SBIR Phase I Final Report 

Feasibility of Monitoring Heavy Metal Emissions from a CoalFired Thermal Hazardous Waste Incinerator Using a MultiMetal Continuous Emissions Monitor 

EPA Contract No.: EP-D-07-026 

August 30th, 2007 

Submitted by: 

Cooper Environmental Services LLC 

10180 SW Nimbus Ave, Ste J6 

Portland, OR 97223 
1 

Project Summary 

Combined uncertainties in current techniques for estimating metal concentrations at area sources 

can be 100% or more. These large uncertainties would be eliminated if continuous measurements 

of emissions were possible. To meet this need, Cooper Environmental Services LLC (CES) has 

developed a multi-metal continuous emissions monitor (the Xact CEMSTM). The Xact CEMS 

has already been EPA-approved for compliance at a gas-fired hazardous waste incinerator. The 

objective of this research is to evaluate the feasibility of using the Xact to measure hazardous 

metal emissions on a coal-fired hazardous waste incinerator. Specifically, CES sought to answer 

three questions regarding the Xact’s performance at a coal-fired facility: 

1. Are Xact measurements impacted by the chemistry of the stack effluent? 

2. Can the Xact accurately measure over a concentration range including the emission limits? 

3. Can the techniques used previously to validate the Xact be used on a coal-burning facility? 

To answer these questions, CES tested the Xact’s ability to take measurements at the EPA’s 

Multi-Pollutant Control Research Facility in Research Triangle Park, North Carolina, which was 

used to simulate a full scale coal-fired hazardous waste incinerator. During testing, the Xact 

sampled stack gas that was dynamically spiked with reference concentrations of arsenic (As), 

cadmium (Cd), chromium (Cr), lead (Pb), and mercury (Hg) at three concentration levels 

spanning existing source emission limits: approximately 27, 92 and 250 μg/dscm. CES also 

spiked ambient air at the highest concentration level. 

CES used several criteria to help evaluate the Xact’s performance at the test coal-fire incinerator. 

First, the ratio of Xact measured concentrations to the reference concentrations was determined 

for each data point. Ratios between 0.80 and 1.20 indicate that the accuracy of the Xact’s 

measurements was not impacted by the chemistry of the stack effluent. Second, a comparison 

was made between ratios determined for flue gas and for ambient air. If no significantly 

difference was detected, than the Xact’s measurements were not impacted by the chemical 

characteristics of the coal-fired flue gas. Finally, a linear regression analysis was performed on 

the Xact measured concentrations versus the reference concentrations for the experimental 

concentration range. If the slope of this line was between 0.85 and 1.15 and the correlation 

coefficient was greater than 0.90, than the Xact’s measurements were accurate over a 

concentration range that included the emission limit. 

The results of the experiment showed that all criteria were met: measured-to-reference ratios 

were between 0.80 and 1.20, linear regression slopes were between 0.85 and 1.15, correlation 

coefficients were all 0.99, and there was no difference between measurements taken with flue 

gas or with ambient air. CES therefore concludes that (1) chemical composition of the stack gas 

from a coal-fired facility does not impact the Xact’s measurements, (2) the Xact can accurately 

measure metals over a concentration range that includes the emission limit, and (3) the validation 

techniques used in this experiment were successful on a coal-fired furnace. It is therefore feasible 

to use the Xact instrument to measure metal emissions from coal-fired sources including: 

hazardous waste incinerators, coal-fired power plants, municipal and medical waste incinerators, 

industrial furnaces and boilers, and primary and secondary metal smelters. Currently, there are 

no other continuous emissions monitors capable of measuring multiple metals at area sources.
2 

1.0 Introduction 

1.1 Problem Significance 

Eight of the 33 hazardous air pollutants (HAP) identified by the U.S. Environmental Protection 

Agency (EPA) as posing the greatest potential environmental health threat in urban areas are 

metals and their compounds.1

 Negative environmental and health effects caused by metals 

include respiratory and pulmonary disorders, neurotoxicity and cancer.2,3 Hazardous metals are 

unique in that they will not biodegrade; once released into the environment, they will always be 

available for re-introduction into the air, water and food chain. Monitoring HAP emissions, 

especially metal compounds, is an important part of reducing exposure pathways and thus 

protecting human health and the environment. 

The Hazardous Waste Combustor Maximum Achievable Control Technology (HWC MACT) 

currently regulates six enumerated metals directly (arsenic, beryllium, cadmium, chromium, lead 

and mercury) and additionally regulates another five “nonenumerated” metals (antimony, cobalt, 

manganese, nickel, and selenium) using particulate matter (PM) as a surrogate.4

 Unfortunately, 

the emission levels of these metals from the nation’s hazardous waste incinerators are mostly 

estimates because of limitations in monitoring technology. Under the current MACT rule, 

emissions of the enumerated metals are estimated based on control efficiencies determined for 

each class of metals (mercury, semi-volatile, and low volatile) during a performance test and the 

estimated metal feed rates during normal operations. The control efficiency is determined by 

spiking a known amount of metal(s) at a known rate and measuring the resulting concentration 

using an EPA reference method, Method 29.5 The determined control efficiency is then used for 

the next five years, at the end of which another performance test is required. Sources of 

uncertainty in the control efficiency may result from Method 29, which has a measurement error 

of about 15%,6,7 and from the assumption that the control efficiency remains the same over the 

entire five year span. During normal operations, the feed rate is determined by sampling various 

drums or solid waste to be burned. The uncertainties from this process result from two 

assumptions: 

1. That the waste container(s) sampled is representative of others from the same source. 

2. That the sub-sample taken from a particular waste container for analysis is representative 

of the waste in that container. 

Thus, combined uncertainties in control efficiency and feed rate can result in errors in 

uncertainties in emission estimates on the order of 100% or more. 

These large uncertainties in metals emissions would be eliminated if continuous or nearlycontinuous measurements of emissions were possible. The result would be a better 

understanding of the contribution of hazardous waste incineration to ambient levels of toxic 

metals and a better understanding of the contribution of hazardous waste incinerators’ impact on 

the health of those in the immediate vicinity. Cooper Environmental Services LLC (CES) has 

already developed a multi-metal continuous emissions monitor (CEM) that is currently accepted 

by the U.S. EPA for compliance purposes at one gas-fired incinerator.8

 Extending the 

demonstrated capabilities of this instrument to other types of hazardous waste incinerators may 
3 

encourage its use at other facilities, and in turn contribute to a better understanding of hazardous 

metals emissions. 

1.2 Background 

There have been several attempts over the past decade to develop a multi-metal continuous 

emissions monitoring system. These attempts have included CEMs based on laser-induced 

breakdown spectroscopy and atomic absorption spectroscopy.9,10,11 However, none of the CEMs 

based on these approaches are commercially available nor have they been approved for 

compliance purposes. 

Over the last decade, CES has also developed a multi-metal CEM based on X-ray fluorescence 

(XRF) spectroscopy. This CEM, called the Xact CEMSTM (hereafter referred to as “the Xact”), 

was recently approved by the EPA for compliance purposes on a gas-fired incinerator as defined 

in an alternative monitoring petition.8 To demonstrate the Xact’s abilities on a gas-fired thermal 

hazardous waste, the instrument was tested with EPA Method 30112 (M301), the procedure by 

which new emission technologies are validated by the U.S. EPA. For the test, the Xact was 

challenges with an aerosol containing a known metal concentration generated using CES’ 

Quantitative reference Aerosol Generator (QAG). The QAG, which itself has been validated 

using M301, delivers a traceable-to NIST aerosol into stack effluent.13 During M301 testing of 

the Xact, three concentration levels (20, 60, and 130 μg/dscm) of five metals (arsenic, cadmium, 

chromium, lead, and mercury) were spiked using the QAG. The average percent relative 

accuracy and the linearity of the Xact’s response were determined by comparing the Xact’s 

measured concentrations with the QAG’s reference concentrations. The average relative percent 

accuracy of the Xact for all five metals was less than 8.3%.13 A linear least squares regression 

analysis showed that the correlation coefficient for all five elements was greater than 0.99 and 

the average slope was 0.96.13 The strong linear relationship between the concentrations reported 

by the Xact and the QAG reference concentration confirms the linearity of the Xact’s response 

and demonstrates that the instrument is accurate and precise over a wide range of concentrations. 

1.3 Research Objectives 

The objective of this experiment is to demonstrate the feasibility of using the Xact CEMS to 

measure metals emissions from a coal-burning thermal hazardous waste facility. The ability of 

the Xact to measure metal emission levels at new types of sources is most likely to be impacted 

by the trapping efficiency of its reactive filter tape. The trapping efficiency, in turn, is most 

likely to be affected the following physical and chemical characteristics of the source effluent: 

• SOx and NOx emission levels 

• PM levels 

• Moisture content 

• Acid gas levels (e.g. HCl) 

• Temperature 

The Xact has already been successfully validated on a gas-fired thermal hazardous waste 

incinerator, however, in terms of these key effluent characteristics, the facility does not represent 
4 

a particularly “challenging” environment. In this experiment, CES tested the Xact on a coalfired facility because it is likely to represent a much more “challenging” environment. The 

levels of SOx, acid gases, and PM are likely to be much higher at a coal-fired incinerator than at 

a natural gas-fired incinerator. Also, the temperature and moisture (if a wet scrubber is 

operating) levels may be higher. CES tested the Xact on a coal-fired thermal hazardous waste 

incinerator because if the instrument can operate successfully there, it is likely that it would 

operate successfully on numerous other types of sources that burn coal and are regulated for 

hazardous metals. These other types of sources include but are not limited to the following: 

• Municipal waste incinerators 

• Medical waste incinerators 

• Coal-fired power plants 

• Industrial furnaces and boilers 

• Primary and secondary metal smelters 

• Sewage sludge incinerators 

For this research, CES used procedures similar to those used during the M301 validation of the 

Xact on a gas-fired facility. These procedures included spiking the source effluent with the QAG 

and measuring the resulting concentration with the Xact. The Phase I feasibility demonstration 

sought to answer three technical questions regarding the function and validation of the Xact in 

the more challenging environment of a coal-fired facility. 

