&EPA
United States
Environmental Protection
Agency
EPA-600/R-05/042
April 2005
Evaluation of a Former
Landfill Site in Fort
Collins, Colorado Using
Ground-Based Optical
Remote Sensing
Technology
Downwind Sensor
Configuration
Cache
i Poudre
River
Ammonia
and
Methane
. Source ,
Upwind Sensor
Configuration
\
,.*•* --.-,.--'*^ \
\ \
-------
-------
EPA-600/R-05/042
April 2005
Evaluation of a Former Landfill Site in
Fort Collins, Colorado Using
Ground-Based Optical Remote
Sensing Technology
by
Mark Modrak
Ram A. Hashmonay
Ravi Varma
Robert Kagann
ARCADIS G&M, Inc.
4915 Prospectus Dr., Suite F
Durham, NC27713
Contract Number: 68-C99-201
Work Assignment Number: 0-25
EPA Project Officer: Susan Thorneloe
U.S. Environmental Protection Agency
Air Pollution Prevention and Control Division
Research Triangle Park, NC 27711
U.S. Environmental Protection Agency
Office of Research and Development
Washingtion, DC 20460
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Abstract
A former landfill site in Fort Collins, Colorado is being assessed for landfill gas emissions as
part of an effort under the city's Brownfields program to support reuse options for the property.
Before initiating any additional development at the property, the city requested assistance from
the EPA Region 8 Office, and the Office of Superfund Remediation and Technology
Innovation, Technology Integration and Information Branch to perform a site assessment to
search for the presence of any fugitive gas emissions from the former landfill site. This
assessment was necessary due to the potential adverse health effects associated with exposure
to landfill gas.
The focus of this study was to evaluate fugitive emissions of methane and VOCs at the site, in
support of the reuse objectives, using a scanning open-path Fourier transform infrared
spectrometer, open-path tunable diode laser absorption spectroscopy, and an ultra-violet
differential optical absorption spectrometer. The study involved a technique developed through
research funded by the EPA National Risk Management Research Laboratory that uses
ground-based optical remote sensing technology, known as optical remote sensing-radial plume
mapping. The horizontal radial plume mapping method was used to map surface concentrations,
and the vertical radial plume mapping (VRPM) method was used to measure emissions fluxes
downwind of the site.
The study did not detect the presence of any surface methane hot spots at the site. The highest
methane concentrations detected at the site were only slightly above ambient background levels.
However, the survey detected the presence of a gasoline hot spot (average concentration over
81 ppb, with a maximum concentration of about 100 ppb) located in the vicinity of a
recreational building at the site. The VRPM survey of the site detected methane, ammonia, and
gasoline along a downwind configuration at the site. The average calculated gasoline flux from
the VRPM survey was 0.87 g/s. The measured methane and ammonia concentrations were
well-correlated, indicating that the measured concentrations probably came from the same
source. Wind data collected indicated that the source of the methane and ammonia detected is
located across a river adjacent to the site.
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Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting
the Nation's land, air, and water resources. Under a mandate of national environmental laws,
the Agency strives to formulate and implement actions leading to a compatible balance
between human activities and the ability of natural systems to support and nurture life. To meet
this mandate, EPA's research program is providing data and technical support for solving
environmental problems today and building a science knowledge base necessary to manage
our ecological resources wisely, understand how pollutants affect our health, and prevent or
reduce environmental risks in the future.
The National Risk Management Research Laboratory (NRMRL) is the Agency's center for
investigation of technological and management approaches for preventing and reducing risks
from pollution that threaten human health and the environment. The focus of the Laboratory's
research program is on methods and their cost-effectiveness for prevention and control of
pollution to air, land, water, and subsurface resources; protection of water quality in public
water systems; remediation of contaminated sites, sediments and ground water; prevention
and control of indoor air pollution; and restoration of ecosystems. NRMRL collaborates with
both public and private sector partners to foster technologies that reduce the cost of
compliance and to anticipate emerging problems. NRMRL's research provides solutions to
environmental problems by: developing and promoting technologies that protect and improve
the environment; advancing scientific and engineering information to support regulatory and
policy decisions; and providing the technical support and information transfer to ensure
implementation of environmental regulations and strategies at the national, state, and
community levels.
This publication has been produced as part of the Laboratory's strategic long-term research
plan. It is published and made available by EPA's Office of Research and Development to
assist the user community and to link researchers with their clients.
Sally Gutierrez, Acting Director
National Risk Management Research Laboratory
in
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EPA Review Notice
This report has been peer and administratively reviewed by the U.S. Environmental
Protection Agency and approved for publication. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Information
Service, Springfield, Virginia 22161.
