Gila River Indian Community Department of 

Environmental Quality 

Air Quality Program 

 2006 

TRIBAL 

 AMBIENT AIR MONITORING 

NETWORK REVIEW 

Gila River Indian DEQ Air Program 

35 Pima Street, PO Box 97 

Sacaton, AZ 85247
GRIC DEQ Page ii 10/17/2007 

EXECUTIVE SUMMARY

An inherent function of tribal government is the responsibility to control the use of natural 

resources, environmental protection and public health on tribal lands. The quality of ambient air 

as well as the manner in which it is protected is extremely important to the health and economic 

well-being of the Gila River Indian Community (GRIC or Community). Congress recognized 

these principles in Sections 110(o) and 310(d) of the Clean Air Act (CAA). EPA stated its 

intention to achieve these principles in its November 8, 1984 and March 14, 1994 memoranda in 

which the agency set out its policy governing administration of environmental programs on tribal 

lands. More directly, EPA regulations at 40 CFR Part 49 establish the mechanisms for 

exercising tribal CAA authority. The structure of those mechanisms is based upon a general 

recognition that tribes have inherent authority over air resources within the exterior boundaries 

of reservations. See generally 63 Fed. Reg. 7253-7271, February 12, 1998; 59 Fed Reg. 43956-

43979, August 25, 1994. 

The Code of Federal Regulations, Title 40, Part 58 (40 CFR Part 58) contains the United States 

Environmental Protection Agency's (USEPA) ambient air quality surveillance regulations. 

Section 58.10 calls for air monitoring agencies to establish air quality surveillance systems. The 

air quality surveillance system consists of a network of monitoring stations designated as State 

and Local Air Monitoring Stations (SLAMS), which measure ambient concentrations of those 

pollutants for which standards have been established in 40 CFR Part 50. GRIC Department of 

Environmental Quality (DEQ) will utilize the protocols established under the SLAMS air quality 

surveillance systems described in 40 CFR Part 58. 

SLAMS must meet the requirements of 40 CFR Part 58, Appendices A (Quality Assurance 

Requirements), C (Ambient Air Quality Monitoring Methodology), D (Network Design Criteria) 

and E (Probe and Path Siting Criteria). 

Conformance with Appendices A and C is determined in part by conducting periodic systems 

and performance audits required by Section 2.4 of Appendix A. Conformance with Appendices 

D and E is achieved by monitoring agencies conducting an annual network review of their air 

quality surveillance systems, which is stated in 40 CFR 58.10(d). 

The annual network review determines if an ambient air quality monitoring network is achieving 

its required air monitoring objectives, and identifies modifications to the network which will 

enable an organization to meet those objectives. An effective ambient air quality monitoring 

network collects adequate, representative, and useful data. The air quality data collected by the 

Gila River Indian Community Department of Environmental Quality (GRIC DEQ) monitoring 

network is used for a variety of purposes including: determining compliance with the national 

ambient air quality standards (NAAQS), determining maximum pollutant concentrations, the 

effectiveness of air pollution control programs, evaluating the effects of air pollution on public 
GRIC DEQ Page iii 10/17/2007 

health, supporting dispersion models, developing responsible and cost-effective pollution 

control strategies and determining air quality trends. 

This document identifies modifications to DEQ’s ambient air monitoring network. DEQ’s 

ambient air quality monitoring needs, goals and priorities are also included.
GRIC DEQ Page iv 10/17/2007 

TABLE OF CONTENTS

Section Page

1.0 Introduction............................................................................................................. 1

2.0 Ambient Air Quality Monitoring Requirements and Other Data Needs................ 2 

2.1 Appendix D ........................................................................................... 2 

2.1.1 Monitoring Objectives and Spatial Scales...................................... 2 

2.1.2 Number of SLAMS Sites................................................................ 3 

2.2 Appendix E Requirements ......................................................................... 3 

2.3 Other Ambient Air Monitoring Needs........................................................ 4 

3.0 Network Review Procedure.................................................................................... 5 

3.1 Network Review Team and Preparation..................................................... 5 

3.2 Network Modifications............................................................................... 5 

3.3 Determining Conformance with Appendix D and 

Special Monitoring Requirements.............................................................. 5 

