Air Monitoring Network Plan 2013

NCUAQMD

2300 Myrtle Ave

Eureka, CA 95501
Page 2 of 27

Table of Contents

Definition of Terms 30

Executive Summary 4

Overview of Network Operation 5

Network Design 5

Maps of monitoring Station Locations 6

Minimum monitoring Requirements 11

Ozone 11

PM2.5 12

PM10 13

NO2 14

SO2 14

CO 15

Pb 15

Quality Control 16

Collocation 16

Recent or Proposed Changes to Network 16

Review of Changes to PM2.5 monitoring Network 16

Data Submission Requirements 17

Data Availability 17

Detailed Site Information 18

Jacobs 18

Eureka Ist 20

Humboldt Hill 22

Weaverville 24

Crescent City 26

Signature 27
Page 3 of 27

Definition of Terms

AAC: Atmospheric Analysis and Consulting

AQS: Air Quality System

BAAQMD: Bay Area Air Quality Management District

CARB: California Air Resources Board

E-BAM: Emergency Beta-Attenuation Monitor

FEM: Federal Equivalency Method

FRM: Federal Reference Method

MSA: Micropolitian Statistical Area

NAAQS: National Ambient Air Quality Standards

NOAA: National Oceanographic and Atmospheric Administration

NCUAQMD: North Coast Unified Air Quality Management District

POC: Parameter Occurrence Code

PQAO: Primary Quality Assurance Organization

SIP: State Implementation Plan

SLAMS: State and Local Air Monitoring Station

SPM: Special Purpose Monitor
Page 4 of 27

Executive Summary

The North Coast Unified Air Quality Management District (NCUAQMD) maintains a 

network of air pollution monitoring equipment. This network has developed slowly, 

beginning in 1986 with a solitary PM10 monitoring station. Currently there are five 

stations in operation.

The NCUAQMD is located in the far northwestern portion of California. It is comprised 

of three counties: Humboldt, Del Norte, and Trinity, which together cover 7,753 square 

miles. It is bordered on the west by the Pacific Ocean and extends from the Oregon 

Border south approximately 140 miles to the Mendocino County line. Eureka, the 

county seat of Humboldt County, is 284 miles north of San Francisco, 466 miles south 

of Portland, Oregon and on the coast of the Pacific Ocean. The area is made up of

varied terrain, from coastal wetlands to rugged mountains. Inversions and diurnal 

offshore wind patterns are common. 

Major sources located in the Humboldt Bay region (Eureka, Arcata) include the

Fairhaven Power Plant, and PG&E's Humboldt Bay Power Plant. The first source is

located on the Samoa Peninsula just east of Eureka. The PG&E plant is located just 

south of Eureka. 

In addition to these Title 5 sources, the NCUAQMD is impacted by mobile and large 

industrial sources. The District is also impacted by wood smoke in the winter and 

agricultural crop residue burning and wildfires in the summer.
Page 5 of 27

Overview of Network Operation

Network Design.

The North Coast Unified Air Quality Management District operated 5 monitoring sites in 

2012. The following maps show the locations of the monitoring sites. Tables 1 and 2

list the pollutants measured at each site.

Table 1. List of Special Purpose Monitoring Sites

Site Name AQS Site # Pollutant Monitored

Jacobs 060231004

PM10, PM2.5, O3, NO2, 

CO, SO2

Humboldt Hill 060231005

PM10, PM2.5, O3, NO2, 

CO, SO2, NH3

Weaverville 061050002 PM2.5

Table 2. List of State and Local Air Monitoring Sites

Site Name AQS Site # Pollutants Monitored

Eureka Ist 060231002 PM10, PM2.5

Weaverville 061050002 PM10

Crescent City 060150006 PM10
Page 6 of 27

Monitoring Station Locations

Jacobs Monitoring Station (717 South Ave, Eureka, Humboldt County)

 

 
Page 7 of 27

Eureka Ist Monitoring Station (529 I Street, Eureka, Humboldt County)

 

 
Page 8 of 27

Humboldt Hill Monitoring Station (7333 Humboldt Hill Rd., Eureka, Humboldt County)

 

 
Page 9 of 27

Crescent City Monitoring Station, (880 Northcrest Dr., Crescent City, Del Norte County)

 

 
Page 10 of 27

Weaverville Monitoring Station, (11 Court Street, Weaverville, Trinity County)
Page 11 of 27

Minimum Monitoring Requirements

This network meets the minimum monitoring requirements for all criteria pollutants 

(Tables 3-11).

