ASSESSMENT OF CARBON SAMPLING ARTIFACTS IN THE IMPROVE, 

STN/CSN, AND SEARCH NETWORKS 

Prepared by: 

John G. Watson, Judith C. Chow, and L.-W. Antony Chen 

With contributions from: 

Steven D. Kohl, Richard J. Tropp, Dana Trimble, 

Shammah Chancellor, David Sodeman, and Senem Ozgem 

Division of Atmospheric Sciences 

Desert Research Institute 

2215 Raggio Parkway, Reno, Nevada, U.S.A. 

Prepared for: 

Neil Frank 

U.S. Environmental Protection Agency (MD-14) 

Office of Air Quality Planning & Standards 

4201 Alexander Dr., Room 463 

Research Triangle Park, North Carolina, U.S.A. 

August 22, 2008 
 

ii

Table of Contents 

Page

List of Tables ........................................................................................................................... iii 

List of Figures............................................................................................................................v 

Carbon Nomenclature ............................................................................................................. vii 

1. Introduction..................................................................................................................... 1-1 

1.1. Background.................................................................................................... 1-1 

1.2. Objectives ...................................................................................................... 1-3 

1.3. Hypotheses..................................................................................................... 1-3 

1.4. Report Structure ............................................................................................. 1-4 

2. Experimental Methods and DataBases ........................................................................... 2-1 

2.1. Sampling Protocols for IMPROVE, STN/CSN, and SEARCH Networks.... 2-1 

2.2. Procedures for Handling Laboratory, Trip, and Field Blanks........................ 2-1 

2.3. Quartz-fiber Backup Filter (QBQ) behind Quartz-fiber Front Filter (QF).... 2-2 

2.4. Databases Acquired for the Study.................................................................. 2-3 

2.5. Data Sources .................................................................................................. 2-4 

2.5.1. Complications in Data Retrieval from Various Networks ................. 2-4 

2.6. Resuspension and Liquid Injection of Levoglucosan onto Diesel Soot and 

Blank Filters................................................................................................... 2-5 

3. Results............................................................................................................................. 3-1 

3.1. Comparison of Field Blank Levels among the IMPROVE, STN/CSN, and 

SEARCH Networks ....................................................................................... 3-1 

3.2. Comparison between STN/CSN Field and Trip Blanks ................................ 3-2 

3.3. Quartz-Fiber Backup Filters from the IMPROVE and SEARCH Networks. 3-3 

3.4. Seasonal Variations of Blanks and Backup Filter OC Concentration 

Density ........................................................................................................... 3-4 

3.5. Comparison of Blanks between Collocated IMPROVE and STN/CSN........ 3-5 

3.6. Sulfate, Adjusted Nitrate, Derived Water, Inferred Carbonaceous Material 

(SANDWICH) Method.................................................................................. 3-8 

3.7. Influence of Levoglucosan on OC/EC Split for Carbon by IMPROVE and 

STN/CSN Protocols..................................................................................... 3-10 

3.7.1. Recovery Rate for the Solid and Liquid Levoglucosan Doping 

Experiment....................................................................................... 3-11 

3.7.2. Distribution of Carbon Fractions for Diesel Samples Mixed with 

Solid and Liquid Levoglucosan ....................................................... 3-12 

3.8. Radiative Transfer Modeling for the Diesel/Levoglucosan Experiment ..... 3-14 

4. Summary and Conclusions ............................................................................................. 4-1 

5. Recommendations........................................................................................................... 5-1 

6. References....................................................................................................................... 6-1 
 

iii

LIST OF TABLES 

Page

Table 2-1. Sampling protocols for the IMPROVE, STN/CSN, and SEARCH networks.......... 2-11 

Table 2-2. Summary of filter handling procedures for different long-term networks. ..............2-14 

Table 2-3. Collocated PM2.5 speciation data for the IMPROVE network and STN/CSN. ........2-15 

Table 2-4. Examples of organic carbon (OC) database differences among air quality 

networks.................................................................................................................. 2-16 

Table 2-5. Tests for diesel and levoglucosan-doping experiments. ...........................................2-17 

Table 2-6. Comparison of the IMPROVE, IMPROVE_A, and STN/CSN thermal/optical 

carbon analysis protocols........................................................................................2-18 

Table 3-1. Comparison of average field blank levels (± standard deviation) among the 

IMPROVE, STN/CSN, and SEARCH networks for the period from 1/1/2005 

through 12/31/2006................................................................................................. 3-28 

Table 3-2. Average field blank concentration by carbon fraction at the 181 sites in the 

IMPROVE network from 1/1/2005 to 12/31/2006.................................................3-29 

Table 3-3. Average field blank concentrations by thermal carbon fractions at the 239 sites 

in STN/CSN for the period from 1/1/2005 through 12/31/2006. ........................... 3-35 

Table 3-4. Average field blank concentrations by carbon fractions at the eight sites in the 

SEARCH network for the period from 1/1/2005 through 12/31/2006................... 3-45 

Table 3-5. Average blank concentration by PM2.5 speciation sampler type for the 239 sites 

in STN/CSN for the period from 1/1/2005 through 12/31/2006. ........................... 3-46 

Table 3-6. Summary of average (± standard deviation) field and trip blank carbon 

densities and equivalent ambient concentrations for each STN/CSN samplers 

for the period from 1/1/2005 to 12/31/2006. ..........................................................3-47 

Table 3-7. Comparison of the quartz-fiber backup (QBQ) filter behind the quartz-fiber 

front filter between the IMPROVE and SEARCH networks for the period 

from 1/1/2005 through 12/31/2006.........................................................................3-48 

Table 3-8. Summary of field blanks acquired at the 181 sites in the IMPROVE network 

from 1/1/2005 to 12/31/2006..................................................................................3-49 

Table 3-9. Summary of field blanks acquired at the 239 sites in the STN/CSN network 

from 1/1/2005 to 12/31/2006..................................................................................3-53 

Table 3-10. Summary of field blanks acquired at the eight sites in the SEARCH network 

from 1/1/2005 to 12/31/2006..................................................................................3-59 

Table 3-11. Comparison of quartz-fiber backup filter carbon fractions among the urban, 

non-urban, and rural sites between the IMPROVE and SEARCH networks 

for the period from 1/1/2005 through 12/31/2006..................................................3-60 

Table 3-12. Average TC blank and sample concentrations for the eight collocated 

IMPROVE –STN/CSN sites...................................................................................3-61 
 

iv

LIST OF TABLES, continued 

Page

Table 3-13. Regression statistics of uncorrected STN/CSN TC against IMPROVE TC for 

data from the eight collocated sites. ....................................................................... 3-63 

Table 3-14. Comparison between estimated and measured field blanks for the eight 

collocated IMPROVE/STN sites. ...........................................................................3-64 

Table 3-15. Summary of average PM2.5 concentration and field blanks at four collocated 

IMPROVE sites. .....................................................................................................3-65 

Table 3-16. Estimates of organic carbon mass (OCM) based on the SANDWICH method 

(Frank, 2006) for the four collocated IMPROVE/STN sites..................................3-66 

Table 3-17. Summary of percent recovery for: a) solid and b) liquid levoglucosan..................3-67 

Table 3-18. Distribution of carbon fractions on the blank samples doped with solid and 

liquid levoglucosan.................................................................................................3-68 

Table 3-19. Carbon fractions for the diesel/levoglucosan experiment following the 

IMPROVE and STN/CSN protocols. .....................................................................3-69 

Table 3-20. Distribution of carbon fractions for the diesel/levoglucosan experiment 

following the IMPROVE_A and STN/CSN protocols. ..........................................3-71 

Table 3-21. Ratio of the bottom half of quartz-fiber front filter (QFbott) or quartz-fiber 

backup filter (QBQ) to quartz-fiber front filter (QF) in different carbon 

fractions. .................................................................................................................3-72 

Table 5-1. Summary of findings for the five hypotheses.............................................................5-3 
 

v

LIST OF FIGURES 

Page

Figure 2-1. Sampling sites in the IMPROVE network from VIEWS (2007). The six 

circled sites are locations where secondary filters (i.e., quartz-fiber backup 

[QBQ] filters) are acquired~6% of the time: #78 (MORA) Mount Rainier 

National Park; #96 (YOSE) Yosemite National Park; #48 (HANC) Hance 

Camp at Grand Canyon National Park; #39 (CHIR) Chiricahua National 

Monument; #6 (SHEN) Shenandoah National Park; and #16 (OKEF) 

Okefenokee National Wildlife Refuge; the eight sites indicated by squares 

(#202 [PUSO] Seattle, WA; #78 [MORA] Mount Rainier National Park; #187 

[FRES] Fresno, CA; #201 [PHOE] Phoenix, AZ; #44 [TONT] Tonto National 

Monument, AZ; #31 [BIBE] Big Bend National Park, TX; #8 [DOSO] Dolly 

Sods, WV; and #119 [WASH] Washington, DC) have collocated IMPROVE 

and STN/CSN samples. ............................................................................................ 2-7 

Figure 2-2. Sites in the Speciation Trends Network/Chemical Speciation Network 

(STN/CSN;U.S.EPA, 2006)...................................................................................... 2-8 

Figure 2-3. The SEARCH network, consisting of: Mississippi pair: urban Gulfport (GLF) 

in Gulfport and rural Oak Grove (OAK) near Hattiesburg; Alabama pair: 

urban Birmingham (BHM) in North Birmingham and rural Centreville (CTR) 

south of Tuscaloosa; Georgia pair: urban Jefferson Street (JST) in Atlanta and 

rural Yorkville (YRK) northwest of Atlanta; and Florida pair: urban 

Pensacola (PNS) in Pensacola and suburban outlying field (OLF) northwest 

of Pensacola..............................................................................................................2-9 

Figure 2-4. Flow diagram for diesel and levoglucosan experiments......................................... 2-10 

Figure 3-1. Field blank organic carbon (OC) concentration density (μg/cm2

) for: a) 181 

IMPROVE sites, b) 239 STN/CSN sites, and c) eight SEARCH sites for the 

period from 1/1/2005 through 12/31/2006 (each bar represents the 

concentration sector less than or equal to the assigned value). .............................. 3-17 

Figure 3-2. Seasonal variations of blanks among: a) IMPROVE, b) SEARCH, c) 

STN/CSN field blanks, and d) STN/CSN trip blanks............................................. 3-18 

Figure 3-3. Seasonal variations of average blank quartz-fiber backup (QBQ) filter organic 

carbon (OC) concentrations for the: a) six IMPROVE sites, and b) eight 

SEARCH sites. ....................................................................................................... 3-19 

Figure 3-4. Comparison of field blank carbon concentrations between the urban, nonurban, and rural sites among the IMPROVE, STN/CSN, and SEARCH 

networks. There are 13 urban and 168 rural IMPROVE sites, 239 STN/CSN 

urban sites, and five urban and three non-urban SEARCH sites; see Table 3-8 

for the urban IMPROVE site names); the IMPROVE_A_TOR protocol is 

used for the IMPROVE and SEARCH networks, the STN_TOT protocol is 

used for STN/CSN. See Table 2-6 for carbon fraction temperatures. ....................3-20 
 

vi

LIST OF FIGURES, continued 

Page

Figure 3-5. Comparison of quartz-fiber backup filter carbon fractions between the urban, 

non-urban, and rural sites in the IMPROVE and SEARCH networks. (See 

Figures 2-1 and 2-3 for the 181 IMPROVE and eight SEARCH sites. Carbon 

fractions follow the IMPROVE_A_TOR protocol................................................. 3-21 

Figure 3-6. Time series of IMPROVE and STN/CSN blank TC concentrations at eight 

collocated sites (IMP_bQF: IMPROVE field blank filter; STN_FB: 

STN/CSN field blanks; STN_TB: STN/CSN trip blanks). .................................... 3-22 

Figure 3-7. Ordinary linear regression of uncorrected STN/CSN TC against IMPROVE 

TC acquired from the Phoenix site (PHOE1). The non-zero intercept 

indicates the different sampling artifacts between STN/CSN and the 

IMPROVE network. ...............................................................................................3-23 

Figure 3-8. The uncorrected STN-IMPROVE TC regression Intercept for all data and 

seasonally-segregated data from the eight collocated sites: PUSO1 (Seattle, 

WA); MORA1 (Mount Rainier, WA); PHOE1 (Phoenix, AZ); TONT1 (Tonto 

National Monument, AZ) WASH1 (Washington, DC); DOSO (Dolly Sods 

Wilderness, WV); FRES1 (Fresno, CA); and BIBE1 (Big Bend National 

Park, TX). ............................................................................................................... 3-24 

Figure 3-9. Thermograms of IMPROVE_A_TOR/TOT analyses on: a) blank filter with 

solid levoglucosan (0.97 μg/cm2), and b) blank filter with liquid levoglucosan 

(22.9 μg/cm2

).......................................................................................................... 3-25 

Figure 3-10. Thermograms of IMPROVE_A_TOR/TOT analyses on: a) pure diesel soot, 

and b) diesel soot/liquid levoglucosan mixture (22.9 μg/cm2

)...............................3-26 

Figure 3-11. Filter reflectance (R) and transmittance (T) of pure diesel soot and liquid 

levoglucosan on blank filter through the IMPROVE_A thermal/optical 

analysis protocol. Samples are the same as those listed in Figure 3-9. R0 and 

T0 are reflectance and transmittance of blank filters, respectively. The dashed 

lines indicate the “best fits” with a radiative transfer equation (RTE) model 

(see text)..................................................................................................................3-27 
 

vii

CARBON NOMENCLATURE 

VOC:...................................................................................................Volatile Organic Compounds 

SVOC:....................................................................................... Semi-Volatile Organic Compounds 

gSVOC:............................................................ Gaseous-Phase Semi-Volatile Organic Compounds 

pSVOC:..............................................................Particle-Phase Semi-Volatile Organic Compounds 

TC: ....................................................................................................Total Carbon (TC = OC + EC) 

OC:...........................................................................................................................Organic Carbon 

pOC:........................................................................... Non-Volatile Particle-Phase Organic Carbon 

EC: ........................................................................................................................Elemental Carbon 

QBT:..........................................Quartz-Fiber Backup Filter behind Teflon-Membrane Front Filter 

QBQ:................................................. Quartz-Fiber Backup Filter behind Quartz-Fiber Front Filter 

bQBQ:.....................................Blank Quartz-Fiber Backup Filter behind Quartz-Fiber Front Filter 

dQBQ:................................Denuded Quartz-Fiber Backup Filter behind Quartz-Fiber Front Filter 

QBQtop:.............Top Half of a Sliced Quartz-Fiber Backup Filter behind Quartz-Fiber Front Filter 

QBQbott:......Bottom Half of a Sliced Quartz-Fiber Backup Filter behind Quartz-Fiber Front Filter 

QF: .............................................................................................................Quartz-Fiber Front Filter 

bQF ...............................................................................................Field Blank (Quartz-Fiber Filter) 

dQF ............................................................................................ Denuded Quartz-Fiber Front Filter 

QFtop .................................................................................... Top Half of a Quartz-Fiber Front Filter 

QFbottom.......................................................................... Bottom Half of a Quartz-Fiber Front Filter 
1-1

1. INTRODUCTION 

1.1. Background 

The adsorption of organic vapors onto quartz-fiber filters during PM2.5 and PM10

sampling for thermal/optical carbon analyses causes organic carbon (OC) concentrations to be 

overestimated. There organic vapors may char during thermal/optical analysis, thereby causing 

differences in elemental carbon (EC) corrections determined by reflectance and transmittance 

(Chen et al., 2004; Chow et al., 2004). The composition of the adsorbed material, its exchange 

between the adsorbed and gaseous phases, the degree to which filters become saturated, and how 

the amount of OC adsorbed differs among filter media and sampling environments has been 

recognized, but it is poorly understood (Kukreja and Bove, 1976; Lee et al., 1980a; 1980b; Cadle 

et al., 1983; Eldred et al., 1983; Galasyn et al., 1984; McDow, 1986; 1999; Coutant et al., 1988; 

Fung, 1988; Eatough et al., 1989; 1990; 1993; 2001; 2003a; 2003b; de Raat et al., 1990; Fitz, 

1990; Helmig et al., 1990; McDow and Huntzicker, 1990; 1993; Chow et al., 1991a; 1991b; 

1992; 1993; 1996; 1998; 2002; 2004; 2005a; 2006b; Lewis et al., 1991; Cotham and Bidleman, 

1992; Gu et al., 1994; Hart and Pankow, 1994; Chow, 1995; Gundel et al., 1995; Chow and 

Watson, 1997a; 1997b; Allen et al., 1999; Kavouras et al., 1999; Kim et al., 2001; 2005; Mader 

and Pankow, 2000; 2001a; 2001b; 2002; Kirchstetter et al., 2001; Kirchstetter et al., 2003; 

Lewtas et al., 2001; Chen et al., 2002; 2004; Flanagan et al., 2002; Green et al., 2002; Baumann 

et al., 2003; Lim et al., 2003; Long et al., 2003; Matsumoto et al., 2003; Fan et al., 2004a; 2004b; 

Fung et al., 2004; Jeong et al., 2004; Khalek, 2004; Arhami et al., 2006; Galarneau and Bidleman, 

2006; Galarneau et al., 2006; Grover et al., 2006; Lipsky and Robinson, 2006; Dhammapala et 

al., 2007; Kim and Hopke, 2007; NAREL, 2001; Obeidi and Eatough, 2002; Offenberg et al., 

2007; Olson and Norris, 2005; Pang et al., 2002; Pankow et al., 1984; Pankow and Bidleman, 

1991; Pimenta and Wood, 1980; Pitts, Jr. et al., 1986; Ray and McDow, 2005; Rice, 2004; Salma 

et al., 2004; Salma et al., 2007; Sanderson and Farant, 2005; Schwartz et al., 1981; Sihabut et al., 

2005; Subramanian et al., 2004; ten Brink, 2004; ten Brink et al., 2004; Thrane and Mikalsen, 

1981; Tolocka et al., 2001; Turpin et al., 1993; Turpin et al., 1994; Turpin et al., 1997; Turpin et 

al., 1999; Turpin et al., 2000; van Vaeck et al., 1984; Viana et al., 2006a; Viana et al., 2006b; 

Watson et al., 1988; Watson et al., 1991a; Watson et al., 1991b; Watson et al., 1996; Watson and 

Chow, 2002; Watson et al., 2005; Wittmaack and Keck, 2004; Wolff et al., 1991; Zhao et al., 

2006). 
1-2

This positive OC artifact is distributed throughout the filter, as evidenced by visible 

darkening of the back side of the filter when it chars during heating in a non-oxidizing 

atmosphere (Chow et al., 2004). Attempts are made to quantify and correct for the positive OC 

artifact in U.S. long-term monitoring networks. The Interagency Monitoring of Protected Visual 

Environments [IMPROVE] and the Southeastern Aerosol Research and Characterization 

[SEARCH] networks use quartz-fiber front filters (QF) to collect atmospheric OC and elemental 

carbon (EC) and use backup filters to estimate the adsorbed OC so it can be subtracted from the 

total. These networks also ship field blanks with the sampled filters to estimate passive 

adsorption. The Speciation Trends Network (STN) (or Chemical Speciation Network [CSN]) 

measures field blanks but does not adjust the reported data for them or propagate the variability 

of the blank to the OC uncertainty. There are differences in how the blanks are handled among 

the networks with regard to exposure times and temperatures for shipping and storage. The use 

of field blank and backup filter concentrations to compensate for OC artifacts is also different in 

each network. 

Artifact corrections assume that vapors are adsorbed uniformly throughout the front and 

backup filters. This implies that a saturation level is attained, as organic vapors would be 

preferentially scavenged in the upper sections of a filter before the gas is transmitted to lower 

sections. When blanks are used to estimate the artifact, it is assumed that passive adsorption is 

the same as active adsorption. When a subset of filters is used to represent all samples, it is also 

assumed that the saturated OC artifact values are invariant with respect to the filter batch, 

sampled environment, and sampling period. 

There is mounting evidence that substantial deviations from these assumptions exist in 

long-term U.S. networks. Kirchstetter et al. (2001) suggest that each filter may have a different 

capacity for organic vapor adsorption. IMPROVE observes a seasonal variability in backup filter 

OC and uses monthly averages for blank corrections (Chow et al., 2007c). In addition, field 

blanks do not always have the same exposure time as the front and backup filters. 

It is possible that urban environments have more gases that can be adsorbed than nonurban environments, especially non-urban locations in the arid western U.S. where biogenic 

volatile organic compound (VOC) levels are low. The oxidation of low-volatility hydrocarbons 

is a main channel for secondary aerosol formation. Fresh plumes may contain substantial 

amounts of semi-volatile organic compounds (SVOCs) in both gaseous- (gSVOC) and particle-
1-3

phases (pSVOC) that come into equilibrium as the plumes age. In rural and remote atmospheres 

(which are represented by most IMPROVE sites), many SVOCs will have evaporated or 

converted to more stable compounds. In this case, backup filter OC may be similar to the OC 

field blank, especially when both are subjected to long passive periods in the sampler. Urban 

locations, represented by the STN/CSN and urban/suburban SEARCH samples, experience more 

fresh emissions, and the adsorbable vapors may be more plentiful. These materials are more 

likely to be adsorbed when air is drawn through the filter than on the passive field blank. Owing 

to higher ambient temperatures, more of the SVOC is expected in the vapor phase during 

summer than during winter. 

1.2. Objectives 

The goal of this study is to better understand the magnitude and nature of measured OC 

artifacts on field blanks (bQF) and quartz-fiber filters behind quartz-fiber front filters (QBQ) and 

to evaluate strategies to compensate for these artifacts. Specific objectives are: 

• Compile existing databases of mass, elements, and ions, non-processed data for OC, 

EC, and thermal fractions, as well as laboratory, field, and trip blanks for collocated 

IMPROVE, STN/CSN, and/or SEARCH sites. 

• Describe how blanks have been handled and used in each network. 

• Compare the magnitudes of adsorbed organic vapors estimated by different methods 

and evaluate how well the applied methods compensate for these artifacts in the 

reported OC concentrations. 

• Examine the influence of water-soluble organics as powders and in solution on the 

blank/backup filters and the quantification of OC and EC with the IMPROVE and 

STN/CSN thermal/optical protocols. 

• Acquire information that can better relate carbon measurements from the IMPROVE 

and STN/CSN network. 

1.3. Hypotheses 

The following hypotheses are tested, to the extent possible, using existing IMPROVE, 

STN/CSN, and/or SEARCH samples and data. 

A. The sampling artifact on blank/backup filters depends on sampling protocol and 

differs among ambient networks. 
1-4

B. Adsorbed organic carbon on the field blank is less than that on the backup filter, 

which is less than that on the bottom half of the front filter. 

C. Aerosol aging reduces SVOC content and the organic sampling artifact. 

D. OC estimated by the Sulfate, Adjusted Nitrate, Derived Water, Inferred Carbonaceous 

Material (SANDWICH) method better represents the particulate organic matter in 

PM2.5. 

E. The organic sampling artifact influences the OC/EC split for both IMPROVE and 

STN/CSN carbon analyses. 

1.4. Report Structure 

Section 1 states the background, objectives, and hypotheses being tested. Section 2 

describes the experimental methods and database assembled to attain the objectives. Challenges 

in data retrieval and reconciling blank and sampled filters from different networks are compared. 

Sampling protocols for the IMPROVE, STN/CSN, and SEARCH networks are summarized. 

Procedures for handling laboratory, trip, and field blanks are documented. Databases are 

assembled to pair the collocated IMPROVE and STN/CSN samples for special studies at the 

three urban (Seattle, WA; Phoenix, AZ; and Washington, DC) and three rural (Mt. Rainier, WA; 

Tonto National Monument, AZ; and Dolly Sods Wilderness, WV) sites, and for the long-term 

measurements at Fresno, CA, and Big Bend National Park, TX. Filter doping with solid and 

liquid levoglucosan to evaluate effects of complex mixtures on filter carbon content is attempted. 

Section 3 uses these data sets to evaluate the five hypotheses. It compares the magnitudes of 

adsorbed organic artifact among laboratory, trip, and field blanks, and between blanks and 

backup filters. Measured OC is compared to estimated OC or organic carbon mass (OCM) using 

the SANDWICH method developed by Frank (2006). It also examines the influence of 

levoglucosan concentration on the OC/EC split using dry (resuspension) and wet (liquid 

injection) methods. Section 4 relates these observations to the hypotheses being tested and 

summarizes conclusions on the findings. Section 5 provides relevant references resulting from 

the literature survey performed as part of this project. 
2-1

2. EXPERIMENTAL METHODS AND DATABASES 

2.1. Sampling Protocols for IMPROVE, STN/CSN, and SEARCH Networks 

Table 2-1 compares the sampling protocols for the IMPROVE, STN/CSN, and SEARCH 

networks. Site locations for these networks are shown in Figures 2-1 to 2-3, respectively. Five 

types of samplers, varying from single to five parallel channels, are used in STN/CSN. With 

respect to carbon, only the particle composition monitor (PCM3) in the SEARCH network is 

configured with a preceding organic denuder. 

The IMPROVE, STN/CSN, and SEARCH networks also use different quartz-fiber filters 

that have diameters of 25 mm (Pallflex® Tissuquartz), 47 mm (Whatman QMA, with 5% 

borosilicate binder), and 37 mm (Pallflex® Tissuquartz), respectively. The deposit area is 3.53 

cm

2

 for IMPROVE, 11.76 cm2 for STN/CSN, and 7.12 cm2 for SEARCH samples. The deposit is 

denser on the smaller filters, and the amount of organic artifact relative to the deposit is less for 

smaller deposit areas. Sample volumes also differ among the 24-hour samples acquired in these 

networks, with 32.7 m3 for IMPROVE, from 9.6 to 24 m3 for the STN/CSN sampling systems 

and 24 m3 for SEARCH. The organic artifact is larger relative to the deposit area for lower flow 

rates. 

The filter holder (e.g., single or tandem filter packs) and magazine (i.e., R&P 2025 

sequential Federal Reference Method [FRM] sampler) materials might also affect carbon blank 

levels owing to out gassing of organic vapors. 

2.2. Procedures for Handling Laboratory, Trip, and Field Blanks 

Types of blanks and backup filters used in the IMPROVE, STN/CSN, and SEARCH 

networks include: 

• Laboratory Blanks: These are retained in the laboratory and are used for 

acceptance testing after pre-firing and to assess filter contamination levels and 

proper operation of analytical instruments. After the receipt of each batch of 

samples, ~2% of the samples are pre-fired and submitted for acceptance testing 

with the limits for each network noted in Table 2-2. Laboratory blanks are 

maintained for each network, but the acceptance testing data are not reported. 

They are used to estimate background level of the unexposed filter, but they are 

not used to adjust the organic artifact. 
2-2

• Trip Blanks: These pre-fired filters are loaded into sample holders and accompany 

the sampled filter to and from the laboratory. They are not exposed to ambient air 

and are intended to assess contamination during shipping. They follow the same 

filter handling procedures as those for ambient filter samples, but they are 

retained in their original protective enclosures. Trip blanks are used only in 

STN/CSN, and constitute ~3% of all samples. These trip blank (and field blank) 

levels are available from July, 2003 to date (U.S.EPA, 2007). Trip blank values 

are reported separately and are not used to adjust for STN/CSN sampling artifacts. 

• Field Blanks: Sometimes called dynamic blanks, field blanks accompany sample 

shipments and are placed in the sampler along with the sampled filters (Chow and 

Richards, 1990) The only difference is that air is not drawn through them. Field 

blanks allow passive deposition and adsorption to be assessed. Since the number 

of field blanks is relatively small compared to the number of samples, average 

concentrations of the measured observables are used to correct the sampled values 

and the standard deviation of the average is used to estimate the blank precision. 

Blank outliers are usually identified (values > 3 or four times the standard 

deviation) and excluded to minimize biases. 

As shown in Tables 2-1 and 2-2, the quantity of field blanks and the time they are 

exposed for passive sampling differs among networks. Field blanks constitute ~2% of sample 

filters for IMPROVE, ~10% of sample filters for STN/CSN, ~10-25% of sample filters for 

Texas’ non-trends CSN, and ~10% of sampled filters for SEARCH. 

The passive period for the field blanks is determined by the site visit schedule. This 

period is on the order of 1-15 minutes for most sites in STN/CSN and SEARCH networks, which 

is probably insufficient to adsorb organic vapors retained by the sampled filters. For Texas’ nontrends sites, which use the R&P 2025 sequential FRM sampler, the field blank stays in the 

magazine for 5-7 days, but it resides in the sampling position (without air being drawn through) 

for only a few seconds. 

2.3. Quartz-fiber Backup Filter (QBQ) behind Quartz-fiber Front Filter (QF). 

The IMPROVE and SEARCH networks use quartz-fiber backup filters (QBQ) behind 

quartz-fiber front filters (QF) to estimate the positive and negative OC artifacts. These QBQ are 

placed at six sites (Figure 2-1) in the IMPROVE network (i.e., Mt. Rainier National Park 
2-3

[MORA]; Yosemite National Park [YOSE]; Hance Camp at Grand Canyon National Park 

[HANC], Chiracahua National Monument [CHIR], Shenandoah National Park [SHEN]; and 

Okefenokee National Wildlife Reserve [OKEF]) and at eight sites (Figure 2-3) in the SEARCH 

network (Mississippi pair: urban Gulfport [GLF] in Gulfport and rural Oak Grove [OAK] near 

Hattiesburg; Alabama pair: urban Birmingham [BHM] in North Birmingham and rural 

Centreville [CTR] south of Tuscaloosa; Georgia pair: urban Jefferson Street [JST] in Atlanta and 

rural Yorkville [YRK] northwest of Atlanta; and Florida pair: urban Pensacola [PNS] in 

Pensacola and suburban outlying field [OLF] northwest of Pensacola). Both networks collect 

QBQ on an every-third-day sampling schedule with the exception of daily sampling at the BHM 

and JST sites for the SEARCH network. However, only 10% of the SEARCH backup filters 

(selected randomly) are analyzed by DRI. Since a preceding organic denuder is used in the 

SEARCH PCM3 sampler, QBQ from the SEARCH network likely represent a negative OC 

artifact that occurs when some of the SVOC in the PM2.5 deposit evaporates and is recaptured on 

the backup filter. Since IMPROVE does not remove atmospheric VOCs before the front filter, 

the IMPROVE QBQ represents a combination of positive and negative OC artifacts. The 

IMPROVE network uses the monthly median value of the carbon fractions from the six sites for 

blank subtraction at all sites in the network. SEARCH corrects the organic sampling artifact by 

calculating the quarterly mean concentrations for the QBQ and front filter field blank (bQF) and 

attributing them to negative and positive artifacts, respectively. Since OC front bQBQ and bQF 

are similar, 2 times bQF OC is subtracted as blank correction. Thus, OC (blank corrected) = 

OCQF + OCQBQ - 2OCbQF. (Note: QBQ and bQF are quarterly mean values while QF is calculated 

using individual sampling days.) 

2.4. Databases Acquired for the Study 

Collocated IMPROVE and STN/CSN data were acquired from: 1) three urban sites 

(Seattle, WA; Phoenix, AZ; and Washington DC) for 10/16/2001 through 12/29/2003; 2) three 

non-urban sites in the vicinity of the urban sites (Mt. Rainier, WA; Tonto National Monument, 

AZ; and Dolly Sods Wilderness, WV) for 10/16/2001 through 12/29/2003 (Mount Rainier for 

10/16/2001 through 11/1/2002); 3) the urban Fresno, CA Supersite for /1/2005 through 

7/31/2005; and 4) the Big Bend, TX, IMPROVE site for 1/4/2005 through 12/30/2005. As 

indicated in Table 2-3, four types of STN/CSN samplers were collocated with the IMPROVE 

samplers. 
2-4

2.5. Data Sources 

Both non-processed and blank corrected mass and chemical data along with field and trip 

blanks were obtained from several data bases. Data validation and analysis were done using: 1) 

valid concurrent IMPROVE/STN/CSN data pairs, and 2) data pairs with complete mass, 

elements, ions (i.e., a minimum of SO4

=

 and NO3

-

) and carbon measurements. Non-processed 

IMPROVE carbon data was retrieved from the DRI SQL database server, while the STN/CSN 

blank data was requested from RTI (Flanigan, 2007, personal communication). Blank corrected 

mass and chemical composition data (including elements, ions, and carbons) from the 

IMPROVE-STN comparison study were requested from U.C. Davis (McDade, 2007, personal 

communication). The assembled database contains 1,021 data pairs for IMPROVE and 

STN/CSN at the six sites, including 38 IMPROVE and 142 STN/CSN field blanks. 

Non-processed IMPROVE carbon data for the Fresno and Big Bend sites was retrieved 

from the DRI SQL server and related to blank-corrected mass and chemical composition data 

from VIEWS (2007). STN/CSN chemical composition data for these two sites was retrieved 

from the AIRS database (U.S.EPA, 2007). Due to missing nitrate (NO3

-

) data at the Big Bend 

site and incomplete 2006 data, 172 data pairs, as well as 7 IMPROVE and 32 STN/CSN field 

blanks were included. For carbon analysis, the completed 2005 and 2006 data provided 308 

sample pairs and 49 field blanks. 

2.5.1. Complications in Data Retrieval from Various Networks 

IMPROVE, STN/CSN and SEARCH data bases are inconsistent with respect to: 1) 

parameter names, 2) treatment of blank data, and 3) data formatting. Efforts should be made to 

reconcile these differences. Examples of data base issues are given in Table 2-4. The following 

section documents some findings during data retrieval for this study. 

• Observable names: Observable codes vary between sampling networks, and are not 

always completely defined. In order to compare data between networks, consistent 

parameter names for analysis methods, analytes, units, etc., are required for data 

queries. Concentrations are often reported in different units, which also need to be 

reconciled. 

• Blank Data: Blank data are independent of flow rates. They should be reported as 

μg/cm2

 with documentation. Typically, blank data are available in measurements of 

absolute mass on the filter, or values normalized to the nominal sampling volume for 
2-5

the instrument. For this study, values were converted from μg/m3

 to μg/cm2 for the 

STN/CSN sites. This correction is site-specific because of the different samplers and 

flow rates used at each site. Additionally, units of FRM blank data changed in AQS 

during early 2005 from μg/filter to μg/m3. 

• Data Formatting.: Data for the IMPROVE/STN/CSN comparison study was not in a 

common format, and was not uploaded to AQS or VIEWS. Special requests were 

made for this study, but the data received did not include blanks. The STN/CSN blank 

data was requested and obtained from RTI (Flanigan, 2007, personal communication), 

and the IMPROVE blank data was obtained from DRI’s Environmental Analysis 

Facility (EAF) SQL server (Reno, NV). 

2.6. Resuspension and Liquid Injection of Levoglucosan onto Diesel Soot and Blank 

Filters 

Source samples from diesel exhaust were collected using a dilution sampling system 

(Hildemann et al., 1989) at DRI’s Source Characterization Laboratory. An Onan-Cummins 12.5 

kW diesel generator was operated at a load of 4 kW (Chow et al., 2006a). A portion of the 

exhaust (20 L/min) was diluted (nominal dilution ratio of 70:1) and allowed to reach equilibrium 

for ~100 seconds before being sampled onto four 47 mm filter packs with quartz-fiber front 

filters (QF) and quartz-fiber backup behind quartz-fiber front filters (QBQ). 

A dry mixture of 46% levoglucosan (99% purity, Sigma Aldrich, St. Louis, MO) and 

54% silicon dioxide (99.5% purity, Alfa Aesar, Ward Hill, MA) was resuspended onto six of the 

diesel soot filters and six unexposed blank filters using a laboratory resuspension chamber 

(Chow et al., 1994). Loadings were in the range of 5 – 76 μg/cm2

, equivalent to 2 – 34 μg carbon 

(C)/cm2

. 

