San Joaquin Valley Air Pollution Control District June 25, 2013 

Appendix G: Comments and Responses 

Annual Air Monitoring Network Plan 

APPENDIX G: Comments and Responses

 
San Joaquin Valley Air Pollution Control District June 25, 2013 

Appendix G: Comments and Responses 

Annual Air Monitoring Network Plan 

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San Joaquin Valley Air Pollution Control District June 25, 2013 

Appendix G: Comments and Responses G-1 

Annual Air Monitoring Network Plan 

Appendix G: Comments and Responses 

This Appendix contains responses to comments made by the public on the Annual Air 

Monitoring Network Plan (Plan). The District held a 30-day public inspection period on 

the Plan from March 18, 2013 through April 18, 2013. 

G.1 WRITTEN COMMENTS ON THE 2012 AIR MONITORING NETWORK PLAN 

Comment period held from March 18, 2013 through April 18, 2013. 

Comments were received from the following organization: 

Earthjustice 

Earthjustice’s April 18, 2013 comment letter referenced and incorporated a previous 

comment letter dated October 18, 2012. The material below combines comments from 

both letters. 

Comment: Earthjustice asks for more details about District’s rationale on air monitoring 

site mergers, site closures, and the siting of NO2 near-road monitoring sites. 

Response: The District has determined that closing and/or consolidating certain sites 

will streamline operations and reduce maintenance costs without compromising 

National Ambient Air Quality Standards (NAAQS). Streamlining operations and reducing 

costs will allow the District to use the resources for other air monitoring purposes, such 

as, adding additional capabilities to existing sites and decreasing down time of the 

analyzers. The NO2 near-road monitoring documentation contained in Appendixes D 

and E has all of the required information that EPA needs to approve the site locations 

and closely follows the Technical Assistance Document published by EPA. 

Comment: The Plan requirements are described in the introduction but the criteria on 

which they are based are not explained in detail. For example, what population 

threshold is used for determining population sites? If a threshold was not used, how 

were those sites determined? Also, brief descriptions of each of the monitoring sites are 

provided in Appendix A and B but specific information about the area within which the 

sites are located is not provided. 

Response: For each monitoring site, the District’s network plan provides information on 

criteria listed in 40 CFR Part 58 Subpart B Section 58.10 which includes objective and 

spatial scale of representativeness. For more detailed information on the objective and 

spatial scales, site types, and population please refer to 40 CFR 58 Appendix D. 

Comment: The District notes that the California Regional Particulate Air Quality Study 

(CRPAQS) is the basis of the PM2.5 monitoring network and that the completion date of 

the final report is expected to be June 2012. Has the report been completed? If so, 
San Joaquin Valley Air Pollution Control District June 25, 2013 

Appendix G: Comments and Responses G-2 

Annual Air Monitoring Network Plan 

please make it available to the public. How did the study influence the District’s network 

design? 

Response: Data collection for the study has been completed and many reports have 

been finalized and published. In addition, many peer reviewed scientific and journal 

articles have appeared in a wide variety of scientific publications. The results of this 

study are used in air quality modeling and in the District’s SIPs. These results aid in the 

understanding of the formation of air pollution and the areas of the District which have 

the worst air quality. All of this knowledge as contributed to the design of the air 

monitoring network. The final synthesis document, a summary of findings, is not yet 

complete, but the studies and analysis have been consistently used by the District as 

they have become available. Information on CRPAQS is available to the public on the 

Central California Air Quality Studies page of the California Air Resources Board 

website at http://www.arb.ca.gov/airways/CRPAQS/default.htm . 

Comment: The District states that the Bakersfield-Muni PM2.5 and PM10 monitors met 

the criteria for a move under 40 CFR Part 58, however it did not request or receive 

approval from the Regional Administrator as required under 40 CFR Part 58.14(b) prior 

to shutting down the monitors. 