3.3.1 Number and Location of Monitors................................................. 6 

4.0 Network Evaluation and Recommendations........................................................... 7 

4.1 Ozone................................................................................................... 7 

4.2 PM10.................................................................................................. 9 

 4.3 Other PM10 Monitoring........................................................... 10 

5.0 References............................................................................................................... 12 

6.0 Appendix ................................................................................................................ 13 

A GRIC Ambient Air Monitoring Data........................................................... 14 

List of Tables....................................................................................................................... iv 

LIST OF TABLES

Number Page

2-1 Relationship Among Monitoring Objectives and 

Scales of Representativeness................................................................................... 7 

2-2 Summary of Spatial Scales for SLAMS and Required Scales for NAMS.............. 7 

2-3 Summary of Probe and Monitoring Path Siting Criteria......................................... 8 

A-1 Sacaton and St Johns Ozone Data, 1 Hour Averages ............................................ 14 

A-2 Sacaton and St Johns Ozone Data, 8 Hour Averages ............................................ 14 

A-3 Casa Blanca PM10 Data, 24 Hour Averages ...................................................... 15 
GRIC DEQ Page 1 12/4/2007 

1.0 Introduction 

The Code of Federal Regulations, Title 40, Part 58 (40 CFR Part 58) contains the EPA’s ambient 

air quality surveillance regulations. Section 58.10 calls for air monitoring agencies to establish 

air quality surveillance systems in their Implementation Plans. The air quality surveillance 

system consists of a network of monitoring stations designated as SLAMS, which measure 

ambient concentrations of those pollutants for which standards have been established in 40 CFR 

Part 50. SLAMS must meet the requirements of 40 CFR Part 58, Appendices A (Quality 

Assurance Requirements), C (Ambient Air Quality Monitoring Methodology), D (Network 

Design Criteria) and E (Probe and Path Siting Criteria). Conformance with Appendices A and C 

is determined in part by conducting periodic systems and performance audits required by Section 

2.4 of Appendix A. Conformance with Appendices D and E is achieved by air monitoring 

agencies conducting an annual review of their air quality surveillance systems, which is required 

by 40 CFR 58.10(d). 

The annual network review determines if the network achieved its required air monitoring 

objectives, and if it should be modified (e.g. termination, relocation or establishment of 

monitoring stations) to meet those objectives. The main purpose of this review is to ensure that 

an ambient air quality monitoring network collects adequate, representative, and useful air 

quality data. The ambient air quality data from the Gila River Indian Community Department of 

Environmental Quality (GRIC DEQ) network is used for a variety of purposes including: 

• determining compliance with the national ambient air quality standards (NAAQS), 

• determining the location of maximum pollutant concentrations, 

• determining the effectiveness of air pollution control programs, 

• evaluating the effects of air pollution on public health, 

• supporting dispersion models, 

• developing responsible, cost-effective control strategies, 

• developing air quality trends. 
GRIC DEQ Page 2 10/17/2007 

2.0 Ambient Air Quality Monitoring Requirements and Other Data Needs

2.1 Appendix D 

Appendix D of 40 CFR 58 describes concepts for designing SLAMS network. It addresses 

monitoring objectives, and the criteria for selecting the location and number of air monitoring 

stations. The concepts and guidance in Appendix D, as well as other non-regulatory EPA data 

needs, should be considered when evaluating the adequacy of the SLAMS network. 

2.1.1 Monitoring Objectives and Spatial Scales

Appendix D calls for the design of SLAMS networks to meet a minimum of three basic 

objectives: 

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

(2) Support compliance with ambient air quality standards and emissions strategy 

development. 

(3) Support for air pollution research studies. 

SLAMS networks are designed to provide data for meeting the monitoring objectives described 

above and to assist the EPA and air monitoring agencies in solving environmental problems. 

