Distance: N/A Urbanization: City Center Site Survey Complete: Yes

 Boom Orientation (Deg): 348

 Temp(Motor/Natural): Natural

 Direction: N/A Ground Cover: Roof Logbook Up To Date: Yes

Action Items

Comments

Imperial County Air Pollution Control District Page 43 of 53

Annual Air Monitoring Network Plan 2013
El Centro Site Survey Report (Cont.)

Monitor Type Carbon Monoxide Nitrogen Dioxide Ozone PM10-SSI

Manufacturer/Model API 300 API 200A API/Teledyne 400 SA 1200

Serial Number 30490 2350 30332 7661

POC 1 1 1 1

Data For Record? Yes Yes Yes Yes

Purpose SLAMS SLAMS SLAMS SLAMS

Objective POPULATION EXPOSURE POPULATION EXPOSURE POPULATION 

EXPOSURE

POPULATION 

EXPOSURE

Scale NEIGHBORHOOD NEIGHBORHOOD NEIGHBORHOOD NEIGHBORHOOD

Height Above Ground 9.3 11.1 11.1 9.8

Height Above Platform 1.8 1.8 1.8 1.4

Sampler Spacing N/A N/A N/A

Current Manual Available? Yes Yes Yes Yes

Instrument Log Up-to-date? Yes Yes Yes Yes

In-line Filter Change Date 2013-01-29 2013-01-29 2013-01-29 N/A

Cal. Gas Cert. Date 2012-02-02 2012-02-02 N/A N/A

Calibration Current? Yes Yes Yes Yes

Calibration Date 2013-01-17 2013-01-17 2013-01-16 1/27/2011

Cal. Equipment Cert. Date 2012-11-16 2012-11-16 2012-03-02 2012-04-24

Obstacle Description None None None None

Distance to Obstacle - - - -

Obs. Height Above Inlet - - - -

Distance to Walls, etc. - - - -

Distance to Dripline - - - -

Dominant Influence Vehicular Vehicular Vehicular Vehicular

Residence Time (sec) 8.8 8.6 8.1 N/A

Monitor Type PM2.5 Outdoor Temperature Wind Direction Horizontal Wind 

Speed

Manufacturer/Model R&P 2025 MET ONE 064-2 MET ONE 020-C MET ONE 010-C

Serial Number 20020959 X4806 X-4360 X4243

POC 1 1 1 1

Data For Record? Yes Yes Yes Yes

Purpose SLAMS SLAMS SLAMS SLAMS

Objective POPULATION EXPOSURE - - -

Scale NEIGHBORHOOD - - -

Height Above Ground 9.8 9.3 9.3 9.3

Height Above Platform 2.1 1.8 2.7 2.7

Sampler Spacing N/A N/A N/A

Current Manual Available? Yes Yes Yes Yes

Instrument Log Up-to-date? Yes Yes Yes Yes

In-line Filter Change Date N/A N/A N/A N/A

Cal. Gas Cert. Date N/A N/A N/A N/A

Calibration Current? Yes Yes Yes Yes

Calibration Date 2013-01-15 2012-08-22 2012-11-28 2012-11-28

Cal. Equipment Cert. Date 2012-01-26 4/23/12 N/A 2012-10-31

Obstacle Description None None None None

Distance to Obstacle - - - -

Obs. Height Above Inlet - - - -

Distance to Walls, etc. - - - -

Distance to Dripline - - - -

Dominant Influence Vehicular - - -

Residence Time (sec) N/A N/A N/A N/A

Imperial County Air Pollution Control District Page 44 of 53

Annual Air Monitoring Network Plan 2013
Calexico-Ethel Monitoring Station Details

Site Name Calexico-Ethel 

AQS ID 060250005 

GIS Coordinates Lat 32° 40' 34" Long 115° 28' 59" 

Location 

Located in suburban (residential) area next to a school in City of 

Calexico 

Address 1020 Belcher St., Calexico, CA 92231 

County Imperial County 

Dist. to road 20 meters 

Traffic count 7000 vehicles per day 

Ground Cover Asphalt 

Representative area MSA (EI Centro) 

Pollutant NO2 O3 CO SO, PM2.5 PM2.5 PM10 TSP

Sampling Method API 200e APl 400e API 300eu Thermo 

43i-TLE

R&P seq. 