1. Does the chemistry or physical nature of emissions from coal-fired hazardous waste 

facilities impact the Xact’s ability to continuously and accurately measure metal 

emissions? 

2. Can the Xact accurately measure metal emission levels over a concentration range that 

includes the emission limit on a coal-fired incinerator? 

3. Can the techniques used to validate the Xact on a natural gas-fired hazardous waste 

combustion facility be used on a coal-burning facility? 

CES will determine that it is feasible to use the Xact CEMS for measuring metals at coal-fired 

hazardous waste facilities if the results of this experiment indicate that the Xact is not impacted 

by the chemical composition of coal-fired incinerator’s emissions and the instrument can take 

accurate measurements over a concentration range that includes the emission limit. Furthermore, 

if the Xact instrument itself is shown to be a feasible method of measuring metals in a coal-fired 

incinerator, than CES will determine it is feasible to apply the Xact validation techniques 

previously used natural gas-fired hazardous waste to a coal-fired incinerator. 
5 

2.0 Experimental Design 

2.1 Experimental Set-Up 

CES used EPA’s Multi-Pollutant Control Research Facility (MPCRF) combustor in Research 

Triangle Park, NC to simulate a coal-fired hazardous waste incinerator. The MPCRF is a pilotscale combustor operated by the Air Pollution Technology Branch (APTB) of the EPA’s 

National Risk Management Research Laboratory. The MPCRF is able to fire pulverized coal, 

distillate oil, and/or natural gas at 4 million Btu/hr, yielding flue gas flow at 300ο

F. The MPCRF 

is equipped with wet and dry flue gas cleaning systems and closely simulates full-scale emission 

sources. During this experiment, the combustor was run by Arcadis, a contractor sanctioned by 

the EPA to run this facility for two days, and burned bituminous coal with no additional waste 

products. CES withdrew a sample of flue gas from the stack at approximately 100 Lpm from a 

point downstream of all controls, including an electrostatic precipitator (ESP) and a wet 

scrubber. The sample effluent was transported from the sampling point to a location 

approximately 60 feet away using heat-traced one-inch flexible PFA (polyfluoroalkoxy) line. 

Figure 1 shows a schematic of the experimental setup at this location. 

Figure 1. Experimental Set-Up 

With the QAG, CES spiked reference concentrations of chromium (Cr), arsenic (As), cadmium 

(Cd), mercury (Hg) and lead (Pb) into the stack effluent upstream of the Xact at three 

concentration levels and with a blank (approximately 27, 92 and 250 μg/dscm). Following 

spiking of the stack gas, CES also spiked ambient air at the highest concentration level. The 

selected concentration levels thus span a range which includes the existing source emission 
6 

limits for all three categories of metals: 92 μg/dscm for low volatile metals (As, Cr), 230 

μg/dscm for semi-volatile metals (Pb, Cd), and 130 μg/dscm for Hg.4

Because there was likely to be significant blank levels of mercury (and possibly other metals of 

interest), CES attempted to measure the native concentrations of these metals in the stack 

effluent upstream of the QAG using a M301-validated X-ray and filter-based method (XFM).13 

Background concentrations for each metal were also measured at the start of each day using the 

Xact, due to difficulties CES encountered with a new sampling inlet design for the XFM (Section 

3.3). During these background measurement periods, the system was operated without the 

addition of any flow from the QAG. 

2.2 Aerosol Generation and Sampling 

2.2.1 Aerosol Generation with the QAG 

The QAG or Quantitative Aerosol Generator produces a reference concentration of aerosolized 

particulate metals and metal vapors. It was approved by the EPA for the purpose of testing the 

Xact.13 The QAG generates an aerosol by nebulizing a solution containing known 

concentration(s) of metal analyte(s). Nebulized droplets are dried, and the resulting metal salts 

and vapors are emitted into stack effluent. The solutions for nebulization are prepared in CES’ 

laboratory by diluting NIST-traceable stock solutions of each metal. The total flow through the 

system is measured using a 0 to 150 Lpm Rosemount flow meter. The mass loss rate is 

determined using an analytical balance. The QAG reference aerosol concentration ( QAG Ci ) is 

determined using the analyte concentration in the nebulized solution ( s Ci , μg/g), the solution 

emission rate (Rm, g/min) corrected for vapor loss (Rv, g/min), and the total volume of gas used to 

create the aerosol ( Ft , Lpm). 

( R R ) F

C C m v

t

s

QAG i

i = − (Eq. 1)

2.2.2 Sampling with the XFM 

The XFM is a multi-metal grab-sample method based on filter technology similar to the Xact. It 

was validated using M301 testing at the same time as the Xact.13 The XFM extracts a small 

sample (about 1 Lpm) which is diluted approximately 1:1 with clean dry air. The sample then 

passes through two filters contained in a single sampling cassette: a PTFE 

(polytetrafluoroethylene) filter for particulate-phase metals, and a reactive filter for gas-phase 

metals. Sample volume is then determined by subtracting dilution flow from the total flow for 

the total sampling period. After sampling, the filters are shipped back to CES for analysis by 

XRF. The concentration of metals in the sampled flue gas ( XFM Ci ) is calculated by dividing the 

XRF-determined mass ( XRF Mi ) by the sample volume (Vs ). 

s

XRF

XFM i

i V

M C = (Eq. 2)
7 

For this experiment, the XFM sampled from a point in the sample transport line upstream of the 

QAG and the Xact (Figure 1). An XFM sample was acquired for 45 minutes out of every hour. 

Additionally, the XFM was equipped with a silica gel water trap. This trap was weighed before 

and after each run to determine the concentration of water in the sampled stack gas. 

2.2.3 Sampling with the Xact 

The Xact is an X-ray fluorescence (XRF) based multi-metals CEMS capable of measuring the 

concentrations of up to 25 different metals at a time. The Xact was recently approved by the 

EPA as a compliance instrument on a gas-fired hazardous waste combustor. The Xact extracts a 

sample of effluent from the source and transports it to a “stilling chamber” where the velocity is 

slowed or “stilled.” The Xact instrument then extracts a small flow from this chamber (0.5 

Lpm), which is diluted and then drawn through a reactive filter tape that quantitatively traps both 

particulate phase and vapor phase metals. Sampling lasts for 15 minutes during which time the 

sample volume is measured. After sampling, the filter tape is advanced to the XRF analysis area. 

The deposit is then analyzed by XRF for 15 minutes while the next sample is being collected. 

The XRF-determined mass ( Xact Mi ) is then divided by the totalized sample volume (Vt ) to give 

the concentration of the Xact ( Xact Ci ) in μg/dscm. 

t

Xact

Xact i

i V

M C = (Eq. 3)

2.3 Feasibility Evaluation 

To determine the feasibility of using the Xact in the more challenging environment of a coalfired facility, the Xact-measured concentrations were evaluated for agreement with a reference 

concentration (the QAG), and agreement among measured elements across concentration levels, 

and linearity over concentration range spanning the emission limits of all measured metals. 

Evaluation of these parameters allowed CES to answer its three technical questions: 

1. Is the Xact’s performance is impacted by the chemistry and physical nature of emissions 

from coal-fired hazardous waste facilities? 

2. Can the instrument accurately measure metal emission levels over a concentration range 

that includes the emission limit on a coal-fired incinerator? 

3. Can the validation techniques used on the Xact at a natural gas-fired incinerator be 

applied to a coal-fired incinerator? 

2.3.1 Agreement with a Reference Concentration 

If the Xact is unaffected by the chemical composition of the stack gas, than theoretically, the 

concentration measured by the Xact (adjusted for background) should equal the reference 

concentration spiked by the QAG. The ratio ( Ri ) of the ith metal as measured by the Xact 

( Xact Ci ) and adjusted for the background concentration ( Bi ; determined by either the XFM or the 

Xact) to the concentration spiked by the QAG ( QAG Ci ) is calculated as follows: 
8 

QAG

i

i

Xact

i

i C

C B

R − = (Eq. 4) 

An Ri value between 0.80 and 1.20 indicates that there is good agreement between the measured 

Xact concentrations and the reference QAG concentrations and that the Xact is unaffected by the 

chemical composition of the stack gas. 

As a further means of determining if Xact measurements are affected by the chemistry of the 

stack gas, Xact-to-QAG ratios for the spiked stack gas were compared with those for the spiked 

ambient air at the high concentration level. Ratios within one standard deviation of each other 

indicate that there is no significant different between measurements made with stack gas and 

measurements made with ambient air, and the Xact therefore is not impacted by stack chemistry. 

2.3.2 Inter-Elemental Agreement 

To further evaluate the potential impacts of coal-fired incinerator emissions on the Xact’s ability 

to accurately take measurements over a range of concentrations that includes the emission limit, 

the ratio (RCd) of the concentration of each element (Ci) to the concentration of Cd (CCd) was 

calculated as follows for each concentration level: 

Cd

i

Cd C

C R = (Eq. 5) 

If inter-elemental ratios generally within one standard deviation of each other across all 

concentration levels, than the Xact can accurately take measurements over the experimental 

concentration range. 

As above for the Xact-to-QAG ratios, inter-elemental ratios for the spiked stack gas were 

compared with those for the spiked ambient air at the high concentration level. Again, ratios 

within one standard deviation of each other indicate that there is no significant different between 

measurements made with stack gas and measurements made with ambient air. If the 

measurements made by the Xact are not significantly impacted by the chemical composition of 

the stack gas, one would not expect to see a difference in the inter-elemental ratios between 

spiked stack gas and spiked ambient air at the high concentration level. 

