-eoSrrUNITEDSTATESENVIRONMENTALPROTECTIONAGENCYREGIONIX-qPRO075HawthorneStreetSanFracc1,(jA2),O5-39O1Dr.MaffMiyasato,DeputyExecutiveOfficerScienceandTechnologyAdvancementSouthCoastAirQualityManagementDistrict21865CopleyDriveDiamondBar,California91765-4178DearDr.Miyasato:ThankyouforyoursubmissionoftheSouthCoastAirQualityManagementDistrict’sAnnualAirQualityMonitoringNetworkPlaninJuly2013.Wehavereviewedthesubmitteddocumentbasedontherequirementssetforthunder40CFR58.Basedontheinformationprovidedintheplan,EPAapprovesallportionsofthenetworkplanexceptthosespecificallyidentifiedbelow.Pleasenotethatwecannotapproveportionsoftheannualnetworkplanforwhichtheinformationintheplanisinsufficienttojudgewhethertherequirementhasbeenmet,orforwhichtheinformation,asdescribed,doesnotmeettherequirementsasspecifiedin40CFR58.10andtheassociatedappendices.EPARegion9alsocannotapproveportionsoftheplanforwhichtheEPAAdministratorhasnotdelegatedapprovalauthoritytotheregionaloffices.Accordingly,thefirstenclosure(A.AnnualMonitoringNetworkPlanItemswhereEPAisNotTakingAction)providesalistingofspecificitemsofyouragency’sannualmonitoringnetworkplanwhereEPAisnottakingaction.Thesecondenclosure(B.AnnualMonitoringNetworkPlanChecklist)isthechecklistEPAusedtoreviewyourplanforoverallitemsthatarerequiredtobeincludedintheannualnetworkplanalongwithourassessmentofwhethertheplansubmittedbyyouragencyaddressesthoserequirements.Thethirdenclosure(C.Region9Near-roadNO2PlanReviewChecklist)isthechecklistEPAusedtoreviewthoseelementsofyourannualmonitoringnetworkplanthatdealspecificallywithnear-roadNO2monitoring.ClrelatesspecificallytotheAnaheimsite,whileC2addressestheEtiwandasite.Thefirstenclosurehighlightsasubsetofthemoreextensivelistofitemsreviewedinthesecondandthirdenclosures.Allcommentsconveyedviathisletter(andenclosures)shouldbeaddressed(throughcorrectionswithintheplan,additionalinformationbeingincluded,ordiscussion)innextyear’sannualmonitoringnetworkplan.PrintedonRecycledPaperIf you have any questions regarding this letter or the enclosed comments, please feel free to contact me at (415) 947-4534

or Michael Flagg

at (415) 972-3372. Sincerely, Meredith Kurpius, Manager Air Quality Analysis Office Enclosures:
A. Annual Monitoring Network Plan Items where EPA

is Not Taking Action B. Annual Monitoring Network Plan Checklist C. Region

9 Near-road NO 2 Plan Review Checklists: Cl. Region

9 Near-road NO 2 Plan Review Checklist— Anaheim Site C2. Region

9 Near-road NO 2 Plan Review Checklist— Etiwanda Site cc: Jason Low, South Coast Air Quality Management District Rene Burmudez, South Coast Air Quality Management District Gayle Sweigert, California
Air Resources BoardA. Annual Monitoring Network Plan Items where EPA

is Not Taking Action We are not acting on the portions

of annual network plans where either EPA Region

9 lacks the authority

to approve specific items of the plan, or EPA has determined
that

a requirement

is either not met or information

in the plan
is insufficient

to judge whether the requirement

has been met. • Per 40 CFR 58.11(c), NCore, PAMS, and STN network design and changes
are subject

to approval

of the EPA Administrator. Therefore,

we are not acting on these items. • System modifications
(e.g., site closures

or moves) are subject

to approval per 40 CFR 58.14(c). Information provided

in the plan was insufficient

for EPA to approve the system modifications listed
in the plan per the applicable requirement. Therefore,

we are not acting on the following items
as part of this year’s annual network plan:— Shutdown

of Van Nuys Airport— Relocation

of South Long Beach— Relocation

of Riverside Magnolia— Proposed NO 2 near-road sites • For annual network plans submitted

in 2013, EPA intends

to act on PM 2 . 5 FEM waiver requests outside
of the annual network plan process. • EPA identified items
in your agency’s annual network plan where

a requirement
was not being met or information

in the plan was insufficient

to judge whether the requirement was being met based on 40 CFR 58.10 and the associated appendices. Therefore,

we are not acting on the following items: Item
Checklist Row Issue Distance from trees

80
Not meeting requirement

in some instances Distance

to roadways

73
Not meeting requirement

in one instance. Insufficient information

to judge
in some instances PM 2 . 5 collocation

37 Insufficient information

to judge PM 2 . 5 sampling frequency

51 Insufficient information

to judge PM 10 collocation

40- Insufficient information

to judge PM 10 sampling frequency

53 Insufficient information

to judge Pb collocation

41 Insufficient information

to judge Dates of last PE audit

34
Not meeting requirement

in some instances Dates of last PM semi-

35
Not meeting requirement

in some annual PM audits

instances Dates of last Pb semi-annual

36
Not meeting requirement

in one instance PM auditsIdentification

of primary

38 Insufficient infonnation

to judge

in some monitor

instances Review
of changes

to PM 2 . 5

26 Insufficient information

to judge network Method code

43 Insufficient information

to judge

in some instances Monitor type

46 Insufficient information

to judge

in some instances Distance

to obstructions

not

79 Insufficient information

to judge

in some on roof

instances Distance

to obstructions

on

78 Insufficient information

to judge

in some roof

instances Distance from supporting

77 Insufficient information

to judge
in some structure

instances Basic monitoring objective

47 Incorrect information

to judge

in some instances Site type

48 Incorrect information

to judge
in some instances Parameter occurrence code

50 Insufficient information

to judge
in some instances Parameter code

49 Insufficient information

to judge

in some.

instances Minimum monitoring

72 Insufficient information

to judge requirements

for PM 10 . 2 5 Sampling and analysis

15 Insufficient information

to judge
in some methods

instances Unrestricted airflow

82 Insufficient information

to judge

in some instances Identification

of NO 2 sites as

23 Insufficient information

to judge near-road

or area wide Additional information

for each of these items may be found for the row listed
in colunm

2, in the second enclosure

(B. Annual Monitoring Network Plan Checklist).

