STN/IMPROVE Comparison StudyPreliminary Results

Paul Solomon, ORDTracy Klamser-Williams, ORIA

Peter Egeghy, ORDDennis Crumpler, OAQPS

Joann Rice, OAQPSOthers

PM Model Performance Workshop

February 10, 2004

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Discussion Topics

Study Background

STN and IMPROVE Protocol Differences

Preliminary STN versus IMPROVE Data Comparison Results and Conclusions

Next Steps

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STN/IMPROVE Intercomparison

Why did we do this study? To establish data comparison

and relationships for historical data

Collecting data since fall ’01 3 areas (1 urban/rural pair)Presenting Analysis of Oct ’01 to Sept ’02 dataFinishing QA of first year dataFinal results early ’04

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STN/IMPROVE Monitoring Intercomparison Sites:Oct. 2001 – Oct. 2002

Mt. Rainier NPS

Phoenix

TontoNational Monument

Haines Point, NPS

Wash. DC

Official or designated STN site, host to IMPROVE sampler

Official IMPROVE site, host to STN sampler

Anderson RAAS 401 STN Samplers

Met One SASS STN Samplers

URG MASS STN Samplers

SeattleBeacon Hill

USDA FS Dolly SodsWildersness

Operated According to Each Network’s Protocols

STN/IMPROVE Intercomparison

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It is Not Just the Analysis Methods

From Monitor Inlet* to Data Mgmt Sample Collection Handling, Shipping, and Storage (after collection) Chemical Analysis

Extraction Analysis Methods

Standards Or Lack Thereof for Ambient Field PM Measurements

Data Manipulation Blank Subtraction and Artifacts

Comparative Protocol Analysis

* Begins w/ Filter Purchase, Acceptance Testing, Handling & Storage

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How Protocols Might Affect Results

Between Networks * Inlets

Effect on Slope of Efficiency Curve and Cutpoint

Flow Rate Differences Effect of Pressure Drop, Face Velocity

and Residence Time Influences Collection of Semi-Volatiles

Negative vs Positive Artifacts Blank Values Likely Different

* Not an Exhaustive List

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Between Networks (cont) * Shipping and Storage

STN at Reduced Temperatures IMPROVE at Ambient Temperatures

Influences Collection of Semi-Volatiles

Use of IMPROVE in Urban Areas Higher Flow Rate, Smaller Filters

Filter Clogging Potential in urban areas Effect on Semi-volatiles

Denuder Capacity and Efficiency Na2CO3 vs MgO

Refurbishing Frequency of Na2CO3

How Protocols Might Affect Results

* Not an Exhaustive List

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Bottom Line

Given All these Differences, Do the

Networks Provide Similar Results for

Mass and the Components

?

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Median Ratio of STN/IMPROVE

Haines Pt. PhoenixBeacon

HillDOSO TONT MORA

IMP/STN

PM2.5 0.91 1.05 0.96 0.89 0.91 0.90

EC 1.09 1.01 1.04 1.29 0.68 1.39

OC 0.54 0.48 0.90 0.53 0.36 0.58

Nitrate 0.89 0.87 1.31 0.87 1.22 0.86

Sulfate 1.00 1.31 1.06 1.01 0.90 0.86

As 0.62 0.49 0.67 0.46 0.46 0.63

Ca 0.87 1.61 1.37 0.95 1.46 1.16

Cr 0.55 0.27 0.75 2.22 0.11 0.28

Cu 0.93 1.28 0.63 0.78 1.44 0.16

Fe 0.93 1.59 1.34 0.91 1.35 1.11

Mn 0.70 1.11 1.19 0.84 0.90 0.85

Pb 0.83 0.84 1.01 0.88 0.69 0.72

S 0.98 0.97 1.03 1.03 0.95 0.84

Si 1.42 1.82 1.57 1.48 1.45 1.43

Zn 1.03 1.55 1.18 1.01 1.20 1.00

Median Ratio (IMP/STN)

Urban (E to W) Rural (E to W)

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Urban – Rural Temporal Analysis: PM2.5 Mass