2.3.3 Linearity 

For each element across all concentration levels, Xact-reported concentrations for each element 

were plotted against adjusted QAG reference concentrations, and a linear least squares regression 

analysis was performed in the form of y = mx + b. The slope of the line (m) and the correlation 

coefficient (r) were used to evaluate linearity. Slope values between 0.85 and 1.15 and 

correlation coefficient values greater than 0.90 accurate Xact measurements over the 

experimental concentration range. 
9 

3.0 Pre-Test Laboratory Preparation 

3.1 QAG Low Flow Rate Confirmation 

The QAG was initially designed to spike into a flow of about 600 Lpm and use about 100 Lpm 

of spiking gas, giving a spike-to-stack-gas ratio of about 1:6. During testing at the combustor 

site, a much lower flow rate (around 150 Lpm) was needed while maintaining a reasonable ratio 

of spike to stack gas. To confirm that the QAG could be used at lower flow rates, the QAG was 

used to spike Cr, As, Cd, Hg, and Pb into an Xact manufactured in 2007 at an operational flow 

rate of about 125 Lpm. The same Xact instrument was then spiked at 45 and 30 Lpm. For each 

15 minute Xact period, the ratio of the Xact reported concentration was compared to the QAG 

aerosol concentration. The ratio of the QAG to the Xact for each element at each QAG flow rate 

was found to be approximately 1.00 (Table 1). These results show that (1) there was great 

agreement between the QAG concentration and the reported Xact concentration and (2) the QAG 

can generate a quantitative aerosol at the lower flow rates. This test therefore confirmed that it 

was possible to use a flow rate of about 150 Lpm at our combustor test site. 

Table 1. Results of Testing QAG at Various Flow Rates 

Xact/ 

QAG

STDEV of 

Xact/Qag

Xact/ 

QAG

STDEV of 

Xact/Qag

Xact/ 

QAG

STDEV of 

Xact/Qag

Xact/ 

QAG

STDEV of 

Xact/Qag

Xact/ 

QAG

STDEV of 

Xact/Qag

125 1.02 0.03 1.01 0.07 1.02 0.03 1.00 0.09 1.04 0.03

45 1.00 0.03 1.08 0.02 1.03 0.03 1.08 0.02 1.03 0.02

30 0.99 0.04 1.06 0.05 1.01 0.05 0.95 0.06 1.03 0.05

Pb

Flow 

(Lpm)

Cr As Cd Hg

3.2 CES Xact Calibration 

For the testing at the MPCRF, CES used an Xact manufactured in 2004. This Xact was 

calibrated with XRF thin film standards typically used for the calibration of instruments for PM10 

and PM2.5 filter analysis. The Xact was then challenged using the QAG at three different 

concentration levels (20, 75, and 180 μg/dscm). Linearity was evaluated for each analyte (Cr, 

As, Cd, Hg, and Pb), according to Section 2.2.3. For this test, slopes ranged for a low of 0.74 for 

chromium and cadmium to a high of 0.82 for lead (Pb) with correlation coefficients (r) of greater 

than 0.99 for all elements. The reason for the discrepancy between the Xact and the QAG is not 

well understood at this time. However, the 2007 Xact (Section 3.1) did not exhibit this 

difference. The two units differ in the design of the flow system and the XRF calibration 

method, indicating two potential sources of the discrepancy. Due to time and cost limitations, 

the Xact used for testing at the MPCRF could not be retrofitted with components from the newer 

Xact design. The calibration of the unit was, therefore, adjusted to match the QAG aerosol 

similar to the way that mercury or SO2 CEMS are calibrated.14 Following recalibration, the unit 

was again challenged using the QAG. The concentrations reported by the Xact were found to be 

within 3% of the spiked concentration. 

3.3 XFM Adjustments 

During testing at the MPCRF, CES used the XFM to determine the native concentrations of 

metals in the stack. The XFM sampling inlet was redesigned to make it usable for this project. 
10 

CES tested the redesigned sampling inlet by challenging the XFM with an aerosol of known 

concentration at three different concentration levels (30, 70, 110 μg/m3) using the QAG. The 

XFM-reported concentrations were compared with those of the QAG for each sampled element 

(Cr, As, Cd, Hg, and Pb). Ratios (Table 2) of the XFM-reported concentration to the QAG were 

found to be less then 1.00 (a value of 1.00 indicates complete agreement between the XFM and 

the QAG), with mercury (0.70) and arsenic (0.71) being particularly low. Post-test analyses 

revealed a likely cold spot and flow disturbance at the point where dilution air enters into the 

sampling nozzle. This cold spot and flow disturbance causes loss of material to the walls of the 

sampling inlet tube, particularly for the species most likely to exist in the vapor phase (mercury 

and arsenic). Because of the problems with the redesigned XFM sampling inlet, CES elected to 

use the Xact to determine background concentrations while the facility was burning coal. The 

Xact therefore sampled stack gas prior to spiking on each day of testing at the MPCRF and 

reported background concentrations. XFM samples were still acquired, however, to check for 

variability in background concentrations while spiking was occurring. 

Table 2: QAG Spiked Concentration Versus XFM Reported Concentration 

Cr As Cd Hg Pb Cr As Cd Hg Pb Cr As Cd Hg Pb

31.4 31.4 31.3 31.3 31.3 28.1 25.6 26.2 27.3 26.7 0.89 0.82 0.84 0.87 0.85

31.6 31.6 31.5 31.5 31.6 28.1 25.4 27.0 25.4 27.4 0.89 0.80 0.86 0.81 0.87

30.8 30.7 30.7 30.7 30.7 30.7 27.1 30.8 25.3 29.5 1.00 0.88 1.00 0.82 0.96

30.1 30.1 30.0 30.0 30.0 29.0 24.7 26.9 22.6 28.2 0.96 0.82 0.90 0.75 0.94

71.8 71.7 71.6 71.6 71.7 67.0 45.5 64.2 55.1 64.7 0.93 0.63 0.90 0.77 0.90

70.0 69.9 69.8 69.8 69.9 66.3 43.9 65.5 49.7 64.7 0.95 0.63 0.94 0.71 0.93

68.6 68.6 68.5 68.5 68.5 65.4 45.2 61.4 50.0 64.6 0.95 0.66 0.90 0.73 0.94

68.6 68.6 68.5 68.5 68.5 66.9 44.6 64.8 49.6 65.5 0.97 0.65 0.95 0.72 0.96

110.1 110.0 109.8 109.9 109.9 106.1 72.7 102.4 75.0 104.0 0.96 0.66 0.93 0.68 0.95

108.0 107.9 107.7 107.7 107.8 106.9 71.3 101.8 69.5 104.8 0.99 0.66 0.95 0.65 0.97

108.0 107.9 107.7 107.7 107.8 97.3 62.2 83.1 56.2 87.4 0.90 0.58 0.77 0.52 0.81

108.0 107.9 107.7 107.7 107.8 103.5 66.2 90.9 56.9 55.4 0.96 0.61 0.84 0.53 0.51

0.95 0.70 0.90 0.71 0.88

Low

Mid

High

QAG Predicted Conc. (μg/m3) XFM-Reported Conc. (μg/m3) XFM/QAG

AVERAGE

Concentration 

Level

4.0 Test Results and Discussion 

4.1 Xact-to-QAG Agreement 

Table 3 shows the results of the ratio comparison between QAG and the Xact. The ratio of the 

Xact to the QAG should be close to unity if the Xact is not significantly impacted by the 

chemical composition of the stack gas. A value of greater than 1 indicates that the Xact is high 

relative to the QAG a value of less than 1 indicates the Xact is low relative to the QAG. Table 4 

summaries the results with regards to the agreement criteria established in Section 2.3. 
Table 3. Xact Concentrations, QAG Concentrations and Xact-to-QAG Ratios 

Cr As Cd Hg Pb Cr As Cd Hg Pb Cr

As Cd Hg 

0 0 0 0 0 0 0.4 1.5 23.1 0.26 NA NA NA NA 0 0 0 0 0 0 0 0.88 21.31 0.8 NA NA NA NA 0 0 0 0 0 0 0.33 1.42 14.28 0 NA NA NA NA 0 0 0 0 0 0 0 0 10.64 0.66 NA NA NA NA 0 0 0 0 0 0 0.49 0 8.85 0.12 NA NA NA NA 0 0 0 0 0 0 0.23 0 7.41 0.12 NA NA NA NA 0 0 0 0 0 0 0.43 1.08 6.28 0.43 NA NA NA NA 

27.58 27.56 27.49 27.53 27.60 29.96 28.21 28.94 31.30 26.17 1.09 1.02 1.05 1.14 27.58 27.56 27.49 27.53 27.60 27.71 28.43 29.86 32.11 26.36 1.00 1.03 1.09 1.17 27.58 27.56 27.49 27.53 27.60 29.35 29.73 31.50 30.45 25.61 1.06 1.08 1.15 1.11 27.58 27.56 27.49 27.53 27.60 31.19 30.32 28.48 30.88 26.50 1.13 1.10 1.04 1.12 27.58 27.56 27.49 27.53 27.60 27.20 30.01 28.57 30.77 25.98 0.99 1.09 1.04 1.12 27.86 27.83 27.76 27.81 27.88 27.28 28.45 29.01 30.68 28.30 0.98 1.02 1.04 1.10 27.86 27.83 27.76 27.81 27.88 28.75 31.08 31.70 29.99 25.63 1.03 1.12 1.14 1.08 27.86 27.83 27.76 27.81 27.88 28.94 30.97 28.70 31.31 28.29 1.04 1.11 1.03 1.13 27.86 27.83 27.76 27.81 27.88 29.29 30.32 30.11 30.16 27.85 1.05 1.09 1.08 1.08 27.86 27.83 27.76 27.81 27.88 30.72 29.38 31.85 29.22 26.65 1.10 1.06 1.15 1.05 92.87 92.84 92.89 92.91 92.87 96.74 102.13 104.27 103.96 91.75 1.04 1.10 1.12 1.12 92.23 92.20 92.25 92.27 92.23 95.40 101.44 96.64 102.73 89.02 1.03 1.10 1.05 1.11 92.23 92.20 92.25 92.27 92.23 97.09 102.63 98.80 104.93 90.84 1.05 1.11 1.07 1.14 92.23 92.20 92.25 92.27 92.23 98.83 104.87 103.73 105.11 90.95 1.07 1.14 1.12 1.14 92.23 92.20 92.25 92.27 92.23 96.78 100.45 99.61 101.80 91.32 1.05 1.09 1.08 1.10 91.01 90.99 91.03 91.06 91.01 97.52 102.01 99.30 102.70 90.42 1.07 1.12 1.09 1.13 91.01 90.99 91.03 91.06 91.01 97.60 101.78 98.58 102.69 89.65 1.07 1.12 1.08 1.13 91.01 90.99 91.03 91.06 91.01 96.32 100.05 94.45 102.48 91.52 1.06 1.10 1.04 1.13 91.01 90.99 91.03 91.06 91.01 99.68 105.65 108.04 104.54 93.53 1.10 1.16 1.19 1.15 