### B. ANNUAL MONITORING NETWORK PLAN CHECKLIST (Updated 11/26/2013)
Year: Agency:
40 CFR 58.10(a)(1) requires that each Annual Network Plan (ANP) include informationregarding the following types ofmonitors: SLAMS monitoring stations including FRM, FEM, 

### and ARM monitors that are part ofSLAMS, 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.
40 CFR 58.1 0(a)(1) further directs that, “The plan shall include a statement ofpurposes for each monitor 

### and evidence that siting 

### and operation of each monitor meets the requirements ofappendices A, C, D, and E of

### this part, where applicable.” On 

### this basis, review ofthe 

### ANPs is based on the requirements listed in 58.10 along with those in Appendices A, C, D, 

### and E.
EPA Region 9 will not 

### take action to approve or disapprove 

### any item forwhich 

### Part 58 

### grants approval authority to the Administratorratherthan the Regional Administrators, but we will do a checkto see ifthe required information is included and correct. The items requiring approval by the Administrator are: PAMS, NCore, 

### and Speciation (STN/CSN).
Please note that 

### this checklist summarizes many ofthe requirements of40 CFR

### Part 58, but does not substitute forthose requirements, nor do its contents provide a binding determination ofcompliance with those requirements. The checklist is subjectto revision in the future and we welcome comments on its contents and structure. Key: White

= 

### meets the requirement. Yellow

= 

### requirement is not met, or information is insufficientto make a determination. Action requested in next year’s plan or outside the ANP process. (items listed in Enclosure A)

1ANP 

### requirement Citation Was the info Does the Notes within 

### 40 submitted? 1 If information CFR 58 yes, page #s. provided 3 meet Flag if the req? 4 incorrect 2

? 1. Submitplan by July 1 58.10 (a)(1) Y Y 2. Statement ofpurpose for each monitor 58.10 (a)(l) Y, p.5 Y

3. 30-daypublic comment / inspectionperiod 5 58.10 (a)(1), Y, p.1 Y 58.10 (a)(2) 4. Modifications to SLAMS network— case when we are 58.10 (a)(2) V. p. 31-32 Insufficient info The plan discusses potential discontinuation ofPb not approving actual system modifications (i.e., we 58.10(e) monitoring atVan Nuys Airport site and the will do it outside the ANP process 6 ) relocation ofthe South Long Beach or Riverside Magnolia sites, as well as new near-road NO 2 sites. EPA will not be approving the proposed modifications as part ofthe 2013 ANP review. 5. Modifications to SLAMS network— case when we are 58.10 (a)(2) N/A N/A EPA will not be approving any system approving actual system modifications per 58.14(c) 58.10 (b)(5) modifications as part ofthe 2013 ANP review. 58. 10(e) 58.14 (c) 6. Does plan include documentation (e.g., attached N/A N/A No system modifications in 2013 approval letter) for system modifications thathave been approved since lastANP approval? 7. NCore site operational (by 1/1/2011) 58.10 (a)(3) Y, p.17 Y 8. Pb site for 0.5-1.0 tpy sources operational (by 58.10 (a)(4) Y, App. B V 12/27/2011) 9. NO 2 plan for area-wide and RA4O sites submittedby 58.10 (a)(5) Y, p.8 N/A HQapproval required for NO 2 RA-40 monitoring 7/1/20 12 sites 10. NO 2 area-wide and RA4O sites operational by 58.10 (a)(5) Y, p. 8 V 1/1/2013 11. NO 2 plan fornear-road sites submittedby 7/1/20 13 58.10 (a)(5) Y, p.20-31 N/A See near-road checklists

Response options: NA (NotApplicable), Yes, No, Incomplete, Incorrect. The responses “Incomplete” and “Incorrect” assume that some information has been provided. 2 To the best ofour knowledge.

Assuming the information is correct 4 Response options: NA (Not Applicable)

— [reason], Yes, No, Insufficientto Judge.

The affected state or local agency must documentthe process for obtaining public comment and include any comments received throughthe public notificationprocess within their submittedplan.

6 See58.14(c) 

### 2

### ANP requirement Citation Was the info Does the Notes

within 40 submitted?’ If information

CFR 

### 58 yes, page #s. provided 3 meet
Flag if the req? 4

incorrect 2

? 12. SO 2 sites operational (by 1/1/2013) 58.10 (a)(6) Y, App. B V and 58.13(d) 13. AQS site identification numbçr for each site 58.10 (b)(1) V. p.4, App. B Y 14. Location ofeach site: street address and geographic 58.10 (b)(2) Y, App. B V coordinates 15. Sampling and analysis method(s) for each measured 58.10 (b)(3) Y, App. B Insufficient info There are a number of monitors that reference parameter Table 26 in App. B (i.e. “see Table 26”) for method code which makes it difficult to determine which method code is applicable to a specific monitor at
a site. 16. Any proposals to remove or move a monitoring station 58.10 (b)(5) Y, p.20, App. B V within a period of 18 months following plan submittal 17. Scale ofrepresentativeness for each monitor as 58. 10(b)(6); Y, p. 5, App. B Y defined in Appendix D App D 18. Identification ofsites suitable and sites not suitable for 58.10 (b)(7) Y, App. B Y comparison to the annual PM 2

. 5 NAAQS as described inPart 58.30

- 19. MSA, CBSA, CSA or other area representedby the 58.10 (b)(8) Y, App. B V monitor 20. Designation ofany Pb monitors as either source- 58.10 

### (bX9) V. p. 6, App. B V oriented or non-source-oriented 21. Any source-oriented Pb site for which a waiverhas 58.10 (b)(10) N/A N/A been granted by EPA RA 22. Any Pb monitor for which a waiverhas been 58.10 (b)(1 1) N/A N/A requested or granted by EPA RA foruse ofPb-PM 10 in lieu ofPb-TSP 23. Identification ofrequired NO 2 monitors as either near- 58.10 (b)(l2) V, p.20-31 Insufficient info See “near-road checklists” for details road or area-wide 24. Identification ofany PM 25 FEMs and/orARMs not 58.10 (b)(13) Y, App. C Deferred review EPA will not be approving any FEM waivers as part eligible to be compared to the NAAQS (Note 1: must 58.11 (e) ofthe 2013 ANP approval, but intends to act on include required data assessment.) (Note 2: Required waivers outside annual network plan process. SLAMS must monitor PM 25 with NAAOS comparable monitor at the required sample frequency.)