IV
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Contents
Section Page
Abstract ii
List of Tables vii
List of Figures viii
Acknowledgements ix
Executive Summary x
1 Project Description and Objectives 1-1
1.1 Background 1-1
1.2 Project Description/Purpose 1-3
1.2.1 Horizontal RPM 1-4
1.2.2 Vertical RPM 1-5
1.3 Quality Objectives and Criteria 1-5
1.4 Project Schedule 1-7
2 Test Procedures 2-1
2.1 Area A 2-2
2.2 Area B 2-2
2.3 Area C 2-2
2.4 Area D 2-3
2.5 VRPM Measurements 2-3
2.6 OP-TDLAS Measurements 2-3
2.7 UV-DOAS Measurements 2-4
3 Results and Discussion 3-1
3.1 AreaA 3-1
3.1.1 HRPMResults 3-1
3.1.2 VRPM Results 3-3
3.1.3 UV-DOAS Results 3-5
3.1.4 Summary of Results from Area A 3-5
3.2 Areas B, C, and D 3-5
3.3 OP-TDLAS Measurements 3-6
4 Conclusion 4-1
5 QA/QC 5-1
5.1 Equipment Calibration 5-1
5.2 Assessment of DQI Goals 5-1
5.2.1 DQI Check for Analyte PIC Measurement 5-1
5.2.2 DQI Checks for Ambient Wind Speed and Wind Direction
Measurements 5-2
v
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Contents (continued)
Section Page
5.2.3 DQI Check for Precision and Accuracy of Theodolite
Measurements 5-3
5.3 QC Checks of OP-FTIR Instrument Performance 5-3
5.4 Validation of Concentration Data Collected with the OP-FTIR 5-4
5.5 Internal Audit of Data Input Files 5-4
5.6 OP-TDLAS Instrument 5-5
5.7 UV-DOAS Instrument 5-5
6 References 6-1
Appendix A: OP-FTIR Mirror Coordinates A-l
Appendix B: OP-TDLAS Configuration Path Length Distances B-l
Appendix C: Methane Concentrations C-l
VI
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List of Tables
Table Page
1-1 Summary Information on the ORS Instrumentation Used in the Study 1-4
1-2 Detection Limits for Target Compounds 1-6
1-3 Schedule of Work Performed at the Site 1-7
3-1 Average Methane Concentrations Measured During the HRPM Survey of
Area A 3-1
3-2 Average Concentration of BTX Compounds Measured by the UV-DOAS
Instrument 3-5
3-3 Average Methane Concentrations Found during the HRPM Surveys of
Areas B, C, and D 3-7
3-4 Comparison of Methane Concentrations Measured with the OP-TDLAS
and OP-FTIR Instruments 3-8
5-1 Instrumentation Calibration Frequency and Description 5-1
5-2 DQI Goals for Instrumentation 5-2
A-l Standard Distance and Horizontal Coordinates of Mirrors Used in the
HRPM Survey of Area A A-l
A-2 Standard Distance and Horizontal Coordinates of Mirrors Used in the
HRPM Survey of Area B A-l
A-3 Standard Distance and Horizontal Coordinates of Mirrors Used in the
HRPM Survey of Area C A-l
A-4 Standard Distance, and Horizontal Coordinates of Mirrors Used in the
HRPM Survey of Area D A-l
A-5 Standard Distance, and Horizontal and Vertical Coordinates of Mirrors
Used in the VRPM Survey A-2
B-l Standard Distance of Path Lengths Used in OP-TDLAS Configurations B-l
C-l Methane Concentrations Found during the Area A HRPM Survey C-l
C-2 Methane Concentrations Found during the Area B HRPM Survey C-2
C-3 Methane Concentrations Found during the Area C HRPM Survey C-2
C-4 Methane Concentrations Found during the Area D HRPM Survey C-3
C-5 Methane Concentrations Found during the Downwind VRPM Survey Run 1 .... C-4
C-6. Methane Concentrations Found during the Downwind VRPM Survey Run 2 .... C-5
vn
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List of Figures
Figure
E-l Map of the Ft. Collins Site Detailing the Location of the HRPM Survey Areas .
E-2 Map of the Ft. Collins Site Detailing the Location of the VRPM Configurations.
1-1 Map of the Ft. Collins Site Detailing the Location of the HRPM Survey Areas .
