model for relating pm 2.5 federal reference method & nephelometer measurements presented by...
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Model For Relating PM2.5 Federal Reference Method & Nephelometer Measurements
Presented by
Jenny Parikh
04/21/23 2EPA AQI Conf. 2/3-5/02
Agenda
What was doneValue to PublicHow the model is developedWhat’s Next
04/21/23 3EPA AQI Conf. 2/3-5/02
GOAL
Develop Statistical Linear regression model relating PM2.5 FRM and Nephelometers (continuous monitors)
04/21/23 4EPA AQI Conf. 2/3-5/02
WHY
FRM is used for NAAQS compliance (FILTER based)• 1999-to date• PM2.5 measurement are below NAAQS• Continuous Monitor data is available
Temporally resolved data : Diurnal cycles Need to estimate PM2.5 in real time (AQI) Push from EPA to complete Real time network QA TOOL
04/21/23 5EPA AQI Conf. 2/3-5/02
VALUE TO PUBLIC
Ability to represent unhealthy air conditions while it is occurring
Part 58.50 of 40CFR requires all MSAs with population of 350,000 or greater to report daily AQI
04/21/23 6EPA AQI Conf. 2/3-5/02
METHODOLOGY
Determine required environmental measurements, suitable data and data reduction
Perform exploratory data analyses• Histogram • Scatter plots and outliers• Time series analyses
Determine the “best” model Evaluate the ability of the model to estimate PM2.5
04/21/23 7EPA AQI Conf. 2/3-5/02
Guidance Document
04/21/23 8EPA AQI Conf. 2/3-5/02
Guidance document
http://www.epa.gov/ttn/amtic/files/ambient/monitorstrat/aqidqorept.pdf
04/21/23 9EPA AQI Conf. 2/3-5/02
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0 40 8020Miles
®
Nephelometer Monitoring Sites
Nephelometer Sites
2005
04/21/23 10EPA AQI Conf. 2/3-5/02
MODEL DEVELOPMENT
Eastern Sites• Chewelah, Coleville, Pullman, Ritzville, Walla Walla,• Kennewick, Yakima, Twisp, Moses Lake……
Western Sites• Longview, Lacey, North Bend, Yew Street, Beacon Hill,
Redmond, Bellevue Goldfarb, Vancouver…
04/21/23 11EPA AQI Conf. 2/3-5/02
RESULTS: Chewelah
FRM vs Modeled FRM
0.0
5.0
10.0
15.0
20.0
25.0
FRM 2.5
Modeled FRM
04/21/23 12EPA AQI Conf. 2/3-5/02
Next Step
Strong FRM- CM relationship indicated it was worth considering a comparison of CM and FRM that are not collocated
04/21/23 13EPA AQI Conf. 2/3-5/02
How the E. WA model was developed
FRM and Neph Data for the sites started from 04/01 till todate, about 75 days of data
44 days where all five sites had data
04/21/23 14EPA AQI Conf. 2/3-5/02
Comparison of Nephelometers
Comparison of Neph from all sites
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43
Colville Bscat
Chew elah Bscat
PullmanBscat
RitzvilleBscat
Ww alla Bscat
04/21/23 15EPA AQI Conf. 2/3-5/02
Comparison of FRMs from all E. WA sites
Comparison of FRMs
0.0
5.0
10.0
15.0
20.0
25.0
30.0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43
Colville FRM
Chew elahFRM 2.5
PullmanFRM
Ritzville FRM
W Walla FRM
04/21/23 16EPA AQI Conf. 2/3-5/02
Analysis of Data Strong CM-FRM relationship was observed
Compared CM and FRM data that are not co-located
Strong relationship indicated a possibility of developing a model using the average of the set of FRM measurements with CM measurements
This also gives measurements that are better representative of the overall region
04/21/23 17EPA AQI Conf. 2/3-5/02
Colville and E. Washington Model
Colville FRM and East. WA model
0.05.0
10.015.020.025.030.0
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43Colville FRMEast.Wa model
04/21/23 18EPA AQI Conf. 2/3-5/02
Pullman and E. WA Model
Pullman vs. Eastern Wa model
0.02.0
4.06.0
8.010.0
12.014.0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43PullmanFRMEastern WA model
04/21/23 19EPA AQI Conf. 2/3-5/02
Eastern Washington Model
Colville FRM and East. WA model
0.05.0
10.015.020.025.030.0
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43Colville FRMEast.Wa model
04/21/23 20EPA AQI Conf. 2/3-5/02
Ritzville and E. Washington Model
Ritzville vs. Eastern WA model
0.0
5.0
10.0
15.0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43Ritzville FRM
Eastern WA model
04/21/23 21EPA AQI Conf. 2/3-5/02
WallaWalla and E.WA Model
WWalla vs. Eastern Wa model
0.0
5.0
10.0
15.0
20.0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43W Walla FRM
Eastern WA model
04/21/23 22EPA AQI Conf. 2/3-5/02
Models All Eastern Sites PM2.5 correlated = 10 (0.710771(logBscat)+1.325303)
This model is applied to Lacrosse, Rosalia, Starbucks, Mesa)
Final NorthBend PM2.5 correlated = 10 (0.892521 (log Bscat)+1.394775) Previous North BendPM2.5 correlated = 10 (0.93537 (log Bscat)+1.424513)
Previous Beacon Hill PM2.5 correlated = 10 (0.689323 (log Bscat)+1.390065)
( R2 = 0.84) New Beacon Hill PM2.5 correlated = 10 (0.793263 (log Bscat)+1.420227)
( R2 = 0.90)
NWAPA Model PM2.5 correlated = 10 (0.755345 (log Bscat)+1.36943)
This is applied to Mt. Vernon
04/21/23 23EPA AQI Conf. 2/3-5/02
IMPLICATIONS
Valuable tool for Eastern WA – covers large geographical area with Nephelometer
Divest from PM2.5 FRM network- optimization and modification
Resource allocations• Workforce demands• Monitor costs
04/21/23 24EPA AQI Conf. 2/3-5/02
WHAT’S NEXT
Refine and update with additional data for Western Washington Model• Quarterly / Seasonal basis
Additional sites e.g; Stevenson (Bonneville, Mt. Zion, Wishram), Leavenworth
04/21/23 25EPA AQI Conf. 2/3-5/02
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0 40 8020Miles
®
Nephelometer Monitoring Sites
Nephelometer Sites w/correlated PM2.5Nephelometer Sites
2005
04/21/23 26EPA AQI Conf. 2/3-5/02
Nephelometer/Correlated PM2.5
Most of our nephelometer site data has been analyzed to create a correlation to PM2.5 .
Those sites with a PM2.5 correlation are shown on the site operators’ page https://fortress.wa.gov/ecy/aqp/Site/ AND the public page as NPM2.5 https://fortress.wa.gov/ecy/aqp/Public/aqn.shtml