### 3ANP requirement Citation Was the info Does the Notes

within 40 submitted? 1 If information

CFR 58 yes, page #s. provided 3 meet

Flag if the req? 4

incorrect 2

? 25. For SPMS listed as non-regulatory, note the start Date 58.20(c) N/A N/A No monitortype ofSPM in current network ofFRM/FEM/ARM at SPM. If> 24 months, and monitor is eligible for comparison to the NAAQS per 58.11 (e) and 58.30, the agency must supply informationthatApp A, C or E requirements were not met. 26. Document how states and local agencies provide for 58.10 (c) N Insufficient info Information not included the review ofchanges to a PM 2

. 5 monitoring network that impact the location ofa violating PM 2

. 5 monitor. 27. Does the plan include a request for approval for and 58.11 (a) (2) N/A N/A No request for app. A alternatives alternative to appendix A requirements for SPMs operating a FRM/FEMJARM which also meets appendix E? 28. Precision/Accuracyreports submittedto AQS 58.16(a); Y, p.40 Y App A, 1.3 and 5.1.1 29. Annual data certification submitted 58.15 V. p.40 V App. A 1.3 30. Frequency offlow rate verification for manual PM App A 3.3.2 V 1 App. B Y samplers audit

V 31. Frequency offlow rate verification for automated PM App A 3.2.3 V. App. B Y analyzers audit 32. Frequency ofone-point flow rate verification for Pb App A 3.3.4.1 Y, App. B V samplers audit 33. Frequency ofone-point QC check (gaseous) App. A 3.2.1 Y, App. B Y 34. Date oflast Annual Performance Evaluation (gaseous) App. A 3.2.2 Y, App. B N In some instances the information is out ofdate, and therefore not meeting the requirement:

. lndio,0 3

. Glendora, CD, NO 2 , 03 35. Dates oflast two semi-annual flow rate audits for PM App A, 3.2.4 Y, App. B N In some instances the information is out ofdate, monitors and 3.3.3 and therefore not meeting the requirement:

V • lndio, PM 10 and PM 25

. Glendora, PM 10 and PM 25

• Fontana, PM 10 and PM 25



### 4

### ANP requirement Citation Was the info Does the Notes within 40 submitted?’ If information CFR 58 yes, page#s. provided 3 meet Flag if the req? 4

. 

### incorrect 2

? 36. Dates oflast two semi-annual flow rate audits for Pb App A 3.3.4.1 Y, App. B N Note that flow audits performed outside ofthe 5-7 monitors mos. time period will notbe accepted by AQS as valid and could therefore impact certification documentation (i.e., P/A reports).

. Uddehoim (Trojan Battery) 37. PM 2

. 5 collocation App A 3.2.5 Y, p.29, App. B Insufficient info The collocated monitor at LA N. Main St. reference Table 26 in App. B (i.e. “see Table 26”) for method code which makes it difficult to determine which method code is applicable to the collocated monitor at the site.
The ANP should discuss and provide the relevant data to determine whether the collocated sites meet the requirement that 80% ofthe collocated monitors are located at sites with PM 25 concentrations within 20% ofthe relevant NAAQS.
The App. B tables indicate the multiple continuous monitors are collocated with FRMS. This should be reflected in the collocation tables. 38. Designation ofa primary monitor ifthere is more than Needto Y, App. B Insufficient info Fontana, Glendora, lndio, and Pasadena are the one monitor for a pollutant at a site. determine only sites that identify a monitor as “primary”. All collocation other detailed site tables do not contain this information. 39. Distance between collocated monitors (Note: waiver App. A V. App. B Y request orthe date ofprevious waiver approval must 3.2.5.6 and be included ifthe distance deviates fromrequirement.) 3.2.6.3



### 5

### ANP requirement Citation Was the info Does the Notes within 40 submitted? 1 If information CFR 58 yes, page #s. provided 3 meet Flag if the req? 4 incorrect 2

? 40. Manual PM 10 method collocation met? (note: App A 3.3.1 Y, p. 29, App. B Insufficient info The collocated monitors at LA N. Main St., continuous PM 10 does not have this requirement) Ontario, and Rubidoux reference Table 26 in App. B (i.e. “see Table 26”) for method code which makes it difficult to determine which method code is applicable to the collocated monitor at the site.
The ANP should discuss and provide the relevant data to determine whether the collocated PM 10 sites are located at sites with annual mean particulate matter concentrations among the highest 25 percent ofthe annual mean concentrations for all the sites in the network. 41. Pb collocation App A 3.3.4.3 Y, p. 29, App. B Insufficient info The ANP should discuss and provide the relevant data to determine whether the collocated Pb sites
are located at the sites measuring the highest Pb concentrations in the network. Also, many sites contain multiple Pb monitors, but LA N. Main St. is the only site to identify Pb monitors as “QA Collocated”. All other detailed site tables for Pb do not contain this information.

42. PM 1

.. 25 collocation (note: only applies to Fresno and App A 3.3.6 N/A N/A Phoenix NCore sites) 43. Instrument/monitoring method code for each monitor: App C 2.4.1.2 Y, App. B Insufficient info Some monitors in App. B reference Table 26 for is it reported properly? Is it reported correctly (i.e., method code which makes it difficult to determine appropriate method code forregulatory monitors)? which method code is applicable to the monitor at the site, as there are multiple method codes applicable to a single instrument.

44. For agencies that share monitoring responsibilities in App D 2(e) N/A N/A an MSAJCSA: does each affected State or local agency meet full monitoring requirements or is
an agreement between the affected agencies and the EPA Regional Administrator in place? 45. Start date for each monitor Required to Y, App. B Y 

### 6

### ANP requfrement Citation Was the info Does the Notes 

### within 40 submitted? 1 If information

CFR 58 yes, page #s. provided 3 meet
Flag if the req? 4
incorrect 2

? determine if otherreq. (e.g., mm # and colloc) are met 46. Instrument monitor type for each monitor Required to Y, App. B Incorrect Info Fontana, Glendora, Indlo, and Pasadena sites determine if continue to list the “monitor type” incorrectly as other req. the “site type” (e.g., mm # and colloc) are met 47. Monitoring objective for each instrument App D 1.1 Y, App. B Incorrect Info Fontana, Glendora, and Indio sites continue to 58.10 (b)(6) conflate the terms “site type” and “basic monitoring objective” 48. Site type for each instrument App D 1.1.1 V. App. B Incorrect info Fontana, Glendora, and lndio sites continue to conflate the terms “site type” and “basic monitoring objective” 49. Instrument parameter code for each instrument Required to Y, App. B Insufficient info Some monitors in App. B reference Table 26 for determine if parameter code which makes it difficult to other req. determine which parameter code is applicable to (e.g., miii # the monitor at the site, as there are multiple and colloc) parameter codes applicable to a single are met instrument.
While this approach makes sense for NATTS, PAMS, and Speciated PM 2