Ozone

Table 3. Minimum Monitoring Requirements for Ozone.

Micropolitian 

Statistical

Area

County

Pop. In 

Year 

2010

4th 

highest 8-

hour max. 

(ppm)

(2010-

2012)

3 year 

design 

value

SLAMS 

Monitors 

Required

Active 

SLAMS

Monitors

Active 

SPM

Monitors

Monitors 

Needed

EurekaArcataFortuna

Humboldt 134,623

Jacobs

0.047

Jacobs

0.045

0 0 2 0

Humboldt 

Hill*

0.046

Humboldt 

Hill*

0.043

Crescent 

City Del Norte 28,610 - - 0 0 0 0

none Trinity 13,786 - - 0 0 0

0

* Humboldt Hill data calculated using only 2011 and 2012

No monitors are required for either a SIP or Maintenance Plan. The NCUAQMD 

monitors Ozone as an examination of population exposure levels.
Page 12 of 27

PM 2.5

Table 4. Minimum Monitoring Requirements for FRM PM2.5.

Table 5. Minimum Monitoring Requirements for Continuous PM2.5 monitors.

Micropolitian 

Statistical

Area

County Pop. In Year 

2010

SLAMS FEM 

monitors required

SLAMS Monitors 

Active

SPM Monitors 

Active

Eureka, Arcata, 

Fortuna Humboldt 134,623 0 0 1*

Crescent City Del Norte 28,610 0 0 0

none Trinity 13,786 0 0 1*

*Non-Regulatory instruments

Table 6. Collocation of continuous PM2.5 monitors

Method Code # Primary 

Monitors

Required 

Collocated 

monitors

Active 

Collocated FRM 

monitors

Active Collocated 

FEM Monitors

195 0 0 0 0

No PM2.5 monitors are required for either a SIP or Maintenance Plan. 

Micropolitian 

Statistical

Area

County

Pop. In 

Year 

2010

Annual 

Design 

Value

(ug/m3)

(2010-

2012)

Daily 

Design 

Value 

(ug/m3) 

(2010-

2012)

FRM 

Monitors 

Required

SLAMS 

Monitors 

Active

SPM 

Monitors 

Active

Monitors 

Needed

Eureka, 

Arcata, 

Fortuna

Humboldt 134,623

I street

5.7

I street 

16.7

0 1 1 0

Jacobs 

6.0

Jacobs

19.5

Crescent City Del Norte 28,610 - - 0 0

0 0

none Trinity 13,786 - - 0 0 0 0
Page 13 of 27

The NCUAQMD participates in the Federal Fine Particulates monitoring program by 

operating instruments at the Eureka Ist, Jacobs and Weaverville stations. The 

NCUAQMD monitors PM2.5 with FRM instruments at the Jacobs and Ist sites. Both of 

these instruments are suitable for national comparison. FEM PM2.5 monitors are located 

at the Weaverville and Humboldt Hill Stations. These instruments are non-regulatory

and their data is not expected to meet the FRM similarity requirements which would 

enable them to be used for in national comparison. Collocation is not required as they 

are Special Purpose Monitors.

PM10

Table 7. Minimum Monitoring Requirements for PM10.