1-2 Map of the Ft. Collins Site Detailing the Location of the VRPM Configurations
1-3 Example of a HRPM Configuration 1-5
1-4 Example of a VRPM Configuration 1-5
2-1 Schematic of the HRPM Configuration Used in Area A 2-2
2-2 Partial Picture of the HRPM Configuration Used in Area A 2-2
2-3 Partial Picture of the HRPM Configuration Used in Area B 2-3
2-4 Partial Picture of the HRPM Configuration Used in Area C 2-3
2-5 Partial Picture of the HRPM Configuration Used in Area D 2-3
2-6 Partial Picture of the VRPM Configuration Used at the Site 2-4
2-7 OP-TDLAS System 2-4
2-8 UV-DOAS Instrument 2-4
3-1 Reconstructed Gasoline Surface Concentrations in Area A 3-2
3-2 Time Series of Wind Direction and Concentrations of Methane and Ammonia
Concentrations Measured on Beam Path #5 of the VRPM Downwind Survey . . . 3-3
3-3 Reconstructed Gasoline Plume Map from the Downwind VRPM Survey 3-4
3-4 Gasoline, Methane, and Ammonia Fluxes Measured During the Downwind
VRPM Survey 3-4
3-5 Time Series of Path-Averaged Concentrations of Benzene, Toluene, and p-Xylene
Measured with the UV-DOAS Instrument and Gasoline Measured with the
OP-FTIR in Area A 3-5
3-6 Results Summary Map from Area A Measurements 3-6
3-7 Time Series of Methanol Concentrations Measured along Beam Path #3 of the
Area B HRPM Survey 3-7
5-1 Comparison of a Spectrum Measured at the Site (Green Trace) to Reference
Spectra of Gasoline (Red Trace) 5-4
5-2 Comparison of a Spectrum Measured at the Site (Blue Trace) to Reference
Spectra of Ammonia (Red Trace) 5-4
5-3 Post-Fort Collins Comparison of Methane Concentrations Measured with the
OP-TDLAS and OP FTIR Instruments 5-5
Vlll
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Acknowledgments
This study was j ointly sponsored by the United States Environmental Protection Agency (EPA)
Region 8 Office, and the Office of Superfund Remediation and Technology Innovation,
Technology Integration and Information Branch under its Monitoring and Measurement for the
21st Century (21M2) initiative. The 21M2 initiative is intended to provide EPA staff with
resources to apply new approaches to real site problems.
IX
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Executive Summary
Background and Site Information
A former landfill site in Fort Collins, Colorado is being assessed for landfill gas emissions as
part of an effort under the city's Brownfields program to support reuse options for the property.
The city of Fort Collins is interested in developing a larger recreation facility on this property,
which is already being used primarily for recreational purposes. Before initiating any additional
development at the property, the city requested assistance from EPA to perform a site
assessment to search for the presence of any fugitive gas emissions from the former landfill site.
This assessment was necessary due to the potential adverse health effects associated with
exposure to landfill gas. The EPA Region 8 Office requested assistance with this study through
the Monitoring and Measurement for the 21 st Century program to utilize innovative approaches
for performing an assessment at the site.
The focus of this study was to evaluate emissions of fugitive gases and VOCs at the site, in
support of the reuse objectives, using an open-path Fourier transform infrared (OP-FTIR)
spectrometer, open-path tunable diode laser absorption spectroscopy (OP-TDLAS), and an
ultra-violet differential optical absorption spectrometer(UV-DOAS). The OP-FTIR instrument
provided the critical measurements in the current study, and the OP-TDLAS and UV-DOAS
provided noncritical, supplemental data. The study involved a technique developed through
research funded by the EPA National Risk Management Research Laboratory (NRMRL) that
uses ground-based optical remote sensing technology, known as optical remote sensing-radial
plume mapping (ORS-RPM) (Hashmonay and Yost, 1999; Hashmonay et al., 1999; Wu et al.,
1999; Hashmonay et al., 2001; Hashmonay et al., 2002).
The study consisted of one field campaign performed during September 2003 by ARCADIS and
EPA personnel. Figure E-l presents the overall layout of the site, detailing the geographic
location of each horizontal radial plume mapping (HRPM) survey area. Figure E-2 shows the
location of the vertical radial plume mapping (VRPM) configurations, which were used to
collect data for emission flux calculations.
Testing Procedures
HRPM surveys were done in Areas A, B, C, and D to search for surface emissions hot spots.
A VRPM survey was done in Area A to measure emissions of fugitive gases and VOCs upwind
and downwind of the area. The OP-TDLAS instrument was deployed in each area of the site
to provide additional information on methane concentrations at the site. The UV-DOAS
instrument was deployed in Area A to provide information on concentrations of benzene,
toluene, and xylenes (BTX) at the site.
x
-------
Figure E-1. Map of the Ft. Collins Site Detailing the
Location of the HRPM Survey Areas.