. 5 the parameter codes for GMW 1200 PM 10 and the Anderson RAAS PM 25 monitors are difficultto determine. 50. Instrument parameter occurrence code for each Required to V 1 App. B Insufficient Info Some monitors do not have an assigned POC and instrument determine if some monitors measuring the same pollutant other req. have the same POC. See the following: (e.g., mm #

• Burbank: Carbonyls and colloc)

• Fontana: PM 25 are met

• lndio: PM 10

• Los Angeles N. Main: PM 10 , VOCs, PM 2

. 5 

### 7

### ANP 

### requirement Citation Was the info Does the Notes within 40 submitted? 1 If information CFR 58 yes, page #s. provided 3 meet Flag if the req? 4 incorrect 2

? STN

. Pico Rivera: VOCs, Carbonyls

. Rubidoux: VOCs, PM 25 STN

• Santa Clarita: VOCs

51. Sampling season for ozone (note: date ofwaiver 58.10 

### (b)(4) Y, App. B Y approval mustbe included ifthe sampling season App D, 4.1(i) deviates fromrequirement) 52. Sampling schedule for PM 2

. 5

- applies to year-round 58.10 (b)(4) Y, p.16, App. B Insufficient Info Design values for PM 2

. 5 monitors were not and seasonal sampling schedules (note: date ofwaiver 58.12(d) provided; therefore there is insufficient approval mustbe included ifthe sampling season App D 4.7 information to determine whetherthe sampling deviates from requirement) EPA schedules identified in the plan are appropriate. flowchart 53. Sampling schedule for PM 10 58.10 (b)(4) Y, App. B Insufficient Info Ambient PM 10 data were not provided; therefore 58.12(e) there is insufficient information to determine App D 4.6 whether the sampling schedules identified in the plan are appropriate. 54. Sampling schedule forPb 58.10 (b)(4) Y, App. B Y 58.12(b) App D 4.5 55. Sampling schedule for PM 125 58.10 

### (b)(4) Y, App. B V 58.12(f) AppD4.8 56. Minimum# ofmonitors for 03 [Note: should be App D, 4.1(a) Y, p. 34 Y supported by MSA ID, MSA population, DV, # and monitors, and # required monitors] (see footnote) 7 Table D-2 57. Identification ofmax. conc. 03 monitor(s) App D 4.1 (b) V. p.5-6, App. B V 58. Minimum monitoring requirements met for near-road App D 4.3.2 Y, p.20-31, p.36 N/A Two near-road monitors are required to be NO 2 (2014 start date) implemented January 1, 2014. 59. Minimum monitoring requirements met for area-wide App D 4.3.3 V. p.36 V NO 2 60. Minimum monitoring requirements met forRA-40 App D 4.3.4 Y, p.8 V
Only monitors considered to be required SLAMs are eligible to be countedtowards meeting minimum monitoring requirements. In addition, ozone monitors that do not meet traffic count/distance requirements to be neighborhood scale (40 CFR 58 Appendix E, Table E-1) cannotbe countedtowards minimum monitoring requirements. 

### 8

### ANP requirement Citation Was the info Does the 

### Notes

within 40 submitted? 1 If information
CFR 58 yes, page #s. provided 3 meet Flag if the req? 4

. incorrect 2

? NO 2 61. Minimum monitoringrequirements met for SO 2 App D 4.4 Y, p.37 V [Note: Only monitors considered to be required SLAMs are eligible to be countedtowards meeting minimum monitoring requirements.] 62. Minimum monitoringrequirements met forPb [Note: App D 4.5 Y, p.37-38 Y Only monitors considered to be required SLAMs are 58.13(a) eligible to be counted towards meeting minimum monitoring requirements.] 63. Minimum# ofmonitors for PM 2

. 5 [Note 1: shouldbe App D, 1, p.34 V supported by MSA ID, MSA population, DV, # 4.7.1(a) and monitors, and# requiredmonitors] [Note 2: Only Table D-5 monitors consideredto be required SLAMs are eligible to be counted towards meeting minimum

. monitoringrequirements.] 64. Optional PM 2 .5 Network Clarifications: Provide a list Needto N/A N/A ofrequired sites ifit does not include all SLAMS. assess several [Note: defaultwill assume all SLAMS are considered requirements required sites.] 65. Required PM 2

. 5 sites represent area-wide air quality App D Y, p.5 V 4.7.1(b) 66. For PM 2

. 5 , is at least one site atneighborhood or larger App D Y, p.5 V scale in an areaofexpected maximum concentration 4.7.1(b)(l) 67. Ifadditional SLAMS PM 2

. 5 required, is there a site in App D Y, p. 5 Y an area ofpoor air quality 4.7.1(b)(2) 68. Minimum monitoring requirements for continuous App D 4.7.2 V 1 p.35, App. B V PM 2

. 5 69. Requirements for PM 2

. 5 background andtransport App D 4.7.3 N/A N/A sites 70. Are PM 2

. 5 Chemical Speciationrequirements met for App D 4.7.4 V. p.35 V official STN sites? 71. Minimum # ofmonitors for PM 10 App D, 4.6 (a) Y, p.36 V and Table D-4 72. Minimum monitoring requirements met for pM 10

. 2 5 App D 4.8

- N Insufficient Info Information on minimum requirements for mass PM 1025 are not included.



### 9

### ANP requirement Citation Was the info Does the Notes within 40 submitted? 1 If information

• CFR 58 yes, page #s. provided 3 meet

. 