Three punches (0.53 cm2 each) from two diesel soot filters were spiked with 10 μl of a 

2.3 g/L levoglucosan solution, equivalent to 22.9 μg C/cm2

. Twenty-five single blank quartz 

filter punches were spiked with liquid levoglucosan (5, 10, 12, 20 μl corresponding to low 9.6 μg 

C/cm2

, medium 19.2 and 22.9 μg C/cm2, and high 38.3 μg C/cm2 loads). Figure 2-4 and Table 2-

5 summarize these test matrices. The spiking of the levoglucosan on blank filters gives the 

possibility of determining the positive bias in the EC measurement. As there is no native EC on 

the blank filter, any EC measured on the filter will be due to the charred OC in the filter mistaken 

as EC and should be corrected by pyrolysis correction. 
2-6

Chow et al. (2004) show the TOT pyrolysis corrections for the two thermal/optical 

protocols yield different OC and EC concentrations, but the TOR pyrolysis corrections yield the 

same values. Table 2-6 documents the IMPROVE, IMPROVE_A, and STN/CSN protocols. The 

carbon fractions in the STN_TOT protocol vary by sample loadings and are constrained by the 

fixed analysis time (45-90 sec) per temperature plateau, and therefore are not useful for 

comparison. 
2-7

MORA

YOSE

HANC

CHIR

SHEN

OKEF

MORA

YOSE

HANC

CHIR

SHEN

OKEF

FRES

PUSO

PHOE

TONT

WASH

DOSO

BIBE

MORA

YOSE

HANC

CHIR

SHEN

OKEF

MORA

YOSE

HANC

CHIR

SHEN

OKEF

FRES

PUSO

PHOE

TONT

WASH

DOSO

BIBE

Figure 2-1. Sampling sites in the IMPROVE network from VIEWS (2007). The six circled sites 

are locations where secondary filters (i.e., quartz-fiber backup [QBQ] filters) are acquired~6% of 

the time: #78 (MORA) Mount Rainier National Park; #96 (YOSE) Yosemite National Park; #48 

(HANC) Hance Camp at Grand Canyon National Park; #39 (CHIR) Chiricahua National 

Monument; #6 (SHEN) Shenandoah National Park; and #16 (OKEF) Okefenokee National 

Wildlife Refuge; the eight sites indicated by squares (#202 [PUSO] Seattle, WA; #78 [MORA] 

Mount Rainier National Park; #187 [FRES] Fresno, CA; #201 [PHOE] Phoenix, AZ; #44 

[TONT] Tonto National Monument, AZ; #31 [BIBE] Big Bend National Park, TX; #8 [DOSO] 

Dolly Sods, WV; and #119 [WASH] Washington, DC) have collocated IMPROVE and 

STN/CSN samples. 
2-8

Figure 2-2. Sites in the Speciation Trends Network/Chemical Speciation Network 

(STN/CSN;U.S.EPA, 2006).
2-9

Figure 2-3. The SEARCH network, consisting of: Mississippi pair: urban Gulfport (GLF) in 

Gulfport and rural Oak Grove (OAK) near Hattiesburg; Alabama pair: urban Birmingham 

(BHM) in North Birmingham and rural Centreville (CTR) south of Tuscaloosa; Georgia pair: 

urban Jefferson Street (JST) in Atlanta and rural Yorkville (YRK) northwest of Atlanta; and 

Florida pair: urban Pensacola (PNS) in Pensacola and suburban outlying field (OLF) northwest 

of Pensacola.
2-10

12 QF filters with

Diesel Soot

8 QF filters with diesel soot

6 QF filters with

diesel soot + dry

resuspended

levoglucosan

QF QF

9

IMPROVE

Protocol

9 STN

Protocol

6

IMPROVE

Protocol

6 STN

Protocol

12 QBQ filters

with Diesel Soot

12

IMPROVE

Protocol

12 STN

Protocol

2 QF filters with

diesel soot and

liquid spiked

levogluosan

QF

3

IMPROVE

Protocol

3 STN

Protocol

Punch

Punch

Punch

12 bQF f

sampl

6 bQF filter

samples

Punches with

liquid spiked

levoglucosan

Punches

74 IMPROVE

protocol

70 STN

protocol

6 IMPROVE

protocol

6 STN

protocol

Figure 2-4. Flow diagram for diesel and levoglucosan experiments.
2-11

Table 2-1. Sampling protocols for the IMPROVE, STN/CSN, and SEARCH networks. Variable Speciation 

Sampler 

Network IMPROVE STN/CSN STN/CSN STN/CSN CSN CSN Sampler Typea IMPROVE Andersen RAAS Met One SASS URG MASS R&P 2300 R&P 

Sequ

Total Number of Sites 181 18 179 6 14 22 Number of Channels 3 4 5 2 4 2 Inlet Typeb AIHL cyclone AIHL cyclone cyclone PM10 inlet/WINS impactor PM10 

or V

Inlet Materialc anodized Al anodized Al anodized Al anodized Al anodized Al anodFlow Rate 22.7 L/min 7.3 L/min 6.7 L/min 16.7 L/min 10.0 L/min 16.7 Face Velocity 107.2 cm/sec 10.3 cm/sec 9.5 cm/sec 23.7 cm/sec 14.2 cm/sec 23.6 Sample Volume 32.7 m3 10.5 m3 9.6 m3 24 m3 14.4 m3 24 mSampling Frequency 3rd day 3rd day 3rd day 3rd day 3rd day / 6th day 3rd dPassive deposition time (Time Field Blank is in Sampler) 

7 dayse 1-15 min variablef 1-15 min variablef 5 – 7 

Filter Pack Configuration QFh or QBQi QFh QFh QFh QFh QFh Sites with Backup filters (QBQi) 6 0 0 0 0 0 Quartz Filter Deposit Area 3.53 cm2 11.76 cm2j 11.76 cm2j 11.76 cm2j 11.76 cm2j 11.78 Backup Filter Analysis Frequency 100% N/A N/A N/A N/A N/A Quartz Filter Type (QFh) 25 mm Palll 47mm 

Whatmanm

47mm Whatman 47mm Whatman 47mm Whatman 47mm 

Lab Blank Frequency 2% 2 - 3%n 2 - 3%n 2 - 3%n 2 - 3%n Trip Blank Frequency 0% 3% 3% 3% 3% 0% Field Blank Frequency 2% 10% 10% 10% 10% 10-2Field Blank Analysis Frequency 100% 100% 100% 100% 100% 100% Total Number of Field Blanks (2005-2006) 

886 249 2,572 150 236 421 

a IMPROVE: 4 single-channel modules (Eldred et al., 1990) 

– Module A has a 2.5μm AIHL cyclone followed by a filter cartridge for up to four 25mm Teflon filter cassettes – Module B has a sodium carbonate denuder (Ashbaugh et al., 2004) followed by a 2.5μm AIHL cyclone with a filter ca

to four 25mm or 37mm Nylon filter cassettes 

– Module C has a 2.5μm AIHL cyclone followed by a filter cartridge for up to four 25mm quartz-fiber filter cassettes fo

May 2007, the modified IMPROVE Module C, URG 3000N (URG Corp; Chapel Hill, NC) is placed in STN/CSN us

– Module D has a PM10 inlet followed by a filter cartridge for up to four 25 mm quartz-fiber filter cassettes 

– Flow rate through each channel is 22.7 L/min 

 Andersen Reference Ambient Air Sampler (RAAS; Andersen [now Thermo Scientific] Model 25-400; Franklin, MA) (Watson an

channels; each channel has a 2.5μm AIHL cyclone; all filters are 47mm in diameter 

– Ch1 has a single quartz-fiber filter and samples at 7.3 L/min – Ch2 has a single Teflon-membrane filter and samples at 16.7 L/min – Ch3 is currently empty, but could be used for replicates at a flow of 16.7 L/min 
2-12

Table 2-1. Continued 

– Ch4 has a magnesium oxide denuder followed by a single Nylon filter and samples at a flow rate of 7.3 L/min 

 Met One Spiral Aerosol Speciation Sampler (SASS; Met One Model ; Grants Pass, OR) (NAREL, 2001): 5 channels (Super SAS

channels); each channel has a 2.5μm sharp cut cyclone; all filters are 47 mm in diameter 

– Ch1 and Ch 2 each can have a single Teflon-membrane filter – Ch3 has a magnesium oxide coated aluminum (Al) honeycomb denuder followed by a single Nylon-membrane filter 

– Ch4 has a single quartz-fiber filter – Ch5 is empty, can be used to acquire field blanks, but could also have a honeycomb denuder and up to two tandem filt

– The flow rate through each channel is 6.7 L/min 

 URG MASS (Chapel Hill, NC): 2 single-channel modules; all filters are 47 mm in diameter 

– Module A (Model 400 WINS) has a 10μm size-selective inlet followed by a magnesium oxide denuder and then a two

/Nylon-membrane) 

– Module B (Model 450 WINS) has a 10μm size selective inlet followed by a 2.5μm WINS impactor and then a quartz-

– The flow rate through each channel is 16.7 L/min 

 R&P 2300 (Rupprecht & Patashnick [now Thermo Scientific] Model 2300; East Greenbush, NY) (Solomon et al., 2003): 4 chann

that has up to 12 channels configured as a sequential sampler); each channel has a 2.5μm size selective impactor; all filters are 47 

– Ch1 has a single Teflon-membrane filter and samples at 16.7 L/min – Ch2 has a single Teflon-membrane filter and samples at 16.7 L/min – Ch3 has a single quartz-fiber filter (with an optional back-up quartz-fiber filter) and samples at 10 L/min 

– Ch4 has a sodium carbonate honeycomb denuder followed by a Nylon filter and samples at 10 L/min – Currently used at ~12 supplemental speciation sites 

 R&P 2025 (Rupprecht & Patashnick [now Thermo Scientific] Model 2025; Franklin, MA) (Tanner et al., 2005): 2 channels; each 

2025 sequential PM2.5 Federal reference method (FRM) sampler; all filters are 47 mm in diameter 

– Ch1 is for Teflon-membrane filters 

– Ch2 is for quartz-fiber filters – Each channel can take up to 16 filters loaded into a spun fiberglass magazine – The flow rate through each channel is 16.7 L/min 

– Currently used at ~9 supplemental speciation sites in Texas – QBQ is an option 

 Particle Composition Monitor (PCM3) (Edgerton et al., 2005): 3 channels; the flow rate through each channel is 16.7 L/min 

– Ch1 has a sodium carbonate denuder followed by a citric acid denuder and then has four three-stage 47mm filter pack

membrane/Nylon-membrane/Citric Acid coated glass-fiber) 

– Ch2 has a sodium carbonate denuder followed by a citric acid denuder and then has four single-stage 47mm filter pack– Ch3 has a 10μm inlet cyclone followed by a 2.5μm WINS impactor and then a single two-stage 37mm filter pack (QB

b AIHL: Air and Industrial Hygiene Laboratory cyclone (John and Reischl, 1980) 

 WINS: Well Impactor Ninety-Six (Peters et al., 2001a; Peters et al., 2001b; Vanderpool et al., 2001a; Vanderpool et al., 2001b; Va SCC: Sharp-Cut Cyclone (Kenny and Gussman, 2000; Kenny et al., 2000)  VSCC: Very Sharp-Cut Cyclone (Kenny et al., 2004) 

c Al: aluminum d Daily at the urban North Birmingham, AL (BHM) and Jefferson Street, Atlanta, GA (JST) sites 
2-13

Table 2-1. Continued e Based on the assumption of once per week site visits f Field blanks usually in samplers for 1-15 minutes, but in some cases for as long as 5-7 days g Field blank is in inlet and outlet magazines for as long as 5-7 days depending on the sampling frequency, but is in sampling positi

drawn through it) for only a few seconds. 

h Quartz-fiber front filter i Quartz-fiber backup filter behind quartz-fiber front filter j RTI was 11.76 cm2 for quartz and 11.70 cm2 exposed area for STN/CSN k DRI uses 11.78 cm2 for quartz-fiber and Teflon-membrane exposed area for Texas’ non-trends STN/CSN. l Pallflex® Tissuquartz, Ann Arbor, MI m Whatman QMA, Clifton, NJ n 2% acceptance blanks and ~3% as daily instrument blanks 
2-14

Table 2-2. Summary of filter handling procedures for different long-term networks.

 IMPROVE STN/CSN SEARCH 

Filter Size and Type 25mm, Pall 47mm,Whatman QMA 

 37mm, Pall 

Filter Procurement 1,000 per box Varies by project 

1,000 per box 

Filter Pre-firing 100% of filters prefired at 

900°C for minimum of 4 

hours 

100% of filters prefired at 

900°C for minimum of 3 

hours 

100% of filters prefired at 

900°C for minimum of 4 

hours 

 

Filter Acceptance Testing 

 2% 2% 2% 

Filter Acceptance Limits TC ≤2.0 μg/cm2 

OC ≤1.5 μg/cm2 

EC ≤0.5 μg/cm2 

 TC ≤1.0 μg/cm2 TC ≤2.0 μg/cm2 

OC ≤1.5 μg/cm2 

EC ≤0.5 μg/cm2 

Pre-shipping Storage ≤ 4°C ≤ -15°C ≤ 4°C 

Shipping Schedule to the 

field 

Approx. 1,500 per month Project specific Approx. 50-100 per 

month or as needed 

 

Shipping Method/Temp 

to Field 

Vacuum Sealed in FedEx 

Box, FedEx Standard 

Overnight/Ambient (20°C) 

 

Resealable plastic bag, 

FedEx Overnight, Cold 

Vacuum Sealed in FedEx 

Box, FedEx 2-3 day/Ambient 

(20°C) 

Shipping Schedule from 

the field 

 

2,000 per month Unknown 275-300 per month 

Shipping Method/Temp 

from field 

 

 Cold (≤ 4°C) Cold (≤ 4°C) Cold (≤ 4°C) 

Passive Deposition 

Period 

 

~every 7 days (once per 

week) 

Varies (~1-15 minutes) with 

exceptions (~5-7 days)a

Varies (~1-15 minutes) 

Special Handling N/A N/A Samples returned 

wrapped in aluminum 

foil in Petri Dishes 

 

Long-Term Storage 

Temperature 

 

≤ 4°C ≤ -15°C ≤ 4°C 

Long-Term Storage 

Period 

DRI - Indefinitely RTI - Up to 5.5 years DRI – Indefinitely 

a

 For the CSN R&P 2025 sequential Federal reference method (FRM) sampler with magazine filter holders used 

for the Texas non-trend sites and with R&P 2300 speciation sampler in New York 
2-15

Table 2-3. Collocated PM2.5 speciation data for the IMPROVE network and STN/CSN. 

IMPROVE STN/CSN SAMPLER 

IMPROVE Anderson MetOne 

Type Site Name Inclusive Period 

Number of 

Samples Module IMPROVE Data Source 

# of Field Blanks RAAS SASS 

URG MASS 

R&P 2025 sequential FRM 

STD

Special Study 

Puget Sound (PUSO), Seattle (Beacon Hill), WA 10/16/2001-12/29/2003 224 X 8 X Mount Rainier NP (MORA), WA 10/16/2001-11/1/2002 69 X 6 X Phoenix (PHOE), AZ 10/16/2001-12/29/2003 201 X 6 X Tonto National Monument (TONT), AZ 10/16/2001-12/29/2003 181 X 8 X Washington D.C. (WASH) 10/16/2001-12/29/2003 206 X 5 X Dolly Sods Wilderness (DOSO), WA 10/16/2001-12/29/2003 140 X 

Non-processed carbon data from DRI 

database (μg/filter) 

Blank subtracted data from U.C. 

Davis 

5 X 

d

c

D

Total 1021 38 

Complete 

IMPROVE 

Fresno (FRES), + STN CA 1/1/2005-7/31/2006a 146 X 4 X 

Long-term Sites 

Big Bend NP (BIBE), TX 1/4/2005-12/30/2005a 26 X 

Non-processed carbon data from DRI 

database (μg/filter) 

Blank subtracted data from VIEWSb 

databases (μg/m3) 

3 X 

Total 172 

a For carbon comparison, two complete years of data were used for the Fresno, CA and Big Bend National Park, TX, sites, whic

samples, and 23 and 26 field blanks, respectively 

b AIRS and AQS: http://www.epa.gov/ttn/airs/airsaqs/ c VIEWS: http://vista.cira.colostate.edu/views/ 
2-16

Table 2-4. Examples of organic carbon (OC) database differences among air quality networks. 

Data 

Source Description 

Organic 

Carbon Code 

Observable 

Description Clarification 

DRI DRI uses a four letter code to 

represent an observable. The first 

two letters consist of a code for the 

species measured, the third letter 

represents the analysis method, and 

the fourth indicates concentrations 

or uncertainties of the value. 

OCTC Organic Carbon by 

TOR (μg/filter or 

μg/m3

, depending 

on it being in the 

processed or 

unprocessed data 

file. 

The observable name does 

not indicate the thermal 

method used, although this 

is implied by the network. 

The size fraction is 

indicated in another field 

after the data have been 

processed. 

VIEWS VIEWS uses codes that indicate 

the species measured and the 

sampled size fraction. More details 

about the parameter are given in 

the code descriptions. 

OCf Total organic 

carbon. (Units 

μg/m3

 LC) where 

LC refers to sample 

volumes at local 

conditions 

(temperature and 

pressure). 

Observable names do not 

indicate the thermal 

method used, although this 

is implied by the network. 

AIRS STN/CSN uses numerical codes to 

indicate the analysis method, the 

observable, and the unit. Typically, 

the code is specific to a fraction 

and an analyte, while the method 

specifies the sampler used and the 

instrument used for analysis. 

88305 (STN) or 

88324 

(IMPROVE) 

Organic carbon by 

STN_TOT or 

IMPROVE_A_TOR 

methods. 

Parameter codes change 

when a sampler or 

measurement method is 

changed, requiring much 

manual editing to reconcile 

measurements for 

comparisons. 
2-17

Table 2-5. Tests for diesel and levoglucosan-doping experiments. 

 Levoglucosan No. of samples 

Test 

Matrix 

ID 

Sample 

Description 

Generator 

Load 

Dilution 

Ratio 

Resuspended 

(μg/cm2

) 

Liquid 

(μgC/cm2) 

QFa

 QBQb

I Diesel exhaust QF 4 kW 70:1 N/A N/A 8 6 

II Diesel exhaust QF 

plus resuspended solid 

levoglucosan 

4 kW 70:1 76 N/A 6 0 

III Blank filter plus 

resuspended solid 

levoglucosan 

N/A N/A 5 and 11c

 N/A 6 0 

IV Diesel exhaust QF 

plus liquid spiked 

levoglucosan 

4 kW 70:1 N/A 22.9 6 N/A 

V Blank filter plus liquid 

spiked levoglucosan 

N/A N/A N/A 9.6, 19.2, 

22.9, 38.3d

 24 N/A 

a

 QF: Quartz-fiber front filter 

b

 QBQ: Quartz-fiber filter behind quartz-fiber front filter 

c

 Low and high concentrations 

d

 Low, medium and high concentrations 
2-18

Table 2-6. Comparison of the IMPROVE, IMPROVE_A, and STN/CSN thermal/optical carbon 

analysis protocols.

Methods' 

Carrier 

Gas 

Carbon 

Fraction 

IMP_TOR/TOTa

Temperature, Time 

IMPROVE_A_TOR/TOTa

Temperature, Time 

STN_TOT/TORa

Temperature, Time 

He-Purge 30 °C, 90 s 30 °C, 90 s 30 °C, 90 s 

He-1 OC1 120 °C, 150-580 sc

 140 °C, 150-580 sc 310 °C, 60 s 

He-2 OC2 250 °C, 150-580 s 280 °C, 150-580 s 480 °C, 60 s 

He-3 OC3 450 °C, 150-580 s 480 °C, 150-580 s 615 °C, 60 s 

He-4 OC4 550 °C, 150-580 s 580 °C, 150-580 s 900 °C, 90 s 

He-5 - - Cool Oven 

O2/He-1b EC1 550 °C, 150-580 s 580 °C, 150-580 s 600 °C, 45 s 

O2/He-2 EC2 700 °C, 150-580 s 740 °C, 150-580 s 675 °C, 45 s 

O2/He-3 EC3 800 °C, 150-580 s 840 °C, 150-580 s 750 °C, 45 s 

O2/He-4 EC4 - 825 °C, 45 s 

O2/He-5 EC5 - 920 °C, 120 s 

 

a IMPROVE_TOR or IMPROVE_A_TOR Thermal/optical reflectance analysis following the IMPROVE

(Interagency Monitoring of Protected Visual Environments) protocol using DRI/OGC 

analyzers (Desert Research Institute, Reno, NV). IMPROVE_TOR does not advance 

from one temperature to the next until a well-defined carbon peak has evolved (Chow et 

al., 1993, 2001, 2004a). Filter reflectance is monitored throughout the analysis; pyrolyzed 

OC (OP) is defined as the carbon evolving between the introduction of oxygen (O2) in the 

helium (He) atmosphere and the return of reflectance to its initial value (the OC/EC 

split). OP is reported as a positive value if the OC/EC split occurs after the introduction 

of O2, and as a negative value if the OC/EC split occurs before O2 is introduced. In either 

case, OC equals OC1+OC2+OC3+OC4+OP and EC equals EC1+EC2+EC3-OP. Eight 

well-defined fractions of carbon, including four OC fractions (OC1, OC2, OC3, and 

OC4), three EC fractions (EC1, EC2, and EC3), and OP are reported as part of the 

IMPROVE_TOR protocol. 

 IMPROVE_TOR/TOT or IMPROVE_A_TOR/TOT Same as the IMPROVE_TOR protocol but using a 

DRI Model 2001 thermal/optical carbon analyzer (Atmoslytic, Calabasas, CA). The DRI 

Model 2001 performs charring correction through both reflectance and transmittance and 

reports as OPR and OPT, respectively. Subsequently, OC and EC calculated from OPR 

(OPT) are referred to as OCR and ECR (OCT and ECT), respectively (Chow et al., 

2005b; Chow et al., 2007a). 

 STN_TOR/TOT ............Thermal/optical transmission/reflectance analysis following the Speciation Trends 

Network (STN) protocol. Filter transmittance is monitored to split OC and EC 

(STN_TOT). With the DRI Model 2001 thermal/optical carbon analyzer (Atmoslytic, 

Calabasas, CA), reflectance can also be recorded during the STN/CSN analyses. The 

protocol that uses STN/CSN temperature plateaus but reflectance split is referred to as 

STN_TOR. The STN/CSN protocol has a short and fixed residence time per temperature 

plateau and cannot report distinguishable carbon fractions. The STN/CSN protocol is 

currently applied to the United States PM2.5 Speciation Trends Network. 

b

 2% O2 in He. c

 The residence time at each temperature in the IMPROVE protocol depends on when the flame ionization detector 

(FID) signal returns to the baseline to achieve well-defined carbon fractions.
3-1

3. RESULTS 

3.1. Comparison of Field Blank Levels among the IMPROVE, STN/CSN, and SEARCH 

Networks 

Average field blanks levels for OC, EC, and thermal carbon fractions from the 

IMPROVE, STN/CSN, and SEARCH networks for 1/1/2005 through 12/31/2006 are compared 

in Table 3-1. The first columns express the concentration density in μg/cm2

, thereby allowing the 

levels to be compared among the different filter sizes. The second set of columns (μg/filter) 

extends this to the area or the particle deposit on the front filter; this is the value that would be 

subtracted for blank correction. The third set of columns (μg/m3

) normalizes this to the nominal 

sample volumes acquired over 24-hours in each network and approximates the bias that would be 

encountered in the absence of a blank subtraction. EC values are at or near precision levels, 

indicating that passive PM deposition is negligible. As a result, OC and TC are nearly the same 

and can be used interchangeably. Tables 3-2 to 3-4 break down these network-wide data by 

sampling location. These tables should be useful to examine the extent to which there are large 

deviations from the mean, but the small number of samples at each site does not represent the 

true distribution of blank levels over the two-year sampling period. 

Ambient-equivalent field blank TC concentrations are comparable for the IMPROVE 

(0.26 ± 0.05 μg/m3) and SEARCH (0.24 ± 0.18 μg/m3) networks, but four times higher for the 

STN/CSN network (1.03 ± 0.21 μg/m3). Part of the reason for the large STN/CSN field blank 

concentrations (in μg/m3) is the relatively low flow rate for the most commonly used Met-One 

SASS monitors (6.7 L/min) and the larger exposed area of the filter deposit (11.76 cm2

 vs. 3.53 

cm2 for IMPROVE and 7.12 cm2 for SEARCH). 

The areal concentration densities tell a different story; IMPROVE TC densities are 2.5 to 

3 times those of the other networks (2.41 ± 0.48 μg/cm2

 for IMPROVE vs. 0.97 ± 0.27 μg/cm2

for STN/CSN and 0.81 ± 0.61 μg/cm2

 for SEARCH). This probably reflects the longer time that 

the IMPROVE filters spend uncapped in the sampling system as opposed to a short period for the 

other field blanks (See Table 2-2). This suggests that the STN/CSN and SEARCH field blanks 

underestimate OC artifacts. Earlier studies in urban Los Angeles, CA, and Pittsburgh, PA, 

suggested a minimum exposure time for VOC absorption of several hours (Turpin et al., 1994; 

Subramanian et al., 2004), so these field blanks may reach the saturation for VOC absorption in 

the IMPROVE network, but not in the STN/CSN or SEARCH networks. 
3-2

As noted above, OC concentration densities are equivalent to those for TC, at 2.36 ± 0.45 

μg/cm2 for IMPROVE, 0.95 ± 0.25 μg/cm2 for STN/CSN, and 0.76 ± 0.57 μg/cm2 for SEARCH. 

This is consistent with the OC concentration distribution among the sites shown in Figure 3-1, 

where the majority of the OC is in the range of 2 – 2.5 μg/cm2

 for IMPROVE, 0.5 – 1 μg/cm2 for 

STN/CSN, and < 0.5 μg/cm2 for SEARCH. For the Pallflex® Tissuquartz filters and carbon 

analysis protocol (IMPROVE_A), OC on the field blanks in the IMPROVE and SEARCH 

networks is evenly distributed among OC1, OC2, and OC3. The difference in field blank OC 

levels is consistent with the passive deposition period. 

Table 3-5 shows that average field blank OC concentration densities vary among sampler 

types by a factor of two or more, from 0.74 ± 0.66 μg/cm2

 (URG MASS) to 1.49 ± 0.8 μg/cm2

(R&P 2025 FRM). Since over 70% of the sampling sites in STN/CSN are equipped with a Met 

One SASS, the weighted average OC (0.95 ± 0.25 μg/cm2

) in Table 3-1 best represents the 

network as a whole, but the bias for non-SASS samplers is better estimated by the values in 

Table 3-5, with the sampler at a specific site determined from Table 3-3. The all-site average in 

Table 3-3 differs from the non-weighted average in Table 3-5 for this reason. The difference 

between the two averages is ~10%, owing to the dominance of the SASS samplers in STN/CSN. 

Table 3-5 shows that the two R&P samplers (R&P 2300 and R&P 2025 sequential FRM) 

reported the highest field blank OC (1.3 – 1.5 μg/cm2). The passive deposition period for the 

R&P 2300 is variable, in the range of minutes to seven days. More detailed records of field 

blank exposure periods would facilitate an evaluation of the effects of this period on the field 

blank levels. 

3.2. Comparison between STN/CSN Field and Trip Blanks 

Table 3-6 compares field and trip blanks among the five STN/CSN speciation samplers. 

There were 3,628 field blanks and 2,335 trip blanks acquired in STN/CSN during 2005 and 2006. 

These samples were submitted for carbon analysis of OC and EC following the STN/CSN 

thermal/optical transmittance (TOT) protocol (Peterson and Richards, 2002; Flanagan et al., 

2002). The average concentration densities of field and trip blanks by sampler type are similar, 

agreeing within ±0.05 μg/cm2

. OC averages across the five PM2.5 speciation sampler types are 

1.05 ± 0.32 and 0.95 ± 0.23 μg/cm2

 for field and trip blanks, respectively. Trip blank OC 

densities range from 0.80 ± 0.69 μg/cm2

 for the URG MASS to 1.30 ± 0.48 μg/cm2 for the R&P 
3-3

2300, similar to concentration densities found in field blanks (0.74 ± 0.66 to 1.30 ± 0.51 μg/cm2

for the URG MASS and R&P 2300, respectively). 

Operators for the majority of the STN/CSN sites leave the field blank cartridges in place 

for a period of 1 to 15 minutes (information obtained from telephone surveys of field operators), 

which is similar to the field blank passive deposition times in the SEARCH network. Some 

operators in NY leave the field blank cartridge in channel five of the Met One SASS for a period 

of 5 to 7 days, but this is not done consistently throughout the state. Trip blanks are not exposed 

to ambient air and are expected to have much lower concentrations, similar to those found in 

laboratory blanks (typically 0.15 ± 0.15 μg/cm2

). The similarity of the STN/CSN field and trip 

blanks indicates that the passive exposure period for the field blanks is probably too short to 

represent the organic vapors absorbed by the sample. This would probably be the case for the 

SEARCH network if it also used trip blanks. 

3.3. Quartz-Fiber Backup Filters from the IMPROVE and SEARCH Networks 

Comparing the organic artifact among different sampling configurations with and without 

preceding organic denuders, Huebert and Charlson (2000) concluded that the positive organic 

artifact is in the range of 30 – 50%, and that negative organic artifacts could be on the order of 

50% of the actual ambient OC levels. If the SEARCH denuder is 100% efficient in removing 

VOCs and gSVOCs from the sampled air, the increment on the backup filter over the field blank 

level should consist of recaptured SVOC that evaporated from particles on the front filter. This 

increment would represent a negative OC artifact. 

Table 3-7 compares the IMPROVE and SEARCH OC backup filter levels, based on the 

quartz-fiber filter behind quartz-fiber front filter (QBQ), for the period from 2005 – 2006. 

Average OC concentration density is 3.1 ± 0.8 μg/cm2

 for IMPROVE and 1.2 ± 0.52 μg/cm2 for 

SEARCH, 30 and 60% higher than the corresponding field blank levels reported in Table 3-1. 

With the denuded SEARCH PCM3 sampler, the average backup quartz OC level is 0.43 ± 0.97 

μg/cm2

 higher than the field blank. While this might be interpreted as a negative artifact that 

should be added to the OC, it could also be interpreted as a better representation as the true field 

blank, since it spent more passive time in the sampler than the intended field blank. The 

variability is also large. The distributions of carbon fractions (OC1 to OC4) on these QBQ are 

quite similar: 18, 31, 37, and 10% for IMPROVE and 22, 29, 39, and 6% for SEARCH. The 

denuder does result in a lower concentration density on the backup filter, and probably 
3-4

minimizes the positive OC bias on the front filter deposit, but it cannot be entirely attributed to 

negative sampling artifact owing to passive deposition. 

Since IMPROVE uses 25 mm quartz-fiber filters at a high flow rate (22.7 L/min) and 

SEARCH uses 37 mm filters at a lower flow rate (16.7 L/min), Table 3-7 shows that the ambient 

artifact OC concentrations are similar: 0.33 ± 0.10 μg/m3 for IMPROVE and 0.35 ± 0.15 μg/m3

for SEARCH. These levels are 30 – 50% higher than the field blank concentrations of 0.26 ± 

0.05 and 0.23 ± 0.17 μg/m3 for IMPROVE and SEARCH, respectively, but ~65% lower than the 

1.01 ± 0.21 μg/m3

 found in the STN/CSN sites. 

3.4. Seasonal Variations of Blanks and Backup Filter OC Concentration Density 

Tables 3-8 through 3-10 summarize the number of field blanks acquired for each season 

among the IMPROVE, STN/CSN, and SEARCH networks. The number of field blanks for each 

season at a site range from zero to six for IMPROVE, zero to 16 for STN/CSN, and one to seven 

for SEARCH. Average OC levels by season are examined in Figure 3-2. Seasonal variations are 

most apparent for the IMPROVE network, with average field blank OC concentrations varying 

by over 40% between winter (1.97 μg/cm2) and summer (2.92 μg/cm2). There are no apparent 

changes in the abundances of the carbon fractions among the four seasons. 

Seasonal variability is small for STN/CSN and SEARCH field and trip blanks, again 

probably due to their short passive exposure periods. Seasonal OC spans are 0.8 – 1.1 μg/cm2

for STN/CSN and 0.52 – 1.0 μg/cm2 for SEARCH. It is not clear why SEARCH sites shows 

such high levels during fall. 

Seasonal variations of QBQ OC fractions for the six IMPROVE and eight SEARCH sites 

are presented in Figure 3-3. They follow the same pattern as those of the IMPROVE field blanks 

(Figure 3-2) with a summer high and winter low. 

Field blank OC and TC levels do not differ between urban and non-urban locations 

within any of the networks, as shown in Figure 3-4. For the SEARCH sites, average field blank 

OC concentrations are similar between the five urban (0.64 ± 0.74 μg/cm2) and three non-urban 

(0.88 ± 0.91 μg/cm2) sites. Similar urban vs. rural field blank OC levels were found at the 

IMPROVE sites (2.4 ± 0.67 vs. 2.3 ± 0.75 μg/cm2

). 

Backup filters are compared in Figure 3-5 for urban and non-urban locations. In this case, 

only the SEARCH samples had urban backup filters, and these were preceded by the carbon 

denuder. Average OC on the QBQ was ~20% higher at the urban (1.46 ± 1.47 μg/cm2

) than non-
3-5

urban (1.20 ± 0.9 μg/cm2) SEARCH sites, consistent with the sampled urban particles having a 

larger SVOC component than the non-urban particles. Table 3-11 shows that the urban 

increment is only found on the low temperature carbon fractions (OC1 at 140 °C and OC2 at 

280 °C). The urban increment is ~75% OC1 (0.46 ± 0.80 vs. 0.26 ±0.38 μg/cm2) and ~20% for 

OC2 (0.42 ± 0.46 vs. 0.35 ± 0.27 μg/cm2). Average backup filter OC levels from the six nonurban IMPROVE sites (3.1 ± 0.8 μg/cm2

) are 2.5 times higher than the backup filter OC from the 

three non-urban SEARCH sites (1.2 ± 0.9 μg/cm2), again showing the effectiveness of the 

denuder in removing adsorbable VOCs and gSVOCs. 

3.5. Comparison of Blanks between Collocated IMPROVE and STN/CSN 

The IMPROVE/STN comparison study at three urban (Seattle, WA; Phoenix, AZ; and 

Washington, DC) and three rural (Mt. Rainier, WA; Tonto National Monument, AZ; and Dolly 

Sods Wilderness, WV) sites, shown in Figure 2-1, allows for direct comparison of field blanks 

from the two networks. Collocated IMPROVE/STN data are also available at the urban Fresno 

Supersite and non-urban Big Bend National Park site. 

Table 3-12 compares average TC concentrations (uncorrected) and blank levels at these 

sites using five different types of PM2.5 speciation samplers. Time series of blank TC 

concentrations in the two networks are illustrated in Figure 3-6. 

STN/CSN trip blanks are similar between urban-rural paired sites, but they differ among 

samplers, consistent with two-year average blanks in Table 3-6. Trip blank TC densities at the 

Seattle and Mount Rainier sites, using the URG MASS sampler, are 0.53 ± 0.19 and 0.67 ± 0.12 

μg/cm2

, respectively, lower than the 0.84 – 1.12 μg/cm2 found at sites using the Andersen RASS 

or Met One SASS samplers. Field blank TC is consistent with trip blank TC most of the time 

(Figure 3-6), although they were not acquired simultaneously. Occasionally, much higher TC is 

found on field blanks relative to trip blanks at both urban and rural sites, but the limited blank 

dataset does not allow for accurate evaluation of the frequency of occurrence. As discussed in 

Section 3.1, the short passive exposure time (1 – 15 minutes) at most STN/CSN sites for field 

blanks probably minimizes additional vapor adsorption over that experienced by the trip blanks. 

The IMPROVE field blank TC concentration density is two to three times higher than 

STN/CSN field or trip blanks. As discussed in Section 3.1, the IMPROVE field blanks are 

exposed to ambient air for a much longer period (~7 days) and thus have a higher chance of 

saturation. In addition, IMPROVE uses the Pallflex® Tissuquartz while STN/CSN uses QMA 
3-6

filters, and these filters may differ in: 1) capacity and affinity for VOC and gSVOC adsorption 

and desorption, and 2) the rate to reach saturation or equilibrium between gSVOC and particulate 

OC (pOC). 

For IMPROVE Module C field blanks (bQF), TC is most consistent among the four 

urban sites (Seattle, Phoenix, Washington, DC, and Fresno), ranging from 2.40 – 2.66 μg/cm2, 

with lower densities measured at two rural sites: Mount Rainier (1.4 ± 0.4 μg/cm2) and Tonto 

Monument (2.0 ± 1.1 μg/cm2). The variability of STN/CSN field blanks is larger, ranging from 

0.66 ± 0.42 (Mount Rainier using URG MASS) to 1.44 ± 0.48 μg/cm2

 (Big Bend using R&P 

2025 sequential FRM). This supports the hypothesis that longer passive deposition periods result 

in higher field blank levels. There are insufficient blanks to evaluate seasonal variation for 

individual sites. As shown by Chow et al. (2007b), field blank TC is high in summer and low in 

winter throughout the IMPROVE network. 

While the site-averaged non-blank corrected ambient TC concentrations in μg/m3

 among 

the eight collocated IMPROVE/STN sites are similar within ± 30 – 50% (Table 3-11), the siteaveraged ambient TC concentration density is much lower for STN/CSN samples compared to 

IMPROVE samples by a factor of 5 – 11 in terms of μg/cm2

. This is due to a relatively small 

sample volume (e.g., 9.6 m2 for the Met One SASS and 10.5 m2 for the Andersen RAAS) and 

large filter deposit area (11.76 cm2) of the STN/CSN samplers. This suggests that sampling 

artifact is more pronounced for STN/CSN and that blank corrections are needed. In rural areas 

where ambient OC levels are lower than in urban areas, the uncorrected STN/CSN data is 

positively biased. At the Dolly Sod site, the average STN/CSN field blank TC (in μg/cm2

) 

reaches ~49% of front filter TC, but it is only 12% for the collocated IMPROVE samples. The 

actual bias is probably larger, since it appears that the STN/CSN field blanks underestimate OC 

adsorption by the sample filter owing to the short passive exposure period. 

A regression method similar to that of White and Macias (1989) is used to evaluate the 

relative sampling artifact between the collocated IMPROVE and STN/CSN samples. If these 

samples have an equivalent sampling artifact, the regression intercept of uncorrected STN/CSN 

TC (y-axis) against uncorrected IMPROVE TC (x-axis) should be zero. Otherwise, if appropriate 

assumptions are met (Chow et al., 2007c), the intercept indicates the difference between the 

IMPROVE and STN/CSN sampling artifact (net positive and negative sampling artifact). Using 

Phoenix data as an example, Figure 3-7 shows an intercept of 1.75 μg/m3

, meaning a positive 
3-7

STN/CSN carbon sampling artifact of 1.75 μg/m3 or 1.43 μg/cm2 (note: conversion using SASS 

sampling volume and deposit area) relative to IMPROVE sampling artifact. Flipping the x and y 

axis in Figure 3-7 does not change the conclusion. Figure 3-7 also shows that the regression 

intercept and slope may be biased by a few outliers. To mitigate the biases, a robust regression 

method (Dutter and Huber, 1981), which iteratively downweights the outliers, is used. The 

regression was calculated for all data and seasonally segregated data from each site. 

Figure 3-8 shows that the regression intercepts are positive for each season at the eight 

sites. This corroborates a larger STN/CSN TC or OC artifact (relative to the ambient 

concentrations), which has been explained by the lower TC deposit on STN/CSN filters (per 

cm2

). For five of the eight sites, the intercept is largest in summer. It is highest in spring at the 

Mount Rainier and Tonto Monument sites, and highest in fall at the Fresno site. The intercept of 

all data regression appears to represent the average of four seasons. Table 3-13 summarizes the 

intercept, slope, and correlation for the uncorrected IMPROVE/STN pairs at each site. The 

largest two intercepts (μg/cm2

), appear at the Phoenix and Big Bend sites using the Met One 

SASS and R&P 2025 sequential FRM sampler, respectively, while the lowest two appear at the 

Seattle and Mount Rainier sites using the URG MASS samplers. The sampler influences the 

magnitude of the TC/OC artifact. At the Dolly Sod (Andersen RAAS) and Big Bend (R&P 2025 

sequential FRM) sites, the correlation between IMPROVE and STN/CSN TC is low (0.67 – 

0.79) and therefore the regression intercept contains a larger uncertainty. 

If field blank levels adequately compensate for IMPROVE and STN/CSN artifacts, the 

TC would be the same for the collocated blank-corrected ambient concentrations. Based on 

Table 3-13 and the sampling volume/deposit area of each type of sampler (see Table 2-1), the 

relationship between the IMPROVE and STN/CSN sampling artifacts (i.e., IMPart vs. STNart) is 

formulated as follows: 

Seattle, WA: STNart = IMPart × 0.22 + 0.24 (1) 

Mount Rainier, WA: STNart = IMPart × 0.22 + 0.50 (2) 

Phoenix, AZ: STNart = IMPart × 0.088 + 1.34 (3) 

Tonto Monument, AZ: STNart = IMPart × 0.088 + 0.69 (4) 

Washington, DC: STNart = IMPart × 0.096 + 0.85 (5) 

Dolly sod, WV: STNart = IMPart × 0.096 + 0.74 (6) 
3-8

Fresno, CA: STNart = IMPart × 0.088 + 0.90 (8) 

Big Bend NP, TX: STNart = IMPart × 0.22 + 1.29 (7) 

where the sampling artifact and intercept are in μg/cm2

. 