Micropolitian 

Statistical

Area

County

Population 

in Year 

2010

Max 

Concentration

(2010-2012)

(ug/m3)

SLAMS 

Monitors 

Required

SLAMS 

Monitors 

Active

SPM 

Monitors 

Active

Monitors 

Needed

Eureka, 

Arcata, 

Fortuna

Humboldt 134,623

I street

64

0

1

2 0 Jacobs

49

Humboldt Hill*

28

Crescent City Del Norte 28,610 61 0 1 0 0

none Trinity 13,786 41 0 1 0 0

* Humboldt Hill data calculated using only 2012 data

NCUAQMD is non-attainment for the State PM10 standard in all three counties.
Page 14 of 27

NO2

Table 8. Minimum Monitoring Requirements for NO2.

Micropolitian 

Statistical

Area

County

Pop. in 

Year 

2010

Annual Design 

Value (ppb) 

(2010-2012)

SLAMS 

Monitors 

Required

Active 

SLAMS 

Monitors

Active 

SPM 

Monitors 

Monitors 

Needed

EurekaArcata, 

Fortuna

Humboldt 134,623

Jacobs

2.77 0 0

2 0

Humboldt Hill

0.77

Crescent City Del Norte 28,610 - 0 0 0 0

none Trinity 13,786 - 0 0 0 0

No monitors are required for SIP or Maintenance Plans. NCUAQMD monitors NO2 in 

Humboldt County to examine population exposure. Based on population, no near-road 

NO2 monitors are required within the NCUAQMD boundaries.

SO2

Table 9. Minimum Monitoring Requirements for SO2.

Micropolitian 

Statistical

Area

County

Pop. in 

Year 

2010

Annual 

Design 

Value 

(ppb) 

(2010-

2012)

Max 24 

hour 

(ppb) 

(2010-

20012)

Max 1 hour 

(ppb)

(2010-

2012)

SLAMS 

Monitors 

Required

Active 

SLAMS 

Monitors 

Active 

SPM 

Monitors

Monitors 

Needed

EurekaArcata, 

Fortuna

Humboldt 134,623

Jacobs 

0

Jacobs 

1.4 Jacobs 2.2

0 0 2

Humboldt 0

Hill*

0

Humboldt 

Hill*

0

Humboldt 

Hill*

0

Crescent 

City Del Norte 28,610 - - - 0 0 0 0

none Trinity 13,786 - - - 0 0 0 0

*Humboldt Hill data calculated using only 2011 and 2012.

No monitors are required for SIP or Maintenance Plans. The NCUAQMD is not required 

to monitor SO2. NCUAQMD monitors SO2 in Humboldt County to examine population 

exposure.
Page 15 of 27

CO

Table 10. Minimum Monitoring Requirements for CO.

Micropolitian 

Statistical

Area

County

Pop. in 

Year 

2010

8-hour 

Design 

Value 

(ppm) 

(2010-

2012)

1 hour. Design Value 

(2010-2012)

SLAMS Monitors 

Required

Collocated 

Monitors 

Required

Active 

SLAMS 

Monitors

Active 

SPM

Monitors

Monitors 

Needed

EurekaArcataFortuna

Humboldt 134,623

Jacobs

0.7

Jacobs

1.0

Humboldt 0 0 0 2 0

Hill

0.6

Humboldt 

Hill

0.6

Crescent 

City Del Norte 28,610 - - 0 0 00

0

none Trinity 13,786 - - 0 0 0 0 0

No monitors are required for SIP or Maintenance Plans. The NCUAQMD is not required

to monitor CO. NCUAQMD monitors CO in Humboldt County to examine population 

exposure.

Pb

Table 11. Minimum Monitoring Requirements for Pb.

MSA County Pop. In 

Year 2010

Annual

Design Value 

Monitors 

Required

Active 

Monitors

Monitors 

Needed

Eureka, Arcata, 

Fortuna Humboldt 134,623 - 0 0 0

Crescent City Del Norte 28,610 - 0 0 0

none Trinity 13,786 - 0 0 0

No monitors are required for SIP or Maintenance Plans. The NCUAQMD is not required 

to monitor Pb and does not do so.
Page 16 of 27

Quality Control

All NCUAQMD ambient air monitoring meets stringent ARB Quality Control and Quality 

Assurance requirements. ARB audit records and site information for NCUAQMD can be 

found on the ARB website at http://www.arb.ca.gov/aaqm/qmosqual/qmosqual.htm, or 

obtained by contacting NCUAQMD at (707) 443-3093.