### Flag if the req? 4 incorrect 2

? 73. Distance ofsite from nearest road App E 6 Y, App. B N, Insufficient Info The Pomona site is not meeting this requirement for Ozone. Therefore, this site should not be counted towards meeting minimum monitoring requirements, as data may not be suitable for NAAQS comparison. A waiver forthis requirement may be requested. Also, for sites with “separate monitoring compounds”, distance to roadways information should be explicitly provided for each monitor. The following sites need more specific information:

. Long Beach (North) 74. Traffic count ofnearest road App E V. App. B V See notes for item #73 75. Groundcover App E 3(a) V. App. B V 76. Probe height App E 2 V. App. B Y 77. Distance from supporting structure App E 2 Y, App. B Insufficient Info Distances were not provided for the following sires:

. lndio

. Reseda: PM 25

, POC 3

. Rubidoux: PM2.5, POC 9 & 4; PM 10, POC_9;_VOC5,_multiple_POCs 78. Distance from obstructions on roof App E 4(b) Y, App. B Insufficient Info Height ofobstruction was not included for the following sites:

. LAX

- Hastings

79. Distance from obstructions not on roof App E 4(a) V, App. B Insufficient Info Height ofobstruction was not included forthe following sites:

. Crestline

. Long Beach (North)

. Reseda



### 10

### ANP requirement Citation Was the info Does the Notes within 40 submitted? 1 If information CFR 58 yes, page #s. provided 3 meet Flag if the req? 4 incorrect 2

? 80. Distance from trees App E 5 Y, App. B N The following sites are not meeting this requirement:

. • Crestline

• La Habra

. Long Beach (North)

. Pasadena 81. Distance to furnace or incinerator flue App E 3(b) Y, App. B V 82. Unrestricted airflow App E, 4(a) Y, App. B Insufficient Info Information not provided for the following sites: and 4(b)

• lndio: PM 10 , POC 3 Also, the following sites do not include the degree arc ofunrestricted flow:

. Fontana

• Glendora

• lndio

.

• L.A. North Main St. 83. Probe material (ifapplicable) App E 9 V. App. B V 84. Residence time (ifapplicable) App E 9 V. App. B V 

### Public Comments on Annual NetworkPlan Were comments submittedto the S/LIT agency 

### during the public commentperiod? Yes

If no, 

### skip the remaining questions. 

### If yes:


### • Were 

### any of

### the comments substantive? 

### No

o 

### If yes, 

### which ones?

o 

### Explain basis for determination 

### ifany comments were 

### considered not substantive: 

### The comments submitted with the 2013 plan from NRDC were primarily focused on expedited implementation of

### an additional near-road NO 2 site in the Los Angeles

— 

### Long Beach

—

### Anaheim CBSA, and implementation ofCO and PM 2

. 5 monitors at the 2014 near-road NO 2 sites, all ofwhich are notrequired to be implemented unifi January 1, 2015. NRDC also expressed concerns with the PM 2

. 5 FEM waiver request from South Coast. As mentioned in the checklist above, EPA wifi notbe acting on the approval ofthe FEM waivers as part ofthe 2013 AM’ review process. 11

### • Did the agency respond to the substantive comments? Yes
o Ifyes, was the response adequate? Yes

• Do the substantive comments require separate EPA response (i.e., agency response wasn’t adequate)? No

• Are the sections ofthe annual networkplan that received substantive comments approvable after consideration ofcomments? N/A
o Ifyes, provide rationale:

12

### Cl. Region 9 Near-road NO 2 Plan review checklist- Anaheim Site Checklist Version date: November 26, 2013 Agency: South Coast Air 

### Quality Management District (AQMD) CBSA: Los Angeles-Long Beach-SantaMa, CA (ist 

### site required by January 1, 2014) This checklistis intendedto 

### clarify those elements thatEPA will be looking for 

### during the review ofproposed near-roadNO 2 monitoring sites. Please note that

### this checklist summarizes near-roadNO 2 site requirements of40 CFR Part 58, but does not substitute for those requirements, nor do its contents provide abinding determination ofcompliance 

### withthose requirements. The checklistis subjectto revision in the future and we welcome comments on its contents 

### and structure. Key: White

= 

### meets the requirement. Yellow

= 

### Requirement is notmet, or information is insufficient to make a determination. Action requested in nextyear’s plan or outside the ANP process. Green itemrequires attention m orderto improve nextyear’s plan

1

### COMPLETENESS CHECK: Based on 40 CFR 58 requirements. Network Plan reauirements (40 CFR 58.10)- No. Near-road N02 plan requirement Citation Info Requirement Notes submitted?’ met? 2 Ifyes, page #s. A plan (submitted by July 1, 2013) for 40 CFR Incomplete, Insufficient to Plan with final comments submitted July 3, 

### establishing near-road N02 monitoring 58.l0(a)(5) p.20-31 judge 2013. site(s) Provided the final site selected is accurately characterized by the informationprovided and meets all ofthe applicable 40 CFR Part 

### 58 criteria, we expect that we will be able to approve AQMD’s NO 2 near-roadway site selection presented on p.2’7, Table 11 along Route 5/Lincoln Anaheim. AQMD will need to resubmit a plan thatproposes the final candidate site selection and includes missing information highlighted in this checklist. The re-submitted plan should be submitted as part

. 

### ofthe next annual monitoring network plan and go through a minimum 30 day public inspection period prior to re-submittal to EPA. 2 Evidence ofpublic comment on proposed 40 CFR Incomplete Insufficient to AQMD received and forwarded comments site(s), no changes subsequent to proposal, 58.l0(a)(2) judge. from NRDC pertaining to the selection of and submittal ofany received coniments their near-road NO 2 monitoring sites. These comments support AQMD’s choice ofa first site along Interstate 5 

### in Anaheim or Route 5

### 7/60 in Diamond Bar.

1 Response options: N/A (Not Applicable), Yes, No, Incomplete, Incorrect. The responses “Incomplete” and “Incorrect” assume that some information has been provided. 2 Response options: N/A (Not Applicable)

— [reason], Yes, No, Insufficientto Judge. Assumes information submitted is correct. 

### 2

### EPA is also aware and in support ofpublic workshops held by AQMD in 2013 aimed at engaging the public in the near-road NO 2 site selection process.
The plan for a final proposed candidate site selection, including missing information highlighted in this checklist, will need to be made available for public comment prior to re-submittal to EPA. See item 1. 3 Anticipated operation start date 40 CFR Yes, p.31 Yes Once site begins operation, please include 

### 58.1 0(a)(5) actual operation start date in future ANP

. 

### submittals 4 AQS site identification number 40 CFR No Insufficient to Please include this information in the final 58.10(b)(1) judge. submittal ifavailable. 