Neither IMPart nor STNart are known. Assuming that the average IMPart is adequately 

estimated by the blank filters, the average STNart can be calculated for each site. Table 3-14 

compares the calculated STNart with their corresponding field blank TC concentrations. At six of 

the eight sites, the STN/CSN field blank TC underestimates the sampling artifact by ~20%, 

except for the Fresno site (34%). At the rural Tonto Monument and Dolly Sod sites, however, the 

STN/CSN field blank TC (μg/cm2

) appears to better represent the STNart. Despite a larger 

relative artifact for STN/CSN samples, the blank corrected STN/CSN TC at the two sites agrees 

with the blank corrected IMPROVE TC. Dolly Sod shows a poor correlation between IMPROVE 

and STN/CSN TC. How these blanks are handled at both IMPROVE and STN/CSN sites also 

warrants further investigation (for example, Figure 3-6 shows two field blanks at the IMPROVE 

Tonto Monument site that have very low TC concentrations: 0.4 and 0.3 μg/cm2

, well below the 

average). 

3.6. Sulfate, Adjusted Nitrate, Derived Water, Inferred Carbonaceous Material 

(SANDWICH) Method 

Teflon-membrane filters are believed to adsorb few organic vapors, and therefore would 

have a minimal positive OC artifact. The SANDWICH method (Frank, 2006) assumes that all of 

the unaccounted PM2.5 mass measured on a Teflon-membrane filter when elements and ions are 

summed can be associated with the carbonaceous component. The SANDWICH method might 

minimize the influence of organic artifacts. The OC or organic carbon mass (OCM) estimated 

from the SANDWICH method can be compared to those measured from quartz-fiber filters using 

different corrections to evaluate other artifact correction methods. 

The SANDWICH method was applied to 716 valid collocated filter pairs taken at four 

urban (i.e., Seattle, WA [PUSO]; Phoenix, AZ [PHOE]; Washington, DC [WASH] and Fresno, 

CA [FRES]) sites from 04/28/2001 to 12/29/2004 (Solomon et al., 2004). The number of sample 

pairs varied from 27 at the Fresno Supersite to 354 at the Seattle site. The total carbonaceous 

mass (TCM) is calculated by subtracting sulfate (SO4

=

), nitrate (NO3

-

), ammonium (NH4

+

), water 

(H2O), and crustal components from the measured PM2.5 mass. The calculated OCM is derived 
3-9

by subtracting measured EC from TCM. The resulting OCM is then compared to measured OC 

with the following equations: 

TCM = PM2.5 – [(SO4

=

) + (Retained NO3

-

) + (NH4

+

) + (H2O) + (Crustal Material) + 

(Blank)] (9) 

OCM = TCM – EC (10) 

where: 

Crustal Material = 3.73 × Si + 1.63 × Ca + 2.42 × Fe + 1.94 × Ti (11) 

Blank = 0.5 μg/m3

 for STN/CSN; 0 for IMPROVE 

IMPROVE data were blank-subtracted using the monthly median OC from the backup 

quartz-fiber filters at six sites, and no additional field blank values were subtracted. Field blanks 

were subtracted from the STN/CSN as part of this analysis. Tables 3-15a and 3-15b summarize 

the average PM2.5 sample and field blank concentrations. Site-to-site variations of average field 

blanks for PM2.5 mass ranged from 0.25 ± 0.32 μg/m3

 at the Washington, DC site to 0.89 ± 1.12 

μg/m3 at the Phoenix site using the three types of STN/CSN samplers. A nominal blank value of 

0.5 μg/m3 for blank subtraction, suggested by Frank (2006), is used for this study, which is 

similar to the 0.66 ± 0.94 μg/m3

 three-site (field blank data for the Fresno site for this period was 

not available) STN/CSN field blank averages for the study period. Retained nitrate was 

calculated as described in Frank (2006) using the daily average temperature and relative 

humidity during the sampling period. Particle bound water was calculated using the Aerosol 

Inorganics Model (AIM) as described by Frank (2006). 

OCM concentrations from the SANDWICH method are compared to measured OC using 

a multiplier that accounts for unmeasured hydrogen, oxygen, and other elements in the organic 

compounds (i.e., White and Roberts, 1977; Turpin and Lim, 2001; El Zanan et al., 2005): 

OCM = X × OC (12) 

where: 

X = unmeasured element multiplier (assumed to be 1.4 for fresh and 1.8 for aged 

aerosol) 

OC = measured particulate organic carbon 

For urban IMPROVE samples, average OCM concentrations calculated by the 

SANDWICH method are 3.99 ± 2.96 μg/m3

, 4.40 ± 3.45 μg/m3, 3.00 ± 3.16 μg/m3, and 6.73 ± 

3.56 μg/m3

 at the Seattle, Phoenix, Washington, DC, and Fresno sites, respectively. Better 

agreement was found for a multiplier of 1.4 rather than 1.8 for all but the Fresno site, which 
3-10

showed better agreement using the multiplier of 1.8. Table 3-16 shows that good agreement for 

the Seattle (95%), Phoenix (100%), and Washington, DC (123%) sites, between measured (OC × 

1.4) and estimated [using Eq. (10)] OCM. Reasonable agreement is found at the Fresno (71%) 

site. 

The STN/CSN samples among different samplers also agree. Using OC × 1.4, the URG 

MASS yields good agreement at the Seattle (90%) site. The Andersen RASS reports reasonable 

agreement at the Washington, DC site (79%). Good agreement is found for the Met One SASS at 

the Phoenix (123%) and Fresno (88%) sites. 

To assess whether low, mid-range, or high concentration samples exhibit differences, 

Table 3-16 compares the 10th, 50th, and 90th percentiles. The percent differences between the 

average and median (50% of total) are similar (within ± 25%) for the sites using IMPROVE 

samples for multipliers of 1.4 or 1.8. At low concentrations (the 10th percentile), overestimates 

were observed at the Washington, DC site (217%) as compared to the median concentration. 

Using STN/CSN samples, the SANDWICH method overestimates OCM by a factor of two at 

low concentrations at the Phoenix, AZ site; but the agreement is reasonable (117%) for high 

concentration samples (90th percentile). 

3.7. Influence of Levoglucosan on OC/EC Split for Carbon by IMPROVE and 

STN/CSN Protocols 

The OC sampling artifact not only biases OC but also the EC measurement through the 

thermal/optical reflectance or transmittance charring correction. A laboratory experiment was 

attempted to evaluate this effect by adding solid and liquid levoglucosan (C6H10O5) to unexposed 

blank filters and diesel soot samples. Levoglucosan, a water-soluble sugar that results from 

oxidation of cellulose (Lakshmanan and Hoelscher, 1970), has a melting point of 170 – 180 °C 

(MSDS), a decomposition temperature of 250 – 400 °C, and is often used as a marker for 

vegetative burning emissions (e.g., Poore, 2002; Mazzoleni et al., 2007). 

Liquid levoglucosan can be added to an exposed filter using a syringe, in which case it 

would be expected to penetrate the depth of the filter. A solution can also be nebulized and dried 

to a solid prior to sampling, thereby residing on the filter surface. Levoglucosan granules can 

also be ground to small sizes, then resuspended and sampled onto the filter surface. The liquid 

penetrating the filter would appear similar to adsorbed organic vapors, whereas the solid surface 

deposit would simulate a sampled aerosol deposit.. 
3-11

3.7.1. Recovery Rate for the Solid and Liquid Levoglucosan Doping Experiment 

Levoglucosan (46%) granules were mixed with silicon dioxide (SiO2; 54%) granules for 

dry resuspension and sampling. SiO2 was added to levoglucosan to de-agglomerate the powder. 

Resuspended dust was sampled on to parallel Teflon membrane filters for weighing and quartz 

filters for carbon analysis. To investigate the homogeneity of the sample deposit, the Teflonmembrane filters were submitted for X-ray Fluorescence (XRF) analysis (Watson et al., 1999) of 

silicon (Si). The Si concentration was converted to SiO2 and used to calculate the expected 

levoglucosan concentration on each filter based on the known levoglucosan/SiO2 ratio in the 

suspension mixture. 

Table 3-17a shows that instead of the target of 46%, the levoglucosan consisted of 44% 

for the diesel plus solid levoglucosan mixture, and only 22 and 29% for the low and high 

concentrations levels on the blank filter samples, respectively. Using the calculated 

levoglucosan as a base, the recovery rate was 17 – 39% for the solid levoglucosan. The 

sampling process appears to be imperfect. 

Table 3-18 shows that for the solid levoglucosan resuspension on the blank samples, the 

OC3 at 480 °C (68 – 76%) was most abundant, followed by OC2 at 280 °C (24 – 25%) using the 

IMPROVE_A protocol. OC3 and OC2 contain the levoglucosan decomposition and melting 

temperatures, respectively. The levoglucosan distribution by the STN/CSN protocol does not 

have a clear pattern, ranging from 21 – 27% in OC1 (310 °C) to 44 – 50% in OC2 (480 °C), and 

to 9 – 16% in OC3 (615 °C) for the low and high loadings. The melting point for SiO2 (1610 °C) 

is higher than the maximum carbon analysis temperate (900 °C). 

Table 3-17b shows the recovery rate for the liquid levoglucosan spiked on blank quartzfiber filters and diesel soot samples. The recovery rate ranged from 93 to 97% for the 

IMPROVE_A protocol and from 87 to 93% for the STN/CSN protocol. While the recovery rate 

for medium level levoglucosan (19.2 - 22.9 μC/cm2

) was ~93 - 94% , it varied for higher levels 

(38.3 μgC/cm2

), with 96% recovery for the IMPROVE_A protocol and 87% for STN/CSN 

protocol. The distribution among carbon fractions on the blank filters for solid and liquid 

levoglucosan is shown in Table 3-18. For the IMPROVE_A protocol, similar distributions were 

found between the solid and liquid levoglucosan on blank filters: the OC3 (480 °C) fraction (68 

– 76% for solid and 33 – 36% for liquid levoglucosan) is the most abundant, followed by the 

OC2 (280°C) fraction (19 – 21%). There is charring for liquid levoglucosan on blank filters, 
3-12

with 26.5 ± 0.5% by transmittance and 22.3 ± 4% by reflectance. After both TOR and TOT 

correction, all levoglucosan on the blank plus liquid levoglucosan was attributed to OC. Using 

the STN/CSN protocol, OC2 (480 °C) accounted for most of the carbon evolved (44 – 50% for 

solid and 28 – 34% for liquid levoglucosan), closely followed by OC4 (900 °C) fraction (6 – 7% 

for solid and 22-31% for liquid levoglucosan). The STN/CSN protocol detected ~16% (by 

transmittance) of pyrolyzed OC in one third of the samples for liquid levoglucosan spiked on 

blank filters, and the remaining samples with negative pyrolysis of -4 to -11%. The 

corresponding negative pyrolysis by reflectance ranged from -7 to -11%. Though on average less 

pyrolysis (< 10%) is found by the STN/CSN protocol, it reported levoglucosan as EC1 (14 ± 

12% by transmission and 3 ± 23% by reflectance). 

This experiment points out that water-soluble organics in liquid form do char and are 

detected by the IMPROVE_A protocol, and the extent of pyrolysis is higher by transmission than 

by reflectance. Charring is not apparent in the STN/CSN protocol, but it can be misinterpreted as 

EC. 

3.7.2. Distribution of Carbon Fractions for Diesel Samples Mixed with Solid and Liquid 

Levoglucosan 

Table 3-19a and 3-19b report average and standard deviation of carbon fractions for the 

solid resuspended and liquid levoglucosan samples, respectively. Average TC carbon from the 

pure diesel soot samples (Table 3-19a) ranged from 192 ± 14.8 to 213.3 ± 22.3 μg/filter with 43 

– 54% of EC in TC. 

Resuspended solid levoglucosan, either mixed with blank filters or diesel samples, 

reported negligible pyrolysis by the IMPROVE_A protocol and negative pyrolysis by the 

STN/CSN protocol. Under high combustion temperature (~900 °C in He atmosphere) by the 

STN/CSN protocol, the decomposition of organic substances may supply the oxygen (O2) in the 

He atmosphere that combusted the char OC or native EC, so the optical signal returned to its 

original value before the O2 was supplied in the atmosphere, resulting in negative pyrolysis 

(Chow et al., 2001). Solid levoglucosan plus diesel is measured as OC by the IMPROVE_A 

protocol, but the STN/CSN protocol appears to redistribute a portion of levoglucosan to hightemperature EC4 (825 °C in 98% He/2% O2 atmosphere). For liquid levoglucosan doping (Table 

3-19b) on blank quartz-fiber filter, pyrolysis was apparent as shown in Figure 3-9. Pyrolyzed OC 

accounts for 5.7 ± 0.3 μg/cm2

 by transmittance and 4.8 ± 1.0 μg/cm2 by reflectance using the 

IMPROVE_A protocol. As liquid levoglucosan is doped on the diesel exhaust sample, pyrolysis 
3-13

became insignificant. Figure 3-10 is consistent with the saturation of optical signals with heavy 

aerosol loading (e.g., Arnott et al., 2005). Liquid doping also appears to mobilize soot particles 

on the filter, thus changing the optical baseline before thermal analysis. The effect of liquidinduced particle migration on charring correction is difficult to evaluate since it could vary from 

time to time and the optical corrections assume homogeneous distribution of materials on the 

sample punch. As shown in Table 3-19b, over 50% of the liquid levoglucosan is evolved in OC1 

(at 140 °C) instead of OC3 on blank plus liquid levoglucosan filters, followed with ~10% by 

OC2 (at 280 °C). OPT and OPR are reported in Table 3-19b with the understanding of 

substantial uncertainty caused by liquid doping. 

While there is no observed pyrolysis in pure diesel samples, Table 3-20 shows that lower 

temperature OC (i.e., OC1 at 140 °C) is most abundant (35.7 ± 8%) in OC, followed by 29.5 ± 

2% in OC2 (at 280 °C) and 25.5 ± 7% in OC3 (at 480 °C), whereas high temperature EC (EC2 at 

740 °C) constitutes most of the EC (80.9 ± 6%) for the IMPROVE_A protocol. The abundant 

OC1 and EC2 in diesel source profiles is consistent with those reported in other studies (e.g., 

Watson et al., 1994) and probably contains unburned liquid fuel. The OC/TC ratio by 

IMPROVE_A_TOR also changed from 0.57 ± 0.12 for diesel to 0.74 ± 0.09 for diesel plus solid 

levoglucosan. The corresponding OC/TC ratios by STN_TOT are 0.56 ± 0.11 for diesel and 0.79 

± 0.09 for diesel plus solid levoglucosan. For diesel plus solid levoglucosan, the majority of the 

OC was found in OC1 (45.3 ± 8%, compared to 35.7 ± 8% in pure diesel), followed by 22 ± 4% 

in OC2 and 24 ± 4% in OC3. Not many changes (± 1-2%) of either EC or fractional abundances 

of EC were observed for the diesel plus solid levoglucosan mixture 

While the IMPROVE_A protocol found abundant OC1 (140 °C) and EC2 (740 °C) in 

diesel samples, the STN/CSN protocol reported similar abundances for low temperature OC 

(OC1; 310 °C) and high temperature EC (EC3; 750 °C). Despite the experimental artifact of 

liquid doping, Table 3-20 shows that the addition of liquid levoglucosan redistributes both OC 

and EC fractions with negative pyrolysis. 

However the methodology is questionable owing to the lack of complete recover, and the 

results should not be considered quantitative until the procedural aspects of the experiment are 

perfected. 
3-14

3.8. Radiative Transfer Modeling for the Diesel/Levoglucosan Experiment 

Chow et al. (2004) indicate that charring within a quartz-fiber front (QF) filter might 

interfere the optical OC/EC split because filter reflectance and transmittance respond differently 

to pyrolyzed carbon (OP) and EC. The OC artifact, which is distributed throughout the filter 

while solid particles are collected on the surface, can change not only OC but also EC 

quantification through the charring correction. Only certain types of OC appear to char during 

thermal analysis. Pure diesel soot shows little charring despite the sampling artifact, and the EC 

fraction in diesel soot is consistently reported by various thermal/optical methods (Watson et al., 

2005; Chow et al., 2006b). It is assumed that solid levoglucosan only deposits on the filter 

surface while liquid levoglucosan solution penetrates into the whole filter. The two approaches 

are expected to produce different charring characteristics, as demonstrated in the previous 

section. 

Diesel soot with liquid levoglucosan is not studied here due to the experimental artifact 

mentioned in the last section. In this experiment, charring is much more pronounced for liquid 

levoglucosan on blank filters, than on diesel samples, where the decrease in filter transmittance, 

but not filter reflectance, is more pronounced. Light absorption by charred material, especially 

when it is imbedded in the filter, is enhanced due to a multiple scattering effects (Subramanian et 

al., 2006; Chow et al., 2004). 

The distribution of light-absorbing material, including OP and EC, can be studied with 

radiative transfer equations (RTE). Chen et al. (2004) and Petzold and Schönlinner (2004) 

demonstrate a two-stream model. Chen et al. (2004) used a single parameter, penetration depth 

(de), to describe the particle distribution; de could range from zero (monolayer deposit atop the 

filter) to infinity (uniform deposit throughout the filter). For ambient samples de is consistent 

with a specific sampling configuration but varies between 0.014 and 0.38 for different 

configurations. For OP that forms during thermal analysis, de is much larger, at 6 – 8. Petzold 

and Schönlinner (2004) used a two-layer scheme: the uppermost “aerosol-filter” layer (noted by 

“L”) that occupies 10–50% of the filter thickness and the remaining particle-free (but could have 

OP) filter matrix (noted by “M”). The whole filter is referred to as “F”. The light transmitted 

through the aerosol-filter layer, TL, is divided into two parts, the penetration (PL) and forward 

scattered (FL) light. Light back scattered by the two layers is noted as RL and RM, respectively. 
3-15

As the incident radiation strikes the aerosol-filter layer, it is treated as collimated 

illumination. Diffuse illumination can be assumed for light propagating inside the filter. Petzold 

and Schönlinner (2004) use the radiative transfer scheme developed by Hänel (1987): 

M

L

ML

LL

L

F

F

R

R

RR

FP T

R

R

+ −

+ = *

*

)0( 1 (15) 

ML

LL

F

F

RR

FP

T

T

)0( * 1−

+ =

 (16) 

where: 

RF: Reflected light through the whole filter (F) 

RL: Backscattered light from the aerosol filter or top half of the filter layer (L) 

RM: Backscattered light from the bottom half (or particle-free) of the filter layer (M) 

TF: Transmitted light through the whole filter (F) 

TL: Transmitted light through the aerosol filter layer 

PL: Penetration light 

FL: Forward scattered light through the whole filter *

: values derived from diffuse illumination 

Eqs. (15) and (16) are used to relate PL to measurable quantities, i.e., the reflected 

( RF / )0( RF ) and transmitted (TF / )0( TF ) light intensities where )0( RF and )0( TF are the reflectance and 

transmittance of a reference (blank) filter. The superscript *

 in Eqs. (15) and (16) indicates values 

derived from diffuse illumination. Details on the calculations of FL, RL, RL

*

, RM, and TL

*

 from 

particle absorption and distribution within the filter can be found in Petzold and Schönlinner 

(2004). With measured RF / )0( RF and TF / )0( TF ratios plus predefined fractions of L and M layer 

(i.e, the thickness of L layer relative to the whole filter, a measure of particle penetration 

thickness) and scattering asymmetric g-factor (i.e., the ratio of forward to total particle light 

scattering), Eqs. (15) and (16) can be solved numerically to quantify particle light absorption and 

single scattering albedo. 

Figure 3-11 illustrates the scatter of measured RF / )0( RF versus TF / )0( TF for the pure diesel 

and blank with liquid levoglucosan samples during the IMPROVE_A analysis as well as their 

best fit with the Petzold and Schönlinner (2004) two-stream model. For this study a g-factor of 

0.75 is used, leaving the fraction of L layer as the fitting parameter. In the first trial, the layer M

is assumed to be pristine so the layer L represents the averaged effect of OP and EC (if any). 

The pure diesel filter is best fitted with a L fraction of 0.125 (~13%), i.e., particles reside 

on the top 13% of the filter. The good fit indicates that light-absorbing material remains on the L
3-16

layer throughout the charring and oxidation process. For the diesel soot/solid levoglucosan 

mixture this pattern persists. Some char is formed according to the decrease of filter 

transmittance but mostly on the aerosol layer. For liquid levoglucosan on a blank filter, however, 

the slope of T/R is much larger, implying light-absorbing material within the filter. This is 

supported by the substantial decrease of filter transmittance (Figure 3-9b). In fact, the charring 

and oxidation is best fit with a L fraction of ~50%. Liquid doping apparently penetrates deep into 

the filter. The optical modeling for diesel and liquid levoglucosan mixture is not discussed until 

the problem of particle migration due to spiking is overcome in future experimental designs. 

The radiative transfer model qualitatively explains the observations and is consistent with 

the conceptual model. Since the diesel/liquid levoglucosan mixture likely produces within-filter 

char, EC measurements from this type of samples are expected to be more affected. This is 

evidence that within-filter char could be mistaken as EC when native EC concentrations are low. 
3-17

0

10

20

30

40

50

60

70

80

90

100

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Average Organic Carbon Field Blank Concentration

(μg/cm2

)

Number of Sites

(a) 

0

20

40

60

80

100

120

140

160

180

200

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Average Organic Carbon Field Blank Concentration

(μg/cm2

)

Number of Sites

(b) 

0

1

2

3

4

5

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

Average Organic Carbon Field Blank Concentration

(μg/cm2

)

Number of Sites

(c) 

Figure 3-1. Field blank organic carbon (OC) concentration density (μg/cm2) for: a) 181 

IMPROVE sites, b) 239 STN/CSN sites, and c) eight SEARCH sites for the period from 

1/1/2005 through 12/31/2006 (each bar represents the concentration sector less than or equal to 

the assigned value).
3-18

0.00.51.01.52.02.53.03.54.0

Spring Summer Fall Winter

 Carbon μg/cm

2

OPOC4OC3OC2OC1

(a) 

0.00.51.01.52.02.53.03.54.0

Spring Summer Fall 

Carbon μg/cm

2

(b) 

-0.5

0.00.51.01.52.02.53.03.54.0

Spring Summer Fall Winter

 Carbon μg/cm

2

OPOC4OC3OC2OC1

(c) 

0.00.51.01.52.02.53.03.54.0

Spring Summer Fall 

Carbon μg/cm

2

(d) 

Figure 3-2. Seasonal variations of blanks among: a) IMPROVE, b) SEARCH, c) STN/CSN field blanks, and d) 
3-19

0

0.5

1

1.5

2

2.5

3

3.5

4

Spring Summer Fall Winter

Carbon (μg/cm2

)

OPR

OC4

OC3

OC2

OC1

(a) 

0

0.5

1

1.5

2

2.5

3

3.5

4

Spring Summer Fall Winter

Carbon (μg/cm2

)

OPR

OC4

OC3

OC2

OC1

(b) 

Figure 3-3. Seasonal variations of average blank quartz-fiber backup (QBQ) filter organic 

carbon (OC) concentrations for the: a) six IMPROVE sites, and b) eight SEARCH sites. 
3-20

0.0

0.5

1.0

1.5

2.0

2.5

3.0

TC OC EC OC1 OC2 OC3 OC4 EC1 EC2 EC3

Carbon Fractions

Concentration (μg/cm2

)

IMPROVE Urban

IMPROVE Rural

STN/CSN Urban

SEARCH Non-Urban

SEARCH Urban

Figure 3-4. Comparison of field blank carbon concentrations between the urban, non-urban, and 

rural sites among the IMPROVE, STN/CSN, and SEARCH networks. There are 13 urban and 

168 rural IMPROVE sites, 239 STN/CSN urban sites, and five urban and three non-urban 

SEARCH sites; see Table 3-8 for the urban IMPROVE site names); the IMPROVE_A_TOR 

protocol is used for the IMPROVE and SEARCH networks, the STN_TOT protocol is used for 

STN/CSN. See Table 2-6 for carbon fraction temperatures. 
3-21

0

0.5

1

1.5

2

2.5

3

3.5

TC OC EC OC1 OC2 OC3 OC4 EC1 EC2 EC3

Species

Concentration (μg/cm2

)

IMPROVE

SEARCH Urban

SEARCH Nonurban

Figure 3-5. Comparison of quartz-fiber backup filter carbon fractions between the urban, nonurban, and rural sites in the IMPROVE and SEARCH networks. (See Figures 2-1 and 2-3 for the 

181 IMPROVE and eight SEARCH sites. Carbon fractions follow the IMPROVE_A_TOR 

protocol. 
3-22

PUSO1

0

1

2

3

4

10/16/2001 1/16/2002 4/16/2002 7/16/2002 10/16/2002 1/16/2003 4/16/2003 7/16/2003 10/16/2003

Blank Carbon (μg/cm2

)

IMP_bQF

STN_FB

STN_TB

MORA1

0

1

2

3

4

10/16/2001 1/16/2002 4/16/2002 7/16/2002 10/16/2002 1/16/2003 4/16/2003 7/16/2003 10/16/2003

Blank Carbon (μg/cm2

)IMP_bQF

STN_FB

STN_TB

PHOE1

0

1

2

3

4

10/16/2001 1/16/2002 4/16/2002 7/16/2002 10/16/2002 1/16/2003 4/16/2003 7/16/2003 10/16/2003

Blank Carbon (μg/cm2

)

IMP_bQF

STN_FB

STN_TB

TONT1

0

1

2

3

4

10/16/2001 1/16/2002 4/16/2002 7/16/2002 10/16/2002 1/16/2003 4/16/2003 7/16/2003 10/16/2003

Blank Carbon (μg/cm2

)

IMP_bQF

STN_FB

STN_TB

WASH1

0

1

2

3

4

10/16/2001 1/16/2002 4/16/2002 7/16/2002 10/16/2002 1/16/2003 4/16/2003 7/16/2003 10/16/2003

Blank Carbon (μg/cm2

)

IMP_bQF

STN_FB

STN_TB

DOSO1

0

1

2

3

4

10/16/2001 1/16/2002 4/16/2002 7/16/2002 10/16/2002 1/16/2003 4/16/2003 7/16/2003 10/16/2003

Blank Carbon (μg/cm2

)

IMP_bQF

STN_FB

STN_TB

BIBE1

0

1

2

3

4

1/1/2005 4/1/2005 7/1/2005 10/1/2005 1/1/2006 4/1/2006 7/1/2006 10/1/2006

Blank Carbon (μg/cm2

)

IMP_bQF

STN_FB

STN_TB

FRES1

0

1

2

3

4

1/1/2005 4/1/2005 7/1/2005 10/1/2005 1/1/2006 4/1/2006 7/1/2006 10/1/2006

Blank Carbon (μg/cm2

)

IMP_bQF

STN_FB

STN_TB

Figure 3-6. Time series of IMPROVE and STN/CSN blank TC concentrations at eight 

collocated sites (IMP_bQF: IMPROVE field blank filter; STN_FB: STN/CSN field blanks; 

STN_TB: STN/CSN trip blanks). 
3-23

 y = 1.07x + 1.75

R2

 = 0.89

0

5

10

15

20

25

30

0 5 10 15 20 25 30

Uncorrected IMPROVE TC (μg/m3

)

Uncorrected STN TC (

μg/m3

)

N = 201

Figure 3-7. Ordinary linear regression of uncorrected STN/CSN TC against IMPROVE TC 

acquired from the Phoenix site (PHOE1). The non-zero intercept indicates the different sampling 

artifacts between STN/CSN and the IMPROVE network. 
3-24

0.0

0.5

1.0

1.5

2.0

2.5

PUSO1

MORA1

PHOE1

TONT1

WASH1

DOSO1

FRES1

BIBE1

STN-IMP TC Intercept (

μg/m3

)

All

Spring

Summer 

Fall

Winter

Figure 3-8. The uncorrected STN-IMPROVE TC regression Intercept for all data and 

seasonally-segregated data from the eight collocated sites: PUSO1 (Seattle, WA); MORA1 

(Mount Rainier, WA); PHOE1 (Phoenix, AZ); TONT1 (Tonto National Monument, AZ) 

WASH1 (Washington, DC); DOSO (Dolly Sods Wilderness, WV); FRES1 (Fresno, CA); and 

BIBE1 (Big Bend National Park, TX). 
3-25

(a) 

(b) 

Figure 3-9. Thermograms of IMPROVE_A_TOR/TOT analyses on: a) blank filter with solid 

levoglucosan (0.97 μg/cm2

), and b) blank filter with liquid levoglucosan (22.9 μg/cm2). 
3-26

(a) 

(b) 

Figure 3-10. Thermograms of IMPROVE_A_TOR/TOT analyses on: a) pure diesel soot, and b) 

diesel soot/liquid levoglucosan mixture (22.9 μg/cm2

). 
3-27

0

0.2

0.4

0.6

0.8

1

1.2

0.2 0.4 0.6 0.8 1 1.2

R/R0

T/T0

Pure Diesel Soot

Spiked Liquid Levoglucosan

L fraction = 0.50

L fraction = ~0.13

Figure 3-11. Filter reflectance (R) and transmittance (T) of pure diesel soot and liquid 

levoglucosan on blank filter through the IMPROVE_A thermal/optical analysis protocol. 

Samples are the same as those listed in Figure 3-9. R0 and T0 are reflectance and transmittance of 

blank filters, respectively. The dashed lines indicate the “best fits” with a radiative transfer 

equation (RTE) model (see text). 
3-28

Table 3-1. Comparison of average field blank levels (± standard deviation) among the 

IMPROVE, STN/CSN, and SEARCH networks for the period from 1/1/2005 through 

12/31/2006. 

 μg/cm2 μg/filter μg/m3

Carbon 

Species IMPROVE STNa

 SEARCHb IMPROVE STNa SEARCHb IMPROVE STNa SEARCHb

TC 2.41 ± 0.48 0.97 ± 0.27 0.81 ± 0.61 8.5 ± 1.69 11.42 ± 3.21 5.74 ± 4.32 0.26 ± 0.05 1.03 ± 0.21 0.24 ± 0.18 

OC 2.37 ± 0.45 0.95 ± 0.25 0.76 ± 0.57 8.37 ± 1.6 11.22 ± 2.93 5.43 ± 4.05 0.26 ± 0.05 1.01 ± 0.21 0.23 ± 0.17 

EC 0.04 ± 0.05 0.02 ± 0.03 0.04 ± 0.06 0.14 ± 0.17 0.2 ± 0.36 0.31 ± 0.43 0 ± 0.01 0.01 ± 0.02 0.01 ± 0.02 

OC1 0.66 ± 0.18 0.26 ± 0.06 0.23 ± 0.3 2.33 ± 0.64 3.02 ± 0.68 1.66 ± 2.16 0.07 ± 0.02 0.28 ± 0.07 0.07 ± 0.09 

OC2 0.78 ± 0.15 0.4 ± 0.14 0.2 ± 0.17 2.75 ± 0.53 4.72 ± 1.66 1.41 ± 1.21 0.08 ± 0.02 0.42 ± 0.09 0.06 ± 0.05 

OC3 0.81 ± 0.16 0.22 ± 0.06 0.27 ± 0.07 2.84 ± 0.57 2.55 ± 0.71 1.95 ± 0.5 0.09 ± 0.02 0.23 ± 0.06 0.08 ± 0.02 

OC4 0.12 ± 0.06 0.08 ± 0.07 0.04 ± 0.05 0.43 ± 0.21 0.96 ± 0.86 0.3 ± 0.37 0.01 ± 0.01 0.08 ± 0.05 0.01 ± 0.02 

EC1 0.02 ± 0.03 0.03 ± 0.05 0.07 ± 0.1 0.25 ± 0.35 0 ± 0 0.01 ± 0.01 

EC2 0.02 ± 0.02 0.02 ± 0.01 0.07 ± 0.08 0.14 ± 0.09 0 ± 0 0.01 ± 0 

EC3 0 ± 0.01 0 ± 0.01 0.01 ± 0.04 0.04 ± 0.04 0 ± 0 0 ± 0 

No. of 

Sites in 

Average 181 239 8 181 239 8 181 239 8 

No. of 

Samples 

in 

Average 886 3628 144 886 3628 144 886 3628 144 

a

 Weighted average depends on number of sites per type of instrument specified in Table 2-1. There are a 

variety of samplers using in STN. Most of them are MetOne samplers. 

b

 The SEARCH network uses denuded PCM3 with preceding organic denuders 
3-29

Table 3-2. Average field blank concentration by carbon fraction at the 181 sites in the IMPROVE network from 

12/31/2006. 

 Sampling Period Carbon Concentrations (μg/cm2) 

Site ID Site Name State From To 

No. of Field 

Blanks TC OC EC OC1 OC2 OC3 OC4 

ACAD1 Acadia NP ME 1/13/2005 1/5/2006 3 2.49 ± 0.64 2.44 ± 0.57 0.06 ± 0.1 0.56 ± 0.1 0.81 ± 0.21 0.92 ± 0.27 0.15 ± 0.07 ADPI1 Addison Pinnacle NY 1/13/2005 5/11/2006 6 2.09 ± 0.29 2.09 ± 0.29 0 ± 0 0.52 ± 0.11 0.76 ± 0.16 0.72 ± 0.13 0.07 ± 0.06 AGTI1 Agua Tibia CA 5/19/2005 11/16/2006 7 3.13 ± 0.77 3.1 ± 0.77 0.03 ± 0.03 0.91 ± 0.32 1.04 ± 0.21 1 ± 0.34 0.14 ± 0.06 AREN1 Arendtsville PA 1/13/2005 3/30/2006 5 2.03 ± 0.89 1.99 ± 0.85 0.04 ± 0.06 0.58 ± 0.28 0.66 ± 0.37 0.62 ± 0.25 0.13 ± 0.11 ATLA1 Atlanta GA 1/13/2005 11/19/2006 8 2.31 ± 0.54 2.28 ± 0.55 0.02 ± 0.04 0.59 ± 0.21 0.84 ± 0.21 0.73 ± 0.16 0.13 ± 0.07 BADL1 Badlands NP SD 1/13/2005 12/7/2006 7 3.17 ± 1.04 3.11 ± 0.97 0.05 ± 0.09 1.07 ± 0.75 0.9 ± 0.24 0.97 ± 0.32 0.17 ± 0.11 BALD1 Mount Baldy AZ 3/17/2005 6/1/2006 5 2.19 ± 0.83 2.18 ± 0.82 0.01 ± 0.02 0.75 ± 0.33 0.62 ± 0.24 0.72 ± 0.23 0.09 ± 0.08 BALT1 Baltimore MD 1/13/2005 12/15/2005 4 2.21 ± 0.43 2.19 ± 0.4 0.02 ± 0.03 0.63 ± 0.19 0.76 ± 0.14 0.71 ± 0.13 0.09 ± 0.06 BAND1 Bandelier NM NM 3/17/2005 12/28/2006 9 2.82 ± 0.83 2.79 ± 0.8 0.02 ± 0.05 0.91 ± 0.23 0.88 ± 0.33 0.87 ± 0.28 0.13 ± 0.08 BIBE1 Big Bend NP TX 3/17/2005 8/24/2006 7 2.4 ± 0.68 2.3 ± 0.46 0.11 ± 0.28 0.62 ± 0.13 0.77 ± 0.2 0.79 ± 0.13 0.11 ± 0.06 BIRM1 Birmingham AL 1/13/2005 8/24/2006 5 2.25 ± 0.41 2.25 ± 0.41 0 ± 0 0.67 ± 0.16 0.8 ± 0.18 0.7 ± 0.19 0.08 ± 0.06 BLIS1 Bliss SP (TRPA) CA 3/17/2005 10/26/2006 10 2.68 ± 0.64 2.62 ± 0.59 0.06 ± 0.08 0.64 ± 0.31 0.78 ± 0.15 1.02 ± 0.43 0.19 ± 0.1 BLMO1 Blue Mounds MN 1/13/2005 1/5/2006 4 1.53 ± 0.23 1.53 ± 0.23 0 ± 0 0.42 ± 0.13 0.47 ± 0.11 0.61 ± 0.21 0.05 ± 0.02 BOAP1 Bosque del Apache NM 1/13/2005 12/7/2006 8 3.12 ± 1.36 3 ± 1.2 0.13 ± 0.18 0.65 ± 0.24 0.98 ± 0.39 1.09 ± 0.51 0.28 ± 0.24 BOND1 Bondville IL 3/17/2005 11/16/2006 5 1.89 ± 0.93 1.85 ± 0.9 0.04 ± 0.03 0.41 ± 0.23 0.61 ± 0.28 0.7 ± 0.35 0.13 ± 0.08 BOWA1 Boundary Waters Canoe Area MN 3/30/2006 9/14/2006 3 2.01 ± 0.72 1.94 ± 0.62 0.07 ± 0.11 0.42 ± 0.09 0.71 ± 0.21 0.68 ± 0.21 0.14 ± 0.14 BRCA1 Bryce Canyon NP UT 7/21/2005 11/16/2006 5 3.1 ± 1.05 3 ± 0.91 0.1 ± 0.17 0.94 ± 0.43 0.96 ± 0.25 0.9 ± 0.16 0.19 ± 0.1 BRET1 Breton LA 2/3/2005 2/3/2005 1 2.32 ± 0 2.32 ± 0 0 ± 0 0.6 ± 0 0.78 ± 0 0.88 ± 0 0.07 ± 0 BRID1 Bridger Wilderness WY 5/19/2005 12/7/2006 2 2.45 ± 0.51 2.39 ± 0.39 0.07 ± 0.1 0.56 ± 0.22 0.88 ± 0.09 0.83 ± 0.18 0.13 ± 0.06 BRID9 Bridger Wilderness WY 1/13/2005 1/13/2005 1 2.62 ± 0 2.47 ± 0 0.15 ± 0 0.62 ± 0 0.87 ± 0 0.77 ± 0 0.21 ± 0 BRIG1 Brigantine NWR NJ 2/3/2005 5/11/2006 6 2.1 ± 0.81 2.09 ± 0.8 0.01 ± 0.02 0.57 ± 0.29 0.76 ± 0.37 0.7 ± 0.22 0.06 ± 0.06 BRMA1 Bridgton ME 1/13/2005 10/26/2006 6 2.19 ± 0.87 2.16 ± 0.8 0.03 ± 0.08 0.47 ± 0.23 0.71 ± 0.15 0.82 ± 0.37 0.15 ± 0.16 CABA1 Casco Bay ME 5/19/2005 12/28/2006 6 2.53 ± 0.68 2.52 ± 0.67 0.01 ± 0.02 0.74 ± 0.22 0.9 ± 0.2 0.76 ± 0.24 0.11 ± 0.07 CABI1 Cabinet Mountains MT 5/19/2005 2/16/2006 3 2.08 ± 0.66 2.05 ± 0.63 0.03 ± 0.04 0.67 ± 0.17 0.57 ± 0.28 0.7 ± 0.13 0.11 ± 0.07 CACO1 Cape Cod MA 10/13/2005 12/28/2006 2 1.93 ± 0.49 1.9 ± 0.46 0.03 ± 0.02 0.61 ± 0.04 0.68 ± 0.3 0.55 ± 0.16 0.06 ± 0.05 CACR1 Caney Creek AR 1/13/2005 9/14/2006 7 2.58 ± 0.72 2.42 ± 0.57 0.16 ± 0.25 0.48 ± 0.17 0.78 ± 0.29 0.99 ± 0.29 0.17 ± 0.07 CADI1 Cadiz KY 5/19/2005 11/16/2006 7 2.17 ± 0.53 2.14 ± 0.5 0.03 ± 0.04 0.56 ± 0.17 0.76 ± 0.23 0.72 ± 0.2 0.1 ± 0.09 CANY1 Canyonlands NP UT 7/21/2005 10/5/2006 9 2.63 ± 1.14 2.53 ± 1.02 0.1 ± 0.21 0.76 ± 0.39 0.79 ± 0.31 0.83 ± 0.27 0.15 ± 0.13 CAPI1 Capitol Reef NP UT 3/17/2005 12/7/2006 6 2.75 ± 0.84 2.72 ± 0.84 0.03 ± 0.05 0.82 ± 0.42 0.87 ± 0.25 0.87 ± 0.26 0.16 ± 0.1 CEBL1 Cedar Bluff KS 1/13/2005 10/26/2006 10 2.02 ± 0.69 2.01 ± 0.68 0.01 ± 0.01 0.57 ± 0.19 0.64 ± 0.27 0.72 ± 0.21 0.09 ± 0.08 CHAS1 Chassahowitzka NWR FL 6/9/2005 10/5/2006 8 2 ± 0.54 1.96 ± 0.5 0.04 ± 0.06 0.44 ± 0.16 0.67 ± 0.17 0.77 ± 0.22 0.09 ± 0.06 CHER1 Cherokee Nation OK 10/13/2005 9/14/2006 3 2.1 ± 0.35 2.1 ± 0.35 0 ± 0 0.53 ± 0.16 0.76 ± 0.21 0.72 ± 0.1 0.08 ± 0.05 
3-30

Table 3-2. Continued. 