WINS BAM 1020 Anderson 1200

Anderson 

1200

Analysis Method N/A N/A N/A N/A Weighed 

by ARB N/A Weighed by ARB

Weighed 

by ARB

Start Date 3/1/94 3/1/94 3/1/94 3/1/94 3/1/94 3/1/94 3/1/94 3/1/94

Operation Schedule Continuous Continuous Continuous Continuous 1 in 3day Continuous

1 in 6

day

1 in 6 

day

Sampling Season All year All year All year All year All year All year All year All year

Probe height 5.7 m 5.7 m 5.7m 5.7m 2.5m 2.5m 6.0m 6.0m

Dist. from supporting 

structure 2.2m 2.2 m 2.2m 2,2m 1.5m 1.5m 1.5m 1.5 m

Dist. from obstructions on 

roof None None None None None None None None

Distance from trees None None None None 3.5 m 3.5 m 5 m -

Unrestricted airflow 360° 360° 360° 360° 360° 360° 360° 360°

Probe Material Glass & 

Teflon

Glass & 

Teflon

Glass & 

Teflon

Glass &

Teflon N/A N/A N/A N/A

Residence Time 9.6 sec 6.3 sec 7.1 sec 10.3 sec N/A N/A N/A N/A

Is it suitable for comparison 

against the annual PM2.5? N/A N/A N/A N/A Yes yes No No

Frequency of flow rate 

verification for manual PM 

samplers audit

N/A N/A N/A N/A Monthly NIA Monthly Monthly

Frequency of flow rate 

verification for automated 

PM analyzers audit

N/A N/A N/A N/A N/A Monthly N/A N/A

Frequency of 1-ponit QC

check (gaseous) Bi-Weekly Bi-Weekly Bi-Weekly BI-Weekly N/A N/A N/A N/A

last annual performance 

evaluation (gaseous) 01/24/12 01/24/12 01/24/12 01/24/12 N/A N/A N/A N/A

Last two semi-annual flow 

rate audits for PM monitors

N/A N/A N/A N/A 8/22/12 

1/29/13

8/22/12 

1/29/13

8/22/12 

1/29/13

8/22/12 

1/29/13

Imperial County Air Pollution Control District Page 45 of 53

Annual Air Monitoring Network Plan 2013
Calexico-Ethel Monitoring Station Details

AIRS 

Number ARB Number Site Start Date Reporting Agency and Agency Code

060250005 13698 3/1/94 California Air Resources Board (001)

Site Address County Air Basin Latitude (N) Longitude 

(W) Elevation

1029 Belcher St, Calexico 

CA 92231 Imperial Salton Sea 32o 40' 34" 115o 28' 59" 6

Pollutants Monitored (click on parameter link for real-time data)

CO, SO2, NO2, H2S, O3, PM10, BAMPM2.5, PM2.5, TSP, Toxics, Cr6+, Outdoor Temperature, 

Relative Humidity, Wind Direction, Horizontal Wind Speed, Barometric Pressure, Solar 

Radiation

Imperial County Air Pollution Control District Page 46 of 53

Annual Air Monitoring Network Plan 2013
Calexico Site Survey Report

Site Survey Report

Siting Information

Site Name: Calexico-Ethel Street Audit Date: 2013-01-29 ARB Number: 13698 AIRS Number: 060250005

Address: 1029 Belcher St

 Calexico, CA 92231

Latitude: N 32.67618 Longitude: W -115.48307 Elevation (m): 3

Auditors: Leena Khangura

 Alvin Danque Site Technician: Tony Royer Site Phone:

Operating Agency: California Air Resources Board Site Report: Yes Site Photos: Yes

General Siting Conditions

Station Temperature Traffic Topography Predominant Wind Direction: West

 Controlled: Yes Description: Residential Site: Level Arc Air Flow (Deg): 360 Degrees

 Recorded: Yes Distance: 20 meters Region: Level Probe Clean: Yes

 Inside Temp: 22 Degrees Celsius Count (Veh/Day): 7000 QA Manual Manifold Clean: Yes

Meteorology Non-vehicular

Local Sources Approved: Yes Cleaning Schedule: Annually

 Located With Instruments: Yes Description: Parking lot Agency: Air Resources Board Autocalibrator Type: Environics 9100

 Shadowing: No Distance: 3 meters Urbanization: Rural Site Survey Complete: Yes

 Boom Orientation (Deg): 348

 Temp(Motor/Natural): Motor

 Direction: 270 Ground Cover: Dirt Logbook Up To Date: Yes

Action Items

Comments

Imperial County Air Pollution Control District Page 47 of 53

Annual Air Monitoring Network Plan 2013
Calexico Site Survey Report (Cont.)