Appendix D also provides guidance on spatial scales of representativeness for stations in a 

SLAMS network (Table 2-1). Ideally, the monitor is located so that its sample represents the air 

quality over the entire area that the monitoring station is intended to represent. 
GRIC DEQ Page 3 10/17/2007 

Table 2-1. Relationship Between Site Types and 

Scale of Representativeness

Monitoring Objectives Appropriate Siting Scales 

Highest concentration Micro, middle, neighborhood, urban 

Population Neighborhood, urban 

Source impact Micro, middle, neighborhood 

General/Background and Regional transport Neighborhood, urban, regional 

Welfare-related impacts Urban/regional 

Table 2-2. Summary of Spatial Scales for SLAMS

Scales Applicable for SLAMS 

Scales O3 PM10

Micro.............. 9

Middle............ 9 9

Neighborhood 9 9

Urban.............. 9 9

Regional......... 9 9

2.1.2 General Monitoring Requirements

Appendix D to 40 CFR Part 58 does not contain criteria for determining the total number of 

stations in the SLAMS network. Factors such as topography, source type, proximity and 

locations of nearby populations may affect the number of stations in the network. Other than 

these requirements, the optimum size of a particular SLAMS network involves tradeoffs between 

data needs and available resources which can best be resolved during the network design 

process. 

2.2 Appendix E Requirements

Appendix E contains siting criteria to be applied to ambient air quality analyzers or samplers 

after the general site location has been selected based on the monitoring objectives and spatial 

scales of representativeness presented in Appendix D and summarized in Section 2.1 of this 

document. The siting criteria presented in Appendix E are summarized in Table 2-6. 

EPA believes that most sampling probes or monitors can be located so that they meet the 

Appendix E siting requirements. Some existing stations, however, may not meet these 

requirements and yet still produce useful data for some purposes. EPA will consider written 

requests from the State/Tribes to waive one or more siting criteria for some monitoring stations 
GRIC DEQ Page 4 10/17/2007 

provided that the State/Tribe can demonstrate the following: (1) the site is as representative of 

the monitoring area as it would be if siting criteria were met; and (2) the siting criteria cannot be 

met because of physical constraints (e.g., inability to locate the station the necessary setback 

distance from roadways or obstructions). Waivers may be granted to existing SLAMS if one of 

these criteria is met; waivers may be granted for new SLAMS only if both criteria are met. 

Written requests for waivers must be submitted to the EPA Regional Administrator. 

2.3 Other Ambient Air Monitoring Data Needs

GRIC has a number of special purpose monitors (SPMs) deployed throughout the Community 

for PM10. They are used for a variety of purposes, including ambient air quality assessment and 

special studies such as the Joint Air Toxics Assessment Project. SPM monitoring sites often 

utilize Federal Reference Method (FRM) and Federal Equivalent Method (FEM) sampling 

equipments, and are operated in accordance with CFR requirements for quality assurance and 

quality control. SPM designation for criteria pollutant monitoring sites allows GRIC DEQ to 

assess ambient particulate levels within regions of the Community, while providing the 

flexibility to relocate the sites if it is determined there is no concern for NAAQS violations in the 

area (typically after three years of data collection). SPM sites may be added to GRIC DEQ’s 

network when elevated pollutant concentrations are consistently measured at the site. 

Table 2-3. Summary of Probe and Monitoring Path Siting Criteria

Pollutant Scale [maximum monitoring 

path length, meters] 

Height from 

ground to probe 

or 80% of 

monitoring 

patha

 (meters) 

Horizontal and 

vertical distance from 

supporting 

structuresb,g to probe 

or 90% of monitoring 

patha

 (meters) 

Distance from 

trees to probe or 

90% of 

monitoring 

patha

 (meters) 

Distance from roadways 

to probe or monitoring 

patha

 (meters) 

O3

c,d,e Middle [300m] Neighborhood 

and Regional [1km] 

3-15 >1 >10 See Table 1h for all scales. 

PM10c,d,e,f Micro; Middle, Neighborhood, 

and Regional 

2-7 (Micro); 

2-15 (All other 

scales). 

>2 (All scales, 

horizontal distance 

only). 

>10 (All scales) 2-10 (Micro); See Figure 

2h

 for all other scales. 

a

Monitoring path for open path analyzers is applicable only to middle or neighborhood scale CO monitoring and all applicable scales 

for monitoring O3. b

When probe is located on a rooftop, this separation distance is in reference to walls, parapets, or penthouses located on roof. c

Should be >20 meters from the dripline of tree(s) and must be 10 meters from the dripline when the tree(s) act as an obstruction. d

Distance from sampler, probe, or 90% of monitoring path to obstacle, such as a building, must be at least twice the height the obstacle 

protrudes above the sampler, probe, or monitoring path. Sites not meeting this criterion may be classified as middle scale. e

Must have unrestricted airflow 270° around the probe or sampler; 180° if the probe is on the side of a building. f

The probe, sampler, or monitoring path should be away from minor sources, such as furnace or incineration flues. The separation 

distance is dependent on the height of the minor source’s emission point, the type of fuel or waste burned, and the quality of the fuel. 