 Sampling Period Carbon Concentrations (μg/cm2) 

Site ID Site Name State From To 

No. of Field 

Blanks TC OC EC OC1 OC2 OC3 OC4 

CHIC1 Chicago IL 1/13/2005 3/17/2005 2 2.28 ± 0.41 2.28 ± 0.41 0 ± 0 0.71 ± 0.03 0.74 ± 0.01 0.74 ± 0.38 0.09 ± 0.05 CHIR1 Chiricahua NM AZ 1/13/2005 8/24/2006 5 2.23 ± 0.94 2.23 ± 0.94 0.01 ± 0.01 0.71 ± 0.47 0.74 ± 0.24 0.69 ± 0.21 0.09 ± 0.06 CLPE1 Cloud Peak WY 3/17/2005 4/20/2006 3 1.87 ± 0.57 1.86 ± 0.56 0.01 ± 0.01 0.56 ± 0.28 0.63 ± 0.14 0.62 ± 0.16 0.05 ± 0.04 COGO1 Columbia Gorge #1 WA 3/17/2005 10/5/2006 6 2.41 ± 0.48 2.38 ± 0.46 0.03 ± 0.06 0.68 ± 0.22 0.84 ± 0.18 0.73 ± 0.11 0.13 ± 0.06 COHI1 Connecticut Hill NY 7/21/2005 12/15/2005 3 2.98 ± 0.87 2.94 ± 0.81 0.04 ± 0.07 0.99 ± 0.2 0.95 ± 0.3 0.87 ± 0.3 0.14 ± 0.06 COHU1 Cohutta GA 3/17/2005 3/17/2005 1 4.45 ± 0 4.24 ± 0 0.21 ± 0 1.77 ± 0 1.13 ± 0 1.15 ± 0 0.19 ± 0 CORI1 Columbia River Gorge WA 3/17/2005 12/7/2006 5 2.25 ± 0.91 2.21 ± 0.85 0.05 ± 0.06 0.58 ± 0.32 0.8 ± 0.33 0.72 ± 0.25 0.11 ± 0.08 CRES1 Crescent Lake NE 3/17/2005 6/1/2006 6 2.14 ± 0.35 2.14 ± 0.34 0 ± 0.01 0.69 ± 0.17 0.73 ± 0.1 0.66 ± 0.11 0.06 ± 0.04 CRLA1 Crater Lake NP OR 5/19/2005 12/7/2006 7 2.23 ± 1.14 2.22 ± 1.13 0.01 ± 0.02 0.77 ± 0.45 0.7 ± 0.35 0.68 ± 0.3 0.08 ± 0.09 CRMO1 Craters of the Moon NM ID 3/17/2005 5/11/2006 4 2.13 ± 0.75 2.12 ± 0.75 0 ± 0 0.64 ± 0.19 0.71 ± 0.24 0.71 ± 0.29 0.06 ± 0.06 DENA1 Denali NP AK 5/19/2005 12/28/2006 7 2.9 ± 0.46 2.89 ± 0.46 0.01 ± 0.01 0.89 ± 0.27 0.96 ± 0.13 0.9 ± 0.14 0.14 ± 0.04 DETR1 Detroit MI 4/7/2005 12/31/2006 8 2.16 ± 1.04 2.09 ± 0.87 0.08 ± 0.18 0.44 ± 0.1 0.66 ± 0.3 0.8 ± 0.36 0.18 ± 0.2 DEVA1 Death Valley NP CA 3/17/2005 10/5/2006 4 2.43 ± 1.23 2.17 ± 0.75 0.26 ± 0.49 0.45 ± 0.09 0.7 ± 0.23 0.84 ± 0.25 0.19 ± 0.22 DOME1 Dome Lands Wilderness CA 12/15/2005 12/28/2006 4 2.93 ± 1.73 2.89 ± 1.64 0.05 ± 0.09 0.74 ± 0.33 0.91 ± 0.32 1.07 ± 0.76 0.18 ± 0.24 DOSO1 Dolly Sods Wilderness WV 3/17/2005 9/14/2006 9 2.78 ± 0.96 2.67 ± 0.78 0.11 ± 0.24 0.77 ± 0.26 0.8 ± 0.31 0.91 ± 0.28 0.19 ± 0.11 DOUG1 Douglas AZ 1/13/2005 12/28/2006 6 2.91 ± 1.2 2.88 ± 1.12 0.04 ± 0.08 0.92 ± 0.53 0.9 ± 0.25 0.89 ± 0.31 0.17 ± 0.12 EGBE1 N/A 9/1/2005 10/5/2006 5 2.4 ± 0.6 2.37 ± 0.55 0.04 ± 0.05 0.55 ± 0.22 0.87 ± 0.19 0.82 ± 0.16 0.13 ± 0.05 ELDO1 El Dorado Springs MO 7/21/2005 7/13/2006 6 2.19 ± 0.75 2.16 ± 0.72 0.03 ± 0.04 0.58 ± 0.29 0.7 ± 0.26 0.76 ± 0.21 0.12 ± 0.07 ELLI1 Ellis OK 3/17/2005 5/11/2006 7 2.79 ± 0.36 2.76 ± 0.36 0.03 ± 0.03 0.74 ± 0.22 0.85 ± 0.16 0.92 ± 0.14 0.21 ± 0.19 EVER1 Everglades NP FL 1/13/2005 9/14/2006 6 2.7 ± 0.5 2.68 ± 0.49 0.02 ± 0.04 0.68 ± 0.28 1.2 ± 0.36 0.69 ± 0.18 0.1 ± 0.07 FLAT1 Flathead MT 1/13/2005 10/5/2006 8 2.5 ± 0.81 2.49 ± 0.81 0.01 ± 0.02 0.73 ± 0.28 0.84 ± 0.26 0.79 ± 0.26 0.12 ± 0.11 FOPE1 Fort Peck MT 3/17/2005 11/16/2006 6 2.86 ± 0.66 2.83 ± 0.66 0.03 ± 0.04 0.84 ± 0.41 0.99 ± 0.29 0.87 ± 0.1 0.13 ± 0.03 FRES1 Fresno CA 5/19/2005 11/16/2006 7 2.58 ± 0.5 2.55 ± 0.44 0.03 ± 0.07 0.68 ± 0.14 0.86 ± 0.2 0.85 ± 0.17 0.16 ± 0.09 FRRE1 Frostburg MD 5/19/2005 8/3/2006 4 2.81 ± 1.01 2.78 ± 0.98 0.04 ± 0.05 0.84 ± 0.3 0.85 ± 0.33 0.92 ± 0.28 0.17 ± 0.13 GAMO1 Gates of the Mountains MT 5/19/2005 10/13/2005 2 2.48 ± 0.36 2.48 ± 0.36 0 ± 0 0.77 ± 0.16 0.82 ± 0.05 0.8 ± 0.12 0.09 ± 0.03 GICL1 Gila Wilderness NM 4/7/2005 7/13/2006 4 2.26 ± 0.95 2.26 ± 0.95 0 ± 0 0.72 ± 0.32 0.7 ± 0.3 0.76 ± 0.29 0.07 ± 0.09 GLAC1 Glacier NP MT 1/13/2005 11/16/2006 5 2.46 ± 0.55 2.45 ± 0.54 0.01 ± 0.02 0.72 ± 0.18 0.89 ± 0.17 0.75 ± 0.18 0.1 ± 0.09 GRBA1 Great Basin NP NV 1/13/2005 12/28/2006 10 2.48 ± 0.43 2.46 ± 0.41 0.01 ± 0.03 0.74 ± 0.23 0.9 ± 0.19 0.73 ± 0.13 0.1 ± 0.05 GRGU1 Great Gulf Wilderness NH 1/13/2005 3/9/2006 5 2.84 ± 0.47 2.76 ± 0.51 0.08 ± 0.06 0.82 ± 0.17 0.94 ± 0.27 0.83 ± 0.28 0.16 ± 0.05 GRRI1 Great River Bluffs MN 5/19/2005 12/15/2005 3 2.4 ± 0.99 2.35 ± 0.9 0.05 ± 0.08 0.65 ± 0.35 0.78 ± 0.31 0.78 ± 0.25 0.15 ± 0.06 GRSA1 Great Sand Dunes NM CO 10/13/2005 10/5/2006 3 3.31 ± 0.59 3.25 ± 0.54 0.06 ± 0.07 1.05 ± 0.24 0.95 ± 0.14 1.08 ± 0.15 0.17 ± 0.03 GRSM1 Great Smoky Mountains NP TN 1/13/2005 10/26/2006 6 2.18 ± 0.97 2.16 ± 0.96 0.02 ± 0.03 0.5 ± 0.26 0.68 ± 0.28 0.83 ± 0.36 0.15 ± 0.1 
3-31

Table 3-2. Continued. 

 Sampling Period Carbon Concentrations (μg/cm2) 

Site ID Site Name State From To 

No. of Field 

Blanks TC OC EC OC1 OC2 OC3 OC4 

GRSM9 Great Smoky Mountains NP TN 1/13/2005 1/13/2005 1 4.56 ± 0 4.37 ± 0 0.19 ± 0 0.74 ± 0 1.28 ± 0 1.88 ± 0 0.46 ± 0 GUMO1 Guadalupe Mountains NP TX 7/21/2005 12/28/2006 5 3.55 ± 0.79 3.44 ± 0.74 0.11 ± 0.09 1.16 ± 0.23 1 ± 0.32 1.06 ± 0.19 0.22 ± 0.11 HALE1 Haleakala NP HI 3/17/2005 12/28/2006 8 2.09 ± 0.45 2.07 ± 0.44 0.02 ± 0.02 0.4 ± 0.19 0.78 ± 0.15 0.79 ± 0.16 0.1 ± 0.06 HANC1 Hance Camp at Grand Canyon NP AZ 1/13/2005 4/20/2006 3 2.15 ± 0.68 2.13 ± 0.66 0.02 ± 0.04 0.61 ± 0.41 0.61 ± 0.24 0.82 ± 0.22 0.09 ± 0.08 HAVO1 Hawaii Volcanoes NP HI 1/13/2005 12/28/2006 8 1.88 ± 0.61 1.87 ± 0.61 0 ± 0.01 0.48 ± 0.21 0.67 ± 0.24 0.65 ± 0.18 0.07 ± 0.05 HECA1 Hells Canyon OR 1/13/2005 11/16/2006 7 2.03 ± 0.86 1.98 ± 0.83 0.05 ± 0.09 0.39 ± 0.12 0.62 ± 0.13 0.87 ± 0.56 0.1 ± 0.1 HEGL1 Hercules-Glades MO 1/13/2005 11/16/2006 7 2.13 ± 0.79 2.09 ± 0.75 0.04 ± 0.05 0.65 ± 0.18 0.62 ± 0.29 0.71 ± 0.25 0.1 ± 0.09 HOOV1 Hoover CA 1/13/2005 9/14/2006 8 2.38 ± 0.6 2.35 ± 0.57 0.02 ± 0.06 0.72 ± 0.26 0.73 ± 0.17 0.8 ± 0.17 0.1 ± 0.06 HOUS1 Houston TX 5/19/2005 7/21/2005 2 3.44 ± 0.87 3.26 ± 0.62 0.18 ± 0.26 0.69 ± 0.11 1.1 ± 0.25 1.15 ± 0.25 0.32 ± 0.22 IKBA1 Ike's Backbone AZ 12/15/2005 12/15/2005 1 1.75 ± 0 1.73 ± 0 0.01 ± 0 0.72 ± 0 0.36 ± 0 0.58 ± 0 0.07 ± 0 INGA1 Indian Gardens AZ 2/3/2005 9/14/2006 6 3.77 ± 1.09 3.68 ± 1.03 0.09 ± 0.09 1.19 ± 0.39 1.21 ± 0.41 1.07 ± 0.29 0.21 ± 0.15 ISLE1 Isle Royale NP MI 1/13/2005 11/16/2006 6 1.54 ± 0.65 1.53 ± 0.64 0 ± 0.01 0.36 ± 0.14 0.54 ± 0.27 0.58 ± 0.22 0.06 ± 0.06 JARI1 James River Face Wilderness VA 1/13/2005 6/1/2006 5 2.42 ± 0.94 2.4 ± 0.92 0.02 ± 0.02 0.71 ± 0.4 0.86 ± 0.31 0.73 ± 0.21 0.11 ± 0.07 JOSH1 Joshua Tree NP CA 1/13/2005 7/13/2006 6 2.6 ± 0.28 2.59 ± 0.27 0.02 ± 0.03 0.75 ± 0.2 0.81 ± 0.28 0.92 ± 0.1 0.11 ± 0.07 KAIS1 Kaiser CA 1/13/2005 1/5/2006 5 2.92 ± 0.7 2.89 ± 0.67 0.03 ± 0.04 0.82 ± 0.25 0.99 ± 0.25 0.93 ± 0.22 0.15 ± 0.07 KALM1 Kalmiopsis OR 1/13/2005 11/16/2006 4 2.26 ± 0.22 2.24 ± 0.19 0.03 ± 0.04 0.54 ± 0.13 0.73 ± 0.08 0.84 ± 0.21 0.12 ± 0.09 LABE1 Lava Beds NM CA 1/13/2005 5/11/2006 7 1.91 ± 0.48 1.88 ± 0.44 0.03 ± 0.04 0.56 ± 0.17 0.61 ± 0.12 0.64 ± 0.15 0.08 ± 0.07 LASU2 Lake Sugema IA 1/13/2005 12/15/2005 3 2.22 ± 0.85 2.21 ± 0.84 0 ± 0 0.62 ± 0.13 0.78 ± 0.39 0.75 ± 0.33 0.07 ± 0.06 LAVO1 Lassen Volcanic NP CA 1/13/2005 1/5/2006 3 1.74 ± 0.59 1.71 ± 0.53 0.03 ± 0.05 0.39 ± 0.18 0.51 ± 0.16 0.76 ± 0.58 0.06 ± 0.1 LIGO1 Linville Gorge NC 3/17/2005 4/20/2006 5 2.24 ± 0.45 2.22 ± 0.41 0.03 ± 0.04 0.67 ± 0.16 0.63 ± 0.15 0.76 ± 0.15 0.15 ± 0.09 LIVO1 Livonia IN 1/13/2005 5/19/2005 2 3.42 ± 1.73 3.15 ± 1.34 0.28 ± 0.39 0.43 ± 0.16 0.79 ± 0.04 1.54 ± 1.01 0.38 ± 0.45 LOST1 Lostwood ND 5/19/2005 11/16/2006 5 2.24 ± 1.15 2.22 ± 1.12 0.02 ± 0.04 0.72 ± 0.47 0.71 ± 0.35 0.68 ± 0.24 0.1 ± 0.08 LYBR1 Lye Brook Wilderness VT 1/13/2005 12/7/2006 6 1.98 ± 0.61 1.97 ± 0.6 0.01 ± 0.02 0.54 ± 0.19 0.72 ± 0.19 0.64 ± 0.2 0.07 ± 0.09 MACA1 Mammoth Cave NP KY 5/19/2005 12/7/2006 5 2.25 ± 0.5 2.25 ± 0.5 0 ± 0 0.72 ± 0.22 0.67 ± 0.1 0.74 ± 0.15 0.11 ± 0.06 MAVI1 Martha's Vineyard MA 5/19/2005 7/13/2006 5 1.94 ± 0.7 1.9 ± 0.62 0.04 ± 0.08 0.49 ± 0.13 0.56 ± 0.16 0.76 ± 0.37 0.1 ± 0.11 MEAD1 Meadview AZ 5/19/2005 5/19/2005 1 2.51 ± 0 2.51 ± 0 0 ± 0 0.78 ± 0 0.87 ± 0 0.78 ± 0 0.09 ± 0 MELA1 Medicine Lake MT 3/17/2005 8/24/2006 3 2.16 ± 0.47 2.12 ± 0.41 0.04 ± 0.06 0.51 ± 0.09 0.68 ± 0.03 0.83 ± 0.37 0.1 ± 0.11 MEVE1 Mesa Verde NP CO 1/13/2005 12/28/2006 9 2.72 ± 0.89 2.7 ± 0.88 0.02 ± 0.04 0.86 ± 0.3 0.91 ± 0.29 0.81 ± 0.27 0.12 ± 0.1 MING1 Mingo MO 5/19/2005 9/14/2006 4 1.98 ± 0.3 1.97 ± 0.3 0.01 ± 0.01 0.54 ± 0.16 0.62 ± 0.14 0.71 ± 0.17 0.11 ± 0.03 MKGO1 M.K. Goddard PA 3/17/2005 8/24/2006 7 2.3 ± 0.66 2.21 ± 0.52 0.09 ± 0.16 0.61 ± 0.2 0.82 ± 0.18 0.68 ± 0.12 0.09 ± 0.07 MOHO1 Mount Hood OR 1/13/2005 8/24/2006 7 2.02 ± 0.64 2.01 ± 0.63 0.01 ± 0.03 0.5 ± 0.18 0.73 ± 0.19 0.7 ± 0.24 0.08 ± 0.09 MOMO1 Mohawk Mt. CT 3/17/2005 12/7/2006 4 1.63 ± 0.35 1.61 ± 0.33 0.02 ± 0.02 0.51 ± 0.2 0.53 ± 0.12 0.53 ± 0.07 0.04 ± 0.04 MONT1 Monture MT 1/13/2005 11/16/2006 7 2.48 ± 0.91 2.43 ± 0.85 0.06 ± 0.1 0.66 ± 0.3 0.78 ± 0.27 0.8 ± 0.29 0.15 ± 0.14 
3-32

Table 3-2. Continued. 

 Sampling Period Carbon Concentrations (μg/cm2) 

Site ID Site Name State From To 

No. of Field 

Blanks TC OC EC OC1 OC2 OC3 OC4 

MOOS1 Moosehorn NWR ME 1/13/2005 12/7/2006 7 2.41 ± 0.41 2.39 ± 0.41 0.02 ± 0.04 0.75 ± 0.25 0.71 ± 0.22 0.8 ± 0.15 0.12 ± 0.06 MORA1 Mount Rainier NP WA 1/13/2005 11/16/2006 5 1.79 ± 0.62 1.77 ± 0.62 0.02 ± 0.05 0.57 ± 0.34 0.52 ± 0.21 0.63 ± 0.28 0.05 ± 0.05 MORA9 Mount Rainier NP WA 1/13/2005 1/13/2005 1 1.42 ± 0 1.42 ± 0 0 ± 0 0.37 ± 0 0.41 ± 0 0.64 ± 0 0 ± 0 MOZI1 Mount Zirkel Wilderness CO 3/17/2005 11/16/2006 8 2.8 ± 0.38 2.79 ± 0.38 0.01 ± 0.02 0.82 ± 0.19 0.96 ± 0.16 0.86 ± 0.13 0.15 ± 0.04 NEBR1 Nebraska NF NE 1/13/2005 6/22/2006 5 3.15 ± 1.1 3.07 ± 1.05 0.08 ± 0.08 0.95 ± 0.53 0.96 ± 0.2 0.94 ± 0.27 0.22 ± 0.15 NEYO1 New York City NY 5/19/2005 12/15/2005 3 2.44 ± 0.48 2.41 ± 0.42 0.03 ± 0.06 0.76 ± 0.25 0.85 ± 0.2 0.69 ± 0.07 0.1 ± 0.07 NOAB1 North Absaroka WY 3/30/2006 10/5/2006 3 2.5 ± 1.08 2.42 ± 0.95 0.07 ± 0.12 0.6 ± 0.15 0.73 ± 0.11 0.97 ± 0.56 0.13 ± 0.13 NOCA1 North Cascades WA 3/17/2005 12/28/2006 7 2.62 ± 0.71 2.53 ± 0.68 0.09 ± 0.08 0.7 ± 0.29 0.81 ± 0.2 0.89 ± 0.23 0.13 ± 0.09 NOCH1 Northern Cheyenne MT 9/1/2005 10/5/2006 3 2.21 ± 0.34 2.21 ± 0.34 0 ± 0 0.63 ± 0.16 0.71 ± 0.16 0.75 ± 0.07 0.12 ± 0.05 OKEF1 Okefenokee NWR GA 6/1/2006 6/1/2006 1 2.99 ± 0 2.99 ± 0 0 ± 0 1.03 ± 0 0.86 ± 0 0.9 ± 0 0.2 ± 0 OLTO1 Old Town ME 5/19/2005 4/20/2006 4 1.93 ± 0.32 1.92 ± 0.31 0 ± 0.01 0.59 ± 0.02 0.62 ± 0.27 0.65 ± 0.04 0.06 ± 0.06 OLYM1 Olympic WA 2/3/2005 2/16/2006 2 1.7 ± 0.88 1.63 ± 0.81 0.06 ± 0.07 0.4 ± 0.26 0.46 ± 0.06 0.65 ± 0.33 0.12 ± 0.17 OMAH1 Omaha NE 3/17/2005 10/5/2006 4 2.3 ± 0.32 2.3 ± 0.32 0 ± 0 0.6 ± 0.25 0.88 ± 0.09 0.75 ± 0.1 0.08 ± 0.06 ORPI1 Organ Pipe AZ 3/17/2005 11/16/2006 5 2.02 ± 0.39 2 ± 0.36 0.02 ± 0.04 0.51 ± 0.08 0.71 ± 0.15 0.72 ± 0.16 0.06 ± 0.05 PASA1 Pasayten WA 5/19/2005 10/5/2006 6 2.29 ± 0.47 2.24 ± 0.49 0.04 ± 0.06 0.59 ± 0.16 0.7 ± 0.17 0.83 ± 0.25 0.12 ± 0.08 PEFO1 Petrified Forest NP AZ 3/17/2005 12/7/2006 6 2.15 ± 0.65 2.12 ± 0.61 0.03 ± 0.06 0.56 ± 0.23 0.59 ± 0.19 0.82 ± 0.28 0.14 ± 0.15 PENO1 N/A 3/30/2006 8/24/2006 2 2.68 ± 0.2 2.68 ± 0.2 0 ± 0 0.72 ± 0.19 0.83 ± 0.07 0.98 ± 0.03 0.15 ± 0.03 PETE1 Petersburg AK 4/7/2005 9/14/2006 8 1.86 ± 0.61 1.84 ± 0.59 0.02 ± 0.03 0.56 ± 0.18 0.61 ± 0.23 0.61 ± 0.17 0.07 ± 0.07 PHOE1 Phoenix AZ 1/13/2005 5/11/2006 6 2.82 ± 1.02 2.73 ± 0.93 0.09 ± 0.13 0.75 ± 0.31 0.92 ± 0.26 0.88 ± 0.26 0.16 ± 0.16 PHOE5 Phoenix AZ 1/13/2005 5/11/2006 5 2.43 ± 0.27 2.42 ± 0.27 0.01 ± 0.01 0.74 ± 0.23 0.77 ± 0.11 0.78 ± 0.15 0.12 ± 0.03 PINN1 Pinnacles NM CA 3/9/2006 5/11/2006 2 1.93 ± 0.05 1.93 ± 0.05 0 ± 0 0.5 ± 0.1 0.67 ± 0.01 0.71 ± 0.12 0.05 ± 0.06 PITT1 Pittsburgh PA 1/13/2005 12/10/2006 8 2.46 ± 0.86 2.38 ± 0.73 0.08 ± 0.15 0.69 ± 0.29 0.7 ± 0.13 0.82 ± 0.25 0.17 ± 0.19 PMRF1 Proctor Maple R. F. VT 3/17/2005 7/13/2006 4 2.56 ± 0.41 2.56 ± 0.41 0 ± 0 0.76 ± 0.22 0.9 ± 0.19 0.79 ± 0.08 0.1 ± 0.03 PORE1 Point Reyes National Seashore CA 7/21/2005 11/16/2006 4 2.2 ± 0.91 2.18 ± 0.87 0.02 ± 0.04 0.64 ± 0.38 0.71 ± 0.29 0.72 ± 0.18 0.1 ± 0.08 PRIS1 Presque Isle ME 2/3/2005 4/20/2006 3 2.43 ± 0.28 2.43 ± 0.28 0.01 ± 0.01 0.79 ± 0.14 0.85 ± 0.16 0.7 ± 0.1 0.09 ± 0.08 PUSO1 Puget Sound WA 3/17/2005 1/5/2006 2 2.47 ± 0.78 2.42 ± 0.71 0.05 ± 0.08 0.58 ± 0.08 0.88 ± 0.3 0.78 ± 0.19 0.18 ± 0.14 QUCI1 Quaker City OH 10/5/2006 10/5/2006 1 2.98 ± 0 2.91 ± 0 0.07 ± 0 0.66 ± 0 0.99 ± 0 1.1 ± 0 0.16 ± 0 QURE1 Quabbin Summit MA 1/13/2005 2/16/2006 4 2.34 ± 0.87 2.34 ± 0.87 0 ± 0 0.44 ± 0.34 0.77 ± 0.29 1.08 ± 0.67 0.05 ± 0.03 QUVA1 Queen Valley AZ 3/17/2005 11/16/2006 3 2.63 ± 0.91 2.62 ± 0.9 0.01 ± 0.01 0.73 ± 0.42 0.92 ± 0.33 0.88 ± 0.2 0.09 ± 0.04 RAFA1 San Rafael CA 1/13/2005 12/7/2006 7 2.81 ± 0.68 2.78 ± 0.67 0.02 ± 0.02 0.91 ± 0.19 0.93 ± 0.23 0.81 ± 0.21 0.13 ± 0.09 REDW1 Redwood NP CA 1/13/2005 12/7/2006 6 2.27 ± 0.39 2.25 ± 0.37 0.02 ± 0.04 0.61 ± 0.17 0.82 ± 0.11 0.73 ± 0.15 0.1 ± 0.07 ROMA1 Cape Romain NWR SC 1/13/2005 7/13/2006 5 2.31 ± 1.15 2.15 ± 0.89 0.17 ± 0.33 0.5 ± 0.34 0.72 ± 0.35 0.76 ± 0.16 0.17 ± 0.15 ROMO2 Rocky Mountain NP CO 1/13/2005 1/13/2005 1 3.03 ± 0 3 ± 0 0.03 ± 0 0.66 ± 0 1.05 ± 0 1.11 ± 0 0.19 ± 0 
3-33

Table 3-2. Continued. 

 Sampling Period Carbon Concentrations (μg/cm2) 

Site ID Site Name State From To 

No. of Field 

Blanks TC OC EC OC1 OC2 OC3 OC4 

RUBI1 Rubidoux CA 3/17/2005 7/21/2005 3 2.93 ± 0.61 2.88 ± 0.55 0.04 ± 0.07 0.73 ± 0.23 1 ± 0.12 1 ± 0.13 0.15 ± 0.1 SACR1 Salt Creek NM 1/13/2005 8/3/2006 5 2.26 ± 0.79 2.25 ± 0.77 0.01 ± 0.02 0.59 ± 0.24 0.85 ± 0.24 0.73 ± 0.24 0.08 ± 0.08 SAFO1 Sac and Fox KS 1/13/2005 2/16/2006 4 2.37 ± 0.75 2.31 ± 0.69 0.05 ± 0.07 0.53 ± 0.13 0.73 ± 0.34 0.93 ± 0.3 0.12 ± 0.07 SAGA1 San Gabriel CA 1/13/2005 10/5/2006 4 2.79 ± 0.38 2.77 ± 0.37 0.02 ± 0.03 0.88 ± 0.23 0.94 ± 0.11 0.8 ± 0.11 0.14 ± 0.06 SAGO1 San Gorgonio Wilderness CA 3/17/2005 9/14/2006 4 2.49 ± 0.07 2.47 ± 0.05 0.02 ± 0.03 0.6 ± 0.11 0.97 ± 0.09 0.78 ± 0.1 0.12 ± 0.02 SAGU1 Saguaro NM AZ 1/13/2005 11/16/2006 2 2.76 ± 0.66 2.76 ± 0.66 0 ± 0 0.58 ± 0.33 0.8 ± 0.07 1.13 ± 0.65 0.18 ± 0.16 SAMA1 St. Marks FL 5/19/2005 11/16/2006 7 2.71 ± 1.24 2.67 ± 1.19 0.04 ± 0.08 0.72 ± 0.44 0.88 ± 0.37 0.91 ± 0.34 0.16 ± 0.13 SAPE1 San Pedro Parks NM 3/17/2005 2/16/2006 3 2.09 ± 0.56 2.05 ± 0.52 0.04 ± 0.03 0.49 ± 0.15 0.61 ± 0.16 0.88 ± 0.34 0.07 ± 0.06 SAWE1 Saguaro West AZ 1/13/2005 6/1/2006 7 2.6 ± 0.66 2.59 ± 0.64 0.01 ± 0.02 0.74 ± 0.37 0.87 ± 0.18 0.85 ± 0.19 0.13 ± 0.08 SAWT1 Sawtooth NF ID 1/13/2005 11/16/2006 4 2.21 ± 0.61 2.21 ± 0.61 0 ± 0.01 0.66 ± 0.18 0.75 ± 0.2 0.7 ± 0.19 0.09 ± 0.07 SENE1 Seney MI 3/17/2005 11/16/2006 3 2.19 ± 0.72 2.13 ± 0.67 0.06 ± 0.05 0.45 ± 0.09 0.73 ± 0.23 0.81 ± 0.3 0.14 ± 0.12 SEQU1 Sequoia NP CA 12/15/2005 11/16/2006 4 2.13 ± 0.31 2.12 ± 0.32 0.01 ± 0.01 0.52 ± 0.08 0.75 ± 0.1 0.74 ± 0.08 0.11 ± 0.07 SEQU9 Sequoia NP CA 1/13/2005 1/13/2005 1 2.23 ± 0 2.19 ± 0 0.04 ± 0 0.76 ± 0 0.68 ± 0 0.65 ± 0 0.1 ± 0 SHEN1 Shenandoah NP VA 1/13/2005 1/5/2006 9 2.36 ± 0.88 2.33 ± 0.83 0.04 ± 0.08 0.52 ± 0.23 0.82 ± 0.28 0.84 ± 0.37 0.16 ± 0.13 SHMI1 Shamrock Mine CO 5/19/2005 5/11/2006 2 2.56 ± 0.11 2.55 ± 0.07 0.02 ± 0.03 0.81 ± 0.21 0.83 ± 0.13 0.82 ± 0.1 0.12 ± 0.06 SHRO1 Shining Rock Wilderness NC 3/17/2005 5/11/2006 6 2.91 ± 0.33 2.83 ± 0.27 0.08 ± 0.07 0.87 ± 0.17 0.93 ± 0.1 0.87 ± 0.13 0.16 ± 0.05 SIAN1 Sierra Ancha AZ 7/21/2005 10/5/2006 4 2.87 ± 0.6 2.81 ± 0.56 0.06 ± 0.04 0.74 ± 0.23 0.85 ± 0.18 1.05 ± 0.35 0.16 ± 0.07 SIKE1 Sikes LA 1/13/2005 8/3/2006 6 2.56 ± 0.65 2.49 ± 0.61 0.07 ± 0.1 0.62 ± 0.08 0.82 ± 0.26 0.9 ± 0.29 0.16 ± 0.06 SIME1 Simeonof AK 1/13/2005 10/5/2006 7 1.81 ± 0.6 1.81 ± 0.6 0 ± 0.01 0.45 ± 0.26 0.65 ± 0.17 0.65 ± 0.18 0.06 ± 0.05 SIPS1 Sipsy Wilderness AL 5/19/2005 12/7/2006 3 2.25 ± 0.79 2.21 ± 0.74 0.04 ± 0.05 0.8 ± 0.28 0.67 ± 0.32 0.62 ± 0.23 0.11 ± 0.05 SNPA1 Snoqualmie Pass WA 7/21/2005 12/28/2006 7 2.32 ± 0.9 2.31 ± 0.89 0.01 ± 0.02 0.71 ± 0.38 0.77 ± 0.27 0.72 ± 0.23 0.12 ± 0.07 SPOK1 Spokane Res. WA 5/19/2005 6/9/2005 2 1.74 ± 1.45 1.71 ± 1.39 0.04 ± 0.05 0.48 ± 0.35 0.57 ± 0.5 0.56 ± 0.37 0.12 ± 0.14 STAR1 Starkey OR 2/3/2005 12/7/2006 4 2.37 ± 1.3 2.28 ± 1.13 0.09 ± 0.18 0.7 ± 0.34 0.66 ± 0.28 0.79 ± 0.43 0.13 ± 0.11 SULA1 Sula Peak MT 5/19/2005 11/16/2006 3 2.06 ± 0.46 2.06 ± 0.46 0 ± 0 0.56 ± 0.21 0.76 ± 0.15 0.65 ± 0.1 0.09 ± 0.01 SWAN1 Swanquarter NC 3/17/2005 3/9/2006 5 2.18 ± 0.43 2.16 ± 0.4 0.02 ± 0.03 0.56 ± 0.14 0.8 ± 0.18 0.71 ± 0.13 0.1 ± 0.09 SYCA1 Sycamore Canyon AZ 1/13/2005 9/14/2006 6 1.91 ± 0.54 1.88 ± 0.49 0.03 ± 0.05 0.44 ± 0.17 0.55 ± 0.16 0.78 ± 0.22 0.1 ± 0.09 TALL1 Tallgrass KS 1/13/2005 11/16/2006 5 2.22 ± 0.7 2.21 ± 0.71 0.01 ± 0.02 0.57 ± 0.17 0.75 ± 0.3 0.78 ± 0.29 0.1 ± 0.08 THBA1 Thunder Basin WY 5/19/2005 11/16/2006 8 2.28 ± 0.6 2.26 ± 0.59 0.02 ± 0.02 0.67 ± 0.21 0.77 ± 0.21 0.71 ± 0.19 0.11 ± 0.05 THRO1 Theodore Roosevelt ND 5/19/2005 5/19/2005 1 2.13 ± 0 2.15 ± 0 0 ± 0 0.6 ± 0 0.81 ± 0 0.7 ± 0 0.08 ± 0 THSI1 Three Sisters Wilderness OR 1/13/2005 12/28/2006 5 1.94 ± 0.67 1.91 ± 0.6 0.03 ± 0.07 0.52 ± 0.11 0.66 ± 0.21 0.66 ± 0.22 0.07 ± 0.14 TONT1 Tonto NM AZ 12/15/2005 12/28/2006 5 1.97 ± 0.24 1.96 ± 0.24 0.02 ± 0.02 0.48 ± 0.15 0.58 ± 0.08 0.78 ± 0.17 0.12 ± 0.07 TRCR1 Trapper Creek AK 3/17/2005 9/14/2006 4 1.62 ± 0.37 1.62 ± 0.38 0 ± 0 0.41 ± 0.12 0.59 ± 0.17 0.6 ± 0.11 0.03 ± 0.03 TRIN1 Trinity CA 1/13/2005 7/21/2005 4 1.89 ± 0.55 1.87 ± 0.57 0.02 ± 0.03 0.52 ± 0.3 0.63 ± 0.23 0.66 ± 0.1 0.06 ± 0.05 
3-34

Table 3-2. Continued. 