Collocation

The NCUAQMD is a member of the ARB PQAO and relies on the ARB PQAO network 

to satisfy collocation requirements. It is ARB’s responsibility to show that this 

requirement is met. No collocation of SPM monitors is required

Recent or Proposed Modifications to Network

The District proposes to discontinue the Eureka I street monitoring station. The two 

largest reasons for this are: there is an exhaust vent in violation of siting criteria and 

access to the site is too limited to allow for the 1 in 3 sampling required by the 2012 

NAAQS revision. The Jacobs station would be reclassified as a SLAMS for PM10 and 

PM2.5. EPA approval is pending.

The Special Purpose PM2.5 FRM sampler currently located at Jacobs station will be 

moved to Humboldt Hill station in 2013. This is to allow data comparison of the FRM 

instrument to the FEM Grimm 180. A continuous PM2.5 FEM BAM1020 or an R&P FRM 

2000 will be installed at the Jacobs station.

A continuous PM10 FEM BAM1020 monitor will be placed in Crescent City in 2013. It is 

not possible to collocate it with the current FRM PM10. The FRM will be removed after 

the FEM is fully operational. EPA approval is pending.

As soon as funding can be secured, a continuous PM2.5 FEM BAM1020 is planned to 

be placed in Crescent City, collocated with the PM10 discussed above to more fully 

understand the PM levels in Crescent City. Also, a continuous PM2.5 BAM1020 is 

planned to be placed in Trinity County at a location distant from the current station to 

more fully understand the PM levels in Trinity County. 

Review of Changes to PM2.5 Monitoring Network

The NCUAQMD has not changed the location of any violating PM2.5 monitor. Any 

changes to the NCUAQMD’s PM2.5 network are reviewed by EPA Region Nine. 

NCUAQMD has never removed a PM2.5 monitor, and has added three monitors since 

the inception of its 2.5 monitoring program. If a violating PM2.5 monitor ever needed to 

be moved, we would use the annual network plan inspection/comment process to

provide for the review of this change.

In March of 2013 the District moved the Special Purpose FRM pm2.5 sampler located at 

Jacobs station to Humboldt Hill Station. This will allow comparison to the FEM Grimm 

180 operating there. A continuous PM2.5 FEM BAM1020 or an R&P FRM 2000 will be 

installed at the Jacobs station.
Page 17 of 27

The District proposes to discontinue the Eureka I street monitoring station. The two 

largest reasons for this are: there is an exhaust vent too close to the samplers, and 

access to the site is too limited to allow for the 1 in 3 sampling required by the 2012 

NAAQS revision. The Jacobs station would be reclassified as a SLAMS for PM2.5. EPA 

approval is pending.

Data Submission Requirements

Data and Precision/Accuracy reports are submitted to the California Air Resources 

Board (CARB) no later than 60 days after the quarter of record. The CARB uploads 

NCUAQMD data to the National Air Quality System (AQS) no later than 90 days after 

the quarter of record. In the past, the CARB has submitted the annual data certification 

no later than May each year. Beginning in 2013, NCUAQMD will take over this 

responsibility.

Data Availability

NCUAQMD air quality data is available on the AQS database. It can also be obtained 

directly from NCUAQMD, in the form of monthly reports. Please contact NCUAQMD at 

707-443-3093 to request copies of these reports.
Page 18 of 27

Detailed Site Information

Site Name: Jacobs

The Jacobs site was established in December of 2006 it is located on the South side of 

Eureka and is expected to represent neighborhood scale air quality.