Haines Point

Dolly Sods

Phoenix

Tonto

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Urban – Rural Comparison of Means: PM2.5 Mass

Annual Average ResultsEast Coast Sites Have Higher Conc. than West

Coast SitesUrban Site Levels Exceed Rural Sites by 20-

100%Similar Agreement, within ~10%, is Observed

at Both Urban and Rural Sites, with Slightly Better Average Agreement at Urban Sites

9.0%*

-5.1%

4.3%

11.0%

11.3%

3.3%

9.5%

10.8%

5.9%

Haines Point1.3

Phoenix -0.6

Beacon Hill0.3

Dolly

Sods1.1

Tonto 0.7

Mt Rainier 0.3

Urban 0.36

Rural 0.71

All Sites 0.52

STN- IMP (ug/m3)

* Relative Percent Diff. (STN-IMP)/((STN+IMP)/2)*100

Urban (EW) Rural (EW)

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Urban – Rural Temporal Analysis: Sulfate

Haines Point

Dolly Sods

Beacon Hill

Mt. Rainier

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Urban – Rural Comparison of Means: Sulfate

Annual Average ResultsEast Coast Sites Have Higher Conc. than West Coast

SitesUrban Site Levels Exceed Rural Sites By 50 to 70%

(Avg 48%) Based on STN Data and By 22-100% (Avg 37%) Based on IMP Data

There Is Better Agreement On Average at Urban SitesThe Dolly Sods STN Sulfate Data For June & July 2001

Will Be Flagged as Invalid Due to a Flow Controller Problem – These Data Contribute Significantly to the Larger Difference Between the Two Networks at Dolly Sods

Haines Pt. -0.05

Phoenix -0.36

Beacon Hill -0.09

Dolly Sods -0.89

Tonto 0.12

Mt. Rainier 0.06

Urban -0.15

Rural -0.25

All Sites -0.20

STN- IMP (ug/m3)

-0.9%

-23.4%

-7.5%

-24.2%

12.0%9.5%

-6.0%

-13.7%

-9.0%

* Relative Percent Diff. (STN-IMP)/((STN+IMP)/2)*100

Urban (EW) Rural (EW)

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Urban – Rural Temporal Analysis: Nitrate

Haines Point

Dolly Sods

Beacon Hill

Mt. Rainier

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Urban – Rural Comparison of Means: Nitrate

Annual Average ResultsOn Average, Nitrate Conc Are Low, < 1.4 µg/m3

East Coast Sites Have Higher Conc. than West Coast Sites

Paired Urban Site Levels Exceed Rural Sites by ~ Factor of 3

By Site, Samplers Agree Within About 30% on Average

At Beacon Hill the Difference is Largest at Higher Conc as Seen in the Temporal Distribution

11.7%

13.1%-31.9%

13.7%-20.8%

-3.3%

0.5%

-2.8%

-0.2%

Haines Pt. 0.15

Phoenix 0.12

Beacon Hill -0.24

Dolly Sods 0.060

Tonto -0.085

Mt. Rainier -0.005

Urban 0.005

Rural -0.009

All Sites -0.002

STN- I MP (ug/m3)

Urban (EW) Rural (EW)

*Relative Percent Diff. (STN-IMP)/((STN+IMP)/2)*100

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Urban – Rural Temporal Analysis: OC

Haines Point Dolly

Sods

Beacon Hill

Mt. Rainier

In General IMP < STN

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Urban – Rural Temporal Analysis: OC

Haines Point

*Note Negative Values in STN After Blank Correction

After STN Blank CorrectionIMP ~ STN*

Mostly On Average Within 15%

IMP/STN OC IMP/STN-Blk OC

Haines Pt. 0.59 0.83

Phoenix 0.56 0.77

Beacon Hill 0.95 1.06

Dolly Sods 0.57 1.07

Tonto 0.41 0.87

Mt. Rainier 0.67 0.84

Urban 0.66 0.88

Rural 0.53 0.94

All Sites 0.62 0.89

STN Values Blank

Corrected

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Annual Average ResultsEast and West Coast Sites Can Have Similar