 Sampling Period Carbon Concentrations (μg/cm2) 

Site ID Site Name State From To 

No. of Field 

Blanks TC OC EC OC1 OC2 OC3 OC4 

TUXE1 Tuxedni AK 6/9/2005 11/16/2006 7 2.05 ± 0.76 2.04 ± 0.74 0.01 ± 0.02 0.52 ± 0.36 0.71 ± 0.21 0.74 ± 0.16 0.08 ± 0.06 ULBE1 UL Bend MT 1/13/2005 12/7/2006 7 2.23 ± 0.49 2.18 ± 0.49 0.05 ± 0.05 0.62 ± 0.21 0.7 ± 0.2 0.72 ± 0.15 0.14 ± 0.08 UPBU1 Upper Buffalo Wilderness AR 3/17/2005 9/14/2006 5 3.42 ± 0.55 3.31 ± 0.49 0.1 ± 0.11 0.93 ± 0.33 1.01 ± 0.18 1.15 ± 0.21 0.22 ± 0.08 VIIS1 Virgin Islands NP VI 3/17/2005 11/16/2006 8 1.74 ± 0.76 1.69 ± 0.69 0.06 ± 0.09 0.24 ± 0.18 0.7 ± 0.21 0.66 ± 0.29 0.08 ± 0.12 VILA1 Viking Lake IA 1/13/2005 7/13/2006 4 2.33 ± 0.47 2.29 ± 0.47 0.04 ± 0.03 0.79 ± 0.09 0.66 ± 0.21 0.73 ± 0.14 0.12 ± 0.04 VOYA1 Voyageurs NP #1 MN 1/13/2005 7/13/2006 5 2.32 ± 0.7 2.3 ± 0.68 0.02 ± 0.03 0.65 ± 0.19 0.77 ± 0.22 0.77 ± 0.31 0.1 ± 0.08 WARI1 Walker River Paiute Tribe NV 5/19/2005 10/13/2005 4 2.64 ± 0.28 2.61 ± 0.26 0.03 ± 0.05 0.77 ± 0.07 0.94 ± 0.13 0.79 ± 0.08 0.11 ± 0.03 WASH1 Washington D.C. DC 12/7/2006 12/7/2006 1 3.53 ± 0 3.33 ± 0 0.2 ± 0 1.13 ± 0 1.06 ± 0 0.83 ± 0 0.3 ± 0 WEMI1 Weminuche Wilderness CO 1/13/2005 2/16/2006 4 2.43 ± 0.54 2.43 ± 0.53 0 ± 0 0.74 ± 0.11 0.84 ± 0.3 0.78 ± 0.19 0.07 ± 0.03 WHIT1 White Mountain NM 5/19/2005 11/16/2006 4 2.82 ± 0.97 2.77 ± 0.92 0.05 ± 0.06 0.75 ± 0.29 0.9 ± 0.21 0.99 ± 0.4 0.13 ± 0.09 WHPA1 White Pass WA 3/17/2005 7/13/2006 7 2.59 ± 0.79 2.58 ± 0.8 0.01 ± 0.02 0.8 ± 0.35 0.85 ± 0.25 0.82 ± 0.21 0.1 ± 0.08 WHPE1 Wheeler Peak NM 4/16/2005 4/8/2006 3 2.2 ± 0.5 2.2 ± 0.49 0 ± 0 0.67 ± 0.25 0.75 ± 0.25 0.75 ± 0.09 0.05 ± 0.04 WHRI1 White River NF CO 3/17/2005 12/7/2006 4 2.76 ± 0.31 2.68 ± 0.27 0.08 ± 0.08 0.58 ± 0.23 0.84 ± 0.13 0.95 ± 0.07 0.21 ± 0.1 WICA1 Wind Cave SD 1/13/2005 12/7/2006 4 1.71 ± 0.74 1.69 ± 0.72 0.02 ± 0.03 0.56 ± 0.29 0.46 ± 0.14 0.62 ± 0.31 0.05 ± 0.05 WIMO1 Wichita Mountains OK 7/21/2005 11/16/2006 6 2.63 ± 0.45 2.63 ± 0.45 0 ± 0.01 0.73 ± 0.21 0.94 ± 0.15 0.84 ± 0.12 0.11 ± 0.05 YELL1 Yellowstone NP 1 WY 1/13/2005 9/14/2006 6 2.62 ± 0.51 2.56 ± 0.44 0.06 ± 0.07 0.76 ± 0.18 0.86 ± 0.12 0.83 ± 0.17 0.12 ± 0.06 YOSE1 Yosemite NP CA 3/17/2005 8/24/2006 4 1.81 ± 0.68 1.8 ± 0.68 0.01 ± 0.02 0.53 ± 0.41 0.62 ± 0.13 0.61 ± 0.15 0.05 ± 0.04 ZICA1 Zion Canyon UT 2/3/2005 12/7/2006 5 2.13 ± 0.6 2.13 ± 0.59 0.01 ± 0.01 0.63 ± 0.26 0.75 ± 0.16 0.69 ± 0.2 0.06 ± 0.06 All 181 Sites 886 2.41 ± 0.48 2.37 ± 0.45 0.04 ± 0.05 0.66 ± 0.18 0.78 ± 0.15 0.81 ± 0.16 0.12 ± 0.06 
3-35

Table 3-3. Average field blank concentrations by thermal carbon fractions at the 239 sites in STN/CSN for the p

through 12/31/2006. 

Sampling Period Carbon Concentrations (μg/cm2) 

Site ID State From To 

No. of 

Field 

Blanks TC OC EC OC1 OC2 OC3 OC

020900010 AK 4/13/2005 12/4/2006 18 0.83 ± 0.18 0.83 ± 0.18 0 ± 0 0.26 ± 0.09 0.3 ± 0.08 0.2 ± 0.07 0.07 ± 011130001 AL 5/16/2005 11/7/2006 12 1.04 ± 0.27 1.04 ± 0.27 0.01 ± 0.02 0.26 ± 0.09 0.4 ± 0.14 0.29 ± 0.14 0.08 ± 010050002 AL 1/28/2005 3/12/2006 7 0.77 ± 0.26 0.77 ± 0.26 0 ± 0 0.25 ± 0.13 0.3 ± 0.13 0.17 ± 0.08 0.04 ± 010730023 AL 1/28/2005 12/4/2006 24 0.86 ± 0.33 0.85 ± 0.33 0.01 ± 0.03 0.24 ± 0.14 0.37 ± 0.16 0.19 ± 0.11 0.05 ± 010970003 AL 1/28/2005 3/12/2006 7 0.91 ± 0.27 0.9 ± 0.27 0 ± 0 0.28 ± 0.15 0.38 ± 0.15 0.19 ± 0.07 0.05 ± 011030011 AL 1/28/2005 9/7/2005 5 0.66 ± 0.24 0.65 ± 0.23 0 ± 0 0.2 ± 0.11 0.28 ± 0.11 0.14 ± 0.11 0.03 ± 010890014 AL 1/28/2005 11/7/2006 12 0.83 ± 0.25 0.82 ± 0.24 0.02 ± 0.05 0.27 ± 0.13 0.32 ± 0.13 0.17 ± 0.09 0.06 ± 011011002 AL 1/28/2005 11/7/2006 10 0.8 ± 0.19 0.78 ± 0.19 0.01 ± 0.02 0.25 ± 0.08 0.31 ± 0.12 0.17 ± 0.08 0.05 ± 010731009 AL 1/28/2005 5/11/2006 9 0.88 ± 0.24 0.87 ± 0.24 0.01 ± 0.02 0.27 ± 0.13 0.34 ± 0.09 0.21 ± 0.07 0.05 ± 010732003 AL 1/28/2005 11/7/2006 12 0.89 ± 0.23 0.89 ± 0.23 0 ± 0 0.26 ± 0.1 0.35 ± 0.13 0.22 ± 0.09 0.05 ± 051190007 AR 1/28/2005 11/7/2006 12 0.81 ± 0.23 0.8 ± 0.23 0.01 ± 0.03 0.24 ± 0.07 0.31 ± 0.09 0.18 ± 0.1 0.05 ± 050030005 AR 1/28/2005 5/16/2005 3 0.77 ± 0.13 0.77 ± 0.13 0 ± 0 0.24 ± 0.13 0.28 ± 0.08 0.19 ± 0.05 0.07 ± 051450001 AR 1/28/2005 5/16/2005 3 0.73 ± 0.26 0.73 ± 0.26 0 ± 0 0.24 ± 0.1 0.31 ± 0.14 0.14 ± 0.05 0.04 ± 040137003 AZ 3/11/2005 11/7/2006 11 1.09 ± 0.39 1.08 ± 0.39 0.01 ± 0.02 0.3 ± 0.1 0.48 ± 0.21 0.25 ± 0.11 0.06 ± 040191028 AZ 1/28/2005 11/7/2006 11 0.78 ± 0.19 0.78 ± 0.19 0 ± 0 0.26 ± 0.08 0.3 ± 0.1 0.17 ± 0.07 0.04 ± 040137020 AZ 3/11/2005 11/7/2006 11 1.01 ± 0.18 0.99 ± 0.17 0.01 ± 0.04 0.28 ± 0.09 0.43 ± 0.12 0.22 ± 0.08 0.06 ± 040130019 AZ 1/28/2005 11/12/2005 6 0.91 ± 0.34 0.91 ± 0.34 0 ± 0 0.3 ± 0.17 0.31 ± 0.11 0.2 ± 0.13 0.1 ± 040139997 AZ 1/28/2005 12/4/2006 24 0.83 ± 0.17 0.82 ± 0.17 0 ± 0.01 0.24 ± 0.08 0.34 ± 0.11 0.19 ± 0.07 0.06 ± 040139998 AZ 1/28/2005 11/12/2005 6 0.83 ± 0.2 0.81 ± 0.2 0.02 ± 0.04 0.24 ± 0.05 0.34 ± 0.12 0.17 ± 0.09 0.06 ± 060290014 CA 1/28/2005 12/4/2006 41 0.86 ± 0.61 0.85 ± 0.61 0.01 ± 0.04 0.23 ± 0.07 0.35 ± 0.3 0.21 ± 0.23 0.06 ± 060670006 CA 1/28/2005 12/4/2006 24 0.78 ± 0.21 0.78 ± 0.21 0 ± 0.01 0.2 ± 0.08 0.34 ± 0.11 0.18 ± 0.08 0.05 ± 060190008 CA 1/28/2005 12/4/2006 24 0.75 ± 0.23 0.75 ± 0.23 0 ± 0.01 0.2 ± 0.08 0.32 ± 0.13 0.16 ± 0.06 0.06 ± 060371103 CA 1/28/2005 11/7/2006 12 0.9 ± 0.32 0.9 ± 0.32 0.01 ± 0.02 0.22 ± 0.08 0.38 ± 0.16 0.22 ± 0.13 0.07 ± 061112002 CA 1/28/2005 11/7/2006 12 0.95 ± 0.25 0.95 ± 0.25 0.01 ± 0.01 0.26 ± 0.13 0.41 ± 0.13 0.22 ± 0.12 0.04 ± 060658001 CA 1/28/2005 12/4/2006 34 0.77 ± 0.21 0.77 ± 0.21 0 ± 0.02 0.24 ± 0.06 0.32 ± 0.12 0.16 ± 0.07 0.05 ± 060730003 CA 1/28/2005 12/4/2006 24 0.92 ± 0.72 0.92 ± 0.72 0 ± 0.01 0.21 ± 0.1 0.41 ± 0.38 0.22 ± 0.18 0.07 ± 060850005 CA 1/28/2005 12/4/2006 24 0.76 ± 0.35 0.75 ± 0.34 0.02 ± 0.04 0.2 ± 0.06 0.31 ± 0.17 0.18 ± 0.14 0.06 ± 080410011 CO 1/28/2005 11/7/2006 12 0.77 ± 0.19 0.76 ± 0.19 0.01 ± 0.03 0.23 ± 0.09 0.31 ± 0.12 0.16 ± 0.05 0.06 ± 080770017 CO 1/28/2005 11/7/2006 12 0.91 ± 0.18 0.91 ± 0.18 0 ± 0.01 0.27 ± 0.07 0.38 ± 0.11 0.2 ± 0.08 0.05 ± 
3-36

Table 3-3. Continued. 

Sampling Period Carbon Concentrations (μg/cm2) 

Site ID State From To 

No. of 

Field 

Blanks TC OC EC OC1 OC2 OC3 OC

080010006 CO 1/28/2005 12/4/2006 24 0.76 ± 0.23 0.76 ± 0.23 0 ± 0.01 0.22 ± 0.08 0.31 ± 0.12 0.18 ± 0.1 0.05 ± 081230008 CO 1/28/2005 11/7/2006 12 0.85 ± 0.12 0.84 ± 0.12 0 ± 0 0.26 ± 0.07 0.33 ± 0.07 0.19 ± 0.06 0.06 ± 090090027 CT 1/28/2005 12/4/2006 22 0.77 ± 0.44 0.76 ± 0.44 0.01 ± 0.02 0.2 ± 0.08 0.32 ± 0.22 0.18 ± 0.18 0.06 ± 100032004 DE 1/28/2005 11/7/2006 12 1.01 ± 0.18 1 ± 0.18 0.01 ± 0.03 0.28 ± 0.08 0.42 ± 0.11 0.23 ± 0.11 0.07 ± 100010003 DE 1/28/2005 11/7/2006 12 1.02 ± 0.21 1.02 ± 0.21 0 ± 0 0.3 ± 0.12 0.43 ± 0.11 0.22 ± 0.11 0.07 ± 120861016 FL 1/28/2005 12/9/2005 12 0.8 ± 0.44 0.8 ± 0.44 0 ± 0 0.18 ± 0.1 0.32 ± 0.15 0.24 ± 0.25 0.06 ± 120730012 FL 1/28/2005 11/7/2006 12 0.97 ± 0.45 0.93 ± 0.43 0.04 ± 0.13 0.23 ± 0.06 0.4 ± 0.15 0.21 ± 0.17 0.08 ± 121030026 FL 1/28/2005 12/4/2006 24 0.9 ± 0.63 0.89 ± 0.63 0.01 ± 0.02 0.21 ± 0.1 0.36 ± 0.28 0.24 ± 0.27 0.07 ± 120330004 FL 1/28/2005 3/12/2006 8 1.08 ± 0.6 1.06 ± 0.6 0.02 ± 0.05 0.27 ± 0.07 0.47 ± 0.33 0.26 ± 0.23 0.06 ± 120111002 FL 1/17/2006 12/4/2006 12 1.08 ± 1.34 1.07 ± 1.34 0.01 ± 0.01 0.17 ± 0.06 0.38 ± 0.33 0.42 ± 0.79 0.11 120573002 FL 1/28/2005 12/4/2006 24 0.97 ± 0.93 0.96 ± 0.93 0.01 ± 0.03 0.21 ± 0.15 0.41 ± 0.38 0.24 ± 0.28 0.09 ± 130690002a GA 1/17/2006 11/7/2006 6 1.06 ± 0.35 1.06 ± 0.35 0 ± 0 0.27 ± 0.08 0.43 ± 0.21 0.27 ± 0.14 0.09 ± 132150011a GA 1/28/2005 11/12/2005 6 1.05 ± 0.31 1.05 ± 0.31 0 ± 0 0.34 ± 0.21 0.39 ± 0.15 0.23 ± 0.12 0.07 ± 131150005a GA 1/17/2006 11/7/2006 6 0.94 ± 0.12 0.94 ± 0.12 0 ± 0 0.28 ± 0.07 0.4 ± 0.07 0.23 ± 0.06 0.03 ± 130690002a GA 1/28/2005 11/12/2005 5 0.73 ± 0.28 0.73 ± 0.28 0 ± 0.01 0.25 ± 0.12 0.27 ± 0.16 0.16 ± 0.12 0.05 ± 131150005a GA 1/28/2005 11/12/2005 6 0.72 ± 0.15 0.7 ± 0.15 0.02 ± 0.04 0.23 ± 0.1 0.26 ± 0.04 0.17 ± 0.06 0.05 ± 130890002a GA 1/28/2005 12/9/2005 12 0.89 ± 0.37 0.87 ± 0.37 0.02 ± 0.04 0.26 ± 0.09 0.38 ± 0.24 0.19 ± 0.11 0.05 ± 130590001a GA 1/28/2005 11/12/2005 7 0.91 ± 0.24 0.9 ± 0.23 0.01 ± 0.01 0.3 ± 0.15 0.32 ± 0.12 0.2 ± 0.06 0.07 ± 130210007a GA 1/28/2005 11/12/2005 6 0.91 ± 0.25 0.88 ± 0.24 0.02 ± 0.06 0.3 ± 0.15 0.32 ± 0.09 0.2 ± 0.09 0.05 ± 130890002a GA 1/17/2006 12/4/2006 13 0.95 ± 0.19 0.95 ± 0.19 0 ± 0.01 0.24 ± 0.11 0.41 ± 0.09 0.24 ± 0.07 0.05 ± 132450091a GA 1/28/2005 11/12/2005 6 1.03 ± 0.37 1.01 ± 0.36 0.02 ± 0.04 0.32 ± 0.13 0.44 ± 0.17 0.19 ± 0.06 0.04 ± 130210007a GA 1/17/2006 11/7/2006 6 1.17 ± 0.24 1.15 ± 0.23 0.02 ± 0.03 0.29 ± 0.06 0.53 ± 0.1 0.28 ± 0.13 0.05 ± 130590001a GA 1/17/2006 11/7/2006 6 1.06 ± 0.2 1.06 ± 0.2 0 ± 0 0.35 ± 0.06 0.46 ± 0.11 0.21 ± 0.09 0.04 ± 132450091a GA 5/11/2006 11/7/2006 4 1.18 ± 0.18 1.18 ± 0.18 0 ± 0 0.31 ± 0.11 0.5 ± 0.15 0.3 ± 0.19 0.06 ± 132150011a GA 1/17/2006 11/7/2006 6 1.14 ± 0.32 1.14 ± 0.32 0 ± 0.01 0.29 ± 0.02 0.51 ± 0.18 0.28 ± 0.12 0.05 ± 150032004 HI 1/28/2005 11/7/2006 12 1.01 ± 0.37 0.99 ± 0.36 0.02 ± 0.04 0.26 ± 0.05 0.37 ± 0.13 0.26 ± 0.18 0.1 ± 191130037 IA 1/28/2005 11/7/2006 12 1.29 ± 0.38 1.25 ± 0.35 0.05 ± 0.15 0.19 ± 0.08 0.42 ± 0.18 0.35 ± 0.16 0.29 ± 191630015 IA 1/28/2005 12/4/2006 23 1.18 ± 0.5 1.18 ± 0.5 0 ± 0 0.2 ± 0.09 0.35 ± 0.16 0.32 ± 0.2 0.3 ± 191530030 IA 1/28/2005 11/7/2006 12 1.42 ± 0.5 1.37 ± 0.49 0.05 ± 0.11 0.2 ± 0.06 0.45 ± 0.13 0.39 ± 0.2 0.32 160270004 ID 1/28/2005 6/7/2006 18 0.65 ± 0.17 0.64 ± 0.17 0 ± 0 0.19 ± 0.09 0.28 ± 0.09 0.13 ± 0.04 0.05 ± 
3-37

Table 3-3. Continued. 

Sampling Period Carbon Concentrations (μg/cm2) 

Site ID State From To 

No. of 

Field 

Blanks TC OC EC OC1 OC2 OC3 OC

160010010 ID 7/10/2006 12/4/2006 6 0.61 ± 0.12 0.61 ± 0.12 0 ± 0 0.2 ± 0.05 0.24 ± 0.04 0.13 ± 0.08 0.04 ± 170310057* IL 1/17/2006 11/7/2006 6 1.04 ± 0.19 1.03 ± 0.19 0 ± 0.01 0.32 ± 0.13 0.4 ± 0.08 0.26 ± 0.1 0.06 ± 170310076* IL 1/28/2005 12/27/2005 13 0.63 ± 0.45 0.63 ± 0.45 0 ± 0 0.15 ± 0.09 0.27 ± 0.24 0.15 ± 0.12 0.05 ± 170434002 IL 1/28/2005 11/7/2006 12 0.91 ± 0.31 0.9 ± 0.31 0.01 ± 0.02 0.25 ± 0.07 0.36 ± 0.13 0.2 ± 0.12 0.07 ± 170310076* IL 1/17/2006 12/4/2006 12 0.91 ± 0.25 0.9 ± 0.25 0 ± 0.01 0.24 ± 0.07 0.35 ± 0.14 0.25 ± 0.13 0.06 ± 171150013 IL 1/28/2005 11/7/2006 12 0.99 ± 0.23 0.98 ± 0.23 0 ± 0 0.28 ± 0.06 0.43 ± 0.16 0.21 ± 0.08 0.06 ± 171192009 IL 1/28/2005 11/7/2006 12 0.91 ± 0.25 0.91 ± 0.25 0 ± 0 0.25 ± 0.11 0.37 ± 0.12 0.22 ± 0.11 0.06 ± 170310057* IL 1/28/2005 11/12/2005 6 0.67 ± 0.18 0.67 ± 0.18 0 ± 0 0.24 ± 0.09 0.26 ± 0.11 0.13 ± 0.04 0.04 ± 170314201 IL 1/28/2005 11/7/2006 12 0.81 ± 0.25 0.8 ± 0.25 0.01 ± 0.01 0.23 ± 0.08 0.34 ± 0.12 0.18 ± 0.06 0.05 ± 180390003 IN 1/28/2005 11/7/2006 12 0.82 ± 0.21 0.81 ± 0.21 0.01 ± 0.01 0.26 ± 0.08 0.34 ± 0.11 0.18 ± 0.08 0.04 ± 181630012 IN 1/28/2005 11/7/2006 12 0.75 ± 0.17 0.75 ± 0.17 0 ± 0.01 0.22 ± 0.06 0.31 ± 0.09 0.17 ± 0.08 0.05 ± 180970078 IN 1/28/2005 12/4/2006 25 0.73 ± 0.23 0.72 ± 0.23 0 ± 0.01 0.22 ± 0.08 0.29 ± 0.13 0.16 ± 0.07 0.06 ± 180372001 IN 1/28/2005 11/7/2006 12 0.72 ± 0.14 0.72 ± 0.14 0 ± 0.01 0.25 ± 0.07 0.28 ± 0.1 0.14 ± 0.04 0.05 ± 180892004 IN 1/28/2005 11/7/2006 12 0.95 ± 0.42 0.94 ± 0.41 0.01 ± 0.03 0.27 ± 0.08 0.39 ± 0.32 0.21 ± 0.13 0.06 ± 180650003 IN 1/28/2005 11/7/2006 12 0.69 ± 0.17 0.69 ± 0.17 0 ± 0 0.22 ± 0.08 0.26 ± 0.1 0.15 ± 0.07 0.05 ± 180890022 IN 1/28/2005 11/7/2006 12 0.9 ± 0.14 0.9 ± 0.14 0 ± 0 0.28 ± 0.07 0.35 ± 0.08 0.2 ± 0.09 0.05 ± 202090021 KS 1/28/2005 12/4/2006 23 0.77 ± 0.21 0.77 ± 0.21 0 ± 0.01 0.21 ± 0.06 0.32 ± 0.1 0.18 ± 0.08 0.05 ± 201730010 KS 1/28/2005 11/7/2006 12 1.43 ± 0.51 1.32 ± 0.43 0.11 ± 0.27 0.22 ± 0.09 0.43 ± 0.12 0.36 ± 0.2 0.3 211451004 KY 1/28/2005 1/17/2006 7 0.84 ± 0.36 0.83 ± 0.36 0 ± 0 0.25 ± 0.15 0.34 ± 0.17 0.19 ± 0.09 0.05 ± 211110048 KY 1/28/2005 1/17/2006 7 0.92 ± 0.59 0.92 ± 0.59 0 ± 0 0.26 ± 0.1 0.34 ± 0.23 0.25 ± 0.29 0.07 ± 210670012 KY 1/28/2005 11/7/2006 11 0.99 ± 0.24 0.98 ± 0.24 0 ± 0.01 0.29 ± 0.07 0.39 ± 0.13 0.24 ± 0.11 0.06 ± 210190017 KY 1/28/2005 11/7/2006 12 0.93 ± 0.21 0.93 ± 0.21 0 ± 0 0.29 ± 0.09 0.36 ± 0.09 0.22 ± 0.08 0.06 ± 211930003 KY 1/28/2005 11/7/2006 12 0.98 ± 0.19 0.98 ± 0.19 0 ± 0.01 0.31 ± 0.08 0.4 ± 0.12 0.21 ± 0.09 0.05 ± 210590005 KY 1/28/2005 1/17/2006 7 0.72 ± 0.24 0.72 ± 0.24 0 ± 0 0.26 ± 0.11 0.28 ± 0.11 0.14 ± 0.07 0.03 ± 211250004 KY 1/28/2005 3/12/2006 8 0.95 ± 0.24 0.94 ± 0.24 0.01 ± 0.03 0.28 ± 0.09 0.35 ± 0.1 0.23 ± 0.14 0.07 ± 211170007 KY 1/28/2005 11/7/2006 12 0.87 ± 0.17 0.87 ± 0.17 0 ± 0 0.31 ± 0.11 0.32 ± 0.09 0.19 ± 0.05 0.05 ± 212270007 KY 1/28/2005 1/17/2006 7 0.8 ± 0.22 0.79 ± 0.21 0.02 ± 0.04 0.23 ± 0.1 0.38 ± 0.14 0.14 ± 0.06 0.02 ± 211110043 KY 1/28/2005 11/7/2006 12 0.89 ± 0.23 0.89 ± 0.23 0 ± 0 0.26 ± 0.09 0.36 ± 0.15 0.19 ± 0.08 0.07 ± 220330009 LA 2/12/2005 12/4/2006 24 0.8 ± 0.64 0.8 ± 0.64 0.01 ± 0.01 0.18 ± 0.1 0.33 ± 0.33 0.22 ± 0.23 0.06 ± 
3-38

Table 3-3. Continued. 

Sampling Period Carbon Concentrations (μg/cm2) 

Site ID State From To 

No. of 

Field 

Blanks TC OC EC OC1 OC2 OC3 OC

220150008 LA 1/28/2005 12/1/2006 13 0.71 ± 0.58 0.7 ± 0.57 0.01 ± 0.02 0.18 ± 0.09 0.3 ± 0.32 0.18 ± 0.19 0.04 ± 250130008 MA 1/28/2005 12/4/2006 20 0.91 ± 0.34 0.9 ± 0.34 0.01 ± 0.03 0.22 ± 0.08 0.39 ± 0.16 0.22 ± 0.14 0.06 ± 250250042 MA 1/28/2005 12/4/2006 36 0.84 ± 0.34 0.84 ± 0.34 0.01 ± 0.03 0.21 ± 0.07 0.35 ± 0.19 0.22 ± 0.16 0.05 ± 240053001 MD 1/28/2005 12/4/2006 24 0.73 ± 0.37 0.72 ± 0.36 0.01 ± 0.02 0.19 ± 0.06 0.29 ± 0.21 0.18 ± 0.13 0.05 ± 240330030 MD 1/28/2005 11/7/2006 12 0.92 ± 0.23 0.92 ± 0.23 0 ± 0.01 0.31 ± 0.12 0.36 ± 0.1 0.19 ± 0.09 0.05 ± 261130001 MI 1/28/2005 11/7/2006 12 0.81 ± 0.22 0.81 ± 0.22 0 ± 0 0.24 ± 0.06 0.31 ± 0.12 0.18 ± 0.08 0.07 ± 260770008 MI 1/28/2005 11/7/2006 12 0.94 ± 0.17 0.94 ± 0.17 0 ± 0.01 0.28 ± 0.07 0.41 ± 0.13 0.19 ± 0.06 0.04 ± 261630033 MI 1/28/2005 11/7/2006 12 1.63 ± 1.22 1.49 ± 1.12 0.15 ± 0.48 0.39 ± 0.26 0.62 ± 0.35 0.29 ± 0.24 0.19 ± 260330901 MI 1/28/2005 3/12/2006 11 0.8 ± 0.2 0.8 ± 0.2 0 ± 0.01 0.25 ± 0.07 0.34 ± 0.13 0.16 ± 0.07 0.03 ± 261630001 MI 1/28/2005 12/4/2006 23 0.79 ± 0.38 0.79 ± 0.38 0 ± 0.01 0.21 ± 0.08 0.33 ± 0.2 0.18 ± 0.11 0.06 ± 261610008 MI 1/28/2005 11/7/2006 12 0.88 ± 0.11 0.88 ± 0.11 0 ± 0 0.29 ± 0.08 0.35 ± 0.08 0.19 ± 0.07 0.05 ± 261150005 MI 1/28/2005 11/7/2006 11 0.95 ± 0.24 0.95 ± 0.24 0 ± 0 0.23 ± 0.05 0.48 ± 0.14 0.19 ± 0.1 0.04 ± 260050003 MI 1/28/2005 3/12/2006 8 0.7 ± 0.18 0.7 ± 0.18 0 ± 0 0.22 ± 0.1 0.29 ± 0.1 0.15 ± 0.07 0.04 ± 260810020 MI 1/28/2005 11/7/2006 12 0.81 ± 0.18 0.81 ± 0.18 0 ± 0 0.25 ± 0.08 0.32 ± 0.13 0.18 ± 0.07 0.05 ± 270953051 MN 1/28/2005 7/15/2005 7 0.68 ± 0.32 0.67 ± 0.32 0 ± 0 0.19 ± 0.1 0.25 ± 0.13 0.16 ± 0.1 0.06 ± 271230871 MN 1/28/2005 3/11/2005 2 0.7 ± 0.25 0.69 ± 0.25 0 ± 0 0.26 ± 0.12 0.32 ± 0.11 0.09 ± 0.03 0.0271095008 MN 1/28/2005 11/7/2006 11 0.8 ± 0.22 0.79 ± 0.22 0.01 ± 0.02 0.26 ± 0.11 0.32 ± 0.11 0.17 ± 0.08 0.04 ± 270530963 MN 1/28/2005 12/4/2006 24 0.92 ± 0.38 0.91 ± 0.37 0.01 ± 0.03 0.23 ± 0.08 0.41 ± 0.21 0.21 ± 0.13 0.05 ± 290530001 MO 3/11/2005 5/11/2006 6 1.51 ± 0.33 1.51 ± 0.33 0 ± 0 0.18 ± 0.09 0.42 ± 0.09 0.44 ± 0.15 0.45 ± 291860005 MO 1/28/2005 12/4/2006 24 1.51 ± 0.88 1.47 ± 0.88 0.03 ± 0.11 0.22 ± 0.09 0.49 ± 0.3 0.42 ± 0.36 0.32 290990012* MO 1/28/2005 10/5/2006 21 0.78 ± 0.31 0.77 ± 0.31 0.01 ± 0.01 0.2 ± 0.1 0.34 ± 0.17 0.18 ± 0.12 0.05 ± 290470005 MO 1/28/2005 12/4/2006 23 1.33 ± 0.59 1.3 ± 0.58 0.03 ± 0.1 0.2 ± 0.13 0.39 ± 0.19 0.35 ± 0.14 0.36 ± 295100085 MO 1/28/2005 12/4/2006 23 0.64 ± 0.19 0.64 ± 0.19 0.01 ± 0.02 0.21 ± 0.07 0.25 ± 0.1 0.14 ± 0.06 0.04 ± 290990012* MO 11/7/2006 12/4/2006 2 1.16 ± 0.09 1.16 ± 0.09 0 ± 0 0.2 ± 0.05 0.53 ± 0.05 0.31 ± 0.03 0.12 ± 280350004 MS 1/28/2005 11/12/2005 6 0.91 ± 0.25 0.91 ± 0.25 0 ± 0 0.26 ± 0.11 0.33 ± 0.11 0.22 ± 0.13 0.08 ± 280430001 MS 1/28/2005 1/17/2006 8 1.07 ± 0.52 1.02 ± 0.51 0.05 ± 0.09 0.27 ± 0.09 0.39 ± 0.17 0.24 ± 0.16 0.11 ± 280490018 MS 1/28/2005 5/11/2006 9 1.05 ± 0.31 1.05 ± 0.31 0 ± 0 0.26 ± 0.07 0.47 ± 0.21 0.24 ± 0.12 0.07 ± 280470008 MS 1/28/2005 12/4/2006 19 0.92 ± 0.48 0.91 ± 0.48 0 ± 0.02 0.2 ± 0.08 0.34 ± 0.21 0.23 ± 0.16 0.14 ± 
3-39

Table 3-3. Continued. 

Sampling Period Carbon Concentrations (μg/cm2) 

Site ID State From To 

No. of 

Field 

Blanks TC OC EC OC1 OC2 OC3 OC

280670002 MS 1/28/2005 11/12/2005 6 0.95 ± 0.31 0.93 ± 0.31 0.02 ± 0.03 0.27 ± 0.09 0.35 ± 0.16 0.2 ± 0.09 0.11 ± 300530018 MT 1/28/2005 11/7/2006 12 1.02 ± 0.19 1.02 ± 0.19 0.01 ± 0.01 0.27 ± 0.08 0.42 ± 0.11 0.25 ± 0.08 0.08 ± 300630031 MT 1/28/2005 12/4/2006 24 0.95 ± 0.89 0.94 ± 0.89 0.01 ± 0.02 0.23 ± 0.08 0.42 ± 0.51 0.23 ± 0.31 0.06 ± 371190041 NC 1/28/2005 12/4/2006 24 0.67 ± 0.23 0.66 ± 0.22 0.01 ± 0.02 0.18 ± 0.08 0.28 ± 0.11 0.15 ± 0.07 0.05 ± 370670022 NC 1/28/2005 11/7/2006 11 0.92 ± 0.17 0.91 ± 0.16 0.01 ± 0.02 0.25 ± 0.07 0.4 ± 0.12 0.21 ± 0.12 0.05 ± 371830014 NC 1/28/2005 12/4/2006 17 0.68 ± 0.22 0.67 ± 0.22 0.01 ± 0.05 0.19 ± 0.07 0.28 ± 0.13 0.16 ± 0.07 0.04 ± 371070004 NC 1/28/2005 11/7/2006 12 0.92 ± 0.26 0.91 ± 0.26 0.01 ± 0.02 0.28 ± 0.07 0.38 ± 0.12 0.2 ± 0.13 0.05 ± 370810013 NC 1/28/2005 11/7/2006 11 0.89 ± 0.22 0.87 ± 0.22 0.02 ± 0.05 0.27 ± 0.1 0.35 ± 0.12 0.2 ± 0.07 0.05 ± 370350004 NC 1/28/2005 11/7/2006 12 0.8 ± 0.16 0.8 ± 0.16 0 ± 0 0.25 ± 0.08 0.31 ± 0.08 0.18 ± 0.07 0.05 ± 370570002 NC 1/28/2005 11/7/2006 12 0.99 ± 0.17 0.98 ± 0.17 0.01 ± 0.01 0.25 ± 0.11 0.36 ± 0.13 0.25 ± 0.12 0.1 ± 371590021 NC 1/28/2005 11/7/2006 12 0.8 ± 0.26 0.78 ± 0.26 0.02 ± 0.05 0.22 ± 0.08 0.31 ± 0.14 0.19 ± 0.1 0.06 ± 370210034 NC 1/28/2005 11/7/2006 12 0.97 ± 0.25 0.97 ± 0.25 0 ± 0.01 0.25 ± 0.07 0.46 ± 0.17 0.21 ± 0.09 0.04 ± 380171004 ND 1/28/2005 12/4/2006 23 0.87 ± 0.83 0.87 ± 0.83 0.01 ± 0.02 0.2 ± 0.09 0.4 ± 0.53 0.2 ± 0.22 0.06 ± 380150003 ND 1/28/2005 11/7/2006 12 1 ± 0.35 1 ± 0.35 0.01 ± 0.02 0.25 ± 0.07 0.42 ± 0.14 0.23 ± 0.15 0.08 ± 380530002 ND 1/28/2005 11/7/2006 13 1.09 ± 0.5 1.08 ± 0.5 0.01 ± 0.03 0.3 ± 0.09 0.48 ± 0.33 0.24 ± 0.15 0.06 ± 310550019 NE 1/28/2005 12/4/2006 24 0.83 ± 0.42 0.82 ± 0.42 0.01 ± 0.04 0.22 ± 0.07 0.36 ± 0.26 0.19 ± 0.15 0.04 ± 330150014 NH 2/3/2005 12/7/2006 23 0.78 ± 0.28 0.76 ± 0.27 0.02 ± 0.07 0.23 ± 0.07 0.33 ± 0.16 0.16 ± 0.08 0.05 ± 330110020 NH 1/28/2005 11/12/2005 5 0.95 ± 0.21 0.94 ± 0.21 0.01 ± 0.02 0.37 ± 0.19 0.32 ± 0.09 0.19 ± 0.07 0.06 ± 340390004 NJ 1/28/2005 12/4/2006 23 0.96 ± 0.68 0.95 ± 0.68 0 ± 0.01 0.21 ± 0.09 0.43 ± 0.37 0.23 ± 0.23 0.07 ± 340273001 NJ 1/28/2005 12/4/2006 23 0.79 ± 0.3 0.78 ± 0.3 0.01 ± 0.02 0.23 ± 0.1 0.32 ± 0.14 0.17 ± 0.1 0.05 ± 340230006 NJ 1/28/2005 12/4/2006 34 0.8 ± 0.29 0.79 ± 0.29 0 ± 0.01 0.23 ± 0.07 0.32 ± 0.14 0.18 ± 0.11 0.06 ± 340070003 NJ 1/28/2005 12/4/2006 23 0.64 ± 0.21 0.64 ± 0.21 0.01 ± 0.01 0.2 ± 0.08 0.27 ± 0.11 0.13 ± 0.08 0.04 ± 350010023 NM 1/28/2005 11/7/2006 12 1.42 ± 0.3 1.41 ± 0.3 0.01 ± 0.01 0.25 ± 0.11 0.4 ± 0.12 0.36 ± 0.16 0.39 ± 320310016 NV 1/28/2005 12/4/2006 24 0.82 ± 0.27 0.81 ± 0.27 0 ± 0.01 0.21 ± 0.07 0.35 ± 0.12 0.18 ± 0.11 0.05 ± 320030561 NV 1/28/2005 11/7/2006 12 0.88 ± 0.21 0.88 ± 0.21 0 ± 0 0.27 ± 0.08 0.33 ± 0.12 0.2 ± 0.08 0.07 ± 360810124 NY 1/28/2005 12/4/2006 25 1.28 ± 0.46 1.26 ± 0.46 0.02 ± 0.07 0.2 ± 0.12 0.37 ± 0.14 0.37 ± 0.23 0.32 ± 361010003 NY 1/28/2005 12/4/2006 23 1.24 ± 0.32 1.22 ± 0.31 0.02 ± 0.07 0.19 ± 0.08 0.38 ± 0.13 0.36 ± 0.13 0.28 ± 360310003 NY 1/28/2005 11/7/2006 18 1.33 ± 0.44 1.28 ± 0.42 0.05 ± 0.15 0.21 ± 0.06 0.43 ± 0.22 0.37 ± 0.17 0.27 ± 360610062 NY 1/28/2005 12/4/2006 23 0.94 ± 0.71 0.87 ± 0.65 0.07 ± 0.3 0.21 ± 0.08 0.38 ± 0.43 0.21 ± 0.15 0.07 ± 
3-40

Table 3-3. Continued. 