Response: As stated in Appendix C of the Plan, the PM analyzers were shut down 

when the District realized that the AMS was not sited correctly for PM monitoring. In 

order for an AMS to have NAAQS comparable data, it needs to be sited in accordance 

with federal regulation. Appendix C provides all of the necessary documentation. The 

District will work with EPA and ARB to ensure that all the necessary requirements are 

addressed. 

Comment: Regarding the reason for shutting down the PM monitors at BakersfieldMuni, the rationale suggests that the District is operating under a definition of “ambient 

air” that differs from the definition found in 40 CFR 50.1. 

Response: The District was using the term “ambient air” in conjunction with 

neighborhood scale which PM sites are intended to measure. Specifically, a 

neighborhood scale site measures ambient air with relatively consistent PM 

concentrations over an area of 50.2 square kilometers or 19.3 square miles. 

Comment: Considering the severe public health consequences of the District’s poor air 

quality, the District should prioritize the maintenance of a comprehensive and reliable air 

monitoring network by adhering to pertinent regulations. 

Response: The District strives to maintain its comprehensive air monitoring network 

and the network’s reliability through the efforts of its staff of experts in accordance with 

regulations outlined in 40 CFR. Currently, the air monitoring network exceeds federal 

requirements and the District continues to enhance the network as additional 

requirements, such as NO2 near-road monitoring, are promulgated. 
April 18, 2013

Jennifer Ridgway

San Joaquin Valley Air Pollution Control District 

1990 East Gettysburg Avenue

Fresno, CA 93726

Re: San Joaquin Valley Air Pollution Control District Annual Air Monitoring Network Plan, 

March 19, 2013 

Dear Ms. Ridgway, 

Thank you for the opportunity to submit additional comments on the San Joaquin Valley Air Pollution 

Control District’s (“District”) Annual Air Monitoring Network Plan (“Plan”). These comments build upon 

the comments provided in October 2012 on the September 13, 2012 draft of the Plan, and are 

submitted on behalf of the Central Valley Air Quality Coalition, Greenaction, and the Coalition for Clean 

Air. The October 2012 comment letter is attached for your review. This letter reiterates the request that 

the District provide more detailed information about its decision-making process with respect to 

monitoring site closures and consolidations. Without that information, the Plan does not fully 

communicate the District’s approach toward maintaining and improving its air monitoring network. 

Given the importance of the monitoring network in documenting progress toward attainment and 

improving public health, this Plan is a key tool in meeting the Valley’s air quality goals and should clearly 

explain the District’s air monitoring activities to the public. 

Despite soliciting public comment on the September 13, 2012 draft of the Plan, the District did not 

acknowledge or respond to comments received. District staff reported that comments on the earlier 

draft of the Plan were no longer thought to be relevant given the numerous changes made between the 

September 2012 and March 2013 drafts of the Plan. However, comments that Earthjustice filed in 

October 2012 asked for more detailed information about sites that is not included in the March 2013 

draft. As just one example, the October 2012 comments stated: 

Although the District describes the Plan requirements in the 

introduction, the criteria behind those requirements are not fully 

explained. For example, on page 7,1the Plan details the different 

monitoring site types, such as sites near the highest pollutant 

concentrations, sites in areas of high population density, and sites to 

identify background concentration levels. This section would be more 

helpful if it described how the District assigned specific monitors to the 

different site types. For sites in high population areas, what is the 

population threshold used to determine which sites fall under the 

“population oriented” site type? Or, if a threshold is not used, how are 

 

1

Starts on page 8 in the March 19, 2013 draft of the Plan. 
Jennifer Ridgway, San Joaquin Valley Air Pollution Control District

April 18, 2013

Page 2 of 3

those sites determined? Similar questions should be answered for the 

remainder of the site types.

The section of the Plan to which these comments refer was not updated in the March 2013 draft. 