Site Name Jacobs

AQS ID 060231004

GIS coordinates 103.91015E 4514.83731N WGS84

Location Alice Birney Elementary School

Address 717 South Ave, Eureka

County Humboldt

Dist. to road

(meters)

50

Traffic count

(AADT)

3100 (2007)

Representative 

statistical area 

name

Eureka, Arcata, Fortuna

Groundcover grass

PEP audit? Information maintained by EPA

NPAP audit? Information maintained by EPA

PM10 Flow audits Performed every 15 sampling runs by NCUAQMD, Performed biannually by ARB

PM2.5 Flow 

audits

Performed monthly by NCUAQMD, Performed biannually by ARB

Gaseous audits Performed annually by ARB

Date of most 

recent ARB audit

December 5, 2012

Gaseous Onepoint control 

checks 

Performed a minimum of once every two weeks

Representative 

Area

Humboldt County Micropolitian Statistical Area,

Eureka-Arcata-Fortuna, suburban

Pollutant O3 NO2 CO SO2 PM2.5 PM10

Parameter Code 44201 42602 42101 42401 88101 85101 & 

81102

POC 1 1 1 1 1 1

Basic 

Monitoring

Objective

NAAQS 

comparison

NAAQS 

comparison

NAAQS 

comparison

NAAQS 

comparison

NAAQS 

comparison

NAAQS 

comparison

Site Type Population 

oriented

Population 

oriented

Population 

oriented

Population 

oriented

Population 

oriented

Population 

oriented

Monitor Type Special 

purpose

Special purpose Special purpose Special 

purpose

Special 

purpose

Special 

purpose

Spatial scale Neighborhood Neighborhood Neighborhood Neighborhood Neighborhood Neighborhood

Sampling 

method

Photometric

EQOA-0880-

047

Chemiluminescence

RFNA-1289-074

Gas Filter 

correlation 

RFCA-0981-

054

Pulsed 

Florescence

EQSA-0486-

060

Low Volume

RFPS-0498-

117

High Volume

RFPS-1287-

063

Instrument 

manufacturer

and model

Thermo

49i

Thermo

42i

Thermo

48i

Thermo

43i

R&P 

2000

Thermo

HVol
Page 19 of 27

Site Name Jacobs

Pollutant O3 NO2 CO SO2 PM2.5 PM10

FRM/FEM/ARM FEM FRM FRM FEM FRM FRM

Collecting 

Agency

NCUAQMD NCUAQMD NCUAQMD NCUAQMD NCUAQMD NCUAQMD

Analytical Lab N/A N/A N/A N/A BAAQMD NCUAQMD

Reporting 

Agency

ARB ARB ARB ARB BAAQMD ARB

Start date Dec 15, 2006 Dec 15, 2006 Dec 15, 2006 Dec 15, 2006 Dec 25, 2006 Dec 15, 2006

Current

Sampling 

Frequency

continuous continuous continuous continuous 1:3 Oct-Mar

1:6 Apr-Sept 1:6 

Sampling season Year round Year round Year round Year round Year round Year round

Probe height

(meters)

4.5 4.5 4.5 4.5 N/A N/A

Distance from 

supporting 

structure

(meters)

1.9 1.9 1.9 1.9 N/A N/A

Distance from 

obstructions on 

roof

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

Distance from 

obstructions not 

on roof (meters)

19 19 19 19 19 19

Distance from 

trees (meters)

15 15 15 15 15 17 

Distance to 

furnace or 

incinerator flue

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

Distance 

between 

collocated 

monitors

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

Unrestricted 

airflow (degrees)

360 360 360 360 360 360 

Probe material Teflon Teflon Teflon Teflon N/A N/A

Residence time

(seconds)

9.6 9.6 5.5 11.4 N/A N/A

Will there be 

changes within 

the next 18 

months?

No No No No Yes No

Is it suitable for 

comparison 

against the 

annual PM2.5?

N/A N/A N/A N/A Yes N/A
Page 20 of 27

Site Name: Eureka I Street

The Ist site was established in 1986. It is located in downtown Eureka near HWY 101 

and is expected to represent middle scale air quality.