Sampling Period Carbon Concentrations (μg/cm2) 

Site ID State From To 

No. of 

Field 

Blanks TC OC EC OC1 OC2 OC3 OC

360050110* NY 1/28/2005 12/9/2005 8 1.18 ± 0.26 1.17 ± 0.26 0.01 ± 0.01 0.23 ± 0.09 0.36 ± 0.14 0.28 ± 0.12 0.29 ± 360551007 NY 1/28/2005 12/4/2006 24 1.23 ± 0.42 1.22 ± 0.42 0.01 ± 0.05 0.19 ± 0.1 0.38 ± 0.21 0.34 ± 0.19 0.3 ± 360050110* NY 1/17/2006 12/4/2006 13 0.83 ± 0.53 0.83 ± 0.53 0.01 ± 0.02 0.2 ± 0.06 0.38 ± 0.34 0.2 ± 0.13 0.05 ± 360290005 NY 1/28/2005 11/7/2006 12 1.54 ± 0.68 1.49 ± 0.67 0.06 ± 0.12 0.2 ± 0.07 0.48 ± 0.28 0.44 ± 0.31 0.37 ± 360050083 NY 1/28/2005 12/9/2005 12 0.79 ± 0.16 0.79 ± 0.16 0 ± 0.01 0.19 ± 0.06 0.36 ± 0.11 0.17 ± 0.08 0.06 ± 390171004 OH 1/28/2005 11/7/2006 12 1.16 ± 0.88 1.15 ± 0.88 0.01 ± 0.03 0.28 ± 0.12 0.53 ± 0.45 0.27 ± 0.33 0.06 ± 390933002 OH 1/17/2006 11/7/2006 6 0.78 ± 0.08 0.78 ± 0.08 0 ± 0 0.27 ± 0.05 0.35 ± 0.07 0.13 ± 0.06 0.02 ± 390950026 OH 1/28/2005 11/7/2006 12 0.74 ± 0.21 0.73 ± 0.21 0.01 ± 0.03 0.23 ± 0.07 0.31 ± 0.1 0.15 ± 0.08 0.03 ± 390810017 OH 1/28/2005 11/7/2006 11 0.96 ± 0.49 0.94 ± 0.49 0.02 ± 0.06 0.23 ± 0.08 0.43 ± 0.35 0.23 ± 0.17 0.05 ± 390350060 OH 1/10/2005 12/4/2006 49 0.77 ± 0.29 0.77 ± 0.29 0.01 ± 0.02 0.22 ± 0.13 0.32 ± 0.19 0.17 ± 0.08 0.05 ± 390870010 OH 1/28/2005 11/7/2006 11 0.81 ± 0.2 0.81 ± 0.2 0 ± 0 0.26 ± 0.08 0.33 ± 0.09 0.16 ± 0.06 0.05 ± 390350038 OH 1/28/2005 11/7/2006 12 0.89 ± 0.2 0.89 ± 0.2 0 ± 0 0.28 ± 0.06 0.37 ± 0.14 0.18 ± 0.07 0.06 ± 391130031 OH 3/11/2005 11/7/2006 11 0.86 ± 0.2 0.85 ± 0.2 0.01 ± 0.02 0.27 ± 0.08 0.35 ± 0.1 0.18 ± 0.06 0.05 ± 390990014 OH 1/28/2005 11/7/2006 12 1.06 ± 0.21 1.05 ± 0.21 0.01 ± 0.02 0.28 ± 0.08 0.49 ± 0.17 0.23 ± 0.12 0.06 ± 390930016 OH 1/28/2005 11/12/2005 6 0.73 ± 0.15 0.73 ± 0.15 0 ± 0 0.22 ± 0.08 0.28 ± 0.1 0.16 ± 0.06 0.06 ± 391530023 OH 1/28/2005 11/7/2006 11 0.9 ± 0.2 0.89 ± 0.2 0 ± 0.01 0.29 ± 0.08 0.36 ± 0.09 0.2 ± 0.09 0.05 ± 390610040 OH 1/28/2005 11/7/2006 12 0.93 ± 0.24 0.92 ± 0.24 0.01 ± 0.03 0.26 ± 0.06 0.43 ± 0.23 0.18 ± 0.08 0.06 ± 391510017 OH 3/11/2005 9/8/2006 10 0.81 ± 0.16 0.8 ± 0.16 0 ± 0.01 0.28 ± 0.1 0.31 ± 0.1 0.17 ± 0.07 0.04 ± 390490081 OH 1/28/2005 11/7/2006 12 1 ± 0.18 0.97 ± 0.18 0.03 ± 0.04 0.31 ± 0.12 0.43 ± 0.14 0.19 ± 0.09 0.04 ± 401431127 OK 1/28/2005 12/4/2006 23 0.72 ± 0.25 0.71 ± 0.25 0 ± 0.01 0.18 ± 0.06 0.3 ± 0.11 0.18 ± 0.1 0.05 ± 401091037 OK 1/28/2005 11/7/2006 12 0.85 ± 0.32 0.83 ± 0.32 0.02 ± 0.03 0.24 ± 0.11 0.35 ± 0.13 0.21 ± 0.14 0.03 ± 400450890 OK 1/28/2005 3/12/2006 7 0.78 ± 0.37 0.77 ± 0.37 0.01 ± 0.03 0.22 ± 0.08 0.31 ± 0.17 0.19 ± 0.18 0.04 ± 410510246 OR 1/28/2005 12/4/2006 24 0.73 ± 0.23 0.72 ± 0.23 0.01 ± 0.04 0.21 ± 0.1 0.3 ± 0.11 0.16 ± 0.09 0.05 ± 420710007 PA 1/28/2005 11/7/2006 12 0.99 ± 0.24 0.99 ± 0.24 0 ± 0.01 0.3 ± 0.1 0.4 ± 0.14 0.2 ± 0.11 0.07 ± 420290100 PA 1/28/2005 11/7/2006 11 1.14 ± 0.24 1.14 ± 0.24 0 ± 0 0.3 ± 0.09 0.43 ± 0.12 0.28 ± 0.13 0.14 ± 420950025 PA 1/28/2005 11/7/2006 11 1.05 ± 0.16 1.04 ± 0.15 0.01 ± 0.03 0.28 ± 0.07 0.46 ± 0.08 0.23 ± 0.1 0.07 ± 421330008 PA 1/28/2005 11/7/2006 12 0.78 ± 0.15 0.78 ± 0.15 0 ± 0 0.22 ± 0.07 0.34 ± 0.1 0.16 ± 0.06 0.04 ± 421290008 PA 1/28/2005 11/7/2006 12 0.98 ± 0.22 0.97 ± 0.22 0 ± 0 0.31 ± 0.1 0.4 ± 0.1 0.22 ± 0.11 0.04 ± 420270100 PA 1/28/2005 11/7/2006 12 0.91 ± 0.22 0.89 ± 0.21 0.02 ± 0.07 0.24 ± 0.07 0.4 ± 0.15 0.19 ± 0.09 0.05 ± 420030064 PA 1/28/2005 11/7/2006 12 0.79 ± 0.28 0.78 ± 0.28 0.01 ± 0.02 0.22 ± 0.07 0.33 ± 0.11 0.19 ± 0.18 0.05 ± 
3-41

Table 3-3. Continued. 

Sampling Period Carbon Concentrations (μg/cm2) 

Site ID State From To 

No. of 

Field 

Blanks TC OC EC OC1 OC2 OC3 OC

421010136 PA 1/28/2005 11/7/2006 12 0.89 ± 0.28 0.88 ± 0.27 0.01 ± 0.05 0.26 ± 0.1 0.4 ± 0.14 0.18 ± 0.1 0.04 ± 420692006 PA 1/28/2005 11/7/2006 12 1.14 ± 0.59 1.14 ± 0.59 0 ± 0 0.28 ± 0.05 0.47 ± 0.16 0.31 ± 0.34 0.07 ± 420490003 PA 1/28/2005 11/7/2006 12 1.09 ± 0.37 1.07 ± 0.37 0.02 ± 0.04 0.29 ± 0.06 0.49 ± 0.21 0.23 ± 0.14 0.06 ± 420030008 PA 2/12/2005 12/4/2006 21 0.72 ± 0.26 0.71 ± 0.26 0.01 ± 0.03 0.21 ± 0.1 0.3 ± 0.15 0.15 ± 0.06 0.05 ± 420450002 PA 1/28/2005 11/7/2006 12 1.25 ± 0.5 1.25 ± 0.5 0 ± 0 0.24 ± 0.08 0.53 ± 0.32 0.31 ± 0.15 0.17 ± 421255001 PA 1/28/2005 11/7/2006 12 0.87 ± 0.19 0.86 ± 0.19 0 ± 0.01 0.25 ± 0.08 0.38 ± 0.11 0.18 ± 0.08 0.05 ± 420110010 PA 7/10/2006 11/7/2006 3 1.38 ± 0.33 1.38 ± 0.33 0 ± 0 0.32 ± 0.03 0.73 ± 0.2 0.24 ± 0.09 0.09 ± 420990301 PA 1/28/2005 11/12/2005 6 0.74 ± 0.3 0.74 ± 0.3 0 ± 0 0.17 ± 0.05 0.32 ± 0.13 0.17 ± 0.11 0.06 ± 421010004 PA 1/28/2005 12/4/2006 23 0.92 ± 0.77 0.91 ± 0.77 0.01 ± 0.02 0.2 ± 0.14 0.4 ± 0.47 0.25 ± 0.27 0.06 ± 420430401 PA 1/28/2005 11/7/2006 12 0.89 ± 0.4 0.88 ± 0.4 0.01 ± 0.03 0.24 ± 0.08 0.38 ± 0.17 0.2 ± 0.16 0.06 ± 420110009 PA 3/12/2006 5/11/2006 1 1.26 ± 0 1.26 ± 0 0 ± 0 0.34 ± 0 0.49 ± 0 0.31 ± 0 0.1420010001 PA 1/28/2005 11/7/2006 12 0.78 ± 0.17 0.78 ± 0.17 0.01 ± 0.02 0.23 ± 0.06 0.35 ± 0.09 0.15 ± 0.08 0.04 ± 720610001 PR 1/28/2005 3/12/2006 14 0.81 ± 0.29 0.79 ± 0.29 0.02 ± 0.05 0.2 ± 0.07 0.36 ± 0.17 0.18 ± 0.09 0.05 ± 440070022 RI 1/28/2005 12/4/2006 24 0.82 ± 0.33 0.81 ± 0.32 0.01 ± 0.04 0.22 ± 0.06 0.31 ± 0.16 0.19 ± 0.11 0.07 ± 450450009 SC 1/28/2005 11/7/2006 16 0.81 ± 0.4 0.81 ± 0.4 0.01 ± 0.01 0.2 ± 0.08 0.33 ± 0.16 0.21 ± 0.16 0.06 ± 450790019 SC 1/28/2005 11/7/2006 12 0.9 ± 0.23 0.88 ± 0.22 0.02 ± 0.04 0.26 ± 0.1 0.38 ± 0.14 0.19 ± 0.11 0.05 ± 450190049 SC 1/28/2005 12/25/2006 25 0.81 ± 0.36 0.8 ± 0.36 0 ± 0.01 0.2 ± 0.08 0.34 ± 0.21 0.21 ± 0.13 0.05 ± 450250001 SC 1/28/2005 11/7/2006 12 0.97 ± 0.22 0.96 ± 0.21 0.01 ± 0.03 0.25 ± 0.07 0.42 ± 0.14 0.21 ± 0.13 0.06 ± 460990006 SD 1/28/2005 11/7/2006 12 0.94 ± 0.75 0.94 ± 0.75 0 ± 0 0.22 ± 0.08 0.37 ± 0.31 0.22 ± 0.22 0.12 ± 471650007 TN 1/28/2005 3/12/2006 8 0.67 ± 0.17 0.67 ± 0.17 0 ± 0 0.24 ± 0.08 0.24 ± 0.1 0.14 ± 0.07 0.05 ± 470370023 TN 1/28/2005 11/7/2006 12 1.09 ± 0.51 1.09 ± 0.51 0 ± 0 0.32 ± 0.17 0.4 ± 0.16 0.28 ± 0.24 0.08 ± 471631007 TN 1/28/2005 11/7/2006 12 0.84 ± 0.18 0.83 ± 0.18 0.01 ± 0.02 0.28 ± 0.09 0.31 ± 0.08 0.19 ± 0.08 0.05 ± 470990002 TN 1/28/2005 11/7/2006 12 0.75 ± 0.17 0.74 ± 0.17 0 ± 0.01 0.23 ± 0.07 0.3 ± 0.1 0.16 ± 0.06 0.04 ± 471570047 TN 1/28/2005 4/8/2006 17 0.79 ± 0.44 0.79 ± 0.44 0 ± 0.01 0.24 ± 0.07 0.26 ± 0.13 0.18 ± 0.14 0.1 ± 471570024 TN 6/7/2006 12/4/2006 7 0.82 ± 0.23 0.82 ± 0.23 0 ± 0 0.24 ± 0.08 0.32 ± 0.13 0.2 ± 0.08 0.06 ± 470931020 TN 1/28/2005 11/7/2006 12 0.94 ± 0.23 0.93 ± 0.23 0.01 ± 0.02 0.34 ± 0.09 0.39 ± 0.14 0.17 ± 0.06 0.03 ± 470654002 TN 1/28/2005 11/7/2006 11 0.96 ± 0.54 0.95 ± 0.54 0.01 ± 0.02 0.26 ± 0.08 0.4 ± 0.31 0.23 ± 0.2 0.04 ± 481670014 TX 1/5/2005 8/21/2005 12 1.62 ± 0.44 1.52 ± 0.44 0.1 ± 0.07 0.42 ± 0.14 0.8 ± 0.23 0.28 ± 0.12 0.12 ± 482450021 TX 10/24/2005 12/26/2006 36 1.68 ± 1.2 1.61 ± 1.2 0.07 ± 0.11 0.33 ± 0.18 0.89 ± 0.53 0.31 ± 0.29 0.15 ± 482730314 TX 1/29/2005 8/21/2005 9 1.49 ± 0.51 1.37 ± 0.51 0.11 ± 0.08 0.37 ± 0.18 0.69 ± 0.17 0.27 ± 0.16 0.15 ± 
3-42

Table 3-3. Continued. 

Sampling Period Carbon Concentrations (μg/cm2) 

Site ID State From To 

No. of 

Field 

Blanks TC OC EC OC1 OC2 OC3 OC

480612004 TX 10/8/2005 12/14/2006 15 1.52 ± 0.45 1.48 ± 0.44 0.04 ± 0.08 0.31 ± 0.17 0.82 ± 0.21 0.28 ± 0.12 0.1 ± 482430004 TX 1/29/2005 8/1/2005 8 1.43 ± 0.41 1.33 ± 0.38 0.11 ± 0.14 0.32 ± 0.12 0.66 ± 0.21 0.29 ± 0.16 0.15 ± 482030002 TX 1/17/2005 8/21/2005 19 1.46 ± 1.14 1.39 ± 1.13 0.07 ± 0.13 0.36 ± 0.34 0.7 ± 0.35 0.25 ± 0.23 0.14 ± 483390078 TX 1/5/2005 8/21/2005 20 2.18 ± 1.09 2.05 ± 1.07 0.13 ± 0.15 0.46 ± 0.24 1.12 ± 0.64 0.37 ± 0.19 0.22 ± 481130069 TX 1/28/2005 12/4/2006 24 0.8 ± 0.7 0.8 ± 0.7 0 ± 0 0.21 ± 0.12 0.33 ± 0.36 0.19 ± 0.21 0.07 ± 481410044 TX 1/28/2005 12/4/2006 21 0.71 ± 0.44 0.71 ± 0.44 0 ± 0.01 0.19 ± 0.1 0.28 ± 0.19 0.17 ± 0.14 0.06 ± 481410053 TX 1/17/2005 12/14/2006 29 1.7 ± 0.63 1.6 ± 0.62 0.1 ± 0.1 0.44 ± 0.19 0.84 ± 0.32 0.28 ± 0.14 0.13 ± 482450022 TX 1/5/2005 8/21/2005 19 1.25 ± 0.41 1.19 ± 0.4 0.06 ± 0.07 0.27 ± 0.08 0.65 ± 0.24 0.24 ± 0.11 0.09 ± 482010024 TX 1/5/2005 12/20/2006 30 1.42 ± 0.48 1.38 ± 0.48 0.04 ± 0.06 0.36 ± 0.22 0.75 ± 0.22 0.25 ± 0.11 0.06 ± 482010055 TX 1/5/2005 8/21/2005 16 1.65 ± 0.47 1.56 ± 0.47 0.09 ± 0.08 0.41 ± 0.18 0.83 ± 0.27 0.29 ± 0.12 0.12 ± 483550034* TX 1/17/2005 4/18/2006 20 1.46 ± 0.44 1.4 ± 0.43 0.06 ± 0.07 0.34 ± 0.14 0.75 ± 0.23 0.27 ± 0.13 0.1 ± 484530020 TX 10/8/2005 12/14/2006 16 2.17 ± 1.94 2 ± 1.93 0.16 ± 0.23 0.42 ± 0.35 0.93 ± 0.53 0.36 ± 0.32 0.43 ± 481390015 TX 1/17/2005 8/21/2005 10 1.49 ± 0.62 1.39 ± 0.61 0.1 ± 0.13 0.38 ± 0.14 0.74 ± 0.32 0.22 ± 0.16 0.14 ± 480430002 TX 1/3/2005 7/5/2005 6 1.68 ± 0.8 1.54 ± 0.78 0.13 ± 0.18 0.43 ± 0.18 0.8 ± 0.44 0.32 ± 0.24 0.13 ± 482011039 TX 1/28/2005 12/4/2006 41 0.62 ± 0.25 0.62 ± 0.25 0 ± 0.01 0.18 ± 0.1 0.24 ± 0.12 0.14 ± 0.07 0.04 ± 482570005 TX 1/17/2005 8/21/2005 10 1.48 ± 0.65 1.41 ± 0.64 0.07 ± 0.1 0.32 ± 0.12 0.76 ± 0.35 0.28 ± 0.16 0.12 ± 
3-43

Table 3-3. Continued. 

Sampling Period Carbon Concentrations (μg/cm2) 

Site ID State From To 

No. of 

Field 

Blanks TC OC EC OC1 OC2 OC3 OC

482011034 TX 1/17/2005 8/21/2005 10 1.85 ± 1.08 1.66 ± 1.07 0.19 ± 0.19 0.47 ± 0.37 0.72 ± 0.26 0.33 ± 0.26 0.3 ± 481130050 TX 1/5/2005 12/26/2006 60 1.35 ± 0.43 1.31 ± 0.42 0.04 ± 0.08 0.33 ± 0.16 0.73 ± 0.23 0.21 ± 0.12 0.07 483550034* TX 5/12/2006 11/20/2006 8 1.96 ± 0.72 1.87 ± 0.71 0.09 ± 0.13 0.31 ± 0.09 0.95 ± 0.3 0.43 ± 0.2 0.26 ± 483030001 TX 1/17/2005 6/10/2005 7 1.43 ± 0.53 1.33 ± 0.52 0.1 ± 0.11 0.35 ± 0.1 0.7 ± 0.26 0.26 ± 0.17 0.11 ± 482010026 TX 1/5/2005 8/21/2005 20 1.71 ± 0.49 1.61 ± 0.48 0.1 ± 0.1 0.49 ± 0.25 0.82 ± 0.22 0.28 ± 0.11 0.12 ± 480430101* TX 3/25/2006 12/14/2006 9 1.25 ± 0.36 1.19 ± 0.35 0.06 ± 0.09 0.3 ± 0.13 0.68 ± 0.21 0.19 ± 0.07 0.06 480430101* TX 1/17/2005 3/1/2006 17 1.54 ± 0.45 1.44 ± 0.43 0.1 ± 0.12 0.36 ± 0.19 0.77 ± 0.19 0.27 ± 0.15 0.14 ± 483611100 TX 2/10/2005 8/21/2005 15 1.4 ± 0.24 1.36 ± 0.23 0.05 ± 0.07 0.35 ± 0.11 0.72 ± 0.13 0.25 ± 0.09 0.08 ± 490353006 UT 1/28/2005 12/4/2006 24 0.8 ± 0.37 0.78 ± 0.37 0.02 ± 0.07 0.23 ± 0.08 0.33 ± 0.16 0.17 ± 0.11 0.05 ± 490110004 UT 1/28/2005 11/7/2006 12 0.93 ± 0.24 0.92 ± 0.24 0.01 ± 0.03 0.29 ± 0.08 0.34 ± 0.13 0.21 ± 0.11 0.07 ± 490494001 UT 1/28/2005 11/7/2006 12 0.93 ± 0.2 0.93 ± 0.2 0 ± 0 0.29 ± 0.08 0.4 ± 0.1 0.2 ± 0.1 0.04 ± 515200006 VA 1/28/2005 9/8/2006 11 0.88 ± 0.25 0.87 ± 0.25 0 ± 0.01 0.24 ± 0.07 0.36 ± 0.14 0.21 ± 0.11 0.05 ± 511390004 VA 1/28/2005 9/8/2006 12 0.69 ± 0.2 0.68 ± 0.2 0.01 ± 0.02 0.24 ± 0.1 0.28 ± 0.1 0.13 ± 0.05 0.03 ± 510870014 VA 2/12/2005 12/4/2006 25 0.78 ± 0.18 0.77 ± 0.18 0.01 ± 0.02 0.21 ± 0.06 0.35 ± 0.14 0.17 ± 0.06 0.04 ± 500070012 VT 1/28/2005 12/4/2006 24 0.79 ± 0.44 0.78 ± 0.44 0.01 ± 0.03 0.19 ± 0.08 0.31 ± 0.14 0.21 ± 0.25 0.06 ± 530330080* WA 1/28/2005 2/7/2006 14 1.13 ± 1.49 1.11 ± 1.49 0.01 ± 0.05 0.2 ± 0.12 0.45 ± 0.63 0.36 ± 0.64 0.11 ± 530330048 WA 1/28/2005 11/7/2006 12 0.95 ± 0.31 0.95 ± 0.31 0 ± 0 0.29 ± 0.06 0.38 ± 0.19 0.21 ± 0.1 0.07 ± 530330024 WA 1/28/2005 11/12/2005 6 0.97 ± 0.37 0.97 ± 0.37 0 ± 0 0.32 ± 0.15 0.34 ± 0.19 0.24 ± 0.21 0.06 ± 530330057 WA 1/28/2005 11/7/2006 12 0.98 ± 0.25 0.97 ± 0.25 0 ± 0.01 0.34 ± 0.09 0.38 ± 0.15 0.2 ± 0.07 0.06 ± 530530029 WA 1/17/2006 11/7/2006 6 1.23 ± 0.81 1.23 ± 0.81 0 ± 0 0.37 ± 0.06 0.46 ± 0.27 0.26 ± 0.23 0.09 ± 530630016 WA 1/28/2005 11/7/2006 12 1.16 ± 0.19 1.16 ± 0.19 0 ± 0.01 0.36 ± 0.13 0.44 ± 0.1 0.29 ± 0.11 0.06 ± 530330080* WA 9/8/2006 12/4/2006 4 1.39 ± 0.13 1.39 ± 0.13 0 ± 0.01 0.31 ± 0.11 0.75 ± 0.24 0.28 ± 0.22 0.05 ± 110010042 D.C. 2/12/2005 7/10/2006 18 0.81 ± 0.2 0.8 ± 0.2 0.01 ± 0.02 0.24 ± 0.06 0.3 ± 0.1 0.2 ± 0.11 0.05 ± 110010043 D.C. 1/28/2005 12/4/2006 24 0.69 ± 0.18 0.69 ± 0.18 0.01 ± 0.01 0.23 ± 0.08 0.25 ± 0.07 0.16 ± 0.09 0.05 ± 
3-44

Table 3-3. Continued. 

Sampling Period Carbon Concentrations (μg/cm2) 

Site ID State From To 

No. of 

Field 

Blanks TC OC EC OC1 OC2 OC3 OC

550270007 WI 1/28/2005 12/4/2006 24 0.67 ± 0.23 0.66 ± 0.23 0 ± 0 0.17 ± 0.05 0.27 ± 0.09 0.16 ± 0.1 0.05 ± 551330027 WI 1/28/2005 11/7/2006 12 0.76 ± 0.19 0.75 ± 0.19 0.01 ± 0.01 0.23 ± 0.07 0.31 ± 0.12 0.17 ± 0.09 0.05 ± 551198001 WI 1/28/2005 11/7/2006 12 0.76 ± 0.19 0.75 ± 0.19 0 ± 0 0.23 ± 0.08 0.31 ± 0.11 0.16 ± 0.05 0.05 ± 550590019 WI 1/28/2005 11/12/2005 6 0.78 ± 0.24 0.78 ± 0.24 0 ± 0 0.2 ± 0.06 0.3 ± 0.09 0.24 ± 0.26 0.03 ± 550790026 WI 1/28/2005 12/4/2006 24 0.76 ± 0.26 0.76 ± 0.26 0 ± 0.01 0.19 ± 0.06 0.32 ± 0.11 0.19 ± 0.1 0.06 ± 540390011 WV 1/28/2005 12/4/2006 25 0.71 ± 0.18 0.69 ± 0.18 0.01 ± 0.03 0.2 ± 0.06 0.28 ± 0.1 0.15 ± 0.07 0.06 ± 540511002 WV 1/28/2005 11/7/2006 12 0.88 ± 0.18 0.88 ± 0.18 0 ± 0.01 0.29 ± 0.11 0.33 ± 0.09 0.2 ± 0.1 0.06 ± 540391005 WV 1/28/2005 11/7/2006 12 0.87 ± 0.16 0.87 ± 0.16 0 ± 0.01 0.25 ± 0.08 0.37 ± 0.12 0.21 ± 0.08 0.05 ± All 253 Sites 3628 0.98 ± 0.28 0.96 ± 0.25 0.02 ± 0.03 0.26 ± 0.06 0.4 ± 0.15 0.22 ± 0.06 0.08 ± a Site count includes 14 sites where the sampler type changed between 1/1/2005 and 12/31/2006, therefore there are 239 STN/C
3-45

Table 3-4. Average field blank concentrations by carbon fractions at the eight sites in the SEARCH network for 1/1/2005 through 12/31/2006. 

 Sampling Period Carbon Concentrations (μg/cm2) 

Site ID Site Name State From To 

No. of Field 

Blanks TC OC EC OC1 OC2 OC3 OC4 EC1 

GLF Gulf Port MS 1/1/2005 10/2/2006 14 0.45 ± 0.53 0.42 ± 0.44 0.03 ± 0.1 0.03 ± 0.05 0.12 ± 0.14 0.23 ± 0.17 0.01 ± 0.05 0.04 ± 0.OAK Oak Grove MS 1/31/2005 12/1/2006 19 0.54 ± 0.61 0.46 ± 0.45 0.07 ± 0.21 0.05 ± 0.08 0.09 ± 0.13 0.28 ± 0.26 0.04 ± 0.12 0.02 ± 0.BHM Birmingham AL 1/31/2005 10/31/2006 9 0.35 ± 0.23 0.34 ± 0.22 0.01 ± 0.02 0.1 ± 0.18 0.05 ± 0.11 0.19 ± 0.07 0 ± 0 0 ± CTR Centerville AL 1/31/2005 12/1/2006 23 0.71 ± 0.46 0.7 ± 0.46 0 ± 0.01 0.15 ± 0.23 0.24 ± 0.14 0.25 ± 0.16 0.01 ± 0.02 0 ± 0.JST Jefferson St GA 2/1/2005 11/14/2006 13 2 ± 1.24 1.82 ± 1.01 0.18 ± 0.51 0.87 ± 0.61 0.47 ± 0.28 0.39 ± 0.37 0.09 ± 0.2 0.15 ± 0.YRK Yorkville GA 1/31/2005 11/30/2006 20 1.49 ± 1.28 1.48 ± 1.28 0 ± 0.01 0.53 ± 0.66 0.45 ± 0.34 0.32 ± 0.19 0.15 ± 0.62 0.04 ± 0.PNS Pensacola FL 2/1/2005 12/29/2006 24 0.34 ± 0.2 0.33 ± 0.19 0.01 ± 0.03 0.06 ± 0.09 0.07 ± 0.08 0.19 ± 0.09 0 ± 0 0 ± 0.OLF Outlying Field FL 2/27/2005 12/31/2006 22 0.57 ± 0.64 0.53 ± 0.56 0.04 ± 0.11 0.07 ± 0.13 0.09 ± 0.13 0.34 ± 0.34 0.03 ± 0.11 0.02 ± 0.All 8 sites 144 0.81 ± 0.61 0.76 ± 0.57 0.04 ± 0.06 0.23 ± 0.3 0.2 ± 0.17 0.27 ± 0.07 0.04 ± 0.05 0.03 ± 0.
3-46

Table 3-5. Average blank concentration by PM2.5 speciation sampler type for the 239 sites in STN/CSN for the p

through 12/31/2006. 

μg/cm2 μg/filter 

Type of PM2.5 

Speciation Sampler 

Site 

Count 

No. of 

Field 

Blanks 

Sample

Volume 

(m3) TC OC EC TC OC EC TC 

Andersen RAAS 22 249 10.5 0.88 ± 0.33 0.88 ± 0.33 0.01 ± 0.03 10.4 ± 3.95 10.3 ± 3.93 0.1 ± 0.37 0.99 ± 0MetOne SASS 185 2572 9.6 0.86 ± 0.39 0.85 ± 0.38 0.01 ± 0.05 10.13 ± 4.55 10.03 ± 4.51 0.1 ± 0.59 1.05 ± 0URG MASS 7 150 24 0.75 ± 0.66 0.74 ± 0.66 0 ± 0.02 8.8 ± 7.79 8.75 ± 7.79 0.05 ± 0.2 0.37 ± 0R&P 2300 Sequential Speciation 15 236 14.4 1.33 ± 0.52 1.3 ± 0.51 0.03 ± 0.11 15.66 ± 6.08 15.32 ± 5.95 0.35 ± 1.27 1.09 ± 0R&P 2025 Sequential SCCa 24 421 24 1.57 ± 0.77 1.49 ± 0.76 0.08 ± 0.12 18.49 ± 9.03 17.53 ± 8.93 0.95 ± 1.34 0.78 ± 0Total 253b 3628 1.08 ± 0.35 1.05 ± 0.32 0.03 ± 0.03 12.7 ± 4.17 12.39 ± 3.81 0.31 ± 0.38 0.86 ± 0a R&P 2025 sequential Federal Reference Method (FRM) sampler using either a WINS impactor or a sharp-cut cyclone b Site count includes 14 sites where sampler type changed between 1/1/2005 and 12/31/2006. The actual number of sites is 239 
3-47

Table 3-6. Summary of average (± standard deviation) field and trip blank carbon densities and equivalent ambie

each STN/CSN samplers for the period from 1/1/2005 to 12/31/2006. 

 TC OC 

 μg/cm2 μg/cm2 

PM2.5 Speciation 

Sampler 

No. of Field Blanks 

No. of Trip Blanks 

Field Blank Average ± Std Dev 

Trip Blank Average ± Std Dev 

Field Blank Average ± Std Dev 

Trip Blank Average ± Std Dev 

Field BlanAverage ± Dev 

Andersen RAASa 249 241 0.88 ± 0.33 0.84 ± 0.38 0.88 ± 0.33 0.83 ± 0.34 0.01 ± 0.03 Met One SASSb 2,572 1,832 0.86 ± 0.40 0.89 ± 0.45 0.85 ± 0.38 0.88 ± 0.45 0.01 ± 0.05 URG MASSc 150 159 0.75 ± 0.67 0.81 ± 0.70 0.74 ± 0.66 0.80 ± 0.69 0.00 ± 0.02 R&P 2300d 236 103 1.33 ± 0.50 1.36 ± 0.48 1.30 ± 0.51 1.30 ± 0.48 0.03 ± 0.11 R&P 2025e,f 421 0 1.57 ± 0.83 N/Ag 1.49 ± 0.77 N/Ag 0.08 ± 0.11 Sampler Average 3628 2335 1.08 ± 0.35 0.98 ± 0.26 1.05 ± 0.32 0.95 ± 0.23 0.03 ± 0.03  TC OC 

 μg/m3 μg/m3 

PM2.5 Speciation 

Sampler 

No. of Field Blanks 

No. of Trip Blanks 

Field Blank Average ± Std Dev 

Trip Blank Average ± Std Dev 

Field Blank Average ± Std Dev 

Trip Blank Average ± Std Dev 

Field BlanAverage ± Dev 

Andersen RAASa 249 241 0.99 ± 0.37 0.94 ± 0.42 0.98 ± 0.37 0.93 ± 0.38 0.01 ± 0.03 Met One SASSb 2,572 1,832 1.05 ± 0.49 1.09 ± 0.56 1.04 ± 0.47 1.08 ± 0.55 0.01 ± 0.06 URG MASSc 150 159 0.37 ± 0.33 0.4 ± 0.34 0.36 ± 0.32 0.39 ± 0.34 0 ± 0.01 R&P 2300d 236 103 1.09 ± 0.41 1.11 ± 0.39 1.06 ± 0.41 1.06 ± 0.39 0.02 ± 0.09 R&P 2025e,f 421 0 0.77 ± 0.41 N/Ag 0.73 ± 0.38 N/Ag 0.04 ± 0.06 Sampler Average 3628 2335 0.85 ± 0.30 0.89 ± 0.33 0.83 ± 0.30 0.87 ± 0.32 0.02 ± 0.02 

a Flow rate of 7.3 L/min, 24-hr volume 10.5 m3b Flow rate of 6.7 L/min, 24-hr volume 9.6 m3c Flow rate of 16.7 L/min, 24-hr volume 24.0 m3d Flow rate of 10 L/min, 24-hr volume 14.4 m3e Flow rate of 16.7 L/min, 24-hr volume 24.0 m3f The samples from these Texas sites are analyzed by DRI g Data not available 
3-48

Table 3-7. Comparison of the quartz-fiber backup (QBQ) filter behind the quartz-fiber front filter between the IM

SEARCH networks for the period from 1/1/2005 through 12/31/2006. 

 μg/cm2a μg/filter μg/m3bCarbon Fraction 

IMPROVE (QBQc) 

SEARCH (dQBQd) 

IMPROVE (QBQc) 

SEARCH (dQBQd) 

IMPROVE (QBQc) 

SEARCH (dQBQd) 

TC 3.23 ± 0.96 1.29 ± 0.52 11.42 ± 3.37 9.17 ± 3.69 0.35 ± 0.1 0.38 ± 0.15 OCe 3.08 ± 0.83 1.19 ± 0.52 10.86 ± 2.94 8.45 ± 3.67 0.33 ± 0.09 0.35 ± 0.15 EC 0.16 ± 0.13 0.1 ± 0.06 0.56 ± 0.45 0.71 ± 0.43 0.02 ± 0.01 0.03 ± 0.02 OC1 0.56 ± 0.07 0.26 ± 0.38 1.98 ± 0.25 1.82 ± 2.68 0.06 ± 0.01 0.08 ± 0.11 OC2 0.95 ± 0.23 0.35 ± 0.15 3.36 ± 0.81 2.53 ± 1.05 0.1 ± 0.02 0.11 ± 0.04 OC3 1.15 ± 0.35 0.47 ± 0.06 4.05 ± 1.22 3.37 ± 0.4 0.12 ± 0.04 0.14 ± 0.02 OC4 0.31 ± 0.18 0.07 ± 0.02 1.1 ± 0.64 0.53 ± 0.13 0.03 ± 0.02 0.02 ± 0.01 EC1 0.18 ± 0.16 0.07 ± 0.05 0.64 ± 0.58 0.47 ± 0.34 0.02 ± 0.02 0.02 ± 0.01 EC2 0.08 ± 0.06 0.05 ± 0.04 0.28 ± 0.22 0.38 ± 0.31 0.01 ± 0.01 0.02 ± 0.01 EC3 0 ± 0 0.01 ± 0.01 0.02 ± 0.01 0.07 ± 0.06 0 ± 0 0 ± 0 No. of Sites in Average 6 8 6 8 6 8 No. of Samples in Average 1401 257 1401 257 1401 257 

a The exposed filter area is 3.53 cm2 for the 25 mm IMPROVE Pallflex® Tissuquartz filters and 7.12 cm2 for the 37 mm SEARCH b The sampling volume is 32.7 m3 for the IMPROVE Module C sampler and 24 m3 for the PCM sampler in the SEARCH network c QBQ: Quartz-fiber backup filter behind the quartz-fiber front filter d dQBQ: denuded quartz-fiber backup filter (QBQ with preceding organic denuder) e Following the IMPROVE_A protocol by reflectance 
3-49

Table 3-8. Summary of field blanks acquired at the 181 sites in the IMPROVE network from 1/1/2005 to 12/31/2

 Sampling Period Total Field # of F

SiteID Name State From To Blanks Spring SummACAD1 Acadia NP ME 1/13/2005 1/5/2006 3 1 ADPI1 Addison Pinnacle NY 1/13/2005 5/11/2006 6 3 AGTI1 Agua Tibia CA 5/19/2005 11/16/2006 7 1 AREN1 Arendtsville PA 1/13/2005 3/30/2006 5 2 ATLA1 Atlanta GA 1/13/2005 11/19/2006 8 3 BADL1 Badlands NP SD 1/13/2005 12/7/2006 7 1 BALD1 Mount Baldy AZ 3/17/2005 6/1/2006 5 2 BALT1 Baltimore MD 1/13/2005 12/15/2005 4 1 BAND1 Bandelier NM NM 3/17/2005 12/28/2006 9 3 BIBE1 Big Bend NP TX 3/17/2005 8/24/2006 7 3 BIRM1 Birmingham AL 1/13/2005 8/24/2006 5 1 BLIS1 Bliss SP (TRPA) CA 3/17/2005 10/26/2006 10 3 BLMO1 Blue Mounds MN 1/13/2005 1/5/2006 4 2 BOAP1 Bosque del Apache NM 1/13/2005 12/7/2006 8 0 BOND1 Bondville IL 3/17/2005 11/16/2006 5 3 BOWA1 Boundary Waters Canoe Area MN 3/30/2006 9/14/2006 3 2 BRCA1 Bryce Canyon NP UT 7/21/2005 11/16/2006 5 0 BRET1 Breton LA 2/3/2005 2/3/2005 1 0 BRID1 Bridger Wilderness WY 5/19/2005 12/7/2006 2 1 BRID9 Bridger Wilderness WY 1/13/2005 1/13/2005 1 0 BRIG1 Brigantine NWR NJ 2/3/2005 5/11/2006 6 3 BRMA1 Bridgton ME 1/13/2005 10/26/2006 6 2 CABA1 Casco Bay ME 5/19/2005 12/28/2006 6 2 CABI1 Cabinet Mountains MT 5/19/2005 2/16/2006 3 1 CACO1 Cape Cod MA 10/13/2005 12/28/2006 2 0 CACR1 Caney Creek AR 1/13/2005 9/14/2006 7 3 CADI1 Cadiz KY 5/19/2005 11/16/2006 7 3 CANY1 Canyonlands NP UT 7/21/2005 10/5/2006 9 1 CAPI1 Capitol Reef NP UT 3/17/2005 12/7/2006 6 1 CEBL1 Cedar Bluff KS 1/13/2005 10/26/2006 10 2 CHAS1 Chassahowitzka NWR FL 6/9/2005 10/5/2006 8 3 CHER1 Cherokee Nation OK 10/13/2005 9/14/2006 3 1 CHIC1 Chicago IL 1/13/2005 3/17/2005 2 1 CHIR1 Chiricahua NM AZ 1/13/2005 8/24/2006 5 2 CLPE1 Cloud Peak WY 3/17/2005 4/20/2006 3 2 COGO1 Columbia Gorge #1 WA 3/17/2005 10/5/2006 6 3 COHI1 Connecticut Hill NY 7/21/2005 12/15/2005 3 0 COHU1 Cohutta GA 3/17/2005 3/17/2005 1 1 CORI1 Columbia River Gorge WA 3/17/2005 12/7/2006 5 2 CRES1 Crescent Lake NE 3/17/2005 6/1/2006 6 4 CRLA1 Crater Lake NP OR 5/19/2005 12/7/2006 7 1 CRMO1 Craters of the Moon NM ID 3/17/2005 5/11/2006 4 3 DENA1 Denali NP AK 5/19/2005 12/28/2006 7 1 DETR1 Detroit MI 4/7/2005 12/31/2006 8 2 DEVA1 Death Valley NP CA 3/17/2005 10/5/2006 4 1 DOME1 Dome Lands Wilderness CA 12/15/2005 12/28/2006 4 0 DOSO1 Dolly Sods Wilderness WV 3/17/2005 9/14/2006 9 3 DOUG1 Douglas AZ 1/13/2005 12/28/2006 6 1 EGBE1 N/A 9/1/2005 10/5/2006 5 1 ELDO1 El Dorado Springs MO 7/21/2005 7/13/2006 6 2 
3-50

Table 3-8. Continued. 