District staff should review the previously submitted comments again in their entirety and incorporate

responses to those comments into the next iteration of the Plan. Those comments also request 

additional information on the District’s summary of planned changes, including potential site mergers, 

so that the public understands why the District is considering removing monitors with years of air quality 

data. This information also was not included in the most recent draft of the plan. During the March 28, 

2013 public workshop, District staff explained the rationale behind a few of the potential mergers when 

asked, but that is not sufficient. The District should include those explanations in the next draft of the 

Plan for all proposed site changes.

The District’s recent decision to shut down the PM10 and PM2.5 monitors at the Bakersfield-Muni site 

raises serious concerns about the process by which the District maintains its air monitoring network and 

the reliability of the data collected. The Bakersfield-Muni PM10 and PM2.5 monitors were SLAMS 

monitors, and, as the District notes, are regulated under the criteria in 40 CFR Part 58. The District states 

that the Bakersfield-Muni monitors met the criteria for a move under 40 CFR Part 58; however, the 

District did not request or receive approval from the Regional Administrator as required under 40 CFR 

Part 58.14(b) prior to shutting down the monitors. 

Additionally, the District argued that the PM2.5 and PM10 monitors should be moved due to activities in 

the area, such as street sweeping and disking of an open field, that altered air quality near the monitors 

such that the monitors’ data would not capture “ambient air” in the Valley. This rationale suggests that 

the District is operating under a definition of ambient air that differs from the definition found in 40 CFR 

50.1(e), which defines ambient air as “that portion of the atmosphere, external to buildings, to which

the general public has access.” Street sweeping and disking are common activities throughout the 

Valley, so there is no reason to exclude a site where these activities take place. In the next version of the

Plan, the District should review its rationale for closing the Bakersfield-Muni SLAMS monitors without 

EPA approval and take appropriate action to address the errors identified in these comments. Altering 

the monitoring network without EPA approval and without appropriate notice can jeopardize the 

District’s ability to measure progress toward attainment of the ozone and PM2.5 NAAQS. Considering 

the severe public health consequences of the District’s poor air quality, the District should prioritize the 

maintenance of a comprehensive and reliable air monitoring network by adhering to pertinent 

regulations.

The latest draft of the Plan provides more information on the District’s plans for its air monitoring 

network, particularly as they relate to the siting of near roadway monitors. However, there are still 

many gaps to be filled. We urge the District to provide more detailed information explaining the 

rationale for site selection and for any planned changes to the monitoring network. The District must 

also ensure that its plans for monitor closures and mergers adhere to all applicable regulations before it 

takes any action. 
Jennifer Ridgway, San Joaquin Valley Air Pollution Control District

April 18, 2013

Page 3 of 3

Sincerely,

Adenike Adeyeye

Research & Policy Analyst

Earthjustice 
October 18, 2012

Jennifer Ridgway

San Joaquin Valley Unified Air Pollution Control District

1990 East Gettysburg Avenue

Fresno, CA 93726

Re: San Joaquin Valley Unified Air Pollution Control District, 2012 Air Monitoring 

Network Plan

Dear Ms. Ridgway, 

Thank you for the opportunity to provide comments on the San Joaquin Valley Unified Air 

Pollution Control District’s (“District”) 2012 Air Monitoring Network Plan (“Plan”). This report 

provides information that greatly helps us and other interested parties understand and 

participate in the District’s air monitoring efforts. These comments, submitted on behalf of the 

Central Valley Air Quality Coalition, the Center for Race, Poverty, and the Environment, and

the National Parks Conservation Association, ask for clarification and additional information 

regarding some aspects of the plan, to further facilitate our understanding of the District’s 

approach to meeting federal air monitoring requirements. 

Although the District describes the Plan requirements in the introduction, the criteria behind 

those requirements are not fully explained. For example, on page 7, the Plan details the different 

monitoring site types, such as sites near the highest pollutant concentrations, sites in areas of 

high population density, and sites to identify background concentration levels. This section 

would be more helpful if it described how the District assigned specific monitors to the 

different site types. For sites in high population areas, what is the population threshold used to 

determine which sites fall under the “population oriented” site type? Or, if a threshold is not 

used, how are those sites determined? Similar questions should be answered for the remainder 

of the site types. 