248.93 248.78 248.14 248.53 249.08 266.66 279.51 264.46 291.91 248.18 1.07 1.12 1.07 1.17 248.93 248.78 248.14 248.53 249.08 262.46 277.26 264.40 278.69 243.97 1.05 1.11 1.07 1.12 248.93 248.78 248.14 248.53 249.08 273.43 286.62 273.00 292.01 252.36 1.10 1.15 1.10 1.17 248.93 248.78 248.14 248.53 249.08 271.94 289.75 282.36 292.30 252.26 1.09 1.16 1.14 1.18 245.73 245.58 244.95 245.34 245.88 275.05 290.57 289.08 293.00 252.08 1.12 1.18 1.18 1.19 245.73 245.58 244.95 245.34 245.88 266.92 280.31 275.81 282.73 243.49 1.09 1.14 1.13 1.15 245.73 245.58 244.95 245.34 245.88 260.84 272.15 271.73 273.55 236.20 1.06 1.11 1.11 1.11 245.73 245.58 244.95 245.34 245.88 267.62 282.02 273.88 288.64 245.60 1.09 1.15 1.12 1.18 247.62 247.47 246.83 247.22 247.77 267.36 277.35 266.38 287.20 245.43 1.08 1.12 1.08 1.16 107.85 107.79 107.51 107.68 107.92 109.73 119.63 114.98 128.64 102.22 1.02 1.11 1.07 1.19 108.11 108.05 107.76 107.94 108.18 118.75 124.52 122.78 131.76 109.87 1.10 1.15 1.14 1.22 108.11 108.05 107.76 107.94 108.18 114.50 125.23 116.98 127.72 107.74 1.06 1.16 1.09 1.18 110.53 110.46 110.17 110.35 110.59 116.27 124.89 121.82 123.96 106.72 1.05 1.13 1.11 1.12 110.53 110.46 110.17 110.35 110.59 117.46 127.80 123.13 126.67 108.88 1.06 1.16 1.12 1.15 

AVE 1.06 1.11 1.09 1.13 

STDEV 0.04 0.04 0.04 0.03 

%RSD 3.36 3.61 4.00 2.93 

AVE 1.06 1.14 1.10 1.17 

STDEV 0.03 0.02 0.03 0.04 

%RSD 2.73 1.85 2.47 3.28 

Conc. 

Level

Xact/QAG

Low

Ambient 

Air

Blank 

Spike

QAG Aerosol Conc (אg/m3) Background Corrected Xact Conc. (אg/m3

)

Mid

High

High 

Ambient

Flue Gas

11
12 

Table 4. Summary of Xact-to-QAG Agreement Criteria and Results 

Cr 0.80 to 1.20 1.06 yes

As 0.80 to 1.20 1.11 yes

Cd 0.80 to 1.20 1.09 yes

Hg 0.80 to 1.20 1.13 yes

Pb 0.80 to 1.20 0.98 yes

Element

Xact/QAG Ratio

Criteria

Experime

ntal 

Average

Criteria 

Met?

On average, the Xact was slightly high relative to the QAG, ranging from a low of 0.98 for lead 

to 1.13 for mercury. However, all values were within the experimental target range between 

0.80 and 1.20. Also shown in Table 3, Xact-to-QAG ratios are not significantly different 

regardless of whether the Xact was sampling spiked stack effluent or spiked ambient air. These 

two results indicate that the Xact’s measurement of all five metals of interest (chromium, arsenic, 

cadmium, mercury, and lead) is unaffected by the chemical composition of the stack gas. 

A major difficulty with this experiment was the measurement of the amount of water in the 

system. The Xact measures metals concentrations on a dry basis, however, the QAG spikes into 

a very “wet” air stream. During testing, it appears that CES had a great deal of difficulty 

accurately measuring the amount of water in the system. Since sampling took place downstream 

of a wet scrubber, all of the results assume saturation at a measured temperature of 116 °F and an 

absolute pressure of approximately 27.9 inches of mercury (see appendix A for a more detailed 

explanation).15 The amount of water determined to be present during ambient air spiking was 

based on nearby meteorological data of the relative humidity. 

As noted above, background metal concentrations were determined using the Xact. A 

background level of 6.73 μg/dscm was used for mercury throughout the tests and represents the 

average of all background measurements on the Xact. The mercury is likely due to the coal and 

was expected. For the lowest spike level, a background concentration of 4 μg/dscm of chromium 

was subtracted from the Xact results. During most of the blank spike and the background 

measurements, CES had observed essentially no background metal concentrations for every 

element of interest except mercury. However, just prior to the low-level spike, CES observed a 

jump in the concentration of several metals of interest including chromium (12 μg/dscm) and 

arsenic (20 μg/dscm). This observed spike coincided with a sudden failure in the automatic feed 

of coal. Spiking was not resumed until the arsenic, lead and cadmium values had returned to 

zero; however, the chromium numbers did not return to zero. The value of 4 μg/dscm for 

chromium was therefore used as an estimate and is slightly lower than the last measured value 

for chromium of 4.73 μg/dscm. 

4.2 Inter-elemental Agreement 

Table 5 shows the ratio of all the elements to cadmium under all four spiking conditions (low 

concentration with stack gas, medium concentration with stack gas, high concentration with 

stack gas, high concentration with ambient air). Of these five elements, chromium, lead and 

cadmium are likely to exist in a particle phase, arsenic is likely to be partially in the particle 
13 

phase and partially in vapor phase, and mercury is likely to be entirely in the vapor phase. The 

inter-elemental ratios serve as an additional confirmation that the Xact’s measurement is 

unaffected by stack gas composition. If the measurements made by the Xact were significantly 

impacted by the chemical composition of the stack gas, one would expect a difference in the 

inter-elemental ratios between spiked stack gas and spiked ambient air, particularly for the 

metals likely to have significant vapor phase species (arsenic and mercury). The results in Table 

5 indicate that the inter-elemental ratios are not significantly different for spiked stack gas or 

spiked ambient air. Furthermore, the fact that the inter-elemental ratios remain nearly the same 

across all concentration levels indicates that the chemistry and physical characteristics of the 

stack effluent do not affect the Xact’s measurements at any concentration. 
14 

Table 5. Xact Inter-elemental Ratios 

Cr/Cd As/Cd Hg/Cd Pb/Cd

1 1.04 0.97 1.15 0.90

2 0.93 0.95 1.14 0.88

3 0.93 0.94 1.03 0.81

4 1.10 1.06 1.15 0.93

5 0.95 1.05 1.14 0.91

6 0.94 0.98 1.12 0.98

7 0.91 0.98 1.01 0.81

8 1.01 1.08 1.16 0.99

9 0.97 1.01 1.07 0.92

10 0.96 0.92 0.98 0.84

Average 0.97 1.00 1.09 0.90

STDEV 0.06 0.06 0.07 0.07

%RSD 5.80 5.64 6.38 7.35

1 0.98 1.05 1.06 0.91

2 0.95 1.03 1.05 0.91

3 0.93 0.98 1.02 0.88

4 0.99 1.05 1.08 0.92

5 0.98 1.04 1.08 0.92

6 0.95 1.01 1.03 0.88

7 0.97 1.01 1.04 0.92

8 0.98 1.03 1.05 0.91

9 0.99 1.03 1.06 0.91

10 1.02 1.06 1.11 0.97

11 0.92 0.98 0.99 0.87

Average 0.97 1.02 1.05 0.91

STDEV 0.03 0.03 0.03 0.03

%RSD 2.94 2.66 3.17 3.05

1 0.97 1.02 1.06 0.89

2 1.01 1.06 1.11 0.94

3 0.99 1.05 1.06 0.92

4 1.00 1.05 1.08 0.92

5 0.96 1.03 1.04 0.89

6 0.95 1.01 1.02 0.87

7 0.97 1.02 1.03 0.88

8 0.96 1.00 1.01 0.87

9 0.98 1.03 1.06 0.90

10 1.00 1.04 1.09 0.92

Average 0.98 1.03 1.06 0.90

STDEV 0.02 0.02 0.03 0.02

%RSD 2.09 1.88 2.86 2.65

2 0.97 1.01 1.05 0.89

3 0.98 1.07 1.07 0.92

4 0.95 1.03 0.99 0.88

5 0.95 1.04 1.00 0.88

Average 0.96 1.04 1.03 0.89

STDEV 0.01 0.02 0.03 0.02

%RSD 1.23 2.35 3.40 2.19

0.97 1.02 1.07 0.90

0.04 0.04 0.05 0.04

0.96 1.04 1.03 0.89

0.01 0.02 0.03 0.02

AVE of Stack Gas Spike

STDEV of Gas Stack Spike

AVE of Ambient Air Spike

STDEV of Ambient Air Spike

Low Stack Gas

Mid Stack Gas

High Stack Gas

High Ambient 

Air

Concentration Interelemental Ratios

Level Run Number
15 

4.3 Linearity 

The results of the linear least squares regression analyses for the Xact reported concentration 

compared to the QAG reference concentrations over the experimental concentration range are 

shown in Figures 2 through 6. The slope of each least squares fit is an indicator of the accuracy 

of the Xact with a value of unity indicating complete agreement between the Xact and the QAG. 

