1. IMPROVE/STN Comparison & Implications for Visibility and PM2.5
John Graham, NESCAUM
MANE-VU/MARAMA Science Meeting
January 27, 2004
Goal of presentation:
Present some information on modeling visibility conditions and hopefully stimulate discussion about how this information should be applied in developing a workplan for the MANE-VU planning process.

2. Overview The networks Direct comparison
IMPROVE
STN
Direct comparison
Addison Pinnacle SP, NY April 2001-Feb 2003
Mass, Major Species, Elements
MANE-VU Extrapolated Visibility
Source Apportionment question for consideration
Conclusions/Recommendations

3. Background Origin of the networks Ongoing EPA review of differences:
Sample Collection: monitor types
Handling, Shipping, and Storage (after collection)
Chemical Analysis: extraction and methods
Data Manipulation: Blanks and artifacts
Measurements:
Mass and Elements on Teflon
Ions on Nylon
Organic and Elemental Carbon on Quartz
Differences:
IMPROVE- elemental H, PM-10;
STN-expanded elements, positive ions

4. Monitoring Sites with Data covering June 2001 - May 2002

5. Addison Pinnacle State Park
STN R & P 2300 Monitor
Sample Volume
Elements (24 m3)
Ions & Carbon (14.4 m3)
IMPROVE Volume (32.7 m3)

6. Comparison of PM2.5 Mass

7. Comparison of PM2.5 Reconstructed Mass

8. Comparison of SO42- Mass

9. Comparison of NO3 Mass

10. Elemental Carbon (mg/m3)
Seasonal OC/EC
All Seasons
IMPROVE
STN Original
STN Simple Blank Corr
STN OCX2 Corr'
STN OCX2 Corr
Season
Elemental Carbon (mg/m3)
winter
0.32
0.27
0.37
0.63
spring
0.28
0.22
0.38
0.71
summer
0.45
0.23
0.64
1.37
fall
0.36
0.25
0.42
0.78
Organic Carbon (mg/m3)
1.02
1.93
0.91
0.51
0.94
2.05
1.03
0.83
0.50
1.80
3.48
2.46
1.98
1.25
1.18
2.21
1.19
0.98
0.61

11. Time Series of DTC

12. STN vs. IMPROVE OC/EC
STN is an adaptation of NIOSH Method 5040 “Elemental Carbon (Diesel Particulate)- Chosen to reflect EPA’s concern for PM2.5 Carbon health effects in urban environments
IMPROVE methods designed for visibility impairment
Believed that STN establishes EC/OC split closer to “true” EC
OCX2 defined as OC evolved between time analysis reaches 550 °C and the introduction of O2
OCIMPROVE = OCSTN - OCX2
ECIMPROVE = ECSTN + OCX2
Blank Correction Needed for STN; applied to both OCSTN and OCX2
Recent Change-No longer reporting OCX2, instead multiple fractions as IMPROVE, although peaks remain unresolved

13. Comparison of Thermograms
Temperature Ramp differences
Reflectance (IMPROVE) vs. Transmittance (STN)
IMPROVE 8 fractions vs. STN 2
Figures from JAWMA, Watson 2002

14. Blank Subtraction for C
Trip and Field Blanks
EC often > measured mass
Analysis by Schwab (SUNY) of NYS STN
Other monitor types C blanks ~93% OC
Consistent with IMPROVE results
R&P2300 interference from silicon grease; loading level affect on OC/EC split time
No apparent seasonality
OC blank 1.02 mg/m3 at Pinnacle SP
EC blank 0.08 mg/m3 at Pinnacle SP
Note for VIEWs users: reported STN values may have ½ MDL instead of ND, OC corrected for blank

15. Scatterplots of OC and EC
TC = EC + OC’ + OCX2; OC’ and OCX2 are blank corrected proportionally
OCX2 is split between OC/EC to mimic IMPROVE OC/EC
Green is Original STN split; Blue is EPA’s initial recommendation; Red-MANE-VU
OC, EC and OCX2 are reported for measurements until 7/2003 [OC = OC’ + OCX2]

16. Organic Carbon Timeseries

17. Elemental Carbon Timeseries

23. Timeseries for Select Elements

24. Combination of STN & IMPROVE for Visibility
Interpolation based on available monitors and 1-year of data
Seasonal figures are more spatially complete
Extinction due to Carbon is a best guess estimate for STN, calculated as usual for IMPROVE
Maps generated for each network separately resemble those for combination maps
Units in Mm-1; Rough estimate of mass discernable

25. Fine Particle Extinction
SPRING
SUMMER
FALL
WINTER
(Mm-1)

26. Sulfate Extinction
SPRING
SUMMER
FALL
WINTER
(Mm-1)

27. Nitrate Extinction
SPRING
SUMMER
FALL
WINTER
(Mm-1)
(Mm-1)

28. Organic Carbon Extinction
SPRING
SUMMER
FALL
WINTER
(Mm-1)

29. Elemental Carbon Extinction
SPRING
SUMMER
FALL
WINTER
(Mm-1)

30. Source Apportionment Major Ionic Species and mass correlate well
Many elemental species also well-correlated
Some elements not well-correlated
Questions: To what extent will poorly correlated minor species influence differences in source profile from SA models?
Will inter-network OC/EC differences continue, or to what extent can changes in reporting STN fractions increase comparability?

31. Closing Remarks Substantial differences exist between networks
Source Apportionment models should be applied to EPA’s collocated datasets to assess how these differences may affect source profile characterization
Mass and major ions correlate well, useful in east due to dominance of Sulfate in visibility extinction from fine particles
In depth analysis required to assess data comparability for use in assessing exposure to metals and EC