### 5 Location (street address & geographical 40 CFR No Insufficient to Please include this information in the final coordinates) 58.1 0(b)(2) judge. submittal. 6 Sampling and analysis method (method 40 CFR Incomplete, Insufficient to AQMD notes that data coming from monitors code) 

### 58.10(b)(3) p.20 judge. can be used for comparison to the NAAQS.
Please include specific method codes for the site with the final submittal. 7 Operation Schedule (Season & sampling 40 CFR No Insufficient to Please include this information in the final frequency) 58.1 0(b)(4) judge. submittal. 8 

### Any proposal to remove or move the 40 CFR No Insufficient to Please include this information in the final monitor within a period of 18 months 58.10(b)(5) judge. submittal. following plan submittal 9 Monitoring objective & spatial scale of 40 CFR No Insufficient to Please include this information in the final representativeness 58.10(b)(6) judge. submittal. 10 CBSA represented by the monitor 

### 40 CFR Yes, p.22 Yes 58.10(b)(8) 

### NetworkDesign requirements (40 CFR 58, Appendix D, Section 4.3.2) 11 CBSA population & year 40 CFR 

### 58, Yes, p. 22 

# J Yes 

### App.D 3

### __________________________________

4.3.2(a) 12 

### MaximumAADT counts & year for the 40 CFR 58, Yes, p.22 Yes CBSA(s) App.D 4.3.2(a) 13 Correct # ofrequired near-road NO 2 40 CFR 

### 58, Yes, p.22 Yes monitors for the CBSA(s) App.D 4.3.2(a) 14 Were all road segments 

### within the CBSA 40 CFR 58, Yes, p.23-24 Yes ranked by AADT? App.D 4.3.2(a)(1) 15 Discussion ofhow fleet mix is considered 40 CFR 58, Yes, p.23-24 Yes App.D 4.3 .2(a)( 1) 16 Discussion ofhow roadway design is 40 CFR 58, Yes, p.25-27 Yes Recommend expanding on narrative considered App.D discussion for consideration ofthis factor, 4.3.2(a)(l) specific to the final candidate site selected. 17 Discussion ofhow congestion is 40 CFR 58, Yes, p.29-30 Yes Recommend expanding on narrative considered App.D discussion for consideration ofthis factor, 4.3.2(a)(l) specific to the final candidate site selected. 18 Discussion ofhow terrain is considered 40 CFR 58, Yes, p.25-27 Yes Recommend expanding on narrative App.D discussion for consideration ofthis factor, 4.3.2(a)(l) specific to the final candidate site selected. 19 Discussion ofhow meteorology is 40 CFR 58, Yes, p.25-27 Yes Recommend expanding on narrative considered App D discussion for consideration ofthis factor, 4 

### 3 2(aXl) specific to the final candidate site selected 20 After above factors considered, ifmultiple 40 CFR 58, Incomplete, Insufficient to Please include discussion ofconsideration of candidate sites where max concentrations App.D p.20 judge this factor in next year’s plan submittal. expected: Discussion ofhow population 4.3.2(a)(1) exposure is considered? 21 Where the site proposed is the 2 nd 

### in the 40 CFR 58, N/A N/A- 1 St 

### site CBSA: Discussion ofdiffering factors App.D proposed for compared to first site (i.e. fleet mix; 4.3.2(a)(1) CBSA congestion; terrain; geographic area 

### within CBSA; or different route, interstate, or 4SUPPORTING/ADDITIONAL INFORMATTON 

### Based onNear-road NO 2 monitoring TAD and experience. freeway designation). Siting criteria requirements (40 

### CFR 58, Appendix E) 22 Distance from target road segment as near 40 CFR 58, Yes, p.25-27 Yes Please clarify actual distance from target road as practicable (TAD recommendation is App.E to the probe in next year’s plan. within 20 meters) & no more than 50 6 4(a) meters 9 23 Vertical inlet placement between 2-7 40 CFR 58, No Insufficientto Please include this information in the final meters? App.E 2 judge. submittal. 24 Probe distance from supporting structures 40 CFR 58, No Insufficient to Please include this information in the final is at least 1 meter away vertically or App.E 2 judge. submittal. horizontally? 25 Is air flow unobstructed between the probe 40 CFR 58, No Insufficient to Please include this information in the final and the outside nearest edge ofthe targeted App.E 4(d) judge. submittal. road segment?

Check 

### (Yes, No, N/A, Comments

- 

### Insufficient)

If

### yes, page #s. 

### Iftop FE-AADT segmentnot selected, is adequatejustification Yes, p.26-27 AQMD’s selected site ranks #3 in provided forhigher ranks not selected? FE-AADT.
In Table 10 (p. 26 ), AQMD presents the scoring systemused to rankthe various candidate road segments. 

### This helps describe how FE-AADT

. 

### is weighed againstother factors. The greatest weight is placed on FE-AADT as a factor. If

### similartop FE-AADT candidate sites available, was most Yes, p.29 AQMD lists the I-S as most congested segment selected? congested freeway in Orange County. Is candidate site selected downwind oftarget road segment? Yes, p.26-27 Downwind. Are wind roses included to show predominant

### wind patterns? No Recommend including ifavailable. 5

### Are physical attributes (roadway design, roadside structures, or Yes, p.26-27 See items 16, 18-19. terrain) desirable according to Table 4-2 ofthe Near-road NO 2 TAD (see below)? Ifphysical attributes (roadway design, roadside structures, or terrain) N/A NOT desirable according to Table 4-2 ofthe Near-road NO 2 TAD,
are they TYPICAL for the area? Was population exposure correctly considered as an additional factor Insufficientto See item 20. AFTER consideration ofprimary factors (FE-AADT, congestion, judge roadway design, terrain, meteorology) and IF multiple max concentration candidate sites identified? Will this be amulti-pollutant site? Ifso, list additional parameters Insufficientto Please include information for other planned in Comments, judge parameters that may be monitored atthe site. Does agency ensure candidate selection is NOT in a “unique” Insufficientto Please 

### clarify in nextyear’s location? (See Near-road NO 2 TAD section 13.2 included below) judge networkplan.

6

### Table 4-2. Summary ofphysical considerations for candidate near-road sites.

Roadway design or configuration Feasibility of monitor placements; affects pollutant transport and dispersion. At-grade or nearly at-grade with immediate surrounding terrain. Deep cutsections/significant ly below grade; significantly above grade (fill or bridge); above grade (bridge). Field reconnaissance; satellite imagery Physical Site Impact on Site Desirable Least Desirable Potential Information Component Selection Attributes Attributes Sources