The slopes ranged from a low of 0.99 for lead to a high of 1.14 for arsenic; all elements were 

thus within the experimental target range for the slope of 0.85 to 1.15. The correlation 

coefficient (r) indicates the amount of scatter in the data with a value of 1 indicating no scatter. 

The correlation coefficient for all of the elements had values of 0.99, indicating very little scatter 

and much higher than the experimental target of 0.90. Table 6 summaries the results with 

regards to the linearity criteria established in Section 2.3. Together, the slope and correlation 

coefficient values demonstrate that the Xact can accurately take measurements over a 

concentration range that includes existing source emission limits (92 μg/dscm for As and Cr, 230 

μg/dscm for Pb, Cd, and 130 μg/dscm for Hg).4

Chromium Linearity

y = 1.0858x - 1.035

R2

 = 0.9993

-50

0

50

100

150

200

250

300

0 50 100 150 200 250 300

QAG Cr Conc. (μg/m3)

Xact Cr. Conc (μg/m3)

Figure 2. Chromium Linearity 

r = 0.99 
16 

Arsenic Linearity

y = 1.1432x - 1.3864

R2

 = 0.9991

-50

0

50

100

150

200

250

300

350

0 50 100 150 200 250 300

QAG As Conc. (μg/m3)

Xact As. Conc. (μg/m3)

Figure 3. Arsenic Linearity 

Cadmium Linearity

y = 1.1091x - 0.4478

R2

 = 0.9978

-50

0

50

100

150

200

250

300

350

0 50 100 150 200 250 300

QAG Cd Conc. (μg/m3)

Xact Cd Conc. (μg/m3)

Figure 4. Cadmium Linearity 

r = 0.99 

r = 0.99 
17 

Hg Linearity

y = 1.1365x + 3.7157

R2

 = 0.9959

0

50

100

150

200

250

300

350

0 50 100 150 200 250 300

QAG Hg Conc. (μg/m3)

Xact Hg Conc. (μg/m3)

Figure 5. Mercury Linearity 

Pb Linearity

y = 0.9977x - 0.4203

R2

 = 0.9993

-50

0

50

100

150

200

250

300

0 50 100 150 200 250 300

QAG Pb Conc. (μg/m3)

Xact Pb Conc. (μg/m3)

Figure 6. Lead Linearity 

r = 0.99 

r = 0.99 
18 

Table 6. Summary of Linearity Criteria and Results 

Criteria

Experimental 

Result

Criteria 

Met? Criteria

Experimental 

Average

Criteria 

Met?

Cr 0.85 to 1.15 1.09 yes >0.90 >0.99 yes

As 0.85 to 1.15 1.14 yes >0.90 >0.99 yes

Cd 0.85 to 1.15 1.11 yes >0.90 >0.99 yes

Hg 0.85 to 1.15 1.14 yes >0.90 >0.99 yes

Pb 0.85 to 1.15 1.00 yes >0.90 >0.99 yes

Element

Slope

Linearity

Correlation Cooefficient

5.0 Experimental Conclusions and Technical Feasibility Assessment 

The Phase I feasibility demonstration sought to answer three technical questions regarding the 

function and validation of the Xact in the more challenging environment of a coal-fired facility. 

1. Does the chemistry or physical nature of emissions from coal-fired hazardous waste 

facilities impact the Xact’s ability to continuously and accurately measure metal 

emissions? 

2. Can the Xact accurately measure metal emission levels over a concentration range that 

includes the emission limit on a coal fired incinerator? 

3. Can the techniques used to validate the Xact on a natural gas fired hazardous waste 

combustion facility be used on a coal burning facility? 

To answer the first question, CES evaluated the agreement between Xact-measured 

concentrations and reference concentrations as well as the elemental agreement between 

measurements made in stack gas and measurements made in ambient air. The results 

demonstrated that there was a high level of agreement between the Xact and the reference 

aerosol at all concentration levels and this level agreement was not affected by sampling stack 

gas versus ambient air. The results also showed that measurements made in stack gas and 

measurements made in ambient air were not significantly different for each element. CES 

therefore concludes that the Xact’s measurements are not impacted by the chemical or physical 

characteristics of the stack gas. 

To answer the second question, CES evaluated the linear response and the inter-elemental 

agreement of the Xact’s measurements over a concentration range that included existing source 

emission limits. The results demonstrated excellent agreement between the reference QAG 

concentrations and the Xact measured concentration at all spiking levels, as well as good 

elemental agreement across all spiking levels. CES thus concludes that the Xact can accurately 

measure metals concentrations over a large range including the emission limit. 

Because the results of this experiment indicate that the Xact is not impacted by the chemical 

composition of coal-fired incinerator’s emissions and the instrument can take accurate 

measurements over a concentration range that includes the emission limit, CES concludes that it 
19 

is feasible to use the Xact CEMS for measuring metals at any coal-fired combustion source 

including: hazardous waste incinerators, municipal waste incinerators, medical waste 

incinerators, and coal-fired power plants. Furthermore, the validation techniques used previously 

on a gas-fired hazardous waste incinerator were also successful on a coal-fired furnace. Future 

work however, should incorporate more accurate methods of measuring stack gas water content 

should be used. 

6.0 Commercialization Activities and Plans 

An investigation of potential markets for the Xact multi-metals monitor during Phase I of this 

project has revealed several markets for this instrument: the mercury monitoring market, the 

multi-metal CEMs market, and the multi-metal ambient monitoring market. At the time of this 

study, the most significant market for the Xact CEMS is the mercury monitoring market. The 

mercury monitoring market, estimated at $100 million dollar a year (all goods and services), was 

created in 2005 with the Clean Air Mercury Rule .16 This rule requires monitoring of mercury 

emissions from coal-fired utility boilers. While other technologies exist in this market, the Xact 

technology is unique in that it uses X-ray fluorescence to measure mercury and thus offers 

significant benefits over the other technologies including measurement of more than one metal 

and reduced cost. 

Presently, the multi-metals CEMS and ambient monitoring markets are still emerging. CES 

continues to pursue possible commercial opportunities in the multi-metals CEMS market as 

emission monitors and standards are reviewed by the US and Europe. During 2007, CES 

received and filled orders for two Xact CEMS for the US Army. CES was also approached 

several times throughout the year by parties potentially interested in purchasing units. In terms 

of the multi-metal ambient monitoring market, CES has been contacted by foreign and state 

governments interested in the application of Xact technology ambient monitoring. This market 

should continue to expand as National Ambient Air Quality Standards for lead are review by the 

EPA. In fact, CES has recently received two orders for ambient multi-metals monitors and is 

expecting a third order in October. At this time, however, there are no regulatory drivers for a 

multi-metal CEMs or ambient monitors. 

Given the strength and significance of the mercury monitoring market, CES has elected to focus 

the majority of its commercialization efforts on this market. CES is beginning to optimize the 

Xact design around mercury monitoring while maintaining those features that make the 

instrument applicable to the multi-metals CEMs and ambient monitoring markets as they 

develop. A sustainable commercial business is expected with application of Xact technology to 

the existing mercury market alone. However, this technology will also be applied to additional 

monitoring markets as they are defined by future regulations. 

Progress and our future commercialization activities in this monitoring market are summarized 

below. 

1. Optimization of our Xact for the measurement of mercury. The multi-metals Xact used in 

these Phase I demonstration tests had a single excitation condition optimized for mercury 
20 

but used a detector optimized for multi-metals. Future work will focus on optimization 

of X-ray optics and use of detectors best suited for mercury. Currently, CES is working 

with a detector supplier who has loaned CES an optimum mercury detector. This 

detector is in the early stages of evaluation and testing. 

2. Establishing opportunities to demonstrate the Xact technology on coal-fired utility 

boilers. CES has obtained permission from a local coal-fired power plant to test a 

mercury-optimized monitor on their stack. With funding, CES plans on installing a 

mercury-optimized Xact at the local coal-fired power plant and operating it over an 

extended period to demonstrate its reliability. If funding is available, this unit would also 

be tested for accuracy with a comparative reference method. CES expects to obtain a 

commitment to fund reference method testing of the mercury-optimized Xact when the 

instrument is installed on the stack. 

3. Strengthening patent protection. During this past year, CES has obtained a third patent 

dealing with proprietary filter chemistry. CES submitted two other patent applications 

this past year dealing with quality assurance anticipates submitting an additional patent in 

2008. 

4. Defining and streamlining the Xact production supply chain and cost reduction. In 2007, 

CES built two new multi-metal Xacts for a US Army conventional weapons incineration 

application. This opportunity allowed CES to define its supply chain along with a clearly 

defined database on costs, vendor, lead times, etc. As a result, CES was also able to more 

precisely define fabrication costs and identify areas for cost reduction. 

5. Demonstrating the application of the Xact to the ambient air monitoring market. With 

current EPA funding, CES is in the process of demonstrating the applicability of the Xact 

technology to fence line monitoring. With potential future funding, CES expects to have 

a unit operating in the field near a major source in Portland. 

6. Development of an expanding distribution network. This past year, CES has successfully 

established distribution networks in Korea, Canada and Australia. This distribution 

network has resulted in two purchase orders for ambient multi-metal Xacts from a 

Korean distributor and strong leads from a Canadian and Australian distributor. In 

addition, CES is in the process of expanding the sales territory of our Korean distributor 

to the major pacific rim countries as well as developing distributor relations for Europe 

and India. 

7. Developing sales literature. This literature will help support sales and distribution efforts. 

In addition, CES attendance at seminars will help distributors and regulators better 

understand the Xact technology and its broad applications. 

8. Looking for partners to help address the mercury monitoring market. Discussions with 

sources of capital are in progress that might provide supplemental resources to more 

aggressively attack the mercury monitoring market. In addition, CES is currently in 

discussions with integrators to help service the mercury CEMS market and with key 

component suppliers to provide support. These discussions have already resulted in labor 
21 

and hardware support from an X-ray detector manufacture in the form of equipment loans 

and applications development valued on the order of $100,000 to develop the mercury 

monitoring application. 