This criterion is designed to avoid undue influences from minor sources. g

For collocated PM10 samplers, a 2-4 meter separation distance between collocated samplers must be met. h

Tables and figures are in Appendix E of 40 CFR Part 58. 
GRIC DEQ Page 5 10/17/2007 

3.0 Network Review Procedure

3.1 Network Review Team and Preparation

Network review participants include GRIC DEQ Air Monitoring staff and representatives from 

USEPA Region 9 Technical Support Program. Depending on available resources, network 

reviews may be conducted on, or off-site. In either case, sufficient information must be provided 

to determine conformance of the network with regulatory network design and siting requirements 

specified in 40 CFR Part 58, Appendices D and E as well as to determine conformance of the 

network design and siting requirements specified for all special ambient air monitoring networks. 

 

3.2 Network Modifications

Modifications to the SLAMS networks are addressed in 40 CFR 58.25. Under Section 58.25, 

States/ Tribes are required to annually develop and implement schedules to modify the SLAMS 

network to eliminate any unnecessary stations or to correct any inadequacies indicated by the 

annual network review required by 58.20(d). As part of the annual network review, evaluations 

of the special networks established as partnership agreements between EPA and GRIC DEQ 

should also be conducted. Modifications to these networks should be recommended as a result 

of this annual review. 

An important objective of the network modification process is determining whether or not 

sufficient ambient air quality information and data are being provided by the regulatory and other 

special monitoring networks to satisfy the principal data needs. If sufficient air quality data are 

not being collected, the deficient area must be identified and corrective action taken to resolve 

the problem. Conversely, if it is determined that excessive data are being collected (e.g., there 

are redundant sites resulting in data that agree closely), then efforts need to be taken to determine 

where dis-investment should be made and on what schedule. 

Network modifications may be initiated by EPA or proposed by GRIC DEQ and agreed to by 

EPA. Network modifications may result from revisions to the Part 58 regulations, systems 

audits, site visits, or performance evaluations; special studies, population increases/decreases; air 

quality concentrations consistently recorded below the NAAQS; loss of permission to use a site; 

demolition of a building which is used for monitoring; building construction; growth of trees; 

changes in roadways; change in neighborhood type of use, etc. 

3.3 Determining Conformance with Appendix D and Special Monitoring Requirements

With regard to Appendix D requirements, this network review is intended to determine the 

adequacy of the network in terms of number and location of monitors. Specifically, (1) is GRIC 

DEQ meeting the number of monitors required by the Part 58 Appendix D design criteria 

requirements; (2) are the monitors properly located based on the monitoring objectives and 

spatial scales of representativeness presented in Appendix D. For special monitoring networks, 

conformance determinations will be conducted in accordance with program documents 

applicable to the special networks. 
GRIC DEQ Page 6 10/17/2007 

3.3.1 Number and Location of Monitors

For SLAMS, the number of monitors required and their location is not specified in the 

regulations but rather is determined by EPA Region 9 and GRIC DEQ on a case-by-case basis to 

meet the monitoring objectives specified in Appendix D. Adequacy of the network may be 

determined by using a variety of tools, including the following: 

• analyses of historical monitoring data, 

• maps of emissions densities, 

• dispersion modeling, 

• special studies/saturation sampling, 

• best professional judgement, 

• TIP requirements, 

• revised monitoring strategies (e.g., new regulations, reengineering air monitoring 

network), 

• monitoring network maps and network descriptions with site objectives defined. 

Appropriate location of monitors can be determined on the basis of stated objectives. Maps, 

graphical overlays, and GIS-based information are extremely helpful in visualizing or assessing 

the adequacy of monitor locations. Plots of potential emissions and/or historical monitoring data 

versus monitor locations are especially useful. When questions arise about the adequacy of a 

particular location, modeling or special studies may be appropriate. 
GRIC DEQ Page 7 10/17/2007 

4.0 Network Evaluation and Recommendations/Proposed Modifications 

4.1 Ozone (O3, 44201) 

National Ambient Air Quality Standards (NAAQS): 

• 8-hour average of the 4th highest measured O3 concentration averaged over three 

consecutive years, not to exceed 0.08 ppm at any given monitoring site. 

