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Ozone Data Corrections
Salt River Pima Maricopa Indian Community
Community Development Department
Environmental Protection & Natural Resources Air Quality Program
National Tribal Forum – May 13 - 15, 2014
Reason for correcting raw data
• Ensures data is “actual data” when it is corrected to standard
• Regulatory program associate with standards• One of two agencies in EPA R9 adjusts data
from most recent calibration curve• Derived from QA Handbook Volume II• View it as Traceability of Standards• Standard is carried down to raw data
Raw Data Traces Back to SRP
Standard Reference
Photometer (SRP)
Ozone Primary
Standard
Ozone Transfer Standard
Ozone Monitor
Ozone Raw Data
13. Correct the concentration measured by the DAS by applying the latest calibration equation as:
=
where: Cda = the corrected concentration from the DAS (ppm),Cd = the measured concentration from the DAS (ppm),
a = the intercept of the DAS calibration curve, and b = the slope of the DAS calibration curve.
Referenced to QA Handbook for Air Pollution Measurement Systems, Volume II, Ambient Air Quality Monitoring Program, EPA-454/B-08-003. Section 12.2 when the calibration curve is subsequently used to compute concentration measurements x = (y - a)/m where y represents the analyzer response reading, a is the intercept and m is the slope, Section 12.4 EPA suggests the ambient readings be calculated from the most recent multipoint calibration curve or from a fixed nominal or universal calibration curve, and Section 12.5 Data Reduction Using Calibration Information.
14. Calculate the percent difference between the actual ozone concentration (Ci) and the corrected DAS concentration (Cd) for the audit and span concentrations as:
Percent Difference = x 100%
15. Record all values on the "zero/span check and QC check" worksheet and the precision check control chart. Compare the percent difference with the quality control limits specified in the project Quality Assurance Plan. If the difference is outside of the limits, perform the necessary corrective action.
Intercept value from Analyzer’s calibration curve
Slope value from Analyzer’s calibration curve
Raw data value
Statements from QA Handbook Volume II
• Calibration relationship are applied to analyzer responses to determine actual concentration
• Ideally, all ambient measurements obtained from an analyzer should be calculated on the basis of the most recent multi-point calibration
• The calibration slope and intercept used to calculate ambient measurements are updated only for major calibration
• When this calibration relationship is subsequently used to compute concentration measurements (x) from analyzer response reading (y), the formula is transposed to form, x = (y – b)/m.
It all starts with Transfer Standard’s certificationTransfer Standard Certification
Primary Standard Transfer Standard
Make: API 400E Make: TECO 49C-PS
S/N: 1900 S/N: 75056-378
Certified: 12-12-12
Date Slope Intercept Correlatation
12/1/09 1.0047 -0.1 1.00000
12/2/09 1.0039 -0.1 1.00000
12/3/09 1.0057 0.0 1.00000
12/4/09 1.0026 -0.2 1.00000
12/11/09 0.9939 0.0 1.00000
12/23/09 0.9982 -0.1 1.00000
4/19/10 0.9974 0.2 1.00000
6/25/10 0.9964 0.2 1.00000
10/18/10 0.9946 0.1 1.00000
3/3/11 0.9939 0.2 1.00000
9/26/11 0.9947 1.2 1.00000
2/10/12 1.0012 1.1 1.00000
10/8/12 1.0221 -1.7 1.00000
4/30/13 1.0213 -1.8 1.00000
AVG: 1.00463 -0.15000 1.00000
STDEV: 0.01348 1.31871 0.00000
AQP\AIR MONITORING\Data Records Management\Certification\Ozone\75056 TS\TS Slope Records
Average Slope and Intercept
Created slope & intercept from site monitor calibrationSalt River-Pima Maricopa Indian Community
MULTI-POINT CALIBRATION: OZONE
ANALYZER TRANSFER STANDARD Location: LehiMake/Model: API/400E Make/Model: TEII/49C-PS EPA Site ID: 04 013 7022
Serial No.: 1149 Serial No: 75056-378 Owner: SRPMIC/EPNR03 Meas: 4104 Bench Temp: 32.4 Date: 4/28/2013
03 Ref: 4104 Ozone Lamp Temp: 71.1 Time: 14:30Press: 27 Press: 727.6 Operator: MSlinkey
Samp Flow: 821 Flow Cell A: 0.634Samp Temp: 32.7 Flow Cell B: 0.634 DATA LOGGERPhoto Lamp: 58 Intensity Cell A: 110111 Make/Model: ESC/8832
