1. Continuous Carbon and NHy Measurements
Eric S. Edgerton, ARA, Inc.
EMEP PM Measurement and Modeling Workshop
New Orleans, LA, USA
4/20-23/04
EMEP

2. Outline Continuous Carbon Continuous NHy (NH3)
R&P 5400 (SEARCH)
Aethelometer (SEARCH)
Sunset Labs Particulate Carbon Analyzer (Turner, Robinson)
Continuous NHy (NH3)
An idea for constraining secondary OC
EMEP

3. 5400 Schematic
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4. 5400 Principle of Operation
Collect particles in metal impactor (0.12 µM Dp50) for 60 minutes, or longer
Measure ambient CO2 in analytical loop
Heat impactor in 1-4 temperature plateaus, volatilize carbon (final T C)
Heat afterburner to 750C, complete combustion to CO2
Quantify ΔCO2 via NDIR (Li-Cor)
Repeat (w/o collection step) for artifact (residual) correction
Note: For a 1-hour sample, the system produces
19 ppm of CO2 per ug-C/m3
EMEP

5. 5400 Precision Jefferson Street – July 2001
TC (ug/m3)
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6. 5400i TC vs. TOR TC Jefferson Street, GA - 2001
SEARCH 5400i tends to under predict in winter,
but over predict in summer
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7. 5400f TC vs. TOR TC Jefferson Street, GA – 2003/4
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8. Aethelometer Operation
Collect particles on quartz filter tape at controlled flow
Monitor absorbance continuously with reference ands sensor beam
Advance tape at pre-set time interval or preset absorbance
Wavelength-specific conversion to BC (1-minute + time resolution)
Nafion drier (SEARCH sites)
Activated carbon monolith
EMEP

9. Comparison of AETH-BC and TOR-EC at Jefferson Street (Atlanta), GA
We see a consistent relationship across SEARCH sites,
with regression slopes between 0.5 and 0.7
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10. Time Series of 1-minute AETH-BC Jefferson Street (Atlanta), GA (nafion drier and carbon monolith)
Dislocations observed virtually always at virtually all SEARCH sites,
noise is instrument specific
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11. Sunset Labs Carbon Analyzer
slide courtesy of Jay Turner, STLU
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12. Sunset Labs Temperature Program
slide courtesy of Jay Turner, STLU
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13. EMEP

14. Pittsburgh Air Quality Study: Carbonaceous Aerosol Samplers
CMU Denuder
Sunset in situ
Denuder
PM2.5
Sunset
in-situ
OC/EC Analyzer
Teflon
All Quartz filters analyzed using Sunset Instruments and NIOSH protocol
Denuder
PM2.5
Quartz
CIF
Denuder
Dynamic Blank
Sample
PM2.5
Quartz
CIF
Schematic of different samplers. Definitions of OC & EC shown are the values used in subsequent slides.
Rutgers & Carnegie Mellon
OC = Sample (Q+CIF) –
Dynamic Blank (Q+CIF)
EC = Sample Q – Dynamic Blank Q
Source: Allen Robinson, Carnegie Mellon University; Barb Turpin Rutgers University
EMEP

15. Comparison of Sunset Labs In Situ with Integrated Samples
Excellent agreement except for EC. Note that good agreement with CMU denuder sampler indicates that negative artifact from a denuded in situ not a problem presumably because of short sampling time of in situ? Problems with EC due to refractory build up on in situ filter. This causes premature evolution of EC and biases in split. We changed in situ filter a lot (every few days) during Pittsburgh Supersite. Paper in preparation on this issue.
Source: Allen Robinson, Carnegie Mellon University; Barb Turpin Rutgers University
EMEP

16. Emissions from Biomass Burning
HMS Fire and Smoke Summary for /21/03
Oak Grove
EMEP

17. CO and NOy at Oak Grove – 10/21/03
EMEP

18. Comparison of ERs with Literature Values
FUEL
NOy (as NO)
SO2
PM2.5 TC BC
Savannah/Grassland 60
5.4 83 57
3.1
Trop. Forest 15
5.5 88 64
6.4
non-Trop. Forest 28 9
121 78
5.2
Biofuels 27
3.5 92 51
7.6
Ag. Residues
4.3 42 36
7.5
This Study (Fires)
28+/-14
5.0 +/-2/7
195 +/- 54
63 +/- 14
10 +/- 6.1
This Study (Urban)#
147 +/-10
n.d.
33 +/- 8
9.6 +/- 2.1
Andreae and Merlet. Global Geochem Cyclec 15(4): (A&M)
# Based on Jefferson Street, Atlanta, GA SEARCH data
ER (g/kg CO)
EMEP

19. Continuous Measurements of NHy in SEARCH
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20. SEARCH NH3 and %NHy 4th Quarter 2003
rural-
agricultural
urban-industrial
% NHy
urban-res./ind.
urban-
residential
urban-
residential
NH3 (ppb)
% NHy
rural-
forested
rural-
forested
suburban
0.32 +/- 0.12
0.49 +/- 0.22
2.54 +/- 2.27
EMEP

21. Total Reduced Nitrogen (NHy) Diagram
Hot Pt converts
NHy to NO.
Hot Mo converts
NOy to NO, but
is blind to NHy.
SEARCH
EMEP

22. NO3/NH4 Diagram
SEARCH

23. Continuous NH3 vs Denuder NH3 24 Hour Samples
Gaseous NH3 is deduced by subtracting particulate NH4 from NHy
SEARCH
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24. Hourly NH3 and particulate-NH4+ Yorkville, GA – November 2003
EMEP

25. Continuous NH3 vs. Wind Direction Yorkville, GA – November 2003
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26. 1.8 km
2.3 km
4.5 km
The Smoking Chicken
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27. Continuous NH4+ and NO3- vs
Continuous NH4+ and NO3- vs. Wind Direction Yorkville, GA - November 2003
Wind Direction
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28. WS and WD Yorkville, GA 11/6-8/01
Transport from
Atlanta
Low Wind Speed
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29. Particulate NO3- and NH4+ Yorkville, 11/6-8/01
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30. An Idea for Constraining Secondary OC
Primary
Secondary
Modern OC OC
Fossil OC
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31. Simplified OC Source Matrix
Primary
Secondary
Total
Modern
Speciation/CMB S
peciation ,
Models, D
ifference
14C
Fossil
Difference
Combination of CMB and C-14 data allows calculation of
secondary OC by difference.
EMEP

32. OC Source Matrix Atlanta, GA – January
Primary *
Secondary
Total #
Modern 64
+/- 15
<5 61 +/ - 5
Fossil 36 39
* 2000 Data: Zheng et al., ES&T, 2002.
# from 14Cdata
EMEP

33. OC Source Matrix Atlanta, GA – July 2001
Primary*
Secondary
Total #
Modern
<5
+/- 10
>50 59 +/ - 6
Fossil 40
* +/- 18 41
* Zheng et al. Source Apportionment of Fine Particles at Atlanta, GA, AAAR 2002
# from 14C data
EMEP

34. Summary
For TC, R&P 5400f (with modifications) can reproduce filter-based measurements(+/- 15%), but maintenance (data capture) can be problematic. Log cell pressure.
For BC, aethelometer provides reliable, high time resolution information, but AETH-BC = 0.6(+/- 0.1) TOR-TC. Dislocations and high resolution noise are annoyances that require further investigation. Log fast data.
For OC, TC and possibly EC, early results from Sunset Labs analyzer are promising. Longer term experience necessary.
Continuous carbon and NHy data provide valuable insights into sources, processes, etc.