GRIC’s Ozone monitoring network is comprised of two sites communitywide. 

4.1 Ozone (O3, 44201) 

Parameter Instrument 1 Instrument 2 

AQS # 700104021 700304013 

Pollutant Type Ozone Ozone 

Date Established 7/1/2002 May 2003 

Site ID/ Location Sacaton – GRIC DEQ 

Building 

St Johns – Gila 

Crossing North Middle 

School 

Sampler Make & Model API 400A API 400A 

Classification SLAMS SLAMS 

Scale Regional, rural Regional, rural 

Objective Population Population 

Intlet Height 5 meters 4 meters 

Distance from Tree Dripline NA NA 

Obstacle Description None None 

Height of Obstacle NA NA 

Distance and Direction NA NA 

Airflow Arch 360 degree 360 degree 

Furnace or Incinerator Flue None None 

Distance and Direction NA NA 

Distance between Collocated Samplers NA NA 

Nearest Road Pima Street Pecos Road 

Distance and Direction to Road 12 meters – East 12 meters – North 

Traffic Count (ADT) Not available Not available 

Schedule Continuous, Seasonal 

(Apr-Oct) 

Continuous, Seasonal 

(Apr-Oct) 

Surrounding Area Residential/ Business Residential/ Business 

Site Groundcover Pavement Pavement/gravel rock 

Frequency of instrument check Biweekly Biweekly 

Last two audits June 2007 June 2007 

Does Site Meet App D&E Criteria Yes Yes 

Action for 2006 Continue Continue 
GRIC DEQ Page 8 10/17/2007 

Ozone 

Sacaton Site/ Sacaton, AZ 

AQS # 700104021 

Address: 35 Pima Street, Sacaton, 

AZ 

SLAMS site Ozone

Adequacy 

Sacaton Site is a regional scale State and Local Air Monitoring Site for Ozone. It is 

located ~40 miles southeast of the metro Phoenix. The Sacaton site contains ozone and 

meteorological monitors. 

Exceedences 

 This site has not exceeded the one or eight hour standard. 

Justification for continued monitoring 

The Sacaton site is a long term trend site and operates on a seasonal schedule from April 

through October. 

St Johns Site/ Laveen, AZ 

AQS # 700304013 

Address: 4208 W. Pecos Road, 

Laveen, AZ 85339 

SLAMS site for Ozone 

Adequacy 

St Johns is a regional scale 

site for Ozone established 

in 2002. It is located ~25 

miles southwest of 

Phoenix near South 

Mountain Park. 

Exceedences 

This site has not exceeded 

the one or eight hour standard in the past 3 years. 

Justification for continued monitoring
GRIC DEQ Page 9 10/17/2007 

The St Johns site is a long term trends site and operates on a seasonal schedule from 

April through October. It is located on the northwest end of the Community. 

4.2 Particulate Matter (PM10, 81102) 

National Ambient Air Quality Standard (NAAQS), 2002: 

• Twenty-four hour average PM10 concentration not to exceed 150 μg/m3 on more than one 

occasion per year when averaged over three years. 

GRIC’s Particulate Matter 10 monitoring network consists of one site community-wide. 