Box Temp: Intensity Cell B: 109811 Serial No.:A3257KLast Cal Date: Mar 30, 2012 Slope: 1
Int: 0
CALIBRATION DATA (ppb)
INPUT OZONE: 0 35 90 180 400
STD. DAS STD. DAS STD. DAS STD. DAS STD. DAS
-1 0 35.8 34.4 90 88 181 180 403 400
-2 0 34.6 34.4 90 88 180 180 402 400
2 0 35.2 34.4 90 88 181 180 402 401
-1 0 35.5 34.3 90 88 180 179 403 401
2 0 35.6 34.2 90 87 180 178 400 401
-2 0 35.3 34.3 89 87 180 177 401 400
-1 0 35.7 34.2 89 87 179 176 402 401
-1 0 35.3 34.2 89 87 180 176 399 401
2 0 35.1 34.2 89 87 179 176 401 401
-1 0 34.9 34.2 90 87 180 176 400 401
STD AVG: 0 35 90 180 401
DAS AVG: 0 34 87 178 401
STD CORR AVG: 0 35 89 179 400
X Values 5 Y Values 5
(Slope) 1.003 (Intercept) -1.1 r: 0.99998
COMMENTS: Changed out Sintered Filter, Orifice, 2 O-rings and a new spring.Calibrate pressure sensor and flow checkedMulti-point calibrationEnabled @ 15:43
Transfer Standard’s slope and intercept is integrated to calculate in the ozone Multi-Point Calibration
Slope and intercept is created from site monitor Multi-Point Calibration
Calibration relationships of slope & intercept are calculated to analyzer’s raw data to determine actual concentration
Data Correction in E-DAS Network when applying calibration relationship to actual concentration units
Process of correcting ambient data to actual data
Example
Ambient data is .0302 ppm (parts per million) Apply most recent analyzer calibration curve slope
and intercept (1.001 and -0.0002) to calculate ambient data .0302 ppm and to determine the actual concentrations would be .0304 ppm
(.0302 - -0.0002)/ 1.001 = .0304 ppm
raw data – intercept
slope
EPA data reports are truncated
Sample of QC Data corrected to actualSalt River Pima-Maricopa Indian Community
OZONE: Level 1 & 2 Zero/Span And Precision Checks
Location: SC Date: June 12,2013 Operator: CSmithLogger Disable: 17:25 Logger Enable: 17:59
Analyzer Transfer StandardMake: Thermo Make/Model: TEII/49C-PModel: 49i Serial No: 75056-378
Serial No: CM10310069 Bench Temp: 35.6Bench Temp: 32 Lamp Temp: 56.5Bench Lamp: 54.3 03 Lamp Temp: 71.2
Pressure: 714.6 Pressure: 722.5Flow A: 0.690 Flow A: 0.631Flow B: 0.696 Flow B: 0.600
Intensity A: 76530 Intensity A: 107773Intensity B: 85561 Intensity B: 107028
03 Bkg/Coef: .0004/1.018 03 Bkg/Coef: -0.2/1.00Analyzer Slope: 1.003 Transfer Standard Slope: 1.00463
Analyzer Intercept: -0.0003 Transfer Standard Intercept: -0.00015
PRECISION and LEVEL 1 & 2 DATA RECORDS
.090 PPM Zero .400 PPMStandard DAS Standard DAS Standard DAS0.0900 0.0903 -0.0007 -0.0009 0.403 0.4080.0892 0.0908 -0.0007 -0.0004 0.403 0.4070.0895 0.0902 0.0009 -0.0008 0.402 0.4070.0898 0.0903 -0.0008 0.0006 0.401 0.4080.0899 0.0902 -0.0007 0.0003 0.401 0.4070.0898 0.0898 -0.0007 0.0009 0.402 0.4070.0894 0.0909 -0.0009 0.0005 0.401 0.4060.0898 0.0908 -0.0004 0.0002 0.401 0.4060.0901 0.0905 -0.0001 0.0004 0.400 0.4050.0895 0.0909 0.0009 -0.0007 0.400 0.4060.0897 0.0905 -0.0003 0.0000 0.4014 0.4067
ZERO/SPAN PRECISION
Corrected CorrectedRaw Data Data Raw Data Data
DAS Old Zero: 0.0000 DAS: 0.0905 0.0905DAS New Zero: 0.0000 0.000 STD: 0.0897 0.0894
XFER STD Zero: -0.0003 0.000DAS Old Span: 0.4067 Precision % Difference: 1.23
DAS New Span: 0.4067 0.4058 Span % Difference: 1.53XFER STD Span: 0.4014 0.3997 Zero % Difference: 0.00
Corrected Date=(DAS-Intercept)/Slope STD Data Corrected=(STD-Intercept)/Slope %Diff=(DAS-STD)/STD*100
Ozone Reporting Data to EPA
Most Agency Data Report
Report ambient data
Ambient Data
SRPMIC Data Report to EPA
Report data that is actual concentration
Correct ambient data to calibration relationship
Ambient Data
Purpose
• Data is Corrected to Actual from Raw• Have confidence data is corrected to the next level• Data is fine tuned even though not much
difference from raw data• Data is more defensible especially when it is
certified• We maybe doing extra steps in adjusting data than
other agencies but it is worth reporting actual data
Air Quality/Monitoring Staff
• Stan Belone, Environmental Engineer
Email: [email protected] • Mangas Slinkey, Senior Environmental Specialist
Email: [email protected]• Shimmy Smith, Environmental Specialist
Email: [email protected]
Administration• Chris Horan, Manager, Environmental Protection &
Natural Resources