Site Name Eureka Ist

AQS ID 060231002

GIS coordinates 103.92619E 4517.39332N WGS84

Location Humboldt County Health Department 

Address 529 Ist, Eureka

County Humboldt

Dist. to road 9 meters to 6th St, 30 meters to 5th St.

Traffic count 6

th street has ADT of 9,000 , 5th street has ADT of 25,500

Groundcover Paved

PEP audit? Information maintained by EPA

NPAP audit? Information maintained by EPA

PM10 Flow audit Performed every 15 sampling runs by NCUAQMD, Performed bi-annually by ARB

PM2.5 Flow Audit Performed monthly by NCUAQMD, Performed bi-annually by ARB

Date of most recent

ARB audit

December 5, 2013

Representative Area Humboldt County Micropolitian Statistical Area,

Eureka-Arcata-Fortuna, Urban 

Pollutant PM2.5 PM10

Parameter code 88101 85101 & 81102

POC 1 1

Basic Monitoring 

Objective

NAAQS comparison NAAQS comparison

Site Type Highest Concentration Highest Concentration

Monitor Type SLAMS SLAMS

Spatial scale Middle Scale Middle Scale

Sampling method Low Volume RFPS-0498-117 High Volume RFPS-1287-063

Instrument 

manufacturer and 

model

R & P

2000

Thermo 

HVol

FRM/FEM/ARM FRM FRM

Collecting Agency NCUAQMD NCUAQMD

Analytical Lab BAAQMD NCUAQMD

Reporting Agency BAAQMD ARB

Start date Jan 1999 Nov 1986

Current Sampling 

Frequency

1:3 Oct-Mar

1:6 Apr-Sept 1:6

Sampling season Year round Year round

Probe height (meters) 6 6

Distance from 

supporting structure

(meters)

2 2

Distance from 

obstructions on roof

(meters)

5 5.5

Distance from 

obstructions not on 

roof (meters)

25 25 
Page 21 of 27

Site Name Eureka Ist

Pollutant PM2.5 PM10

Distance from trees 

below probe height 

(meters)

6.5 4.6

Distance to furnace or 

incinerator flue

(meters)

5 5

Distance between 

collocated monitors

N/A N/A

Unrestricted airflow 270 degrees 270 degrees

Probe material N/A N/A

Residence time N/A N/A

Will there be changes 

within the next 18 

months?

Yes No

Is it suitable for 

comparison against 

the annual PM2.5?

Yes N/A
Page 22 of 27

Site Name: Humboldt Hill

The Humboldt Hill site was established in June 2011. It is located in Humboldt Hill on 

the South side of Eureka and is expected to represent neighborhood scale air quality.

Site Name Humboldt Hill

AQS ID 060231005

GIS 

coordinates 40.71528 (N)

-124.20139 (W)

