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
40.00
60.00
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
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
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
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
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
80
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
20
30
40
50
60
70
80
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
20.0
40.0
60.0
80.0
100.0
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
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
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
0.0
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 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
0.0
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
20.00
40.00
60.00
80.00
100.00
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
0
5
10
15
20
25
30
35
40
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
10
15
20
25
30
35
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?