7.0 References 

1. U.S. Environmental Protection Agency. Air Toxics Strategy Fact Sheet. EPA Technology 

Transfer Network Air Toxics Website. http://www.epa.gov/ttn/atw/urban/strategyfs0303.pdf 

(accessed September 2006). 

2. Prieditis, H.; Adamson, I.Y. 2002. Comparative Pulmonary Toxicity of Various Soluble 

Metals Found in Urban Particulate Dust; Exp. Lung. Res., 28, 563-576. 

3. Monn, C.; Becker, S. 1999. Cytotoxicity and Induction of Proinflammatory Cytokines from 

Human Monocytes Exposed to Fine (PM2.5) and Coarse Particles (PM10-2.5) in Outdoor and 

Indoor Air; Tox. Appl. Pharm., 155, 245-252. 

4. U.S. Environmental Protection Agency. 2005. National Emissions Standards for Hazardous 

Air Pollutants for Source Categories; Code of Federal Regulations, 40 CFR 63; U.S. 

Government Printing Office: Washington, DC. 

5. U.S. Environmental Protection Agency. 2005. Method 29, Determination of Metals 

Emissions from Stationary Sources; Code of Federal Regulations, 40 CFR 60; U.S. 

Government Printing Office: Washington, DC. 

6. Rigo, H.G.; Chandler A.J. 1999. Quantitation Limits for Reference Methods 23, 26, and 29; 

J. Air & Waste Manage. Assoc., 49, 399-411. 

7. American Society of Mechanical Engineers [ASME], Research Committee on Industrial and 

Municipal Waste. 2001. Reference Method Accuracy and Precision (ReMAP): Phase 1, 

Precision of Manual Stack Emission Measurements; Report No. CRTD-60; ASME 

International: Washington, DC. 

8. Eli Lilly and Company. 2005. Alternative Monitoring Petition for the Solid-Liquid 

Incinerator, Tippecanoe Laboratories: Lafayette, IN. 

9. Zhang, H.; Yueh, F.Y.; Singh, J.P. 2002. Evaluation of the Potential of Laser-Induced 

Breakdown Spectroscopy for Detection of Trace Element in Liquid; J. Air & Waste Manage. 

Assoc., 51, 681-687.

10. Seltzer, M.D. 2000. Performance Testing of a Multimetals Continuous Emissions Monitor; 

J. Air & Waste Manage. Assoc., 50, 1010-1016. 

11. Sky +. 1998. 1997 Performance Testing of Multi-Metal Continuous Emissions Monitors; 

DOE/ID-10665. U.S. Department of Energy, Idaho Operations Office: Idaho Falls, ID. 

12. U.S. Environmental Protection Agency. 2005. Method 301, Field Validation of Pollution 

Measurement Methods for Various Media; Code of Federal Regulations, 40 CFR 56; U.S. 

Government Printing Office: Washington, DC. 
22 

13. Yanca, C.A.; Barth, D.C.; Petterson, K.A.; Nakanishi, M.P.; Johnsen, B.E.; Cooper, J.A.; 

Lambert, R.H.; Bivins, D.G. 2006. Validation of Three New Methods for Determination of 

Metal Emissions using a Modified EPA Method 301. J. Air & Waste Manage. Assoc., 56, 

1733–1742. 

14. U.S. Environmental Protection Agency. 2002. Continuous Emissions Monitoring; Code of 

Federal Regulations, 40 CFR 75; U.S. Government Printing Office: Washington, DC. 

15. Perry, R.H.; Green, D.W; Editors. 1984. Perry’s Chemical Engineers’ Handbook. 6th Ed. 

McGraw-Hill Book Company: New York. 

16. U.S. Environmental Protection Agency. Clean Air Mercury Rule. 

http://www.epa.gov/mercuryrule (accessed August 2007).
Appendix A to the Final Report 

Feasibility of Monitoring Heavy Metal Emissions from a CoalFired Thermal Hazardous Waste Incinerator Using a MultiMetal Continuous Emissions Monitor 

EPA Contract No.: EP-D-07-026 

August 30th, 2007 

Submitted by: 

Cooper Environmental Services LLC 

10180 SW Nimbus Ave, Ste J6 

Portland, OR 97223 
A-1 

1.0 Introduction 

The initial results from the testing of the CES Xact at the Multi-Pollutant Control Research 

Facility (MPCRF) are enumerated in Table 1. These results indicate a significant discrepancy 

(about 25%) between the Xact and the Quantitative Aerosol Generator (QAG) when sampling 

stack gas and a somewhat smaller discrepancy when sampling ambient air. These results were 

based on what are now believed to be inaccurate measurements of the amount of water in the 

stack gas. The Xact dries the sampled flow before measurement to give a concentration for each 

result in terms of dry standard cubic meters (dscm). The QAG, however, was spiking into what 

should be a wet gas stream (the stack gas sample into which the QAG aerosol was spiked was 

taken downstream of a wet scrubber and transported using flex line heated to 250 °F). To 

accurately compare the Xact and the QAG, the water in the stack gas must be taken into account. 

This appendix presents evidence in support of the conclusion that the water measurement used to 

generate these results was inaccurate, and also outlines why other possible explanations for this 

discrepancy were discounted. 

2.0 Evaluation of Potential Sources of QAG-Xact Discrepancy 

Of particular interest in examining the difference between the concentration measured by the 

Xact and that emitted by the QAG is that fact that the Xact is reporting a higher concentration 

than the QAG is emitting. It is therefore unlikely that much if any of the particulate or vaporphase emissions were being lost to the walls of either the QAG or the transport line. To attempt 

to explain why the Xact was high relative to the QAG, a list of possible explanations was 

generated as follows: 

1. Inaccurate measurement of QAG flow 

2. Problem with the Xact X-ray Fluorescence (XRF) calibration or flow calibration 

3. Evaporative loss in the QAG 

4. Leak in the transport line 

5. Matrix (stack gas) effects 

6. Inaccurate measurement of moisture in stack gas 

2.1 Inaccurate Measurement of QAG Flow 

The QAG reference aerosol concentration ( QAG Ci ) is determined using the analyte concentration 

in the nebulized solution ( s Ci , μg/g), the solution emission rate (Rm, g/min) corrected for vapor 

loss (Rv, g/min), and the total volume of gas used to create the aerosol ( Ft , slpm). 

( R R ) F

C C m v

t

s

QAG i

i = − (Eq. 1)
Table 1. Initial Results Uncorrected for Moisture 

Cr As Cd Hg Pb Cr As Cd Hg Pb Cr As Cd 

10:15 10:30 0.00 0.00 0.00 0.00 0.00 0.00 0.40 1.50 23.10 0.26 NA NA NA 10:30 10:45 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.88 21.31 0.80 NA NA NA 10:45 11:00 0.00 0.00 0.00 0.00 0.00 0.00 0.33 1.42 14.28 0.00 NA NA NA 11:00 11:15 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10.64 0.66 NA NA NA 11:15 11:30 0.00 0.00 0.00 0.00 0.00 0.00 0.49 0.00 8.85 0.12 NA NA NA 11:30 11:45 0.00 0.00 0.00 0.00 0.00 0.00 0.23 0.00 7.41 0.12 NA NA NA 11:45 12:00 0.00 0.00 0.00 0.00 0.00 0.00 0.43 1.08 6.28 0.43 NA NA NA 

2:45 3:00 23.95 23.93 23.87 23.91 23.97 29.96 28.21 28.94 33.21 26.17 1.25 1.18 1.21 3:00 3:15 23.95 23.93 23.87 23.91 23.97 27.71 28.43 29.86 34.02 26.36 1.16 1.19 1.25 3:15 3:30 24.19 24.17 24.11 24.15 24.21 29.35 29.73 31.50 32.36 25.61 1.21 1.23 1.31 3:30 3:45 24.19 24.17 24.11 24.15 24.21 31.19 30.32 28.48 32.79 26.50 1.29 1.25 1.18 3:45 4:00 24.19 24.17 24.11 24.15 24.21 27.20 30.01 28.57 32.68 25.98 1.12 1.24 1.18 4:00 4:15 24.44 24.41 24.35 24.39 24.46 27.28 28.45 29.01 32.59 28.30 1.12 1.17 1.19 4:15 4:30 24.55 24.53 24.47 24.51 24.57 28.75 31.08 31.70 31.90 25.63 1.17 1.27 1.30 4:30 4:45 24.55 24.53 24.47 24.51 24.57 28.94 30.97 28.70 33.22 28.29 1.18 1.26 1.17 4:45 5:00 24.55 24.53 24.47 24.51 24.57 29.29 30.32 30.11 32.07 27.85 1.19 1.24 1.23 5:00 5:15 24.55 24.53 24.47 24.51 24.57 30.72 29.38 31.85 31.13 26.65 1.25 1.20 1.30 9:15 9:30 80.07 80.05 80.09 80.11 80.07 95.03 101.84 97.05 102.81 88.41 1.19 1.27 1.21 9:30 9:45 80.07 80.05 80.09 80.11 80.07 95.36 102.82 99.86 104.43 90.66 1.19 1.28 1.25 9:45 10:00 80.07 80.05 80.09 80.11 80.07 96.74 102.13 104.27 105.87 91.75 1.21 1.28 1.30 