### Roadside Feasibility of present other Presence ofsound Field reconnaissance; Structures monitor than low (<2 m walls, mature (high satellite placement; in and thick) imagery affects pollutant height) vegetation, transport and vegetation or obstructive dispersion. safety features buildings. such as guardrails. Terrain Affects pollutant Flat or gentle Along mountain Field reconnaissance; dispersion, local terrain, within a ridges or peaks, digital atmospheric valley, or along a hillsides, or other elevation models and stability, road grade. naturally vegetation windswept areas. files; satellite imagery. Meteorology Affects pollutant Relative Strongly Local data; National transport and downwind predominant Oceanic and dispersion. locations; winds upwind positions. Atmospheric from road to Administration’s monitor. (NOAA’s) National Weather Service (NWS); EPA’s Air Quality System (AQS).
7

### 13.2 Unique Locations and Background Source Influences In the evaluation process, state and 

### local air agencies may encounter situations where certain road segments ofinterest have characteristics that make the location aunique near-road location thathas elevated pollutant concentrations. In such cases, the pollutant concentrations are not representative ofother near-road locations across the CBSA. The unique characteristics ofthese locations could be due to the close proximity ofa substantial stationary source, non-road mobile
sources, or roadway design features (such as tunnel entrances and exits ortoll plazas). In situations where a state or local air agency has a choice between road segments that otherwise have similarpotential forpeakN02 concentrations, the air agencies should place ahigher weight

on sites that are most influenced by typical roadway activity ratherthan those that are heavily influenced by unique sources or features. This approach increases the probability thatthe chosen site can represent a largerpopulation exposure within and across CBSAs. The EPA recognizes that state and local air agencies will likely have a good understanding of whether candidate near-road N02 monitoring sites have unique characteristics that do or do not represent the CBSA that those sites are within. The EPA encourages state and local air agencies
to use their local knowledge in site selection and to engage the EPA Regional stafffor assistance in evaluating such a situation as necessary.

8

### C2. Region 9 Near-road NO 2 Plan review checklist- Etiwanda Site Checklist Version date: November 26, 2013 Agency: South Coast Air Quality Management District (AQMD) CBSA: Riverside-SanBernardino-Ontario, CA (1 site requiredby January 1, 2014) This checklist is intended to 

### clarify those elements thatEPAwill be looking for during the review ofproposed near-roadNO 2 monitoring sites. Please note that

### this checklist summarizes near-roadNO 2 site requirements of40 CFR

### Part 58, but does not substitute for those requirements, nor do its contents provide abinding determination ofcompliance 

### withthose requirements. The checklist is subject to revision in the 

### future and we welcome comments on its contents 

### and structure. Key: White
= 

### meets the requirement. Yellow
= 

### Requirementis notmet, or information is insufficientto make a determination. Actionrequested in nextyear’s plan or outside the ANP process. 

### Green
= 

### itemrequires attention in orderto improve nextyear’s plan.

1

### COMPLETENESS CHECK: Based on 40 CFR 58 requirements. Network Plan requirements (40 CFR 58.10)- No. Near-road N02 plan requirement Citation Info Requirement Notes submitted?’ met? 2 Ifyes, page #s. A plan (submitted by July 1, 2013) for 40 CFR Incomplete, Insufficient to Plan with final comments submitted July 3, establishing near-road N02 monitoring 58.10(a)(5) p.20-31 judge 2013. site(s) Provided the final site selected is accurately characterized by the information provided and meets all ofthe applicable 40 CFR Part 58 criteria, we expect that we will be able to approve AQMD’s NO 2 near-roadway site

. 

### selection presented on p.28, Table 12 along Route I0/EtiwandaFontana. AQMD will need to resubmit a plan that proposes the final candidate site selection and includes missing information highlighted in this checklist. The re-submitted plan should be submitted as part ofthe next annual monitoring network plan and go through a minimum 30 day public inspection period prior to re-submittal to EPA. 2 Evidence ofpublic comment on proposed 40 CFR Incomplete Insufficientto AQMD received and forwarded comments site(s), no changes subsequent to proposal, 58.1 0(a)(2) judge. from NRDC pertaining to the selection of and submittal ofany received comments their near-road NO 2 monitoring sites. These

. 

### comments do not particularly comment on the selection ofsites in the Riverside-San Bernardino-Ontario, CA CBSA.

Response options: N/A (Not Applicable), Yes, No, Incomplete, Incorrect. The responses “Incomplete” and “Incorrect” assume that some information has been provided. 2 Response options: N/A (Not Applicable)

— [reason], Yes, No, Insufficient to Judge. Assumes information submitted is correct. 2

### EPA is also aware and in support ofpublic workshops held by AQMD in 2013 aimed at engaging the public in the near-road NO 2 site selection process.
The plan for a final proposed candidate site selection, including missing information highlighted in this checklist, will need to be made available for public comment prior to re-submittal to EPA. See item 1. 3 Anticipated operation 

### start date 40 CFR Yes, p.31 Yes Once site begins operation, please include 

### 58.l0(a)(5) actual operation start date in future ANP submittals 4 AQS site identification number 40 CFR No Insufficient to Please include this information in the final 

### 58.1 0(b)( 1) judge. submittal ifavailable. 5 Location (street address & geographical 40 CFR No Insufficient to Please include this information in the final coordinates) 58.10(b)(2) judge. submittal. 6 Sampling and analysis method (method 40 CFR Incomplete, Insufficient to AQMD notes that data coming from monitors code) 

### 58.10(b)(3) p.20 judge. can be used for comparison to the NAAQS.
Please include specific method codes for the site with the final submittal. 

### 7 Operation Schedule (Season & sampling 40 CFR No Insufficient to Please include this information in the final frequency) 

### 58.1 0(b)(4) judge. submittal. 8 

### Any proposal to remove or move the 40 CFR No Insufficient to Please include this information in the final monitor within a period of 18 months 58.l0(b)(5) judge. submittal. following plan submittal 9 Monitoring objective & spatial scale of 40 CFR No Insufficient to Please include this information in the final representativeness 

### 58.1 0(b)(6) judge. submittal. 10 CBSA represented by the monitor 40 CFR Yes, p.22 Yes 58.10(b)(8) 

### NetworkDesign requirements (40 CFR 58, Appendix D, Section 4.3.2) 11 CBSA population & year 40 CFR 58, Yes, p.22 Yes App.D
3

### ___________________________________

4.3.2(a) 12 Maximum AADT counts & year forthe 40 CFR 58, Yes, p.22 Yes CBSA(s) App.D 4.3.2(a) 13 Correct# ofrequired near-road NO 2 40 CFR 58, Yes, p.22 Yes monitors forthe CBSA(s) App.D

• 4.3.2(a) 14 Were 

### all road segments within the CBSA 40 CFR 58, Yes, p.23-24 Yes ranked by AADT? App.D 4.3.2(a)(1) 15 Discussion ofhow fleet mix is considered 40 CFR 58, Yes, p.23-24 Yes App.D

2 1’ 

### ‘1) Discussion

. 