Monitor Type

Nitrogen 

Dioxide Ozone PM10-SSI TSP

Manufacturer/Model API 200E API/Teledyne 400 SA 1200 Tisch TSP

Serial Number 20071346 1302 20004783 20081137

POC 1 1 1 1

Data For Record? Yes Yes Yes Yes

Purpose SLAMS SLAMS SLAMS SLAMS

Objective

HIGHEST 

CONCENTRATION

REGIONAL/TYPICAL 

CONCENTRATIONS

HIGHEST 

CONCENTRATION STATE REQUIREMENT

Scale URBAN URBAN NEIGHBORHOOD -

Height Above Ground 5.7 5.7 6 5.4

Height Above Platform 1.7 1.7 1.5 1.4

Sampler Spacing N/A N/A 2

Current Manual Available? Yes Yes Yes Yes

Instrument Log Up-todate? Yes Yes Yes Yes

In-line Filter Change Date 1/24/2013 1/24/2013 N/A N/A

Cal. Gas Cert. Date 2/2/2012 N/A N/A N/A

Calibration Current? Yes Yes No No

Calibration Date 7/19/2012 6/27/2012 8/7/2011 1/28/2010

Cal. Equipment Cert. Date 7/19/2012 3/2/2012 Not Available Not Available

Obstacle Description None None None None

Distance to Obstacle - - - -

Obs. Height Above Inlet - - - -

Distance to Walls, etc. - - - -

Distance to Dripline - - - -

Dominant Influence Vehicular Vehicular Vehicular

Residence Time (sec) 9.9 6.3 N/A N/A

Monitor Type BAM-PM2.5 BAM-PM2.5 PM2.5 PM2.5

Manufacturer/Model

Met One BAM 

1020

Met One BAM 

1020 R &P 2025 R & P 2025i

Serial Number 20020893 20021151 20020964 20103888

POC 3 4 1 2

Data For Record? Yes Yes Yes Yes

Purpose SPM SPM SLAMS Collocation

Objective SUPPORT SUPPORT

HIGHEST 

CONCENTRATION

HIGHEST 

CONCENTRATION

Scale Neighborhood Neighborhood Neighborhood Neighborhood

Height Above Ground 5.7 5.7 3 3

Height Above Platform 1.7 1.7 2 2

Sampler Spacing 2 2 1 1

Current Manual Available? Yes Yes Yes Yes

Instrument Log Up-to-date? Yes Yes Yes Yes

In-line Filter Change Date N/A N/A N/A N/A

Cal. Gas Cert. Date N/A N/A N/A N/A

Calibration Current? Yes Yes Yes Yes

Calibration Date 11/30/2012 11/30/2012 10/16/2012 1/17/2013

Cal. Equipment Cert. Date 9/20/2012 9/20/2012 9/20/2012 9/20/2012

Obstacle Description None None None None

Distance to Obstacle - - - -

Obs. Height Above Inlet - - - -

Distance to Walls, etc. - - - -

Distance to Dripline - - - -

Dominant Influence Residential Residential Vehicular Vehicular

Residence Time (sec) N/A N/A N/A N/A

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Annual Air Monitoring Network Plan 2013
Calexico Site Survey Report (Cont.)

Monitor Type Xontech

Outdoor 

Temperature Wind Direction

Horizontal Wind 

Speed

Barometric 

Pressure

Manufacturer/Model Xontech 924 MET ONE 060A MET ONE 020 MET ONE 010 MET ONE 090C

Serial Number 20021009 P8795 P3078 E1112 60250005

POC 7 1 1 1 1

Data For Record? Yes Yes Yes Yes Yes

Purpose Unknown SLAMS SLAMS SLAMS Other

Objective UNKNOWN - - - -

Scale - - - -

Height Above Ground 5.5 8 10 10 6

Height Above Platform 1

Sampler Spacing N/A N/A N/A N/A

Current Manual Available? Yes Yes Yes Yes Yes

Instrument Log Up-todate? Yes Yes Yes Yes Yes

In-line Filter Change Date N/A N/A N/A N/A N/A

Cal. Gas Cert. Date N/A N/A N/A N/A N/A

Calibration Current? Yes No No No No

Calibration Date 6/7/2012 2/2/2010 2/2/2010 2/2/2010 2/2/2010

Cal. Equipment Cert. Date 3/2/2012 Not Available N/A Not Available Not Available

Obstacle Description None None None None None

Distance to Obstacle - - - - -

Obs. Height Above Inlet - - - - -

Distance to Walls, etc. - - - - -

Distance to Dripline - - - - -

Dominant Influence Vehicular - - - -

Residence Time (sec) N/A N/A N/A N/A N/A

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Annual Air Monitoring Network Plan 2013
APPENDIX A

Regulatory language of 40 CFR 58.10

§ 58.10 Annual monitoring network plan and periodic network assessment.