Answering these questions for each of the site types would also provide important information 

about the characteristics of each monitoring site. Appendices A and B offer brief descriptions of 

each of the monitoring sites, but neither provides the site-specific descriptions that would be 

especially useful in understanding the scope of the District’s monitoring network. Appendix A 

contains brief narrative descriptions of each monitoring site, with a heavy focus on regional 

characteristics. For example, the Bakersfield-Muni site description gives a brief overview of the 

city of Bakerfield’s location and pollution profile. It does not provide specific information about 

the area in which the monitor is sited. Is it in a residential area? An industrial area? This and 

other pertinent information should be added to the descriptions in Appendix A. In Appendix B, 
Jennifer Ridgway, San Joaquin Valley Unified Air Pollution Control District

October 18, 2012

Page 2 of 3

there are tables that provide some site-specific information, but these still do not supply the 

type of information requested in the questions above. Adding more information about the area 

in which a monitor is sited would offer a more complete picture of air monitoring in the 

District, when reviewed in conjunction with the detailed site information in Appendix B and the 

more general site descriptions in Appendix A.

This information would also allow for more meaningful comments on expected changes to the 

air monitoring network in the District. The summary of planned changes lists potential site 

mergers without any explanation of the reasons for merging the sites. While, for example, the 

District explains that it will include NOy monitors for specific sites “to comply with the 

regulations for PAMS Type 3 sites,”1the same section simply states that “[t]he District may 

investigate consolidating”2two different sites in a given city. The District, in this Plan, considers 

consolidating six sites: Merced-M Street and Merced-Coffee, Madera-Pump and Madera-City, 

and Fresno-Pacific and Fresno-Drummond. What prompted the District to contemplate 

consolidating these sites? What benefits will consolidation provide to the monitoring network? 

How did the District decide where to locate the consolidated monitors? Answers to these 

questions are necessary to enable the public to review and comment on the District’s proposed 

plans as required by 40 CFR §58.10(c). 

The District’s monitoring system will be required to comply with EPA goals regarding nearhighway monitoring for 1-hour NO2 and PM2.5 concentrations, but there is no discussion of 

these goals in the Plan. Has the District considered how it will comply with near-highway 

monitoring requirements? Will the requirements impact other monitors within the system in 

any way? Providing information about compliance with new goals along with other 

information about planned changes to the system would offer a more comprehensive overview 

of the future of the monitoring network. 

The public would also benefit from clarification on the foundation of the District’s particulate 

matter (“PM”) monitoring system. The District cites the California Regional Particulate Air 

Quality Study (“CRPAQS”) as the basis for the PM monitoring system. It also notes that the 

CRPAQS final report compiling key data and analysis of particulates in the region was 

“expected to be completed in June 2012.”3 Has that report been completed? How did it influence 

system design? If the report is complete, please make it available so that the public can use it to 

evaluate the District’s monitoring approach more fully. 

1 San Joaquin Valley Air Pollution Control District. (September 13, 2012). 2012 Air Monitoring Network 

Plan, at 39. 

2

Id.

3

Id., at 18.
Jennifer Ridgway, San Joaquin Valley Unified Air Pollution Control District

October 18, 2012

Page 3 of 3

In conclusion, the Plan supplies important information about the status of the air monitoring 

network in the District. But, without greater detail about how District site selection satisfies 

relevant criteria, the District’s rationale for potential site mergers, the research that influenced

the design of the monitoring system, and the areas in which monitors are sited, meaningful 

public review and comment cannot occur. We look forward to receiving more detailed 

responses to the questions and comments posed in this letter. 

Sincerely,

Adenike Adeyeye

Research & Policy Analyst

Earthjustice