CARB Continuous PM 2.5 Network Experience

Kenneth Stroud

California Air Resources Board

Continuous PM2.5 Monitor Deployments

• ARB Ambient Air Monitoring Sites– 13 Sites with BAM-1020 Monitors

• 3 Collocated BAM-1020 Sites

• 7 Sites with FRM and BAM

Data Analysis

• Slope is indicator of the bias of the BAM compared to the FRM

• Intercept is the offset between the BAM and FRM

• r2 is the correlation coefficient of the linear regression between the two instruments

BAM-1020 Accuracy

Site BAM Unit Slope Intercept r2

South Lake Tahoe - Sandy Way Primary 1.0 -0.49 0.84Modesto - 14th St Primary 1.1 2.9 0.96Fresno - First St Primary 1.0 4.5 0.92Visalia - N Church St Primary 1.0 5.0 0.88Chico - Manzanita Ave Primary 1.1 1.5 0.96Chico - Manzanita Ave Collocated 1.0 3.2 0.97Bakersfield - California Ave Primary 1.1 -4.9 0.87Bakersfield - California Ave Collocated 1.0 -4.3 0.83Calexico - Ethel St Primary 0.80 -0.56 0.77Calexico - Ethel St Collocated 1.1 4.8 0.84

Chico - Manzanita Ave.Met One BAM 2 (Model 1020) vs. PM2.5 FRM

March 3, 2002 - September 18, 2003

0.00

20.00

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80.00

100.00

120.00

0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00

FRM (ug/m3)

BA

M 2

(u

g/m

3)

Slope: 1.0Intercept: 3.2R2: 0.97N:84

Data is preliminary and subject to change

Chico - Manzanita AveMet One BAM 1 (Model 1020) vs. PM2.5 FRM

April 2, 2002 - September 6, 2003

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100.00

0 10 20 30 40 50 60 70 80 90 100

FRM (ug/m3)

BA

M 1

(u

g/m

3)

Slope: 1.1Intercept: 1.5R2: 0.96N: 58

Data is preliminary and subject to change

ModestoMet One BAM (Model 1020 ) vs. PM2.5 FRM

January 2, 2002 - September 21, 2003

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10.00

20.00

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80.00

0 10 20 30 40 50 60 70

FRM (ug/m3)

BA

M (u

g/m

3)

Slope: 1.1Intercept: 2.9R2: 0.96N: 139

Data is preliminary and subject to change

Fresno - First St.Met One BAM (Model 1020) vs. Primary PM2.5 FRM

January 03, 2002 - September 13, 2003

0

20

40

60

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100

120

0 10 20 30 40 50 60 70 80 90 100

FRM (ug/m3)

BA

M (u

g/m

3)

Slope:1.0Intercept: 4.5r2: 0.92N: 481

Data is preliminary and subject to change

Visalia - N Church St.Met One BAM 1020 vs. PM2.5 FRM

January 2, 2002 - September 9, 2003

0

10

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90

0 10 20 30 40 50 60 70 80

FRM (ug/m3)

BA

M (u

g/m

3)

Slope: 1.0Intercept: 5.0R2: 0.88N: 129

Data is preliminary and subject to change

Bakersfield - California Ave.Met One BAM 1 (Model 1020) vs. Primary PM2.5 FRM

December 1, 2001 - September 3, 2003

0.0

20.0

40.0

60.0

80.0

100.0

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0

FRM (ug/m3)

BA

M (

ug

/m3)

Slope: 1.1Intercept:-4.9R2: 0.87N: 487

Data is Preliminary and subject to change

Calexico - Ethel StreetMet One BAM 2 (Model 1020) vs. Primary PM2.5 FRM

December 2002 - August 13, 2003

0

10

20

30

40

50

60

0 10 20 30 40 50 60

Primary FRM (ug/m3)

BA

M (

ug

/m3)

Slope: 1.1Intercept: 4.8R2: 0.84N: 68

Data is preliminary and subject to change

Tahoe - Sandy WayMet One BAM (Model 1020) vs. PM2.5 FRM

October 2002 - September 9, 2003

0

5

10

15

20

25

0 5 10 15 20 25FRM (ug/m3)

BA

M (u

g/m

3)

Slope: 1.0Intercept: -0.49R2: 0.84N: 49

Bakersfield - California Ave.Met One BAM 2 (Model 1020) vs. Primary PM2.5 FRM

December 1, 2001 - September 3, 2003

-20.0

0.0

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120.0

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0

FRM (ug/m3)

BA

M (

ug

/m3)

Slope: 1.0Intercept: -4.3

R2: 0.83N: 482

Data is Preliminary and subject to change

Calexico - Ethel StreetMet One BAM 1 (Model 1020) vs. Primary PM2.5 FRM

January 1, 2001 - August 13, 2003

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0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00

FRM (ug/m3)

BA

M 1

(u

g/m

3)

Slope: 0.80Intercept: -0.56R2: 0.77N: 206

Data is preliminary and subject to change

BAM-1020 Precision

Site Slope Intercept r2

Chico - Manzanita Ave 1.0 1.6 0.98Bakersfield - California Ave 1.0 1.3 0.99Calexico - Ethel St 0.94 0.13 0.84