(a)(1) Beginning July 1, 2007, the State, or where applicable local, agency shall adopt 

and submit to the Regional Administrator an annual monitoring network plan which shall 

provide for the establishment and maintenance of an air quality surveillance system that 

consists of a network of SLAMS monitoring stations including FRM, FEM, and ARM 

monitors that are part of SLAMS, NCore stations, STN stations, State speciation 

stations, SPM stations, and/or, in serious, severe and extreme ozone nonattainment 

areas, PAMS stations, and SPM monitoring stations. The plan shall include a statement 

of purposes for each monitor and evidence that siting and operation of each monitor 

meets the requirements of appendices A, C, D, and E of this part, where applicable. The 

annual monitoring network plan must be made available for public inspection for at least 

30 days prior to submission to US EPA.

(2) Any annual monitoring network plan that proposes SLAMS network modifications 

including new monitoring sites is subject to the approval of the US EPA Regional

Administrator, who shall provide opportunity for public comment and shall approve or 

disapprove the plan and schedule within 120 days. If the State or local agency has 

already provided a public comment opportunity on its plan and has made no changes 

subsequent to that comment opportunity, the Regional Administrator is not required to 

provide a separate opportunity for comment.

(3) The plan for establishing required NCore multi-pollutant stations shall be submitted 

to the Administrator not later than July 1, 2009. The plan shall provide for all required 

stations to be operational by January 1, 2011

. 

(b) The annual monitoring network plan must contain the following information for each 

existing and proposed site:

(1) The AQS site identification number.

(2) The location, including street address and geographical coordinates.

(3) The sampling and analysis method(s) for each measured parameter.

(4) The operating schedules for each monitor.

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Annual Air Monitoring Network Plan 2013
(5) Any proposals to remove or move a monitoring station within a period of 18 months 

following plan submittal.

(6) The monitoring objective and spatial scale of representativeness for each monitor as 

defined in appendix 0 to this part.

(7) The identification of any sites that are suitable and sites that are not suitable for 

comparison against the annual PM2.5NAAOS as described in §58.30.

(8) The MSA, CBSA, CSA or other area represented by the monitor.

(c) The annual monitoring network plan must document how States and local agencies 

provide for the review of changes to a PM2.5 monitoring network that impact the 

location of a violating PM2.5 monitor or the creation/change to a community monitoring 

zone, including a description of the proposed use of spatial averaging for purposes of 

making comparisons to the annual PM2.5 NAAOS as set forth in appendix N to part 50 

of this chapter. The affected State or local agency must document the process for 

obtaining public comment and include any comments received through the public 

notification process within their submitted plan.

(d) The State, or where applicable local, agency shall perform and submit to the EPA 

Regional Administrator an assessment of the air quality surveillance system every 5 

years to determine, at a minimum, if the network meets the monitoring objectives 

defined in appendix 0 to this part, whether new sites are needed, whether existing sites 

are no longer needed and can be terminated, and whether new technologies are 

appropriate for incorporation into the ambient air monitoring network. The network 

assessment must consider the ability of existing and proposed sites to support air 

quality characterization for areas with relatively high populations of susceptible 

individuals (e.g., children with asthma), and, for any sites that are being proposed for 

discontinuance, the effect on data users other than the agency itself, such as nearby 

States and Tribes or health effects studies. For PM2.5, the assessment also must 

identify needed changes to population-oriented sites. The State, or where applicable 

local, agency must submit a copy of this 5-year assessment, along with a revised 

annual network plan, to the Regional Administrator. The first assessment is due July 1, 

2010.

(e) All proposed additions and discontinuations of SLAMS monitors in annual monitoring 

network plans and periodic network assessments are subject to approval according to 

§58.14.

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Annual Air Monitoring Network Plan 2013
Glossary of Acronyms

AQI Air Quality Index

AQS Air Quality System

ARM Approved Regional Method

BAM Beta Attenuation Mass Monitor

CARB California Air Resources Board

CFR Code of Federal Regulations

CO Carbon monoxide

FEM Federal equivalent method

FRM Federal reference method

MSA Metropolitan Statistical Area

NAAQS National Ambient Air Quality Standard

Ncore National Core Ambient Monitoring Network

NO2 Nitrogen Dioxide

O3 Ozone

PAMS Photochemical Assessment Monitoring Sites

Pb Lead

PE Public Exposure

PM10 Particulate Matter less than 10 microns in diameter

PM2.5 Particulate Matter less than 2.5 microns in diameter

PM10-2.5 Coarse Particulate Matter

ppm Parts per million

PQAO Primary Quality Assurance Organization

PWEI Population Weighted Emission Index

SDAPCD San Diego Air Pollution Control District

SIP State implementation plan

SLAMS State and Local Air Monitoring Station

SO2 Sulfur Dioxide

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SPM Special Purpose Monitor

SSI Size Selective Inlet

TCP Transmission Control Protocol

US EPA United States Environmental Protection Agency

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