 Sampling Period Total Field # of F

SiteID Name State From To Blanks Spring SummELLI1 Ellis OK 3/17/2005 5/11/2006 7 3 EVER1 Everglades NP FL 1/13/2005 9/14/2006 6 1 FLAT1 Flathead MT 1/13/2005 10/5/2006 8 1 FOPE1 Fort Peck MT 3/17/2005 11/16/2006 6 1 FRES1 Fresno CA 5/19/2005 11/16/2006 7 2 FRRE1 Frostburg MD 5/19/2005 8/3/2006 4 1 GAMO1 Gates of the Mountains MT 5/19/2005 10/13/2005 2 1 GICL1 Gila Wilderness NM 4/7/2005 7/13/2006 4 1 GLAC1 Glacier NP MT 1/13/2005 11/16/2006 5 2 GRBA1 Great Basin NP NV 1/13/2005 12/28/2006 10 2 GRGU1 Great Gulf Wilderness NH 1/13/2005 3/9/2006 5 2 GRRI1 Great River Bluffs MN 5/19/2005 12/15/2005 3 1 GRSA1 Great Sand Dunes NM CO 10/13/2005 10/5/2006 3 1 GRSM1 Great Smoky Mountains NP TN 1/13/2005 10/26/2006 6 2 GRSM9 Great Smoky Mountains NP TN 1/13/2005 1/13/2005 1 0 GUMO1 Guadalupe Mountains NP TX 7/21/2005 12/28/2006 5 1 HALE1 Haleakala NP HI 3/17/2005 12/28/2006 8 2 HANC1 Hance Camp at Grand Canyon NP CO 1/13/2005 4/20/2006 3 1 HAVO1 Hawaii Volcanoes NP HI 1/13/2005 12/28/2006 8 0 HECA1 Hells Canyon OR 1/13/2005 11/16/2006 7 3 HEGL1 Hercules-Glades MO 1/13/2005 11/16/2006 7 2 HOOV1 Hoover CA 1/13/2005 9/14/2006 8 1 HOUS1 Houston TX 5/19/2005 7/21/2005 2 1 IKBA1 Ike's Backbone AZ 12/15/2005 12/15/2005 1 0 INGA1 Indian Gardens AZ 2/3/2005 9/14/2006 6 0 ISLE1 Isle Royale NP MI 1/13/2005 11/16/2006 6 2 JARI1 James River Face Wilderness VA 1/13/2005 6/1/2006 5 1 JOSH1 Joshua Tree NP CA 1/13/2005 7/13/2006 6 3 KAIS1 Kaiser CA 1/13/2005 1/5/2006 5 1 KALM1 Kalmiopsis OR 1/13/2005 11/16/2006 4 0 LABE1 Lava Beds NM CA 1/13/2005 5/11/2006 7 4 LASU2 Lake Sugema IA 1/13/2005 12/15/2005 3 0 LAVO1 Lassen Volcanic NP CA 1/13/2005 1/5/2006 3 0 LIGO1 Linville Gorge NC 3/17/2005 4/20/2006 5 3 LIVO1 Livonia IN 1/13/2005 5/19/2005 2 1 LOST1 Lostwood ND 5/19/2005 11/16/2006 5 2 LYBR1 Lye Brook Wilderness VT 1/13/2005 12/7/2006 6 1 MACA1 Mammoth Cave NP KY 5/19/2005 12/7/2006 5 2 MAVI1 Martha's Vineyard MA 5/19/2005 7/13/2006 5 3 MEAD1 Meadview AZ 5/19/2005 5/19/2005 1 1 MELA1 Medicine Lake MT 3/17/2005 8/24/2006 3 2 MEVE1 Mesa Verde NP CO 1/13/2005 12/28/2006 9 1 MING1 Mingo MO 5/19/2005 9/14/2006 4 1 MKGO1 M.K. Goddard PA 3/17/2005 8/24/2006 7 4 MOHO1 Mount Hood OR 1/13/2005 8/24/2006 7 3 MOMO1 Mohawk Mt. CT 3/17/2005 12/7/2006 4 1 MONT1 Monture MT 1/13/2005 11/16/2006 7 2 MOOS1 Moosehorn NWR ME 1/13/2005 12/7/2006 7 2 MORA1 Mount Rainier NP WA 1/13/2005 11/16/2006 5 2 MORA9 Mount Rainier NP WA 1/13/2005 1/13/2005 1 0 MOZI1 Mount Zirkel Wilderness CO 3/17/2005 11/16/2006 8 4 NEBR1 Nebraska NF NE 1/13/2005 6/22/2006 5 1 NEYO1 New York City NY 5/19/2005 12/15/2005 3 1 
3-51

Table 3-8. Continued. 

 Sampling Period Total Field # of F

SiteID Name State From To Blanks Spring SummNOAB1 North Absaroka WY 3/30/2006 10/5/2006 3 1 NOCA1 North Cascades WA 3/17/2005 12/28/2006 7 2 NOCH1 Northern Cheyenne MT 9/1/2005 10/5/2006 3 1 OKEF1 Okefenokee NWR GA 6/1/2006 6/1/2006 1 0 OLTO1 Old Town ME 5/19/2005 4/20/2006 4 2 OLYM1 Olympic WA 2/3/2005 2/16/2006 2 0 OMAH1 Omaha NE 3/17/2005 10/5/2006 4 1 ORPI1 Organ Pipe AZ 3/17/2005 11/16/2006 5 2 PASA1 Pasayten WA 5/19/2005 10/5/2006 6 1 PEFO1 Petrified Forest NP AZ 3/17/2005 12/7/2006 6 3 PENO1 N/A 3/30/2006 8/24/2006 2 1 PETE1 Petersburg AK 4/7/2005 9/14/2006 8 3 PHOE1 Phoenix AZ 1/13/2005 5/11/2006 6 2 PHOE5 Phoenix AZ 1/13/2005 5/11/2006 5 1 PINN1 Pinnacles NM CA 3/9/2006 5/11/2006 2 2 PITT1 Pittsburgh PA 1/13/2005 12/10/2006 8 2 PMRF1 Proctor Maple R. F. VT 3/17/2005 7/13/2006 4 2 PORE1 Point Reyes National Seashore CA 7/21/2005 11/16/2006 4 1 PRIS1 Presque Isle ME 2/3/2005 4/20/2006 3 2 PUSO1 Puget Sound WA 3/17/2005 1/5/2006 2 1 QUCI1 Quaker City OH 10/5/2006 10/5/2006 1 0 QURE1 Quabbin Summit MA 1/13/2005 2/16/2006 4 0 QUVA1 Queen Valley AZ 3/17/2005 11/16/2006 3 1 RAFA1 San Rafael CA 1/13/2005 12/7/2006 7 1 REDW1 Redwood NP CA 1/13/2005 12/7/2006 6 1 ROMA1 Cape Romain NWR SC 1/13/2005 7/13/2006 5 3 ROMO2 Cape Romain NWR SC 1/13/2005 1/13/2005 1 0 RUBI1 Rubidoux CA 3/17/2005 7/21/2005 3 2 SACR1 Salt Creek NM 1/13/2005 8/3/2006 5 1 SAFO1 Sac and Fox KS 1/13/2005 2/16/2006 4 0 SAGA1 San Gabriel CA 1/13/2005 10/5/2006 4 2 SAGO1 San Gorgonio Wilderness CA 3/17/2005 9/14/2006 4 3 SAGU1 Saguaro NM AZ 1/13/2005 11/16/2006 2 0 SAMA1 St. Marks FL 5/19/2005 11/16/2006 7 2 SAPE1 San Pedro Parks NM 3/17/2005 2/16/2006 3 2 SAWE1 Saguaro West AZ 1/13/2005 6/1/2006 7 4 SAWT1 Sawtooth NF ID 1/13/2005 11/16/2006 4 0 SENE1 Seney MI 3/17/2005 11/16/2006 3 1 SEQU1 Sequoia NP CA 12/15/2005 11/16/2006 4 0 SEQU9 Sequoia NP CA 1/13/2005 1/13/2005 1 0 SHEN1 Shenandoah NP VA 1/13/2005 1/5/2006 9 6 SHMI1 Shamrock Mine CO 5/19/2005 5/11/2006 2 2 SHRO1 Shining Rock Wilderness NC 3/17/2005 5/11/2006 6 4 SIAN1 Sierra Ancha AZ 7/21/2005 10/5/2006 4 1 SIKE1 Sikes LA 1/13/2005 8/3/2006 6 0 SIME1 Simeonof AK 1/13/2005 10/5/2006 7 2 SIPS1 Sipsy Wilderness AL 5/19/2005 12/7/2006 3 1 SNPA1 Snoqualmie Pass WA 7/21/2005 12/28/2006 7 0 SPOK1 Spokane Res. WA 5/19/2005 6/9/2005 2 1 STAR1 Starkey OR 2/3/2005 12/7/2006 4 1 SULA1 Sula Peak MT 5/19/2005 11/16/2006 3 1 SWAN1 Swanquarter NC 3/17/2005 3/9/2006 5 2 SYCA1 Sycamore Canyon AZ 1/13/2005 9/14/2006 6 1 
3-52

Table 3-8. Continued. 

 Sampling Period Total Field # of F

SiteID Name State From To Blanks Spring SummTALL1 Tallgrass KS 1/13/2005 11/16/2006 5 0 THBA1 Thunder Basin WY 5/19/2005 11/16/2006 8 2 THRO1 Theodore Roosevelt ND 5/19/2005 5/19/2005 1 1 THSI1 Three Sisters Wilderness OR 1/13/2005 12/28/2006 5 1 TONT1 Tonto NM AZ 12/15/2005 12/28/2006 5 1 TRCR1 Trapper Creek AK 3/17/2005 9/14/2006 4 1 TRIN1 Trinity CA 1/13/2005 7/21/2005 4 2 TUXE1 Tuxedni AK 6/9/2005 11/16/2006 7 1 ULBE1 UL Bend MT 1/13/2005 12/7/2006 7 1 UPBU1 Upper Buffalo Wilderness AR 3/17/2005 9/14/2006 5 1 VIIS1 Virgin Islands NP VI 3/17/2005 11/16/2006 8 1 VILA1 Viking Lake IA 1/13/2005 7/13/2006 4 0 VOYA1 Voyageurs NP #1 MN 1/13/2005 7/13/2006 5 2 WARI1 Walker River Paiute Tribe NV 5/19/2005 10/13/2005 4 1 WASH1 Washington D.C. DC 12/7/2006 12/7/2006 1 0 WEMI1 Weminuche Wilderness CO 1/13/2005 2/16/2006 4 1 WHIT1 White Mountain NM 5/19/2005 11/16/2006 4 1 WHPA1 White Pass WA 3/17/2005 7/13/2006 7 3 WHPE1 Wheeler Peak NM 4/16/2005 4/8/2006 3 2 WHRI1 White River NF CO 3/17/2005 12/7/2006 4 1 WICA1 Wind Cave SD 1/13/2005 12/7/2006 4 2 WIMO1 Wichita Mountains OK 7/21/2005 11/16/2006 6 1 YELL1 Yellowstone NP 1 WY 1/13/2005 9/14/2006 6 2 YOSE1 Yosemite NP CA 3/17/2005 8/24/2006 4 1 ZICA1 Zion Canyon UT 2/3/2005 12/7/2006 5 0 Total 886 268 There are 13 Urban sites in the IMPROVE network: Atlanta, GA (ATLA); Baltimore, MD (BALT); Birmingham, AL (BIRM); Chicago(DETR); Fresno, CA (FRES); Houston, TX (HOUS); New York, NY (NEYO); Old Town, ME (OLTO); Phoenix, AZ (PHOE); Pittsburg

(RUBI); Washington, DC (WASH).
3-53

Table 3-9. Summary of field blanks acquired at the 239 sites in the STN/CSN network from 1/1/2005 to 12/31/2

Sampling Period No. of Field Blank

Site Code State From To Total Field Blanks Spring Summer 

010050002 AL 1/28/2005 1/17/2006 7 2 1 010730023 AL 1/28/2005 12/4/2006 24 6 6 010731009 AL 1/28/2005 5/11/2006 9 4 1 010732003 AL 1/28/2005 11/7/2006 12 4 2 010890014 AL 1/28/2005 11/7/2006 12 4 2 010970003 AL 1/28/2005 1/17/2006 7 2 1 011011002 AL 1/28/2005 11/7/2006 10 4 1 011030011 AL 1/28/2005 9/7/2005 5 2 1 011130001 AL 5/16/2005 11/7/2006 12 3 2 020900010 AK 4/13/2005 12/4/2006 18 5 4 040130019 AZ 1/28/2005 11/12/2005 6 2 1 040137003 AZ 3/11/2005 11/7/2006 11 4 2 040137020 AZ 3/11/2005 11/7/2006 11 4 2 040139997 AZ 1/28/2005 12/4/2006 24 6 6 040139998 AZ 1/28/2005 11/12/2005 6 2 1 040191028 AZ 1/28/2005 9/8/2006 11 4 2 050030005 AR 1/28/2005 5/16/2005 3 2 0 051190007 AR 1/28/2005 11/7/2006 12 4 2 051450001 AR 1/28/2005 5/16/2005 3 2 0 060190008 CA 1/28/2005 12/4/2006 24 6 6 060290014 CA 1/28/2005 12/4/2006 41 8 9 060371103 CA 1/28/2005 11/7/2006 12 4 2 060658001 CA 1/28/2005 12/4/2006 34 9 7 060670006 CA 1/28/2005 12/4/2006 24 6 6 060730003 CA 1/28/2005 12/4/2006 24 6 6 060850005 CA 1/28/2005 12/4/2006 24 6 6 061112002 CA 1/28/2005 11/7/2006 12 4 2 080010006 CO 1/28/2005 12/4/2006 24 6 6 080410011 CO 1/28/2005 11/7/2006 12 4 2 080770017 CO 1/28/2005 11/7/2006 12 4 2 081230008 CO 1/28/2005 11/7/2006 12 4 2 090090027 CT 1/28/2005 12/4/2006 22 5 6 100010003 DE 1/28/2005 11/7/2006 12 4 2 100032004 DE 1/28/2005 11/7/2006 12 4 2 110010042 D.C. 2/12/2005 7/10/2006 18 6 5 110010043 D.C. 1/28/2005 12/4/2006 24 6 6 120111002 FL 1/17/2006 12/4/2006 12 3 3 120330004 FL 1/28/2005 3/12/2006 8 3 1 120573002 FL 1/28/2005 12/4/2006 24 6 6 120730012 FL 1/28/2005 11/7/2006 12 4 2 120861016 FL 1/28/2005 12/9/2005 12 3 3 121030026 FL 1/28/2005 12/4/2006 24 6 6 130210007 GA 1/28/2005 11/12/2005 6 2 1 130210007 GA 1/17/2006 11/7/2006 6 2 1 
3-54

Table 3-9. Continued. 

Sampling Period No. of Field Blank

Site Code State From To Total Field Blanks Spring Summer 

130590001 GA 1/28/2005 11/12/2005 7 2 1 130590001 GA 1/17/2006 11/7/2006 6 2 1 130690002 GA 1/17/2006 11/7/2006 6 2 1 130690002 GA 1/28/2005 11/12/2005 5 1 1 130890002 GA 1/28/2005 12/9/2005 12 3 3 130890002 GA 1/17/2006 12/4/2006 13 3 3 131150005 GA 1/28/2005 11/12/2005 6 2 1 131150005 GA 1/17/2006 11/7/2006 6 2 1 132150011 GA 1/28/2005 11/12/2005 6 2 1 132150011 GA 1/17/2006 11/7/2006 6 2 1 132450091 GA 1/28/2005 11/12/2005 6 2 1 132450091 GA 5/11/2006 11/7/2006 4 1 1 150032004 HI 1/28/2005 11/7/2006 12 4 2 160010010 ID 7/10/2006 12/4/2006 6 0 2 160270004 ID 1/28/2005 6/7/2006 18 6 4 170310057 IL 1/17/2006 11/7/2006 6 2 1 170310057 IL 1/28/2005 11/12/2005 6 2 1 170310076 IL 1/28/2005 12/27/2005 13 3 3 170310076 IL 1/17/2006 12/4/2006 12 3 3 170314201 IL 1/28/2005 11/7/2006 12 4 2 170434002 IL 1/28/2005 11/7/2006 12 4 2 171150013 IL 1/28/2005 11/7/2006 12 4 2 171192009 IL 1/28/2005 11/7/2006 12 4 2 180372001 IN 1/28/2005 11/7/2006 12 4 2 180390003 IN 1/28/2005 11/7/2006 12 4 2 180650003 IN 1/28/2005 11/7/2006 12 4 2 180890022 IN 1/28/2005 11/7/2006 12 4 2 180892004 IN 1/28/2005 11/7/2006 12 4 2 180970078 IN 1/28/2005 12/4/2006 25 6 6 181630012 IN 1/28/2005 11/7/2006 12 4 2 191130037 IA 1/28/2005 11/7/2006 12 4 2 191530030 IA 1/28/2005 11/7/2006 12 4 2 191630015 IA 1/28/2005 12/4/2006 23 5 6 201730010 KS 1/28/2005 11/7/2006 12 4 2 202090021 KS 1/28/2005 12/4/2006 23 6 6 210190017 KY 1/28/2005 11/7/2006 12 4 2 210590005 KY 1/28/2005 1/17/2006 7 2 1 210670012 KY 1/28/2005 9/8/2006 11 4 2 211110043 KY 1/28/2005 11/7/2006 12 4 2 211110048 KY 1/28/2005 1/17/2006 7 2 1 211170007 KY 1/28/2005 11/7/2006 12 4 2 211250004 KY 1/28/2005 3/12/2006 8 3 1 211451004 KY 1/28/2005 1/17/2006 7 2 1 211930003 KY 1/28/2005 11/7/2006 12 4 2 212270007 KY 1/28/2005 1/17/2006 7 2 1 220150008 LA 1/28/2005 12/1/2006 13 4 2 
3-55

Table 3-9. Continued. 

Sampling Period No. of Field Blank

Site Code State From To Total Field Blanks Spring Summer 

220330009 LA 2/12/2005 12/4/2006 24 6 6 240053001 MD 1/28/2005 12/4/2006 24 6 6 240330030 MD 1/28/2005 11/7/2006 12 4 2 250130008 MA 1/28/2005 12/4/2006 20 6 6 250250042 MA 1/28/2005 12/4/2006 36 10 8 260050003 MI 1/28/2005 3/12/2006 8 3 1 260330901 MI 1/28/2005 3/12/2006 11 4 2 260770008 MI 1/28/2005 11/7/2006 12 4 2 260810020 MI 1/28/2005 11/7/2006 12 4 2 261130001 MI 1/28/2005 11/7/2006 12 4 2 261150005 MI 1/28/2005 11/7/2006 11 3 2 261610008 MI 1/28/2005 11/7/2006 12 4 2 261630001 MI 1/28/2005 12/4/2006 23 6 6 261630033 MI 1/28/2005 11/7/2006 12 4 2 270530963 MN 1/28/2005 12/4/2006 24 6 6 270953051 MN 1/28/2005 7/15/2005 7 3 2 271095008 MN 1/28/2005 11/7/2006 11 4 1 271230871 MN 1/28/2005 3/11/2005 2 1 0 280350004 MS 1/28/2005 11/12/2005 6 2 1 280430001 MS 1/28/2005 1/17/2006 8 2 1 280470008 MS 1/28/2005 12/4/2006 19 6 6 280490018 MS 1/28/2005 5/11/2006 9 4 1 280670002 MS 1/28/2005 11/12/2005 6 2 1 290470005 MO 1/28/2005 12/4/2006 23 6 6 290530001 MO 3/11/2005 5/11/2006 6 3 0 290990012 MO 1/28/2005 10/5/2006 21 6 6 290990012 MO 11/7/2006 12/4/2006 2 0 0 291860005 MO 1/28/2005 12/4/2006 24 6 6 295100085 MO 1/28/2005 12/4/2006 23 6 5 300530018 MT 1/28/2005 11/7/2006 12 4 2 300630031 MT 1/28/2005 12/4/2006 24 6 6 310550019 NE 1/28/2005 12/4/2006 24 7 5 320030561 NV 1/28/2005 11/7/2006 12 4 2 320310016 NV 1/28/2005 12/4/2006 24 6 6 330110020 NH 1/28/2005 11/12/2005 5 1 1 330150014 NH 2/3/2005 12/7/2006 23 6 5 340070003 NJ 1/28/2005 12/4/2006 23 6 5 340230006 NJ 1/28/2005 12/4/2006 34 10 6 340273001 NJ 1/28/2005 12/4/2006 23 6 5 340390004 NJ 1/28/2005 12/4/2006 23 6 5 350010023 NM 1/28/2005 11/7/2006 12 4 2 360050083 NY 1/28/2005 12/9/2005 12 3 3 360050110 NY 1/17/2006 12/4/2006 13 4 3 360050110 NY 2/12/2005 12/9/2005 8 3 0 360290005 NY 1/28/2005 11/7/2006 12 4 2 360310003 NY 1/28/2005 11/7/2006 18 5 4 
3-56

Table 3-9. Continued. 

Sampling Period No. of Field Blank

Site Code State From To Total Field Blanks Spring Summer 

360551007 NY 1/28/2005 12/4/2006 24 6 6 360610062 NY 1/28/2005 12/4/2006 23 6 6 360810124 NY 2/12/2005 12/4/2006 25 6 7 361010003 NY 1/28/2005 12/4/2006 23 6 5 370210034 NC 1/28/2005 11/7/2006 12 4 2 370350004 NC 1/28/2005 11/7/2006 12 4 2 370570002 NC 1/28/2005 11/7/2006 12 4 2 370670022 NC 1/28/2005 11/7/2006 11 4 1 370810013 NC 1/28/2005 9/8/2006 11 4 2 371070004 NC 1/28/2005 11/7/2006 12 4 2 371190041 NC 1/28/2005 12/4/2006 24 6 6 371590021 NC 1/28/2005 11/7/2006 12 4 2 371830014 NC 1/28/2005 11/7/2006 17 6 1 380150003 ND 1/28/2005 11/7/2006 12 4 2 380171004 ND 1/28/2005 12/4/2006 23 6 6 380530002 ND 1/28/2005 11/7/2006 13 4 2 390171004 OH 1/28/2005 11/7/2006 12 4 2 390350038 OH 1/28/2005 11/7/2006 12 4 2 390350060 OH 1/10/2005 12/4/2006 49 13 11 390490081 OH 1/28/2005 11/7/2006 12 4 2 390610040 OH 1/28/2005 11/7/2006 12 4 2 390810017 OH 1/28/2005 11/7/2006 11 3 2 390870010 OH 1/28/2005 11/7/2006 11 3 2 390930016 OH 1/28/2005 11/12/2005 6 2 1 390933002 OH 1/17/2006 11/7/2006 6 2 1 390950026 OH 1/28/2005 11/7/2006 12 4 2 390990014 OH 1/28/2005 11/7/2006 12 4 2 391130031 OH 3/11/2005 11/7/2006 11 4 2 391510017 OH 3/11/2005 9/8/2006 10 4 2 391530023 OH 1/28/2005 11/7/2006 11 4 2 400450890 OK 1/28/2005 3/12/2006 7 3 1 401091037 OK 1/28/2005 11/7/2006 12 4 2 401431127 OK 1/28/2005 12/4/2006 23 5 6 410510246 OR 1/28/2005 12/4/2006 24 6 6 420010001 PA 1/28/2005 11/7/2006 12 4 2 420030008 PA 2/12/2005 12/4/2006 21 5 6 420030064 PA 1/28/2005 11/7/2006 12 4 2 420110009 PA 3/12/2006 3/12/2006 1 1 0 420110010 PA 7/10/2006 11/7/2006 3 0 1 420270100 PA 1/28/2005 11/7/2006 12 4 2 420290100 PA 3/11/2005 11/7/2006 11 4 2 420430401 PA 1/28/2005 11/7/2006 12 4 2 420450002 PA 1/28/2005 11/7/2006 12 4 2 420490003 PA 1/28/2005 11/7/2006 12 4 2 420692006 PA 1/28/2005 11/7/2006 12 4 2 420710007 PA 1/28/2005 11/7/2006 12 4 2 
3-57

Table 3-9. Continued. 

Sampling Period No. of Field Blank

Site Code State From To Total Field Blanks Spring Summer 

420950025 PA 1/28/2005 11/7/2006 11 3 2 420990301 PA 1/28/2005 11/12/2005 6 2 1 421010004 PA 1/28/2005 12/4/2006 23 5 6 421010136 PA 1/28/2005 11/7/2006 12 4 2 421255001 PA 1/28/2005 11/7/2006 12 4 2 421290008 PA 1/28/2005 11/7/2006 12 4 2 421330008 PA 1/28/2005 11/7/2006 12 4 2 440070022 RI 1/28/2005 12/4/2006 24 6 6 450190049 SC 1/28/2005 12/25/2006 25 6 6 450250001 SC 1/28/2005 11/7/2006 12 4 2 450450009 SC 1/28/2005 11/7/2006 16 5 2 450790019 SC 1/28/2005 11/7/2006 12 4 2 460990006 SD 1/28/2005 11/7/2006 12 4 2 470370023 TN 1/28/2005 11/7/2006 12 4 2 470654002 TN 1/28/2005 11/7/2006 11 4 2 470931020 TN 1/28/2005 11/7/2006 12 4 2 470990002 TN 1/28/2005 11/7/2006 12 4 2 471570024 TN 6/7/2006 12/4/2006 7 0 3 471570047 TN 1/28/2005 4/8/2006 17 5 3 471631007 TN 1/28/2005 11/7/2006 12 4 2 471650007 TN 1/28/2005 3/12/2006 8 3 1 480430002 TX 1/3/2005 7/5/2005 6 1 2 480430101 TX 3/25/2006 12/14/2006 9 2 3 480430101 TX 1/17/2005 3/1/2006 17 4 4 480612004 TX 10/8/2005 12/14/2006 15 2 3 481130050 TX 1/5/2005 12/26/2006 60 16 15 481130069 TX 1/28/2005 12/4/2006 24 6 6 481390015 TX 1/17/2005 8/21/2005 10 3 4 481410044 TX 1/28/2005 11/7/2006 21 5 5 481410053 TX 1/17/2005 12/14/2006 29 7 8 481670014 TX 1/5/2005 8/21/2005 12 2 6 482010024 TX 1/5/2005 12/20/2006 30 11 8 482010026 TX 1/5/2005 8/21/2005 20 8 7 482010055 TX 1/5/2005 8/21/2005 16 5 7 482011034 TX 1/17/2005 8/21/2005 10 3 4 482011039 TX 1/28/2005 12/4/2006 41 10 7 482030002 TX 1/17/2005 8/21/2005 19 8 7 482430004 TX 1/29/2005 8/1/2005 8 3 3 482450021 TX 10/24/2005 12/26/2006 36 8 8 482450022 TX 1/5/2005 8/21/2005 19 8 7 482570005 TX 1/17/2005 8/21/2005 10 3 4 482730314 TX 1/29/2005 8/21/2005 9 3 4 483030001 TX 1/17/2005 6/10/2005 7 3 1 483390078 TX 1/5/2005 8/21/2005 20 8 7 483550034 TX 5/12/2006 11/20/2006 8 1 4 483550034 TX 1/17/2005 4/18/2006 20 6 4 
3-58

Table 3-9. Continued. 

Sampling Period No. of Field Blank

Site Code State From To Total Field Blanks Spring Summer 

483611100 TX 2/10/2005 8/21/2005 15 7 7 484530020 TX 10/8/2005 12/14/2006 16 2 4 490110004 UT 1/28/2005 11/7/2006 12 4 2 490353006 UT 1/28/2005 12/4/2006 24 6 6 490494001 UT 1/28/2005 11/7/2006 12 4 2 500070012 VT 1/28/2005 12/4/2006 24 6 6 510870014 VA 2/12/2005 12/4/2006 25 7 6 511390004 VA 1/28/2005 9/8/2006 12 4 2 515200006 VA 1/28/2005 9/8/2006 11 4 2 530330024 WA 1/28/2005 11/12/2005 6 2 1 530330048 WA 1/28/2005 11/7/2006 12 4 2 530330057 WA 1/28/2005 11/7/2006 12 4 2 530330080 WA 1/28/2005 2/7/2006 14 3 3 530330080 WA 9/8/2006 12/4/2006 4 0 0 530530029 WA 1/17/2006 11/7/2006 6 2 1 530630016 WA 1/28/2005 11/7/2006 12 4 2 540390011 WV 1/28/2005 12/4/2006 25 7 6 540391005 WV 1/28/2005 11/7/2006 12 4 2 540511002 WV 1/28/2005 11/7/2006 12 4 2 550270007 WI 1/28/2005 12/4/2006 24 6 6 550590019 WI 1/28/2005 11/12/2005 6 2 1 550790026 WI 1/28/2005 12/4/2006 24 6 6 551198001 WI 1/28/2005 11/7/2006 12 4 2 551330027 WI 1/28/2005 11/7/2006 12 4 2 720610001 PR 1/28/2005 3/12/2006 14 4 2 Total 253a 3628 1065 781 a Site count includes 14 sites where sampler type changed between 1/1/2005 and 12/31/2006 
3-59

Table 3-10. Summary of field blanks acquired at the eight sites in the SEARCH network from 1/1/2005 to 12/31

 Sampling Period 

Site 

Code Site Name From To 

Number of 

Blanks Spring Summer 

GLF Gulfport, MS 1/1/2005 10/2/2006 14 2 4 OAK Oak Grove, MS 1/31/2005 12/1/2006 19 4 5 BHM Birmingham, AL 1/31/2005 10/31/2006 9 5 2 CTR Centreville, AL 1/31/2005 12/1/2006 23 6 6 JST Jefferson Street, GA 2/1/2005 11/14/2006 13 3 2 YRK Yorkville, GA 1/31/2005 11/30/2006 20 6 4 PNS Pensacola, FL 2/1/2005 12/29/2006 24 5 7 OLF Outlying Field, FL 2/27/2005 12/31/2006 22 7 6 Total 8 144 38 36 
3-60

Table 3-11. Comparison of quartz-fiber backup filter carbon fractions among the urban, non-urban, and rural site

IMPROVE and SEARCH networks for the period from 1/1/2005 through 12/31/2006. 

Average ± Standard Deviation in μg/cm2

 IMPROVE Rural SEARCH Urban/Suburban SEARCH Non-Urban

Number of Samples 1401 182 75 Number of Sites 13c 5b 3aTC 3.23 ± 0.96 1.55 ± 1.67 1.32 ± 1.23 OC 3.08 ± 0.83 1.46 ± 1.47 1.20 ± 0.92 EC 0.16 ± 0.13 0.09 ± 0.34 0.12 ± 0.41 OC1 0.56 ± 0.07 0.46 ± 0.80 0.26 ± 0.38 OC2 0.95 ± 0.23 0.42 ± 0.46 0.35 ± 0.27 OC3 1.15 ± 0.35 0.48 ± 0.42 0.48 ± 0.26 OC4 0.31 ± 0.18 0.08 ± 0.16 0.08 ± 0.14 EC1 0.18 ± 0.16 0.07 ± 0.31 0.08 ± 0.36 EC2 0.08 ± 0.06 0.04 ± 0.20 0.06 ± 0.24 EC3 0.00 ± 0.00 0.01 ± 0.04 0.01 ± 0.07 

a Non-Urban sites: Oak Grove (OAK) near Hattiesburg, MS; Centreville (CTR) south of Tuscaloosa, AL; Yorkville (YRK) northwb Urban or suburban sites: Gulfport (GLF) in Gulfport, MS; Birmingham (BHM) in North Birmingham, AL; Jefferson Street (JST) 

(PNS) in Pensacola, FL; suburban outlying field (OLF) northwest of Pensacola, FL 

c Urban sites: #78 (MORA) Mount Rainier National Park; #96 (YOSE) Yosemite National Park; #48 (HANC) Hance Camp at Gran

#39 (CHIR) Chiricahua National Monument; #6 (SHEN) Shenandoah National Park; and #16 (OKEF) Okefenokee National Wild
3-61

Table 3-12. Average TC blank and sample concentrations for the eight collocated IMPROVE –STN/CSN sites.

Blank Concentration density (μg/cm2) 

Site Code 

Site Name Instrument Used IMP_bQF 

(μg/cm2) 

IMP_bQF 

(number) 

STN_FB 

(μg/cm2) 

STN_FB 

(number) 

STN_TB 

(μg/cm2) 

PUSO Seattle, WA URG MASS 2.66 ± 0.54 8 0.68 ± 0.41 25 0.53 ± 0.1MORA Mount Rainier, 

WA 

URG MASS 1.44 ± 0.36 6 0.66 ± 0.42 12 0.67 ± 0.1

PHOE Phoenix, AZ Met One SASS 2.63 ± 0.58 6 1.40 ± 0.77 26 1.12 ± 0.5TONT Tonto Monument, 

AZ 

Met One SASS 2.00 ± 1.05 8 0.87 ± 0.31 28 0.86 ± 0.3

WASH Washington, DC Andersen RAAS 2.49 ± 0.87 5 0.87 ± 0.40 25 0.84 ± 0.2DOSO Dolly Sods, WV Andersen RAAS 2.57 ± 0.31 5 1.18 ± 0.68 26 0.97 ± 0.3FRES Fresno, CA Met One SASS 2.58 ± 0.50 7 0.74 ± 0.23 18 0.94 ± 0.4BIBE Big Bend 

National Park, TX 

R&P 2025 FRM 2.40 ± 0.68 7 1.44 ± 0.48 15 N/A ± N/A 

 Ambient Concentration density 

(μg/cm2) 

Number 

of Pairs 

Ambient Concentration

(μg/m3) 

Site Code 

Site Name Instrument Used IMP_QF 

(μg/cm2) 

STN_QF 

(μg/cm2) 

QF 

(number) 

IMP_QF 

(μg/m3) 

STN_Q

(μg/m3

PUSO Seattle, WA URG MASS 35.99 ± 24.54 7.37 ± 4.92 224 3.88 ± 2.65 3.62 ± 2MORA Mount Rainier, 

WA 

URG MASS 11.73 ± 9.51 2.77 ± 1.92 69 1.27 ± 1.03 1.36 ± 

PHOE Phoenix, AZ Met One SASS 46.40 ± 29.75 5.80 ± 2.97 201 5.01 ± 3.21 7.12 ± TONT Tonto Monument, 

AZ 

Met One SASS 14.54 ± 12.59 2.15 ± 1.44 181 1.57 ± 1.36 2.64 ± 

WASH Washington, DC Andersen RAAS 35.32 ± 19.68 4.44 ± 2.24 206 3.81 ± 2.12 4.98 ± DOSO Dolly Sods, WV Andersen RAAS 20.20 ± 9.16 2.41 ± 1.04 140 2.18 ± 0.99 2.70 ± FRES Fresno, CA Met One SASS 49.03 ± 33.62 5.98 ± 3.67 227 5.29 ± 3.63 7.34 ± BIBE Big Bend 

National Park, TX 

R&P 2025 FRM 10.67 ± 5.68 4.15 ± 1.81 81 1.15 ± 0.61 2.04 ± 

Sampling Periods

10/16/2001 – 10/29/2003 at PUSO, PHOE, WASH, TONT, and DOSO 10/16/2001 – 10/20/2002 at MORA 1/4/2005 – 12/302005 at BIBE 1/1/2005 – 7/31/2006 at FRES 
3-62

Table 3-12. Continued Abbreviations

IMP: IMPROVE STN: STN/CSN bQF: IMPROVE field blanks FB: STN/CSN field blanks TB: STN/CSN trip blanks. Not taken at the Big Bend National Park, TX (BIBE1), site IMP_QF: uncorrected IMPROVE TC concentration measured from front quartz-fiber filters STN_QF: Uncorrected STN/CSN TC concentration measured from front quartz-fiber filters 
3-63

Table 3-13. Regression statistics of uncorrected STN/CSN TC against IMPROVE TC for data from the eight col

Site 

Code Site Name Sampling Period 

Intercept 

(μg/m3) 

Intercept 

(μg/cm2) Slope 

Correlati

(r) 

PUSO Seattle, WA 10/16/2001 - 12/29/2003 0.12 0.24 0.91 0.MORA Mount Rainier, WA 10/22/2001- 10/20/2002 0.25 0.5 0.87 0.PHOE Phoenix, AZ 10/16/2001 - 12/29/2003 1.65 1.34 1.08 0.TONT Tonto Monument, AZ 10/16/2001 - 12/29/2003 0.85 0.69 1.06 0.WASH Washington, DC 10/16/2001 - 12/26/2003 0.95 0.85 1.08 0.DOSO Dolly Sods, WV 10/16/2001 - 12/29/2003 0.83 0.74 0.87 0.FRES Fresno, CA 1/1/2005 -12/31/2006 1.1 0.9 1.16 0.BIBE Big Bend National Park, TX 1/1/2005 -12/31/2006 0.64 1.29 1.22 0.
3-64

Table 3-14. Comparison between estimated and measured field blanks for the eight collocated IMPROVE/STN 

Site Code Site Name Sampling Period 

IMP bQF 

(μg/cm2)a 

Calculated 

STNart (μg/cm2)b 

STN/CSN bQF 

(μg/cm2)c Difference (%

PUSO Seattle, WA 10/16/2001 - 12/29/2003 2.66 ± 0.54 0.83 0.68 -18% MORA Mount Rainier, WA 10/22/2001- 10/20/2002 1.44 ± 0.36 0.82 0.66 -19% PHOE Phoenix, AZ 10/16/2001 - 12/29/2003 2.63 ± 0.58 1.57 1.40 -11% TONT Tonto Monument, AZ 10/16/2001 - 12/29/2003 2 ± 1.05 0.87 0.87 1% WASH Washington, DC 10/16/2001 - 12/26/2003 2.49 ± 0.87 1.09 0.87 -20% DOSO Dolly Sods, WV 10/16/2001 - 12/29/2003 2.57 ± 0.31 0.99 1.18 19% FRES Fresno, CA 1/1/2005 -12/31/2006 2.58 ± 0.5 1.82 1.44 -21% BIBE Big Bend National Park, TX 1/1/2005 -12/31/2006 2.4 ± 0.68 1.13 0.74 -34% a IMPROVE field blanks b Estimated STN/CSN artifact c STN/CSN field blanks d 100

calculated

measured calculated

×

−
3-65

Table 3-15a. Summary of average PM2.5 concentration and field blanks at four collocated 

IMPROVE sites.