Bakersfield - California AvePrimary vs. Collocated Met One BAM (Model 1020)

December 1, 2001 - September 3, 2003

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20.0

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120.0

0.0 20.0 40.0 60.0 80.0 100.0 120.0

BAM 2 (ug/m3)

BA

M 1

(ug

/m3)

Slope:1.0Intercept: 1.3R2: 0.99N: 582

Data is Preliminary and subject to change

Chico - Manzanita Ave.Primary vs. Collocated Met One BAM (Model 1020)

April 2, 2002 - September 30, 2003

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20.0

40.0

60.0

80.0

100.0

120.0

0.0 20.0 40.0 60.0 80.0 100.0 120.0

BAM 1(ug/m2)

BA

M 2

(u

g/m

3)

Slope: 1.0Intercept: 1.6R2: 0.98N: 372

Data is preliminary and subject to change

Calexico - Ethel StreetPrimary vs. Collocated Met One BAM (Model 1020)

January 1, 2001 - August 13, 2003

0.00

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120.00

0.00 20.00 40.00 60.00 80.00 100.00 120.00

Primary BAM

Sec

on

dar

y B

AM

Slope: 0.94Intercept: 0.13R2: 0.84N: 264

Chico - Manzanita Ave.Primary vs. Collocated Met One BAM (Model 1020)

February 2003 - Hourly Data

0

20

40

60

80

100

120

140

160

0 20 40 60 80 100 120 140 160

Primary BAM (ug/m3)

Col

loca

ted

BA

M (u

g/m

3)

Slope: 0.9508Intercept: 2.9408r2: 0.936n: 622

Chico - Manzanita Ave.Primary vs. Collocated Met One BAM (Model 1020)

February 2003 - 24 Hour Average

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45

50

0 5 10 15 20 25 30 35 40 45 50

Primary BAM (ug/m3)

Col

loca

ted

BA

M 9

ug/m

3)

Slope: 1.0338Intercept: 0.0408r2: 0.9443n: 26

Calexico - Ethel StreetPrimary vs. Collocated Met One BAM (Model 1020)

May 2003 - Hourly Data

0

50

100

150

200

250

300

350

0 50 100 150 200 250 300

Primary BAM (ug/m3)

Col

loca

ted

BA

M (u

g/m

3)

Slope: 0.9560Intercept: 1.9715r2: 0.7466n: 745

Calexico - Ethel Ave.Primary vs. Collocated Met One BAM (Model 1020)

May 2003 - 24 Hour Average

0

5

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40

45

50

0 5 10 15 20 25 30 35 40 45 50

Primary BAM (ug/m3)

Col

loca

ted

BA

M (u

g/m

3)

Slope: 1.043Intercept: 0.4621r2: 0.9344n: 29

Bakersfield California AvePrimary vs. Collocated Met One BAM (Model 1020)

May 2003 - Hourly Data

0

10

20

30

40

50

60

0 10 20 30 40 50 60

Primary BAM (ug/m3)

Col

loca

ted

BA

M (u

g/m

3)

Slope: 0.8352Intercept: 3.9399

r2: 0.629n: 744

Bakersfield - California AvePrimary vs. Collocated Met One BAM (Model 1020)

May 2003 - 24 Hour Average

0

5

10

15

20

25

30

0 5 10 15 20 25 30

Primary BAM (ug/m3)

Col

loca

ted

BA

M (u

g/m

3)

Slope: 0.9519Intercept: 1.9718r2: 0.9174n: 31

CARB BAM Data CaptureData Capture % Data Capture % Data Capture %

Chico-Manzanita Avenue 47% 92% 52%Gridley-Cowee Avenue 93% 96% 85%South Lake Tahoe-Sandy Way 95%Fresno-1st Street 77% 98% 40%Calexico-Ethel Street 91% 34%Calexico-East 80% 63%Bakersfield-5558 California Avenue 54% 93% 56%Point Reyes 95% 89% 98%Yosemite Village-Visitor Center 52%Modesto-14th Street 28% 82% 22%Visalia-N Church Street 47% 62% 56%San Nicolas Island-Building 98 76% 70%

BAM Maintenance

• Bi-Weekly Leak and Flow Checks are absolutely necessary to ensure proper operation

• failed leak and flow checks are associated with poor FRM correlation in ARB’s experience

BAM Datalogger Review

• Review of the internal datalogger is important

• Reveals offsets between the BAM and the external data acquisition system

• Review of Qtot (total volume sampled) hourly values helps detect flow problems

• Detailed Error codes are stored in the internal datalogger data

Summary

• Accuracy– Slopes from 0.80 to 1.1– Intercepts from -4.9 to 5.0– r2 from 0.77 to 0.97

• Precision– Slopes from 0.94 to 1.0– Intercepts from 0.13 to 1.6– r2 from 0.84 to 0.99

Summary

• The BAM-1020 Monitor is well-suited for PM-AQI, Prescribed Fire and Ag-Burn Forecasting, diurnal profiling, quantifying short term events, and characterizing atmospheric dynamics

• Is it good enough for regulatory determinations?