ConcentrationsSTN Urban Site Levels Exceed Rural Sites by 200-

500%Rural Sites Tend to Agree Better Than Urban Sites

Before Blank CorrectionValues Agree Better, but Blank Correcting STN

Results in Negative Numbers That Seem to Be More Prevalent in the Fall & Winter

Urban – Rural Comparison of Means: OC

Blank Correcting STN OC Values Improves the Comparison

Between STN and IMPROVE at Most

Locations

STN Blank Values Are Based on Trip and Field Blanks and Averaged Over the Time Period of the Study

Anderson = 1.3 ug/m3

Haines Pt, Dolly SodsMetOne = 1.4 ug/m3

Phoenix, TontoURG = 0.3 ug/m3

Beacon Hill, Mt Rainier

Urban (EW) Rural (EW)

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Urban – Rural Temporal Analysis: EC

Haines Point Dolly Sods

Beacon Hill Mt Rainier

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Urban – Rural Comparison of Means: EC

Annual Average ResultsEC Data Did Not Require Blank CorrectionUrban Conc Are ~ 2X Rural ConcFactor of 2 Not Observed Between STN and

IMPROVE At Urban or Rural SitesBetter Agreement at Urban Sites (<10%) than at

Rural Sites (± ~ 30%)

IMP/STN EC

Haines Pt. 1.10

Phoenix 1.01

Beacon Hill 1.00

Dolly Sods 1.32

Tonto 0.79

Mt. Rainier 1.52

Urban 1.04

Rural 1.16

All Sites 1.06

-9.6%*

-1.4%

0.4%

-28%23%

-41%

-3.7%

-15%

-6.2%

Urban (EW) Rural (EW)

*Relative Percent Diff. (STN-IMP)/((STN+IMP)/2)*100

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Concentrations at Rural Sites Lower for

Most Species at Most Sites

Less Consistency (Greater Scatter)

Observed at Rural Sites

Higher Data Capture Observed at Urban

Sites

Mass and Sulfate Agreed Well

Typically within 10% for Mass and 20% for

Sulfate

Organic Carbon Agreed Better After STN

Data Blank Corrected

Conclusions

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Species at Higher Concentrations Agree

Better

MDL & Blanks Potential Issue Between

Network Agreement

Site-to-Site Variations Observed for All

Species Even After a Thorough Review

of the Data and Outliers

Questionable Data Still Remain

Factor of 2 Difference not Observed

Between STN and IMPROVE EC

Conclusions (cont’d)

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Finalize report on first year of data from 6 sites

Conduct study to determine the effects of shipping conditions

Begin analyzing quartz filters from STN sites using IMPROVE protocol

Sponsoring projects to specifically look at the effect of carbon meas. protocols on concentration data

Next Steps

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Expanding IMPROVE collocation to nine additional “STN” sites in 2003/2004 New York City Atlanta Pittsburgh Birmingham Detroit Chicago Houston (SS) Riverside-Rubidoux Fresno (SS)

Next Steps

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Disclaimer & AcknowledgementsThis work has been funded wholly by the United States

Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products do not constitute endorsement or recommendation for use.

Acknowledgements:This work was supported by the National Park Service and EPA.

Staff from UC Davis, DRI and NPS personnel have played a significant role in collection and analysis of samples in the IMPROVE Network. Research Triangle Institute has played a significant role in preparing and analyzing samples for the STN network, as well as state site operators who have meticulously been collecting samples since October 2001, which continues to date.

Complete Authors List:Solomon, Paul, A. (EPA, ORD, Las Vegas), Crumpler, Dennis (EPA,

OAQPS, RTP), Klamser-Williams, Tracy (EPA, ORIA, Las Vegas), Egeghy, Peter, Homolya, James, Pitchford, Marc (EPA, OAQPS, Las Vegas), Rice, Joann, Ashbaugh, Lowell (UC Davis, Sacramento), Orourke, James (RTI, RTP), Frank, Neil, McDade, Charles, Flanagan, James, and Rickman, Edward