### considered

After above factors considered, ifmultiple 40 CFR Incomplete, Insuliicient to Please include discussion ofconsideration of candidate sites where max concentrations App.D p.20 judge this factor in next year’s pian submittal. expected: Discussion ofhow population 4.3.2(a)(1) exposure is considered? 21 Where the site proposed is the 211( 

### in the 40 CFR 58, N/A N/A- 1 St 

### site CBSA: Discussion ofdiffering factors App.D proposed for compared to first site (i.e. fleet mix; 4.3.2(a)(1) CBSA congestion; terrain; geographic area within CBSA; or different route, interstate, or 4

### freeway designation). 

# I I Siting criteria requirements (40 CFR 58, Appendix E) 22 Distance from target road segment as near 40 CFR 58, Yes, p.25-28 Yes Please clarify actual distance from target road as practicable (TAD recommendation is App.E to the probe in next year’s plan. within 20 meters) & no more than 50 6 4(a) meters 9 23 Vertical inletplacement between 2-7 40 CFR 58, No Insufficient to Please include this information in the final meters? App.E 2 judge. submittal. 24 Probe distance from supporting structures 40 CFR 58, No Insufficient to Please include this information in the final is at least 1 meter away vertically or App.E 2 judge. submittal. horizontally? 25 Is air flow unobstructed between the probe 40 CFR 58, No Insufficient to Please include this information in the final and the outside nearest edge ofthe targeted App.E 4(d) judge. submittal. road segment? SUPPnDTTNIA1ThTTIONAL TNFfl1MATION: Based on Near-road NO 2 monitoring TAD and experience. Check (Yes, No, N/A, Comments

- 

### Insufficient) Ifyes, page #s. Iftop FE-AADT segment not selected, is adequatejustification Yes, p.26-28 AQMD’s selected site ranks #3 in provided forhigher ranks not selected? FE-AADT forthe CBSA.

V 

### In Table 10 (p. 26 ), AQMD presents the scoring system used to 

### rankthe various candidate road segments. This helps describe how FE-AADT is weighed against other factors. The greatest weight is placed on FE-AADT as a factor. Ifsimilartop FE-AADT candidate sites available, was most Yes, p.30 AQMD lists the 1-10 as most congested segment selected? congested freeway in San Bernardino County. The most congested segment along SR9I in Riverside County is not listed
5

### among highestranked FE-AADT segments for the CBSA. Is candidate site selected downwind oftarget road segment? Yes, p.26-28 Downwind. Are wind roses included to show predominant wind patterns? No Recommend including ifavailable. Are physical attributes (roadway design, roadside structures, or Yes, p.26-28 See items 16, 18-19. terrain) desirable according to Table 4-2 ofthe Near-road NO 2 TAD (see below)? Ifphysical attributes (roadway design, roadside structures, orterrain) N/A NOT desirable according to Table 4-2 ofthe Near-road NO 2 TAD,
are they TYPICAL for the area? Was population exposure correctly considered as an additional factor Insufficient to See item 20. AFTER consideration ofprimary factors (FE-AADT, congestion, judge roadway design, terrain, meteorology) and IF multiple max concentration candidate sites identified? Will this be amulti-pollutant site? Ifso, list additional parameters Insufficientto Please include information for other planned in Comments, judge parameters that may be monitored at the site. Does agency ensure candidate selection is NOT in a “unique” Insufficientto Please clarify in next year’s location? (See Near-roadNO 2 TAD section 13.2 included below) judge networkplan.

6

### Table 4-2. Summary ofphysical considerations for candidate near-road sites.

Feasibility of monitor placements; affects pollutant transport and dispersion. At-grade or nearly at-grade with immediate surrounding terrain. Deep cutsections/significant ly below grade; significantly above grade (fill or bridge); above grade (bridge). Field reconnaissance; satellite imagery Roadway design or configuration Physical Site Impact on Site Desirable Least Desirable Potential Information Component Selection Attributes Attributes Sources



### Roadside Feasibility of present other Presence ofsound Field reconnaissance; Structures monitor than low (<2 m walls, mature (high satellite placement; in and thick) imagery affects pollutant height) vegetation, transport and vegetation or obstructive dispersion. safety features buildings. such as guardrails. Terrain Affects pollutant Flat or gentle Along mountain Field reconnaissance; dispersion, local terrain, within a ridges or peaks, digital atmospheric valley, or along a hillsides, or other elevation models and stability, road grade. naturally vegetation windswept areas. files; satellite imagery. Meteorology Affects pollutant Relative Strongly Local data; National transport and downwind predominant Oceanic and dispersion. locations; winds upwind positions. Atmospheric from road to Administration’s monitor. (NOAA’s) National Weather Service (NWS); EPA’s Air Quality System (AQS).
7

### 13.2 Unique Locations and Background Source Influences In the evaluationprocess, state 

### and local air agencies may encounter situations where 

### certain road segments ofinterest have characteristics that make the location aunique near-road location that has elevated pollutant concentrations. In such cases, the pollutant concentrations 

### are not representative ofothernear-road locations across the CBSA. The unique characteristics ofthese locations could be due to the close proximity ofa substantial stationary source, non-road mobile
sources, or roadway design features (such as tunnel entrances 

### and exits ortoll plazas). In situations where a state or local 

### air agency has a choice betweenroad segments that otherwise have similarpotential forpeakN02 concentrations, the 

### air agencies should place a

### higher weight

on sites that are most influenced by typical roadway activity ratherthan those that are heavily influenced by unique sources or features. This approach increases the probability that the chosen site 

### can represent a largerpopulation exposure within and across CBSAs. The EPA recognizes that state and local air agencies will likely have a good understanding of whether candidate near-roadN02 monitoring sites have unique characteristics that do or do not represent the CBSAthat those sites 

### are within. The EPA encourages state and local air agencies
to use their local knowledge in site selection andto engage the EPA Regional stafffor assistance in evaluating such a situation as necessary.

8