4.2 Particulate Matter 10 (PM10, 81102) 

Parameter Instrument 1 Instrument 2 

AQS # 700404021 poc 1 700404021 poc 2 

Pollutant Type PM10 PM10 

Date Established 1/1/2005 1/1/2005 

Site ID Casa Blanca – Va Ki 

Elementary School 

Casa Blanca – Va Ki 

Elementary School 

Sampler Make & Model R&P FRM Partisol 

2000 

R&P FRM Partisol 

2000 

Classification SLAMS SLAMS 

Scale Neighborhood, regional Neighborhood, regional

Objective Population Population 

Intlet Height 5 meters 5 meters 

Distance from Tree Dripline NA NA 

Obstacle Description None None 

Height of Obstacle NA NA 

Distance and Direction NA NA 

Airflow Arch 360 degree 360 degree 

Furnace or Incinerator Flue None None 

Distance and Direction NA NA 

Distance between Collocated Samplers NA NA 

Nearest Road Casa Blanca Road Casa Blanca 

Distance and Direction to Road 12 meters – East 12 meters – East 

Traffic Count (ADT) Not available Not available 

Schedule One in three day One in six day 

Surrounding Area Residential/ Business/ 

Agriculture 

Residential/ Business/ 

Agriculture 

Site Groundcover Pavement Pavement 

Frequency of Flow rate verification Quarterly Quarterly 

Last two flow rate audits June 2007 June 2007 

Does Site Meet App D&E Criteria Yes Yes 

Action for 2006 Continue Continue 
GRIC DEQ Page 10 10/17/2007 

Additional Monitors: Two 

GRIC DEQ recently deployed two R&P Continuous PM10 TEOM samplers at Casa Blanca Site 

and St Johns Site. DEQ is drafting Quality Assurance Plan and conducting quality control and 

quality control assessments on TEOM samplers. Workplan to implement in 2008. 

Recommendations/Proposed Modifications: GRIC is anticipating expansion of Particulate 

Matter (PM10) FRMs operations with TEOM continuous samplers at this site and at St Johns. 

Operation of the entire PM10 network is under review and recommendations will be made at a 

later date. 

Casa Blanca Site/ Bapechule, AZ

AQS # 700404021 

Address: Casa Blanca/ Preschool 

Road, Bapchule, AZ 85221 

SLAMS site for PM10 

Adequacy 

Casa Blanca Site is a 

neighborhood scale site for 

PM10 established in 2002. It 

is located in a mixed 

agriculture/residential area 

in District 5. 

Exceedences 

This site has exceeded the daily for PM10 three times in 2006. The three exceedances 

have been reported and flagged due to natural events episodes. 

Justification for continued monitoring 

The Casa Blanca PM10 samplers are located in the Community’s central agricultural 

sources. Additional PM10 samplers will be deployed at Casa Blanca. Casa Blanca is 

also a trends monitoring site. 

 

4.3 Other PM10 Monitoring 

Note: 

The following sites have been recommended to USEPA Region 9 for inclusion into the PM10 

network. This information is being provided in this assessment for comment by EPA Region 9. 

Sacaton 

AQS # 700104021 

Address: 35 Pima Street, Sacaton, AZ 85247 

SLAMS site for PM10 

Sampling frequency: Continuous 
GRIC DEQ Page 11 10/17/2007 

Explanation 

Sacaton is neighborhood scale residential site. The site’s primary objective is to characterize air 

quality conditions impacting the town of Sacaton and the nearby residents. Special Purpose 

Monitoring (SPM) conducted since 2005 has documented numerous exceedances of the 24 hour 

NAAQS at Casa Blanca which is approximately 8 miles away. A violation of the current 

NAAQS appears likely. 

The Agency intends to monitor with continuous devices (FEM). 

Recommendation 

Given the likelihood of a NAAQS violation, add Sacaton to the GRIC / EPA Region 9 

monitoring network. 

St Johns

AQS # 700304013 

Address: 4208 W. Pecos Road, Laveen, AZ 85339 

SLAMS site for PM10 

Sampling frequency: Continuous 

Explanation 

St Johns is an existing middle/neighborhood scale residential site. The residential site typifies 

many similar areas in the GRIC community. The site provides air quality information to a 

population of over 2,000 residents. The site plays an essential role in transport and development 

of neighboring jurisdictions. Exceedances of the current or proposed 24 hour NAAQS are not 

expected. 

Recommendation 

Given the number of residents in the St Johns community served by this site, add St Johns into 

the GRIC/ EPA Region 9 network. 
GRIC DEQ Page 12 10/17/2007 

5.0 References 

1. Code of Federal Regulations, Title 40, Part 58, Appendix A, B, D, E, U.S. Government 

Printing Office, 2006. 

2. Code of Federal Regulations, Title 40, Part 50, U.S. Government Printing Office, 2006. 

3. Code of Federal Regulations, Title 40, Part 53, U.S. Government Printing Office, 2006. 

4. Code of Federal Regulations, Title 40, Part 58, U.S. Government Printing Office, 2006. 

5. U.S. EPA, Revised Requirements for Designation of Reference and Equivalent Methods 

for PM2.5 and Ambient Air Quality Surveillance for Particulate Matter -Final Rule. 40 

CFR Parts 53 and 58. Federal Register, 62(138):38763-38853. July 18, 1997. 