10:00 10:15 79.52 79.50 79.54 79.56 79.52 95.40 101.44 96.64 104.64 89.02 1.20 1.28 1.22 10:15 10:30 81.56 81.54 81.58 81.60 81.56 97.09 102.63 98.80 106.84 90.84 1.19 1.26 1.21 10:30 10:45 81.56 81.54 81.58 81.60 81.56 98.83 104.87 103.73 107.02 90.95 1.21 1.29 1.27 10:45 11:00 81.56 81.54 81.58 81.60 81.56 96.78 100.45 99.61 103.71 91.32 1.19 1.23 1.22 11:00 11:15 80.49 80.47 80.51 80.53 80.49 97.52 102.01 99.30 104.61 90.42 1.21 1.27 1.23 11:15 11:30 80.70 80.68 80.72 80.74 80.70 97.60 101.78 98.58 104.60 89.65 1.21 1.26 1.22 11:30 11:45 80.70 80.68 80.72 80.74 80.70 96.32 100.05 94.45 104.39 91.52 1.19 1.24 1.17 11:45 12:00 80.70 80.68 80.72 80.74 80.70 99.68 105.65 108.04 106.45 93.53 1.24 1.31 1.34 12:45 1:00 222.93 222.79 222.21 222.57 223.06 266.75 280.10 275.16 292.08 245.82 1.20 1.26 1.24 

1:00 1:15 219.38 219.25 218.68 219.03 219.52 266.66 279.51 264.46 293.82 248.18 1.22 1.27 1.21 1:15 1:30 219.38 219.25 218.68 219.03 219.52 262.46 277.26 264.40 280.60 243.97 1.20 1.26 1.21 1:30 1:45 219.38 219.25 218.68 219.03 219.52 273.43 286.62 273.00 293.92 252.36 1.25 1.31 1.25 1:45 2:00 217.94 217.81 217.24 217.59 218.07 271.94 289.75 282.36 294.21 252.26 1.25 1.33 1.30 2:00 2:15 215.14 215.01 214.45 214.79 215.27 275.05 290.57 289.08 294.91 252.08 1.28 1.35 1.35 2:15 2:30 215.14 215.01 214.45 214.79 215.27 266.92 280.31 275.81 284.64 243.49 1.24 1.30 1.29 2:30 2:45 215.14 215.01 214.45 214.79 215.27 260.84 272.15 271.73 275.46 236.20 1.21 1.27 1.27 2:45 3:00 214.94 214.81 214.25 214.59 215.07 267.62 282.02 273.88 290.55 245.60 1.25 1.31 1.28 3:00 3:15 216.59 216.46 215.89 216.24 216.72 267.36 277.35 266.38 289.11 245.43 1.23 1.28 1.23 3:30 3:45 107.15 107.09 106.81 106.98 107.22 118.75 124.52 122.78 128.68 109.87 1.11 1.16 1.15 3:45 4:00 107.15 107.09 106.81 106.98 107.22 114.50 125.23 116.98 124.64 107.74 1.07 1.17 1.10 4:00 4:15 109.55 109.48 109.20 109.37 109.61 116.27 124.89 121.82 120.88 106.72 1.06 1.14 1.12 4:15 4:30 109.55 109.48 109.20 109.37 109.61 117.46 127.80 123.13 123.59 108.88 1.07 1.17 1.13 

AVE 1.21 1.26 1.24 

SD 0.04 0.04 0.05 

%RSD 0.03 0.03 0.04 

AVE 1 08 1 16 1 12 

Background Corrected Xact Conc. (μg/m3 QAG Aerosol Conc (μg/m ) Xact/Q

3)

Blank Spike

Conc. 

Level Xact Start 

Time

Xact End 

Time

High 

Stack Gas

Flue Gas

Low

Mid

A-2
A-3 

During the experiments at the MPCRF, the QAG concentration flow ( Ft ) was measured in 

standard liters per minute (slpm) using a newly purchased and calibrated Rosemount orifice plate 

flow meter.1 Prior to shipment to the field, this flow meter was compared to Sierra Instruments 

thermal mass flow meter.2 The two meters were found to be within 5% of each other. 

Furthermore, after spiking was completed, the same two meters were compared against each 

other at a rate of about 140 slpm. The meters differed by less than 1%, both when sampling 

stack gas and when sampling ambient air. It is therefore highly unlikely that the total QAG flow 

( Ft ) is being measured inaccurately. 

2.2 Problems with Xact XRF or Flow Calibration 

The Xact draws a small sample of stack gas (~ 0.5 Lpm) through a reactive filter tape. After 

sampling for 15 minutes the tape is advanced about two inches to the analysis area where the 

mass of each analyte is determined by XRF while the next sample is being collected. The XRFdetermined mass is then divided by the totalized flow to give the concentration in μg/dscm. 

Errors in the Xact measurement can result primarily from errors in the XRF measurement or 

errors in the flow measurement. 

Prior to shipment, the XRF portion of the Xact was calibrated using thin-film standards available 

from Micromatter.3

 These standards are typically used for the calibration of XRF 

instrumentation used for the chemical speciation of PM10 and PM2.5 filters.4

 The XRF 

calibration was also checked with the same standards used for calibration on three different days: 

twice during set up and one during a day of testing (7/30/07). Table 2 shows the results of these 

XRF calibration checks. In all cases, the reported concentration differs from the calibrated value 

by less than two percent, indicating that the Xact’s XRF calibration was stable and accurate. 

Table 2. XRF Calibration Checks with Thin Film Standards 

Reported

Value 

(μg) % Error

Reported

Value 

(μg) % Error

Reported

Value 

(μg) % Error

Cr 8.13 8.09 0.44

As 7.25 7.23 0.30 7.25 0.04 7.19 0.89

Cd 5.44 5.54 1.86 5.41 0.55 5.44 0.04

Hg 9.59 9.53 0.67

Pb 8.04 7.99 0.62

Element

7/26/2007 7/28/2007 7/30/2007

Calibrated 

Value (μg)

 

The Xact measures two separate flows to calculate the flow of stack gas: the dilution flow (~ 

0.20 slpm) and the total flow (~0.70 slpm). The Xact’s flow sensors were recalibrated in the 

field prior to testing using a Dry Cal from Bios International5

 as a reference flow meter. On the 

day after testing, the Xact’s flow sensors were again compared against the Dry Cal both when 

sampling stack gas and when sampling ambient air. The results are shown in Table 3. The error 

in all cases was less than 3.5 percent, indicating that the Xact’s flow sensors were accurate both 

when sampling ambient air and when sampling stack gas. 
A-4 

Table 3. Xact Flow Sensor Checks 

Dry Cal 

(slpm)

Dry 

Sample 

(slpm) % Error

Dry Cal 

(slpm)

Dilution 

Flow 

(slpm) % Error

Sampling 

Stack Gas 0.64 0.66 3.13 0.202 0.20 0.99

Sampling 

Ambient Air 0.66 0.68 3.03 0.194 0.20 3.09

Total Flow Dilution Flow

Condition

2.3 Evaporative Loss in the QAG 

Equation 1 shows that the nebulization rate of solution is the difference between the solution 

mass loss rate (Rm, g/min) as measured by an analytical balance minus the solution evaporation 

rate (Rv, g/min). The evaporation rate for this experiment was about 0.0005 g/min and is based 

on a measured temperature difference. The evaporation rate therefore accounts for less than 0.2 

percent of the overall solution loss rate, making it an unreasonable source of a 25-percent 

discrepancy between the QAG and the Xact. Assuming the evaporation rate was high enough to 

create a discrepancy between the Xact and the QAG, the Xact would report values lower than 

those of the QAG because the QAG would be nebulizing far less solution than measured. 

Clearly, evaporative loss is not source of the 25% discrepancy because the Xact is reporting a 

higher concentration than the QAG. 

2.4 Leak in the Transport Line 

Figure 1 is a schematic showing the experimental set-up used during the testing at the MultiPollutant Control Research Facility. 

Figure 1. Experimental Set-up 
A-5 

The flow meter used for the calculation of the QAG aerosol concentration is located downstream 

of the both the Xact and the QAG. A leak in the transport line between the Xact and the flow 

meter could result in the Xact reporting a higher than expected reading. However, all the seals in 

this region were checked after testing and found to be adequate. Furthermore, the leak would 

need to be on the order of 30 to 40 slpm to get the 25-percent discrepancy observed. A leak of 

that magnitude would generate a great deal of noise and be detected almost immediately. It is 

therefore unlikely that a leak in the transport line is the source of the difference between the 

QAG and Xact-reported values. 

2.5 Matrix (Stack Gas) Effects 

Another potential explanation for the difference between the QAG and the Xact is the effect of 

the stack gas matrix, which could impact the transport and trapping efficiency of the spiked 

elements. During the course of the experiment, CES determined the ratio of each spiked element 

to cadmium when sampling both stack gas and ambient air. The five elements sampled represent 

metals in the particle phase (Cd, Cr, and Pb), mixed phase (As) and vapor phase (Hg). If the 

stack gas matrix inhibited the transport or trapping efficiency of the metals, then it is expected 

that one type of species would be more impacted than another (e.g., vapor phase species are 

more impacted than particle phase species). However, the ratios of each element to cadmium are 

the same for stack gas and ambient air (Table 4). Therefore, the transport and trapping of both 

particle phase and vapor phase species are unaffected by the physical and chemical 

characteristics of the gas matrix. 

Table 4. Inter-Elemental Ratios 

Cr/Cd As/Cd Hg/Cd Pb/Cd

AVE 0.97 1.02 1.07 0.90

STDEV 0.04 0.04 0.05 0.04

AVE 0.96 1.04 1.03 0.89

STDEV 0.01 0.02 0.03 0.02

Ambient 

Air

Matrix

Interelemental Ratios

Stack 

Gas

2.6 Inaccurate Moisture Measurement 

The Xact measures metal concentrations on a dry basis. The QAG aerosol, however, is being 

spiked into a relatively wet air stream. To compare the two concentrations, the QAG 

concentration must be calculated on a dry basis. The dry QAG flow rate Ft is determined using 

Equation 2. This value can then be used in Equation 1 to calculate the QAG aerosol 

concentration. 