Figure E-2. Map of the Ft. Collins Site Detailing the
Location of the VRPM Configurations.
XI
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Results and Discussion
Area A
HRPM and VRPM Results
The HRPM survey of Area A did not detect the presence of any methane hot spots. However,
the survey detected the presence of a gasoline hot spot (average concentration over 81 ppb, with
a maximum concentration of about 100 ppb) located in the southern corner of Area A.
The VRPM survey of the site detected methane, ammonia, and gasoline on the downwind
VRPM configuration (see Figure E-2). The average calculated gasoline flux from the VRPM
survey was 0.87 g/s. The measured methane and ammonia concentrations were well-correlated,
indicating that the measured concentrations probably came from the same source. Wind data
collected indicate that the source of the methane and ammonia detected is located outside of
Area A, across the river adjacent to the site. This is supported by the fact that methane and
ammonia were not detected during the HRPM survey of Area A.
UV-DOAS Results
The UV-DOAS instrument was set up along the surface, approximately parallel to the
downwind VRPM configuration in Area A. The UV-DOAS instrument found average
concentrations of 2.6 ppb for benzene, 21 ppb for toluene, and4.9ppbforp-xylene. The toluene
concentrations measured with the UV-DOAS correlated well with the gasoline concentrations
measured with the OP-FTIR, indicating that the detected gasoline plume contained BTX
compounds.
Areas B, C, and D
HRPM surveys did not detect any methane hot spots in Areas B, C, and D. The average surface
methane concentrations in these areas were close to ambient background levels. The HRPM
survey of Area B detected a small methanol hot spot. The average methanol concentration
measured in this area was 20.9 ppb, with a range of 0 to 127 ppb.
OP-TDLAS Measurements
The OP-TDLAS measured methane concentrations in Areas A, B, C, and D. The configurations
used by the OP-TDLAS in these areas were often similar to the configurations used with the
OP-FTIR instruments. The methane concentrations measured by the OP-TDLAS were only
slightly above ambient background levels, reinforcing the findings of the HRPM surveys. The
methane concentrations measured with the OP-TDLAS were almost always slightly higher than
concentrations measured with the OP-FTIR along similar optical paths.
xn
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Chapter 1
Project Description and Objectives
1.1 Background
As part of its Brownfields redevelopment effort, the
city of Ft. Collins, Colorado, with assistance from the
United States Environmental Protection Agency
(EPA) Region 8 Office, is assessing a former landfill
site for gas emissions. The property, which is approx-
imately 19 acres in size, is composed of a commercial
area, a park, playgrounds, soccer fields, and bike
paths. The site is bounded on the northeast by the
Cache La Poudre River. The City of Fort Collins is
interested in developing a larger recreation facility at
the site and is receiving assistance from EPA Region
8 under the Targeted Brownfields Assessment pro-
gram to perform an assessment at the site. As part of
the 21M2 (Monitoring and Measurement Technolo-
gies for the 21st Century) initiative, the EPA Office
of Superfund Remediation and Technology Innova-
tion provided support to EPA Region 8 for this study.
The site encompasses a landfill approximately 5 acres
in size. Little information is known about the con-
tents of the landfill, or when the landfill opened. The
landfill was operated by the City of Fort Collins and
was closed in the early 1960s. After the landfill was
closed, the site was covered with a clay cap, ranging
in depth from one to three feet. A manufactured gas
plant operated adjacent to the site for approximately
30 years. The plant operated until around 1930, and
produced gas from coal and, possibly, oil.
The focus of this study was to evaluate emissions of
fugitive gases and VOCs at the site using an open-
path Fourier transform infrared (OP-FTIR) spectrom-
eter, open-path tunable diode laser absorption spec-
troscopy (OP-TDLAS), and an ultra-violet differen-
tial optical absorption spectrometer (UV-DOAS). The
OP-FTIR instrument provided the critical measure-
ments in the current study. The OP-TDLAS and
UV-DOAS provided noncritical, supplemental data.
The study involved a technique developed through
research funded by EPA's National Risk Manage-
ment Research Laboratory (NRMRL) that uses
ground-based optical remote sensing technology,
known as optical remote sensing-radial plume map-
ping (ORS-RPM) (Hashmonay and Yost, 1999;
Hashmonay et al., 1999; Wu et al., 1999; Hashmonay
et al., 2001; Hashmonay et al., 2002). The effort
identified emission hot spots (areas of relatively
higher emissions), investigated source homogeneity,
and calculated an emission flux rate for each com-
pound detected at the site. Concentration maps in the
horizontal and downwind vertical planes were gener-
ated using the horizontal radial plume mapping
(HRPM), and vertical plume mapping (VRPM)
methods, respectively.