Location Humboldt Hill Summit

Address 7333 Humboldt Hill Road, Eureka

County Humboldt

Dist. to road 25

Traffic count Unknown, less than 50

Groundcover grass

PEP audit? Information maintained by EPA

NPAP audit? Information maintained by EPA

PM10 Flow 

audits

Performed every 15 sampling runs by NCUAQMD, Performed bi-annually by ARB

Gaseous audits Performed annually by ARB

Date of most 

recent ARB 

audit

Dec 5, 2012

Gaseous Onepoint control 

checks

Performed a minimum of once per two weeks

Representative 

Area Humboldt County Micropolitian Statistical Area,

Eureka-Arcata-Fortuna, suburban

Pollutant O3 NO2 CO SO2 NH3 PM2.5 PM10 Toxics

Parameter 

code

44201 42602 42101 42401 42604 88101 85101 & 

81102

POC 1 1 1 1 1 1 1

Basic 

Monitoring 

Objective

NAAQS 

comparison

NAAQS 

comparison

NAAQS 

comparison

NAAQS 

comparison

Air 

pollution 

data

Air 

pollution 

Data

NAAQS 

comparison

Air 

pollution 

data

Site Type Population 

oriented

Population 

oriented

Population 

oriented

Population 

oriented

Population 

oriented

Population 

oriented

Population 

oriented

Population 

oriented

Monitor Type Special 

purpose

Special 

purpose

Special 

purpose

Special 

purpose

Special 

purpose

Special 

purpose

Special 

purpose

Special 

purpose

Spatial scale NeighborhoodNeighborhoodNeighborhoodNeighborhoodNeighborhoodNeighborhoodNeighborhoodNeighborhood

Sampling 

method

Photometri

c

EQOA0880-047

Chemiluminescence

RFNA1289-074

Gas Filter 

correlation 

RFCA0981-054

Pulsed 

Florescenc

e

EQSA0486-060

ChemiluminescenceLight 

scatter

EQPM0311-195

High 

Volume

RFPS1287-063

Summa 

canister

Instrument 

manufacturer 

and model

Thermo

49i

Thermo

42i

Thermo

48i

Thermo

43i

Thermo 17i Grimm 

180

Thermo 

HVol

ATEC

2200
Page 23 of 27

Site Name Humboldt Hill

Pollutant O3 NO2 CO SO2 NH3 PM2.5 PM10 Toxics

FRM/FEM/

ARM

FEM FRM FRM FEM N/A FEM FRM N/A

Collecting 

Agency

NCUAQMD NCUAQMD NCUAQMD NCUAQMD NCUAQMD NCUAQMD NCUAQMD NCUAQMD

Analytical Lab N/A N/A N/A N/A N/A N/A NCUAQMD AAC

Reporting 

Agency

ARB ARB ARB ARB N/A ARB ARB N/A

Start date June 20, 

2011

June 20, 

2011

June 20, 

2011

June 20, 

2011

Dec 

13,2012

June 20, 

2011

Dec 15, 

2011

Dec 15, 

2011

Current 

Sampling 

Frequency

continuous continuous continuous continuous continuous continuous 1:6 monthly

Sampling 

season

Year round Year round Year round Year round Year round Year round Year round Year round

Probe height 

(meters)

4.5 4.5 4.5 4.5 4.5 5.3 N/A 4.5

Distance from 

supporting 

structure 

(meters)

1.9 1.9 1.9 1.9 1.9 1.2 N/A 1.9 

Distance from 

obstructions 

on roof

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

Distance from 

obstructions 

not on roof 

(meters)

15 15 15 15 15 15 15 15

Distance from 

trees (meters)

93 93 93 93 93 93 93 93

Distance to 

furnace or 

incinerator 

flue

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

Distance 

between 

collocated 

monitors

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

Unrestricted 

airflow 

(degrees)

360 360 360 360 360 360 360 360 

Probe material Teflon Teflon Teflon Teflon Teflon Stainless 

steel

N/A Teflon

Residence 

time

(seconds)

10.7 10.8 10.4 13.7 14.8 N/A N/A N/A

Will there be 

changes within 

the next 18 

months?

No No No No No No No No

Is it suitable 

for comparison 

against the 

annual PM2.5?

N/A N/A N/A N/A N/A No N/A N/A
Page 24 of 27

Site Name: Weaverville

The Weaverville site was established in 1995. It is located downtown Weaverville near 

HWY 299 and is expected to represent middle scale air quality.