( ) Ft = Fm Fm − FQ Pw (Eq. 2)

Where: 

Ft = Total QAG flow on a dry basis (slpm) 

Fm = Total flow as measured by the experimental flow meter (slpm) 
A-6 

FQ = Total flow through the QAG (slpm) (dried compressed air) 

Pw = The measured fraction of water 

During testing, the XFM was used to determine fraction of water. The flow through the XFM 

filter, about 1 slpm, was dried using a silica gel trap prior to flow measurement. This silica gel 

trap was weighed before and after each sample and the difference was used to determine the 

fraction of water vapor in the sampled stack gas. A problem with this approach was later 

discovered; the silica gel was unlikely to trap all of the water in the gas stream. The temperature 

of the silica gel trap is believed to have been at about 80 to 90 οF and operating under a 

significant vacuum (approximately 12 in. Hg vacuum). Silica gel will typically lower the 

relative humidity to around 40%.6

 Under these conditions, air escaping the trap could still 

contain almost 10% moisture.7

 Therefore, the accuracy of this approach is questionable and 

could be the source of the observed discrepancy between the Xact and QAG. 

To estimate the actual fraction of water present in the gas stream, it is reasonable to assume that 

the gas was saturated at temperatures and pressures present at the sampling point because the 

stack effluent was withdrawn from the duct immediately downstream of a wet scrubber,. The 

temperature in the duct was monitored throughout the experiment and averaged about 116 ο

F. 

The pressure in the duct was not measured; however, the pressure in the transport line was 

measured on a continuous basis using the Rosemount flow meter. During stack gas sampling 

and spiking, the pressure at that point was about 13.5 psia. The pressure in the duct would be 

somewhat higher and was estimated to be about 13.8 psia. This value corresponds well with 

engineering estimates of the pressure in the duct at minus 30 inches of water.8

 At this 

temperature and pressure, the moisture content of the duct would be about 26% by volume. The 

QAG flow rate was therefore adjusted based on this assumed moisture content in lieu of the 

potentially inaccurate XFM moisture measurement. For ambient spiking, the QAG flow rate was 

adjusted based on relative humidity as determined by a nearby meteorological station for the date 

and time of the experiment.9 Experimental results with the adjusted QAG flow rates are shown 

in Table 5. 

3.0 Conclusions 

The most likely cause of the discrepancy between the QAG aerosol concentration and the Xact 

reported concentration is inaccuracy in the moisture measurement because (1) other possible 

sources for this error can be discounted, (2) there is ample reason to doubt the accuracy of the 

moisture measurement as it was made, and (3) it makes good engineering sense to assume 

saturation downstream of a wet scrubber. Future experiments of this nature should either find a 

more accurate way of measuring moisture content, or remove all moisture prior to the QAG 

concentration flow measurement. 
Table 5. Results Assuming Saturation Downstream of Wet Scrubber 

Cr As Cd Hg Pb Cr As Cd Hg Pb Cr As Cd Hg P

0 0 0 0 0 0 0.4 1.5 23.1 0.26 NA NA NA NA N0 0 0 0 0 0 0 0.88 21.31 0.8 NA NA NA NA N0 0 0 0 0 0 0.33 1.42 14.28 0 NA NA NA NA N0 0 0 0 0 0 0 0 10.64 0.66 NA NA NA NA N0 0 0 0 0 0 0.49 0 8.85 0.12 NA NA NA NA N0 0 0 0 0 0 0.23 0 7.41 0.12 NA NA NA NA N0 0 0 0 0 0 0.43 1.08 6.28 0.43 NA NA NA NA N

27.58 27.56 27.49 27.53 27.60 29.96 28.21 28.94 31.30 26.17 1.09 1.02 1.05 1.14 0.927.58 27.56 27.49 27.53 27.60 27.71 28.43 29.86 32.11 26.36 1.00 1.03 1.09 1.17 0.927.58 27.56 27.49 27.53 27.60 29.35 29.73 31.50 30.45 25.61 1.06 1.08 1.15 1.11 0.927.58 27.56 27.49 27.53 27.60 31.19 30.32 28.48 30.88 26.50 1.13 1.10 1.04 1.12 0.927.58 27.56 27.49 27.53 27.60 27.20 30.01 28.57 30.77 25.98 0.99 1.09 1.04 1.12 0.927.86 27.83 27.76 27.81 27.88 27.28 28.45 29.01 30.68 28.30 0.98 1.02 1.04 1.10 1.027.86 27.83 27.76 27.81 27.88 28.75 31.08 31.70 29.99 25.63 1.03 1.12 1.14 1.08 0.927.86 27.83 27.76 27.81 27.88 28.94 30.97 28.70 31.31 28.29 1.04 1.11 1.03 1.13 1.027.86 27.83 27.76 27.81 27.88 29.29 30.32 30.11 30.16 27.85 1.05 1.09 1.08 1.08 1.027.86 27.83 27.76 27.81 27.88 30.72 29.38 31.85 29.22 26.65 1.10 1.06 1.15 1.05 0.992.87 92.84 92.89 92.91 92.87 96.74 102.13 104.27 103.96 91.75 1.04 1.10 1.12 1.12 0.992.23 92.20 92.25 92.27 92.23 95.40 101.44 96.64 102.73 89.02 1.03 1.10 1.05 1.11 0.992.23 92.20 92.25 92.27 92.23 97.09 102.63 98.80 104.93 90.84 1.05 1.11 1.07 1.14 0.992.23 92.20 92.25 92.27 92.23 98.83 104.87 103.73 105.11 90.95 1.07 1.14 1.12 1.14 0.992.23 92.20 92.25 92.27 92.23 96.78 100.45 99.61 101.80 91.32 1.05 1.09 1.08 1.10 0.991.01 90.99 91.03 91.06 91.01 97.52 102.01 99.30 102.70 90.42 1.07 1.12 1.09 1.13 0.991.01 90.99 91.03 91.06 91.01 97.60 101.78 98.58 102.69 89.65 1.07 1.12 1.08 1.13 0.991.01 90.99 91.03 91.06 91.01 96.32 100.05 94.45 102.48 91.52 1.06 1.10 1.04 1.13 1.091.01 90.99 91.03 91.06 91.01 99.68 105.65 108.04 104.54 93.53 1.10 1.16 1.19 1.15 1.0

248.93 248.78 248.14 248.53 249.08 266.66 279.51 264.46 291.91 248.18 1.07 1.12 1.07 1.17 1.0248.93 248.78 248.14 248.53 249.08 262.46 277.26 264.40 278.69 243.97 1.05 1.11 1.07 1.12 0.9248.93 248.78 248.14 248.53 249.08 273.43 286.62 273.00 292.01 252.36 1.10 1.15 1.10 1.17 1.0248.93 248.78 248.14 248.53 249.08 271.94 289.75 282.36 292.30 252.26 1.09 1.16 1.14 1.18 1.0245.73 245.58 244.95 245.34 245.88 275.05 290.57 289.08 293.00 252.08 1.12 1.18 1.18 1.19 1.0245.73 245.58 244.95 245.34 245.88 266.92 280.31 275.81 282.73 243.49 1.09 1.14 1.13 1.15 0.9245.73 245.58 244.95 245.34 245.88 260.84 272.15 271.73 273.55 236.20 1.06 1.11 1.11 1.11 0.9245.73 245.58 244.95 245.34 245.88 267.62 282.02 273.88 288.64 245.60 1.09 1.15 1.12 1.18 1.0247.62 247.47 246.83 247.22 247.77 267.36 277.35 266.38 287.20 245.43 1.08 1.12 1.08 1.16 0.9107.85 107.79 107.51 107.68 107.92 109.73 119.63 114.98 128.64 102.22 1.02 1.11 1.07 1.19 0.9108.11 108.05 107.76 107.94 108.18 118.75 124.52 122.78 131.76 109.87 1.10 1.15 1.14 1.22 1.0108.11 108.05 107.76 107.94 108.18 114.50 125.23 116.98 127.72 107.74 1.06 1.16 1.09 1.18 1.0110.53 110.46 110.17 110.35 110.59 116.27 124.89 121.82 123.96 106.72 1.05 1.13 1.11 1.12 0.9110.53 110.46 110.17 110.35 110.59 117.46 127.80 123.13 126.67 108.88 1.06 1.16 1.12 1.15 0.9

AVE 1.06 1.11 1.09 1.13 0.9

STDE

V 0.04 0.04 0.04 0.03 0.0

%RSD 3.36 3.61 4.00 2.93 2.9

AVE 1.06 1.14 1.10 1.17 0.9

STDE

V 0.03 0.02 0.03 0.04 0.0

%RSD 2.73 1.85 2.47 3.28 2.7

Conc. 

Level

Xact/QAG

Low

Ambient 

Air

Blank 

Spike

QAG Aerosol Conc (μg/m3) Background Corrected Xact Conc. (μg/m3

)

Mid

High

High 

Ambient

Flue Gas

A-7
A-8 

4.0 References 

1. Rosemount Inc, PO Box 70114, Chicago, IL 60673-0114 

2. Sierra Instruments, 5 Harris Court Building L, Monterey, CA 93940 

3. Micromatter Co., 18218 18th Ave. NW, Arlington, WA 98223 

4. U.S. Environmental Protection Agency. 1999. Compendium Method IO-3.3 - 

Determination of Metals in Ambient Particulate Matter Using X-Ray Fluorescence 

(XRF) Spectroscopy. In Compendium of Methods for the Determination of Inorganic 

Compounds in Ambient Air; EPA/625/R-96/010a. U.S. Government Printing Office: 

Washington, DC. 

5. Bios International Corporation, 10 Park Place, Butler, NJ 07405 

6. Desiccants Global. Types of Desiccants. http:// desiccants.cn/products.htm (accessed 

August 2007). 

7. Perry, R.H.; Green, D.W; Editors. 1984. Perry’s Chemical Engineers’ Handbook. 6th 

Ed. McGraw-Hill Book Company: New York. 

8. Serre, S. February 27th, 2007. U.S. Environmental Protection Agency, ORD/National 

Risk Management Research Laboratory [Personal communication]. 

9. National Oceanic and Atmospheric Association (NOAA) Cooperative Institute for 

Regional Prediction. Real-Time Observation and Analysis Network (ROMAN). 

http://raws.wrh.noaa.gov/roman/index.html (accessed August 2007)