Site Seattle Phoenix Washington D.C. Fresno 

Site Type Urban Urban Urban Urban 

Site Code PUSO PHOE WASH FRES 

Sampler Type IMPROVE IMPROVE IMPROVE IMPROVE 

Sampling Period 7/12/2001-12/29/2004 4/28/2001-9/30/2004 7/08/2004-12/29/2004 9/03/2004-12/23/2004 

Average Ambient Concentration

(μg/m3) Average ± Std Dev Average ± Std Dev Average ± Std Dev Average ± Std Dev 

PM2.5 Mass 7.94 ± 4.88 10.9 ± 4.93 15.15 ± 9.34 18.62 ± 11.37 

Ammonium 0.58 ± 0.47 0.47 ± 0.28 2.22 ± 1.87 1.79 ± 2.02 

Nitrate 0.97 ± 0.86 1.01 ± 1.39 1.47 ± 2.21 6.31 ± 6.07 

Reduced Nitrate 0.26 ± 0.74 0.08 ± 0.64 0.57 ± 1.98 4.42 ± 6.21 

Water 0.47 ± 0.3 0.43 ± 0.22 1.94 ± 1.67 1.07 ± 1.09 

Sulfate 1.35 ± 0.89 1.18 ± 0.57 5.47 ± 4.66 1.34 ± 0.84 

Silicon 0.08 ± 0.07 0.63 ± 0.55 0.18 ± 0.15 0.41 ± 0.41 

Calcium 0.04 ± 0.03 0.22 ± 0.14 0.03 ± 0.01 0.08 ± 0.06 

Iron 0.07 ± 0.06 0.28 ± 0.17 0.11 ± 0.07 0.19 ± 0.14 

Titanium 0 ± 0.01 0.02 ± 0.01 0.01 ± 0 0.01 ± 0.01 

a

 IMPROVE mass from VIEWS was already field blank subtracted. STN/CSN from AIRS was not field blank 

subtracted. 

b Calculated ammonium based on 0.38 * (4.125 × S) + 0.29 × (1.29 × NO3

-

). The calculated ammonium was used 

instead of an actual measured value because the IMPROVE network does not report measured ammonium. 

Table 3-15b. Summary of average PM2.5 concentration and field blanks at four collocated 

STN/CSN sites. 

Site Seattle Phoenix Washington D.C. Fresno 

Site Typea Urban Urban Urban Urban 

Site Code PUSO PHOE WASH FRES 

Sampler Type URG Met One Andersen Met One 

Sampling Period 7/12/2001-12/29/2004 4/28/2001-9/30/2004 7/08/2004-12/29/2004 9/03/2004-12/23/2004 

Average Ambient Concentration

(μg/m3) Average ± Std Dev Average ± Std Dev Average ± Std Dev Average ± Std Dev 

PM2.5 Mass 8.31 ± 4.9 10.04 ± 4.58 15.15 ± 9.34 19.11 ± 12.33 

Ammonium 0.45 ± 0.38 0.43 ± 0.29 2.22 ± 1.87 1.86 ± 1.99 

Nitrate 0.73 ± 0.59 1.06 ± 1.42 1.47 ± 2.21 6.85 ± 5.91 

Reduced Nitrate 0.13 ± 0.46 0.09 ± 0.68 0.45 ± 1.79 4.66 ± 6.15 

Water 0.42 ± 0.28 0.43 ± 0.24 1.45 ± 1.04 1.15 ± 1.09 

Sulfate 1.24 ± 0.8 1.25 ± 0.6 5.47 ± 4.66 1.46 ± 0.91 

Silicon 0.04 ± 0.04 0.35 ± 0.32 0.18 ± 0.15 0.16 ± 0.19 

Calcium 0.03 ± 0.02 0.14 ± 0.1 0.03 ± 0.01 0.04 ± 0.03 

Iron 0.05 ± 0.04 0.17 ± 0.11 0.11 ± 0.07 0.12 ± 0.08 

Titanium 0 ± 0 0.01 ± 0.01 0.01 ± 0 0.01 ± 0.01 

Average Field Blank Mass Concentration

(μg/m3) 0.48 ± 0.74 0.89 ± 1.12 0.25 ± 0.32 NA 

Number in Average 42 40 5 0 
3-66

Table 3-16. Estimates of organic carbon mass (OCM) based on the SANDWICH method (Frank, 

2006) for the four collocated IMPROVE/STN sites. 

Site Seattle, WA Phoenix AZ Washington, DC Fresno, CA 

Site Type Urban Urban Urban Urban 

Site Code PUSO PHOE WASH FRES 

Number of Collocated Pairs 354 290 45 27 

Sampler Type IMPROVE IMPROVE IMPROVE IMPROVE 

Sampling Period 7/12/2001-12/29/2004 4/28/2001-9/30/2004 7/08/2004-12/29/2004 9/03/2004-12/23/2004 

SANDWICH OCM μg/m3

Average 3.99 ± 2.96 4.40 ± 3.45 3.00 ± 3.16 6.73 ± 3.56 

10%tile 1.22 1.48 0.58 2.86 

50%tile 3.16 3.27 2.47 6.16 

90%tile 8 8.66 6.23 11.29 

Measured OC μg/m3

Average 2.70 ± 2.06 3.13 ± 2.27 2.63 ± 1.51 3.42 ± 1.66 

10%tile 0.87 1.32 0.90 1.47 

50%tile 1.91 2.25 2.51 3.18 

90%tile 5.28 6.10 4.21 5.52 

Measured OC×1.4/OCM 

Average 95% 100% 123% 71% 

10%tile 100% 125% 217% 72% 

50%tile 85% 96% 142% 72% 

90%tile 92% 99% 95% 68% 

Measured OC×1.8/OCM 

Average 122% 128% 158% 91% 

10%tile 128% 161% 279% 93% 

50%tile 109% 124% 183% 93% 

90%tile 119% 127% 122% 88% 

Sampler Type URG MASS Met One SASS Andersen RAAS Met One SASS 

Sampling Period 7/12/2001-12/29/2004 4/28/2001-9/30/2004 7/08/2004-12/29/2004 9/03/2004-12/23/2004 

SANDWICH OCM μg/m3 

Average 4.63 ± 3.27 4.48 ± 3.62 4.85 ± 5.14 7.66 ± 4.37 

10%tile 1.57 1.03 0.65 3.08 

50%tile 3.72 3.64 4.03 6.72 

90%tile 9.59 9.12 9.05 14.22 

Measured OC μg/m3

Average 2.98 ± 2 3.94 ± 2.43 2.75 ± 1.86 4.8 ± 2.71 

10%tile 1.16 1.58 0.56 1.81 

50%tile 2.38 3.34 2.78 4.12 

90%tile 6.06 7.59 5.62 8.91 

Measured OC×1.4/OCM 

Average 90% 123% 79% 88% 

10%tile 103% 215% 121% 82% 

50%tile 90% 128% 97% 86% 

90%tile 88% 117% 87% 88% 

Measured OC×1.8/OCM 

Average 116% 158% 102% 113% 

10%tile 133% 276% 155% 106% 

50%tile 115% 165% 124% 110% 

90%tile 114% 150% 112% 113% 
3-67

Table 3-17. Summary of percent recovery for: a) solid and b) liquid levoglucosan. 

a) solid levoglucosan. 

Levoglucosan Carbon Measured 

Test loadinga (μg) μg/filter μg / cm2 μg/filter μg/cm2

IMPROVE TC (μg/filter) 

STN/CSN TC (μg/filter) 

I

Diesel + Solid Resuspended Levoglucosan 2281 1049 76.0 466 33.8 318 360 Blank + Low Load Solid Resuspended Levoglucosan 331 73 5.3 32 2.3 5.4 14.0 Blank + High Load Solid Resuspended Levoglucosan 520 151 10.9 67 4.9 15.7 26.0  a Total amount of loading based on volume correction for all samples. Teflon-membrane filter samples from the parallel Teflon-

channel were first weighted and analyzed by X-ray Fluorescence (XRF) for silicon (Si). The Si concentration is then converted 

and the total amount of the levoglucosan plus SiO2 mass that is SiO2 is calculated. These numbers are used to calculate the per

levoglucosan, which is then used to calculate μg levoglucosan/filter. 

b) liquid levoglucosan.  Levoglucosan Carbon Measured Levoglucosan 

μg / cm2 μgC/cm2

IMPROVE TC 

(μg/cm2) 

STN/CSN TC 

(μg/cm2) 

IMPROVE TC 

Recovery (%) 

STN/C

Recove

Blank + Low Load Liquid Levoglucosan 11.4 9.6 9.3 9.5 97% 93Blank + Medium Load Liquid Levoglucosan 22.8 19.2 17.9 17.8 93% 93Blank + Medium Load Liquid Levoglucosan 27.3 22.9 21.4 21.3 94% 93Blank + High Load Liquid Levoglucosan 45.7 38.3 36.9 33.4 96% 87
3-68

Table 3-18. Distribution of carbon fractions on the blank samples doped with solid and liquid 

levoglucosan.

 IMPROVE protocol 

 Blank + Resusp. Levoglucosan Blank + Liquid Levoglucosan 

 Low loading High loading Medium Loading 

OC1 / TC 0 0.014 0.054 ± 0.022 

OC2 / TC 0.24 0.248 0.2 ± 0.01 

OC3 / TC 0.76 0.683 0.344 ± 0.012 

OC4 / TC 0 0.054 0.112 ± 0.004 

EC1 / TC 0 0 0.265 ± 0.019 

(EC1-OPR) / TC 0 0 0.04 ± 0.02 

(EC1-OPT) / TC 0 -0.001 0 ± 0.02 

EC2 / TC 0 0 0.025 ± 0.004 

EC3 / TC 0 0.001 0 ± 0 

OPT / TC 0 0.001 0.265 ± 0.005 

OPR / TC 0 0 0.223 ± 0.04 

 STN/CSN protocol 

 Blank + Resusp. Levoglucosan Blank + Liquid Levoglucosan 

 Low loading High loading Medium Loading 

OC1 / TC 0.266 0.212 0.133 ± 0.072 

OC2 / TC 0.438 0.495 0.312 ± 0.022 

OC3 / TC 0.087 0.157 0.116 ± 0.022 

OC4 / TC 0.063 0.065 0.263 ± 0.036 

OC5 / TC 0.001 0 0.004 ± 0.003 

EC1 / TC 0 0 0.145 ± 0.041 

(EC1-OPR) / TC 0.063 0.026 0.23 ± 0.03 

(EC1-OPT) / TC 0.007 0.007 0.14 ± 0.12 

EC2 / TC 0 0.001 0.019 ± 0.008 

EC3 / TC 0 0.001 0.003 ± 0.003 

EC4 / TC 0 0 0 ± 0 

EC5 / TC 0.146 0.071 0.005 ± 0.006 

OPT / TC -0.007 -0.007 -0.087 ± 0.059 

OPR / TC -0.063 -0.026 -0.09 ± 0.019 
3-69

Table 3-19. Carbon fractions for the diesel/levoglucosan experiment following the IMPROVE and STN/CSN pr

a) Solid levoglucosan 

IMPROVE protocol (μg / filter) 

 Diesel Exhaust Diesel + resuspended levoglucosan Blank+ resusp. Levoglucosan  QF QFbott QBQ QF QFbott QF (low load)  avg ± stdev avg ± stdev avg ± stdev avg ± stdev avg ± stdev avg ± stdev TC 195.6 ± 18.1 62.9 ± 21.6 15 ± 4.3 317.8 ± 58.2 68 ± 16.9 5.42 ± 0.95 OCT 112.3 ± 19.4 57.2 ± 16.6 14.9 ± 4.1 232.3 ± 57.9 64 ± 16.4 5.42 ± 0.95 OCR 112.3 ± 19.4 56.3 ± 16 14.9 ± 4.1 233.8 ± 61.3 63.8 ± 16.4 5.42 ± 0.95 ECT 83.4 ± 27 6.6 ± 6.5 0.1 ± 0.4 85.5 ± 25 4.2 ± 3.1 0 ± 0 ECR 83.4 ± 27 6.6 ± 6.5 0.1 ± 0.4 84 ± 28.1 4.2 ± 3.1 0 ± 0 OC1 40.1 ± 4 22.1 ± 3.5 8.1 ± 2.4 105.9 ± 40.1 18.4 ± 5.2 0 ± 0 OC2 33.2 ± 3.1 16 ± 4.2 2.4 ± 0.5 51.9 ± 11.3 16.7 ± 2.7 1.3 ± 0.33 OC3 28.7 ± 13 15.1 ± 8.2 4.3 ± 1.6 56.4 ± 9.5 24.8 ± 16.1 4.12 ± 0.79 OC4 10.4 ± 6.7 3.1 ± 2.4 0.2 ± 0.3 17.1 ± 3.6 3.9 ± 1.6 0 ± 0 EC1 15.9 ± 3.7 1.6 ± 1.8 0.1 ± 0.3 18.1 ± 4.5 1.4 ± 1.4 0 ± 0 EC2 67.4 ± 25.6 5 ± 5.1 0 ± 0.1 68.5 ± 27 2.8 ± 2.5 0 ± 0 EC3 0 ± 0 0 ± 0 0 ± 0 0 ± 0 0 ± 0 0 ± 0 OPT 0 ± 0 0.9 ± 1.1 0 ± 0 1.1 ± 2.6 0.2 ± 0.5 0 ± 0 OPR 0 ± 0 0 ± 0 0 ± 0 2.6 ± 4.2 0 ± 0 0 ± 0 

STN protocol (μg / filter) 

Diesel Exhaust Diesel + resuspended levoglucosan Blank+ resusp. Levoglucosan 

 QF QFbott QBQ QF QFbott QF (low load)  avg ± stdev avg ± stdev avg ± stdev avg ± stdev avg ± stdev avg ± stdev TC 192 ± 14.8 55.3 ± 16.3 17.3 ± 3.8 359.8 ± 119.3 64.9 ± 12.7 13.98 ± 4.93 OCT 107.7 ± 14.8 53.6 ± 15.7 16.7 ± 3.5 283.3 ± 112.9 57.7 ± 13.6 11.85 ± 2.37 OCR 107.7 ± 14.8 52.9 ± 15.9 16.7 ± 3.5 268.5 ± 103.5 56.4 ± 10.9 11.07 ± 2.32 ECT 84.3 ± 26.2 1.6 ± 3.1 0.6 ± 0.9 76.5 ± 26.6 7.3 ± 4.1 2.13 ± 3.35 ECR 84.3 ± 26.2 2.4 ± 3.2 0.6 ± 0.9 91.2 ± 29.1 8.6 ± 3.1 2.91 ± 3.56 OC1 77 ± 4.4 30.9 ± 5 10.6 ± 2.5 184 ± 89.6 35.5 ± 4.3 3.72 ± 0.29 OC2 18.9 ± 6.8 16.5 ± 12.7 4.6 ± 1.2 55.9 ± 10 13.8 ± 7.8 6.12 ± 1.84 OC3 11.3 ± 4.7 5.4 ± 1.7 1.5 ± 0.6 28.7 ± 4.3 7.1 ± 3.5 1.22 ± 0.97 OC4 13.9 ± 2.6 1.6 ± 2.1 0.6 ± 0.9 23.5 ± 4.2 4.7 ± 1.7 0.88 ± 1.35 OC5 0.4 ± 0.1 0 ± 0 0 ± 0 0.3 ± 0.1 0 ± 0 0.01 ± 0.03 EC1 2.4 ± 0.5 0.1 ± 0.2 0 ± 0 2.6 ± 0.7 0 ± 0.1 0 ± 0 EC2 11.5 ± 2.9 0.2 ± 0.4 0 ± 0 7.5 ± 2.3 0.6 ± 0.8 0 ± 0 EC3 40.8 ± 16.5 0.5 ± 0.6 0 ± 0 32.2 ± 13.1 2.5 ± 1.5 0 ± 0 EC4 14.9 ± 8 0 ± 0 0 ± 0 24.4 ± 11.3 0.7 ± 0.9 0 ± 0 EC5 0.7 ± 1.1 0 ± 0 0 ± 0 0.7 ± 0.4 0 ± 0 2.04 ± 2.53 OPT -13.9 ± 2.7 -0.8 ± 2 -0.6 ± 0.9 -9 ± 6.8 -3.4 ± 1.9 -0.09 ± 1.69 OPR -13.9 ± 2.6 -1.6 ± 2.1 -0.6 ± 0.9 -23.8 ± 4.3 -4.7 ± 1.7 -0.88 ± 1.35 
3-70

Table 3-19. Continued. 

b) Liquid levoglucosan 

IMPROVE protocol (μg / filter) 

 Diesel Exhaust Diesel + liquid levoglucosan Blank + liquid levoglucosan B QF QF QFbott QF (low load) 

avg ± stdev avg ± stdev avg ± stdev avg ± stdev 

TC 193.6 ± 19.8 298.1 ± 17.6 156.4 ± 89.3 60.29 ± 4.5 OCT 91.1 ± 9.6 193.9 ± 12.6 134.7 ± 56.3 60.29 ± 4.5 OCR 90.2 ± 10.7 189.5 ± 11.9 135.8 ± 60.2 59.24 ± 4.12 ECT 102.5 ± 10.6 104.2 ± 12 21.7 ± 33.7 0 ± 0 ECR 103.4 ± 9.4 108.6 ± 8 20.6 ± 29.4 1.06 ± 1.26 OC1 33.3 ± 4.5 77.3 ± 19.2 31.3 ± 14.9 0.15 ± 0.26 OC2 32.2 ± 4.1 49.9 ± 6.1 31.6 ± 3.3 18.57 ± 3.34 OC3 17.8 ± 2.7 45.6 ± 3.9 48.3 ± 22.4 33.5 ± 3.78 OC4 6.9 ± 2.4 16.8 ± 1.9 19.9 ± 21.1 7.01 ± 1.55 EC1 5.6 ± 2.8 17.8 ± 3.2 7.6 ± 9.1 1 ± 1.29 EC2 97.4 ± 8.2 90.4 ± 7.9 12.2 ± 18.6 0.05 ± 0.09 EC3 0.5 ± 0.4 0.3 ± 0.4 5.5 ± 12.2 0 ± 0 OPT 0.9 ± 1.3 4.3 ± 6.8 3.6 ± 6.4 1.06 ± 1.26 OPR 0 ± 0 0 ± 0 4.7 ± 10.5 0 ± 0 

STN protocol (μg / filter) 

Diesel Exhaust Diesel + liquid levoglucosan Blank + liquid levoglucosan B

 QF QF QFbott QF (low load) 

avg ± stdev avg ± stdev avg ± stdev avg ± stdev 

TC 213.3 ± 22.3 298 ± 15.7 142 ± 17.4 70.13 ± 0.24 OCT 109.6 ± 14.3 193.2 ± 15.3 126.7 ± 18.6 64.87 ± 4.68 OCR 97 ± 10.3 181.2 ± 9.8 124.3 ± 15.1 62.22 ± 0.17 ECT 103.6 ± 14.1 104.9 ± 14 15.2 ± 7.1 5.26 ± 4.46 ECR 116.2 ± 12.1 116.9 ± 10.1 17.7 ± 3.3 7.91 ± 0.15 OC1 65.1 ± 4.1 113.1 ± 17.8 76.8 ± 9.8 26.24 ± 0.23 OC2 21.3 ± 7.5 45.9 ± 9.7 30.1 ± 4.5 22.34 ± 0.33 OC3 10.6 ± 3.2 22.2 ± 1.6 17.4 ± 1.9 13.63 ± 0.31 OC4 15 ± 8.4 26.1 ± 7.8 12.7 ± 1.7 7.74 ± 0.26 OC5 0 ± 0 0 ± 0.1 0 ± 0 0 ± 0 EC1 1 ± 0.9 1.7 ± 1.8 0.4 ± 0.5 0.11 ± 0.19 EC2 5.8 ± 3.2 12.7 ± 10.6 1.3 ± 1 0.07 ± 0.06 EC3 27.2 ± 11.6 35.1 ± 7.5 2.4 ± 0.8 0 ± 0 EC4 58.4 ± 13 35.9 ± 23.1 1 ± 0.7 0 ± 0 EC5 8.9 ± 5.9 5.2 ± 3.5 0 ± 0 0 ± 0 OPT -2.4 ± 3.7 -14.2 ± 7.6 -10.2 ± 6 -5.08 ± 4.4 OPR -15 ± 8.4 -26.2 ± 7.9 -12.7 ± 1.7 -7.74 ± 0.26 
3-71

Table 3-20. Distribution of carbon fractions for the diesel/levoglucosan experiment following the IMPROVE_A 

protocols. 

IMPROVE protocol 

Diesel Exhaust Diesel + resuspended levoglucosan Diesel 

QF QFbott QBQ QF QFbott QF 

avg ± stdev avg ± stdev avg ± stdev avg ± stdev avg ± stdev avg ± 

OCT / TC 0.574 ± 0.116 0.91 ± 0.062 0.992 ± 0.016 0.731 ± 0.08 0.941 ± 0.036 0.65 ± OCR / TC 0.574 ± 0.116 0.895 ± 0.067 0.992 ± 0.016 0.736 ± 0.094 0.939 ± 0.042 0.636 ± ECR / TC 0.426 ± 0.116 0.105 ± 0.067 0.008 ± 0.016 0.269 ± 0.08 0.061 ± 0.042 0.35 ± ECT / TC 0.426 ± 0.116 0.105 ± 0.067 0.008 ± 0.016 0.264 ± 0.094 0.061 ± 0.042 0.364 ± OCT / ECT 1.347 ± 0.775 8.701 ± 11.82 121.8 ± 280.2 2.718 ± 1.242 15.36 ± 10.34 1.86 ± OCR / ECR 1.347 ± 0.775 8.56 ± 11.85 121.8 ± 277 2.785 ± 1.693 15.31 ± 10.37 1.746 ± OPT / TC 0 ± 0 0.015 ± 0.014 0 ± 0 0.003 ± 0.011 0.003 ± 0.006 0.015 ± OPR / TC 0 ± 0 0 ± 0 0 ± 0 0.008 ± 0.014 0 ± 0 0 ± OC1 / OCR 0.357 ± 0.081 0.393 ± 0.1 0.542 ± 0.064 0.453 ± 0.078 0.289 ± 0.099 0.408 ± OC2 / OCR 0.295 ± 0.022 0.283 ± 0.014 0.159 ± 0.041 0.222 ± 0.035 0.262 ± 0.084 0.263 ± OC3 / OCR 0.255 ± 0.073 0.268 ± 0.079 0.288 ± 0.054 0.241 ± 0.045 0.388 ± 0.127 0.241 ± OC4 / OCR 0.092 ± 0.031 0.055 ± 0.03 0.01 ± 0.015 0.073 ± 0.018 0.061 ± 0.021 0.089 ± EC1 / ECR 0.191 ± 0.06 0.245 ± 0.19 0.79 ± 0.128 0.215 ± 0.148 0.327 ± 0.323 0.164 ± EC2 / ECR 0.809 ± 0.06 0.755 ± 0.19 0.21 ± 0.128 0.816 ± 0.065 0.673 ± 0.323 0.833 ± EC3 / ECR 0 ± 0 0 ± 0 0 ± 0 0 ± 0 0 ± 0 0.003 ± 

STN/CSN protocol 

Diesel Exhaust Diesel + resuspended levoglucosan Diesel 

QF QFbott QBQ QF QFbott QF 

avg ± stdev avg ± stdev avg ± stdev avg ± stdev avg ± stdev avg ± 

OCT / TC 0.561 ± 0.106 0.97 ± 0.05 0.967 ± 0.048 0.787 ± 0.093 0.888 ± 0.059 0.648 ± OCR / TC 0.561 ± 0.107 0.957 ± 0.053 0.967 ± 0.048 0.746 ± 0.078 0.868 ± 0.037 0.608 ± ECR / TC 0.439 ± 0.106 0.03 ± 0.05 0.033 ± 0.048 0.213 ± 0.093 0.112 ± 0.059 0.352 ± ECT / TC 0.439 ± 0.107 0.043 ± 0.053 0.033 ± 0.048 0.254 ± 0.078 0.132 ± 0.037 0.392 ± OCT / ECT 1.279 ± 0.655 32.57 ± 107.3 28.97 ± 7.76 3.704 ± 2.329 7.926 ± 17.01 1.842 ± OCR / ECR 1.277 ± 0.656 22.14 ± 99.86 28.97 ± 7.76 2.944 ± 1.34 6.569 ± 1.96 1.55 ± OPT / TC -0.072 ± 0.038 -0.015 ± 0.121 -0.033 ± 0.059 -0.025 ± 0.089 -0.053 ± 0.098 -0.048 ± OPR / TC -0.073 ± 0.041 -0.028 ± 0.118 -0.033 ± 0.059 -0.066 ± 0.021 -0.073 ± 0.078 -0.088 ± OC1 / OCR 0.715 ± 0.069 0.585 ± 0.124 0.635 ± 0.059 0.685 ± 0.062 0.63 ± 0.122 0.624 ± OC2 / OCR 0.176 ± 0.04 0.312 ± 0.116 0.277 ± 0.052 0.208 ± 0.04 0.245 ± 0.085 0.253 ± OC3 / OCR 0.105 ± 0.029 0.102 ± 0.03 0.089 ± 0.035 0.107 ± 0.023 0.125 ± 0.038 0.122 ± OC4 / OCR 0.13 ± 0.013 0.03 ± 0.041 0.035 ± 0.054 0.087 ± 0.018 0.084 ± 0.015 0.144 ± OC5 / OCR 0.003 ± 0.001 0 ± 0 0 ± 0 0.001 ± 0 0 ± 0 0 ± EC1 / ECR 0.029 ± 0.006 0.028 ± 0.021 0 ± 0 0.029 ± 0.005 0.004 ± 0.006 0.015 ± EC2 / ECR 0.136 ± 0.019 0.081 ± 0.054 0 ± 0 0.082 ± 0.004 0.071 ± 0.069 0.109 ± EC3 / ECR 0.484 ± 0.064 0.222 ± 0.441 0 ± 0 0.353 ± 0.041 0.29 ± 0.071 0.301 ± EC4 / ECR 0.176 ± 0.053 0.01 ± 0.007 0 ± 0 0.267 ± 0.062 0.082 ± 0.059 0.308 ± EC5 / ECR 0.009 ± 0.009 0 ± 0 0 ± 0 0.008 ± 0.005 0 ± 0 0.044 ± 
3-72

Table 3-21. Ratio of the bottom half of quartz-fiber front filter (QFbott) or quartz-fiber backup 

filter (QBQ) to quartz-fiber front filter (QF) in different carbon fractions. 

 IMPROVE 

 Diesel 

Diesel + 

Resus 

Diesel + 

Liquid 

 

QFbott/ 

QF QBQ/QF QBQ/QFbott QFbott/QF QFbott/QF 

TC 0.321 0.077 0.239 0.214 0.525 

OCT 0.51 0.133 0.26 0.275 0.695 

OCR 0.502 0.133 0.265 0.273 0.716 

ECT 0.079 0.001 0.019 0.049 0.208 

ECR 0.079 0.001 0.019 0.05 0.19 

OC1 0.552 0.202 0.365 0.174 0.405 

OC2 0.481 0.071 0.148 0.322 0.634 

OC3 0.527 0.15 0.284 0.439 1.059 

OC4 0.3 0.015 0.05 0.226 1.183 

EC1 0.101 0.006 0.06 0.075 0.428 

EC2 0.074 0 0.005 0.041 0.135 

EC3 N/A N/A N/A N/A 16.308 

OPT N/A N/A 0 0.177 0.826 

OPR N/A N/A N/A 0 N/A 

 

 STN 

 Diesel 

Diesel + 

Resus 

Diesel + 

Liquid 

 

QFbott/ 

QF QBQ/QF QBQ/QFbott QFbott/QF QFbott/QF 

TC 0.288 0.09 0.313 0.181 0.476 

OCT 0.498 0.155 0.312 0.204 0.656 

OCR 0.491 0.155 0.316 0.21 0.686 

ECT 0.02 0.007 0.35 0.095 0.145 

ECR 0.028 0.007 0.242 0.094 0.151 

OC1 0.402 0.138 0.343 0.193 0.679 

OC2 0.872 0.244 0.28 0.247 0.656 

OC3 0.478 0.131 0.273 0.246 0.784 

OC4 0.113 0.041 0.367 0.202 0.485 

OC5 0 0 N/A 0 0 

EC1 0.028 0 0 0.013 0.214 

EC2 0.017 0 0 0.082 0.105 

EC3 0.013 0 0 0.077 0.067 

EC4 0.002 0 0 0.029 0.026 

EC5 0 0 N/A 0 0 

OPT 0.06 0.042 0.696 0.381 0.72 

OPR 0.113 0.041 0.367 0.2 0.484 
4-1

4. SUMMARY AND CONCLUSIONS 

Table 4-1 summarizes the results reported in Section 3 related to the hypotheses posed in 

Section 1. The IMPROVE, STN/CSN, and SEARCH networks have been using different 

sampling configurations, including specific samplers, flow rates, filter material, and filter sizes. 

For field blanks, which accompany sample filters to the field and are intended to emulated their 

passive deposition and adsorption, only the IMPROVE network provides a long enough passive 

exposure period to fulfill the purpose. Based on both the network averages and collocated-site 

studies, IMPROVE field blank TC (or OC) range from 2.0 to 2.5 μg/cm2

, while STN/CSN and 

SEARCH field blanks are below or close to 1 μg/cm2

. The limited exposure times in the 

STN/CSN and SEARCH networks are 1 – 15 minutes, compared to 7 days in the IMPROVE 

network. STN/CSN field and trip blank TC and OC concentrations are within ± 5% for site 

averages. 

Regression analysis using uncorrected TC from collocated IMPROVE and STN/CSN 

samplers indicates a larger net sampling artifact (μg/m3

) in the STN/CSN carbon measurements. 

Without any correction, biases in the STN/CSN data could be 5 – 11 times higher than those in 

the IMPROVE data (μg/m3

), depending on the sampler type. When corrected with respective 

field blanks, STN/CSN TC concentrations are still higher at most sites. STN/CSN field blanks 

could under-represent the organic artifact by up to 34% (e.g., at Fresno, CA), if IMPROVE field 

blanks fully represent the artifact. Blank corrections should be made and uncertainties 

propagated for STN/CSN data, even though the reported OC will be under-corrected for 

adsorbed organic vapors. 

The mass regression method and SANDWICH approach are both based on PM mass 

closure (i.e., the mass measured on a Teflon-membrane filter should be explained by measured 

organic and/or inorganic components with the difference attributed to the sampling artifact). 

Many species are not usually measured on Teflon-membrane filters, including carbon, nitrate, 

sulfate, and ammonium. For URG speciation samplers that measure ions after XRF analysis, 

volatile components, such as ammonium nitrate and some SVOCs, are likely to evaporate in the 

vacuum due to the heating during XRF analysis. Different collection/retention efficiencies of 

Teflon-membrane, quartz-fiber, and nylon-membrane filters with respect to these species have 

been reported. The mass of water and unidentified species cannot be definitely determined. All 

these contribute to mass closure uncertainties. Even if organic carbon mass (OCM) can be 
4-2

calculated from the SANDWICH method, this study shows that variation in OCM concentration 

due to the choice of OC multiplier (e.g., 1.4 or 1.8) is comparable to the magnitude of the 

organic sampling artifact (5 – 30% of OCM). It is not possible to determine whether the excess 

OCM mass, if any, is due to sampling artifact or the correction coefficient used to convert OC to 

OCM. 

This study also demonstrates that sampling artifacts could influence the OC/EC split and 

therefore EC quantification. Charring from liquid levoglucosan on clean filters is apparent. A 

two-stream radiative transfer model was used to estimate the depth of layer containing lightabsorbing material during thermal analysis. For a pure diesel soot sample, this layer is ~13% of 

the whole filter throughout the IMPROVE_A thermal/optical analysis, whereas for liquid 

levoglucosan doping this layer extends to ~50% of the whole filter (i.e., light absorbing material 

penetrates into the filter). Observational and model investigations suggest that within-filter char 

occurs, altering the reflectance/transmittance relationship. However, in this experiment, the 

effect of liquid levoglucosan additions to diesel soot samples is inconclusive due to: 1) heavy 

soot loading that saturates the optical signal and 2) particle migration caused by liquid spiking. 

Experiments using lower diesel soot loadings and better levoglucosan application techniques 

need to be perfected to obtain quantitative results. 
5-1

5. RECOMMENDATIONS 

This study shows that there is no simple way to correct for sampling artifacts using 

current measurements. However, sampling artifacts are reduced with increasing aerosol sample 

deposit. This is achieved via a higher flow rate (e.g., 22 L/min instead of 7.1 L/min) and a 

smaller deposit area (3.8 cm2

 instead of 11.8 cm2). Subtractions made using blank, backup, 

back-half of the front filter, and/or mass closure approaches need to be evaluated against true 

artifact levels, which can only be achieved through well-designed field and laboratory 

experiments. Experiments are needed to evaluate: 1) sample duration for filter saturation; 2) 

dependence of saturation on particle composition, temperature, relative humidity, and sampling 

face velocity; 3) evaporation rates of semi-volatile compounds during sampling; and 4) sourcespecific variables. Near-term, middle-term, and long-term goal recommendations are: 

• Near term 

– Maximize sample volume and minimize filter size 

– Standardize procedures for field blank collection frequency and duration (e.g., 

once a month on an every-sixth-day sampling schedule; expose field blanks for 

several days in the SEARCH and CSN networks) 

– Include backup filters in CSN 

– Add locations and times for field blanks and backup filters (different source 

environments) 

• Middle term 

– Continue laboratory and field experiments to determine adsorption capacities and 

retention for filter media and semivolatile organic compounds 

– Evaluate modeling of simultaneous TOR/TOT to estimate adsorbed organic 

vapors and their influence on OC/EC split 

• Long term 

– Develop, evaluate, and deploy new carbon analysis methods that achieve more 

information (e.g., finer thermal fractions, specific organic compounds, reflectance 

and transmittance at different wavelengths, inorganic as well as organic 

compounds) for same or lesser cost 
5-2

The long-term goal may involve state-of-the-art mass and optical spectrometric detectors 

(e.g., Streibel et al., 2006). This development also needs to maintain the continuity of long-term 

trends established by the currently applied methods. 
5-3

Table 5-1. Summary of findings for the five hypotheses. 

Hypothesis Findings 

A: The OC artifact on 

blank/backup filters 

depends on sampling 

protocol and differs among 

ambient networks. 

This is confirmed, and is demonstrated by network descriptions and 

comparison of the trip blanks, field blanks, and backup filters. 

IMPROVE field blanks TC (or OC) are generally in the range of 2.0 – 

2.5 μg/cm2

 while the STN/CSN and SEARCH field blanks are below or 

close to 1 μg/cm2

. Since both IMPROVE and SEARCH use Pallflex® 

Tissuquartz filters, filter material does not appear to be the cause of the 

difference. The lower SEARCH and STN/CSN field blank levels are 

probably caused by short passive exposure periods (on the order of 

minutes) which do not allow sufficient time for organic vapors to 

diffuse to and through the filters. IMPROVE field blanks reside for 

seven days in the sampler with the sampled filters. Among the five 

STN/CSN samplers, URG MASS reports the lowest field blank levels. 

The IMPROVE backup filter OC (from six sites only) is ~20% higher 

than its network average field blank OC, while the SEARCH backup 

filter OC is 57% higher than network average field blank OC. For the 

SEARCH network, the backup filters contain both positive and 

negative artifacts, and the negative artifact could be enhanced by the 

preceding organic denuder equipped in the Particle Composition 

Monitor (PCM3; Chow et al., 2007c) 

B: Adsorbed organic 

carbon on the field blank is 

less than that on the 

backup filter, which is less 

than that on the bottom 

half of the front filter. 

This is confirmed, although the IMPROVE field blanks are similar to 

backup filters within the variability of the averages. Chow et al. 

(2007c) showed a decreasing gradient of OC with depth in the front and 

backup filters. It cannot be assumed that the front and backup filters 

are saturated with adsorbed organic vapors. In this study, diesel soot 

sample filters were sliced and it was found that the bottom half of 

quartz-fiber front filters contained four times higher OC than quartzfiber backup filters. Liquid particles can also penetrate into the front 

and backup filters, and this will give a different result than if the same 

substance were collected on the surface as a dry particle. This was 

demonstrated by adding levoglucosan to diesel soot samples. 

C: Aging of aerosol 

reduces SVOC content and 

the organic sampling 

artifact. 

Comparisons between urban and non-urban sites in the SEARCH 

network are consistent with this hypothesis, but they are not sufficient 

to prove it. Average OC on quartz-fiber backup filters was ~22% 

higher at the urban sites, with 1.46 ± 1.47 μg/cm2

 at urban sites and 

1.20 ± 0.9 μg/cm2

 at the non-urban sites in the SEARCH network. The 

urban increments between the urban and non-urban sites were ~77% for 

OC1 and 20% for OC2. The majority of this low temperature OC is 

gaseous VOCs. During the IMPROVE/STN comparison study, field 

blank carbon levels were not necessarily lower at rural sites than at 

urban sites, though this could be due to the extent of VOC saturation. 

The contrast between urban and rural sites can only provide indirect 

indication of aging effect since the degree of aging is not known. 
5-4

Table 5-1. Continued 

Hypothesis Findings 

D: OC estimated by the 

SANDWICH method 

better represents the 

particulate organic matter 

in PM2.5. 

The SANDWICH method does not provide a better representation of 

OC, but under certain conditions it can provide an estimate when 

carbon measurements are not available. Water and volatile nitrate 

content could strongly interfere the mass closure between the 

gravimetric mass measured from the Teflon-membrane filters and 

species measured from the quartz-fiber filters. These are also problems 

for the intercept approach demonstrated by Chow et al. (2007c). The 

SANDWICH method is inaccurate for low concentrations, for which 

the calculated and measured OC ratio exceeded 200% (e.g., 

Washington, DC). For sites where better agreement between OC and 

OCM was found, such as Seattle, WA and Phoenix, AZ, the difference 

due to the OCM/OC ratio (1.4 or 1.8) was 5 – 30% of OCM mass, 

comparable to the magnitude of OC artifact. 

E: The organic sampling 

artifact influences the 

OC/EC split for both 

IMPROVE and STN/CSN 

analysis 

This was demonstrated for a relatively simple case that mixed diesel 

exhaust (for which the IMPROVE_A_TOR and STN_TOT protocols 

usually agree) with liquid and solid levoglucosan. When a diesel soot 

sample is mixed with levoglucosan, the reflectance and transmittance 

relationship (as determined by thermal/optical methods) only changes 

when the liquid levoglucosan is spiked into the filter rather than when 

solid levoglucosan is collected onto the filter surface. When sampling 

artifact does char and the char occurs within the filter, it is expected to 

influence the OC/EC split for either TOR or TOT analysis. This is due 

to the different distribution and absorption efficiency between char 

(pyrolyzed OC) and EC. The magnitude of this influence should depend 

on the amount of char with respect to the amount of EC. However, in 

the current experiment, the effect of liquid levoglucosan doping on 

diesel soot samples cannot be further quantified due to: 1) heavy soot 

loading that saturates the optical signal and 2) particle migration caused 

by liquid spiking. Experiments to lower diesel soot loading and 

minimize particle migration are recommended for the future. 
6-1

6. REFERENCES 

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