6. Guidance for Network Design and Optimum Site Exposure for PM2.5 and PM10, J.G. 

Watson, et. Al., U.S. EPA/OAQPS, December 15, 1997. 

7. SLAMS/NAMS/PAMS Network Review Guidance, EPA-454/R-98-003, March 1998. 

8. Guideline on Ozone Monitoring Site Selection, EPA-454/R-98-002, August 1998. 
GRIC DEQ Page 13 10/17/2007 

Appendix A 

GRIC Ambient Air Monitoring Data 
GRIC DEQ Page 14 10/17/2007 

Table A-1. Sacaton and St Johns Ozone Data (IN PPM), 1 Hour Averages 

Table A-2. Sacaton and St Johns Ozone Data (IN PPM), 8 Hour Averages 

Year Maximum 

Reading 

2nd

Highest 

Reading 

3rd

Highest 

Reading

4th

Highest 

Reading

Number of 

Daily 

Exceedances

Expected 

Exceedance 

Rate 

Number of 

Sample 

Hours 

Sacaton 

2004 0.093 

7/13/04 

0.077 

4/24/04 

0.075 

5/12/04

0.075 

5/14/04

0 0 5020 

seasonal 

2005 0.089 

7/19/05 

0.087 

5/23/05 

0.082 

4/16/05

0.079 

4/13/05

0 0 5087 

seasonal 

2006 0.085 

8/9/06 

0.084 

7/1/06 

0.084 

7/26/06

0.079 

6/30/06

0 0 4927 

seasonal 

St Johns 

2004 0.082 

9/12/04 

0.079 

4/27/04 

0.079 

5/1/04 

0.079 

9/11/04

0 0 5050 

seasonal 

2005 0.093 

7/19/05 

0.086 

4/16/05 

0.086 

5/18/05

0.086 

6/23/05

0 0 5085 

seasonal 

2006 0.078 

6/26/06 

0.075 

6/20/06 

0.074 

6/15/06

0.070 

6/7/06 

0 0 4694 

seasonal 

Year Maximum 

Reading 

2nd

Highest 

Reading 

3rd

Highest 

Reading

4th

Highest 

Reading

3 Year Avg 

of the 4th

Highest 

Number of 

Daily 

Exceedances 

Number of 

Sample 

Hours 

Sacaton 

2004 0.076 

7/13/04 

0.072 

4/24/04 

0.071 

5/14/04

0.071 

5/15/04

NA 0 5020 

seasonal 

2005 0.080 

7/19/05 

0.076 

4/16/05 

0.073 

7/20/05

0.072 

4/15/05

NA 0 5087 

seasonal 

2006 0.074 

7/1/06 

0.072 

4/18/06 

0.072 

8/9/06 

0.070 

6/18/06

0.07 0 4927 

seasonal 

St Johns 

2004 0.076 

5/1/04 

0.074 

7/25/04 

0.072 

4/25/04

0.072 

5/12/04

NA 0 5050 

seasonal 

2005 0.079 

7/19/05 

0.078 

4/16/05 

0.075 

5/18/05

0.073 

6/30/05

NA 0 5085 

seasonal 

2006 0.066 

6/7/06 

0.066 

6/26/06 

0.065 

6/15/06

0.062 

5/10/06

0.07 0 4694 

seasonal 
GRIC DEQ Page 15 10/17/2007 

TABLE A-3. Casa Blanca PM10 Data (IN ug/m3)

 

a - At least one data point during this year was flagged due to an exceptional event and excluded from calculation. 

Year Maximum 

Reading 

(Date) 

2nd 

Highest 

(Date) 

3rd 

Highest 

(Date) 

4th 

Highest 

(Date) 

Number of 

Daily 

Exceedances

Expected 

Exceedance 

Rate 

3 Year 

Average of 

the Expected 

Exceedance 

Rate 

 

2005 146 

12/12/05 

106 

07/18/05 

98 

04/22/05

98 

11/09/05 

0 0 NA 

2006a 246a

04/14/06 

184a

06/25/06 

161a

08/21/06

152 

12/16/066

0 0 NA