Site Name Weaverville

AQS ID 061050002

GIS coordinates 104.95617E 4509.31330N WGS84

Location Trinity County Courthouse

Address 11 Court Street, Weaverville

County Trinity

Dist. to road 7 meters to side road, 21 meters to highway 299

Traffic count 1408 AADT for Garden Gulch; 5,100 AADT for HWY 299

Groundcover Paved

PEP audit Information maintained by EPA

NPAP audit Information maintained by EPA

PM10 Flow audit Performed every 15 sampling runs by NCUAQMD Performed biannually by ARB

Date of most recent 

ARB audit

October 2, 2012

Representative Area Rural, no MSA in Trinity County

Pollutant PM2.5 PM10

Parameter Code 88101 85101 & 81102

POC 1 1

Basic monitor 

objective

Air Pollution Data NAAQS comparison

Site Type Population oriented Population oriented

Monitor Type SPM SLAMS

Spatial scale Middle Scale Middle Scale

Sampling method GRIMM 180 FEM High Volume RFPS-1287-063

Instrument 

manufacturer and 

model

Grimm

180

Thermo

HVol

FRM/FEM/ARM FEM FRM

Collecting Agency NCUAQMD NCUAQMD

Analytical Lab N/A NCUAQMD

Reporting Agency ARB ARB

Start date Aug 2011 Jan 1995

Current Sampling 

Frequency

Continuous 1:6 

Sampling season Year round Year round

Probe height

(meters)

9.4 7

Distance from 

supporting structure

(meters)

3 1.5

Distance from 

obstructions on roof

(meters)

10 7 

Distance from 

obstructions not on 

roof (meters)

20 20 
Page 25 of 27

Site Name Weaverville

Pollutant PM2.5 PM10

Distance from trees 

(meters)

15 15

Distance to furnace 

or incinerator flue

N/A N/A

Distance between 

collocated monitors

N/A N/A

Unrestricted airflow

(degrees)

270 270 

Probe material N/A N/A

Residence time N/A N/A

Will there be

changes within the 

next 18 months?

No No

Is it suitable for 

comparison against 

the annual PM2.5?

No N/A
Page 26 of 27

Site Name: Crescent City

The Crescent City site was established in 1998. It is located at the Del Norte County 

Health Department near HWY 101 and is expected to represent neighborhood scale air 

quality.

Site Name Crescent City

AQS ID 060150006

GIS coordinates 103.90908E 4624.31858N WGS84

Location Del Norte County Health Department

Address 880 Northcrest Dr

County Del Norte

Dist. to road 600 meters to HWY 101 200 meters to Northcrest

Traffic count 38,500 ADT HWY101 8,222 ADT Northcrest

Groundcover Paved/grass

PEP audit Information maintained by EPA

NPAP audit Information maintained by EPA

Flow audit Performed every 15 sampling runs by NCUAQMD, Performed annually by EPA, Performed 

annually by ARB

Date of most recent 

ARB audit

December 4, 2012

Representative Area Del Norte County, Micropolitian Statistical Area,

Crescent City Urban

Pollutant PM10

Parameter Code 85101 & 81102

POC 1

Basic Monitoring 

Objectives

NAAQS comparison

Site Type Population oriented

Monitor Type SLAMS

Spatial scale Neighborhood

Sampling method High Volume RFPS-1287-063

Instrument 

manufacturer and 

model

Thermo HVol

FRM/FEM/ARM FRM

Collecting Agency NCUAQMD

Analytical Lab NCUAQMD

Reporting Agency ARB

Start date Mar-1998

Current Sampling 

Frequency

1:6

Sampling season Year round

Probe height 5.5 meters

Distance from 

supporting structure

1.5 meters

Distance from 

obstructions on roof

N/A
Page 27 of 27

Site Name Crescent City

Pollutant PM10

Distance from 

obstructions not on 

roof

N/A

Distance from trees 90 meters

Distance to furnace or 

incinerator flue

N/A

Distance between 

collocated monitors

N/A

Unrestricted airflow

(degrees)

360 

Probe material N/A

Residence time N/A

Will there be changes 

within the next 18 

months?

Yes

Is it suitable for 

comparison against 

the annual PM2.5?

N/A

Signature

The Executive Office of the North Coast Unified Air Quality Management District hereby 

verifies this plan has gone through a 30 day public comment period, and approves the 

“Air Monitoring Network Plan for 2013”. Staff is directed to begin implementation 

effective immediately.

____________________________________________ __________________

Mr. Richard L. Martin Jr. date