The study consisted of one field campaign performed
during September 2003 by ARCADIS and EPA
personnel. The Fort Collins site was divided into four
survey areas. Figure 1-1 presents the overall layout of
the site, detailing the geographic location of each
HRPM survey area. The red dots denote the location
of the OP-FTIR used in each configuration. Figure
1-2 shows the location of the VRPM configurations
that were used to collect data for emission flux
calculations. The red square indicates the location of
the scissors jack (vertical structure) used in each
VRPM configuration.
1-1
-------
Evaluation of Fugitive Emissions at a
,. ... _ , ,
4
Figure 1 -1. Map of the Ft. Collins Site Detailing the
Location of the HRPM Survey Areas.
SSL
4
•*• •sss^' Q
*
Figure 1-2. Map of the Ft. Collins Site Detailing the
Location of the VRPM Configurations.
1-2
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Brownfield Landfill in Ft. Collins, Colorado
1.2 Project Description/Purpose
The objectives of the study were to
• Collect OP-FTIR data in order to identify
major emissions hot spots at the Ft. Collins,
CO landfill by generating surface concentra-
tion maps in the horizontal plane,
• Measure emission fluxes of detectable com-
pounds downwind from major hot spots, and
• Demonstrate the operation and function of the
various ORS technologies
The ORS techniques used in this study were designed
to characterize the emissions of fugitive gases from
area sources. Detailed spatial information is obtained
from path-integrated ORS measurements by the use
of iterative algorithms. The HRPM method involves
the use of a configuration of nonoverlapping radial
beam geometry to map the concentration distributions
in a horizontal plane. This method can also be applied
to a vertical plane downwind from an area emission
source to map the crosswind and vertical profiles of
a plume. By incorporating wind information, the flux
through the plane can be calculated, which leads to
the emission rate of the upwind area source. An
OP-FTIR sensor was chosen as the primary instru-
ment for the study because of its capability of accu-
rately measuring a large number of chemical species
that might occur in a plume.
The OP-FTIR Spectrometer combined with the
ORS-RPM method is designed for both fence-line
monitoring applications, and real-time, on-site,
remediation monitoring and source characterization.
An infrared light beam, modulated by a Michelson
interferometer is transmitted from a single telescope
to a retroreflector (mirror) target that is usually 100 to
500 meters from the telescope. The returned light
signal is received by the single telescope and directed
to a detector. Some of the light is absorbed by the
molecules in the beam path as the light propagates to
the mirror, and more is absorbed as the light is
reflected back to the analyzer. Thus, the round-trip
path of the light doubles the chemical absorption
signal. One advantage of OP-FTIR monitoring is that
the concentrations of a multitude of infrared absorb-
ing gaseous chemicals can be detected and measured
simultaneously, with high temporal resolution.
The OP-TDLAS system (Unisearch Associates, Inc.)
is a fast, interference-free technique for making
continuous concentration measurements of many
gases. The OP-TDLAS used in the current study is
capable of measuring concentrations of gases such as
carbon monoxide (CO), carbon dioxide (CO2),
ammonia (NH3), and methane (CH4) in the range of
tens of parts per billion over an open path up to 1 km.
The laser emits radiation at a particular wavelength
when an electrical current is passed through it. The
light wavelength depends on the current and therefore
allows scanning over an absorption feature and
analyzing the target gas concentration using Beer's
law. The OP-TDLAS used in this study is a multiple
channel TDL instrument that allows fast scanning
electronically (few seconds) among many beam-paths
(presently 8 beams). The OP-TDLAS utilizes a small
4-inch telescope, which directs the laser beam to a
mirror. The laser beam is returned by the mirror to
the telescope, which is connected with fiber optics to
a control box that houses the laser and a multiple
channel detection device. For this particular field
campaign, data from the OP-TDLAS were used to
provide additional information on methane concentra-
tions at the site. At the time of the field campaign, the
OP-TDLAS system had only recently been acquired
by EPA. Consequently, standard operating and
calibration procedures were still being developed.
The UV-DOAS AR500 instrument (OPSIS, Inc.) has
proven to be particularly useful for determining the
concentration of unstable species like free radicals or
nitrous acid. Additionally, many of the aromatic
species can be determined at high sensitivity (Platt,
1994). For the current field campaign, the UV-DOAS
instrument was deployed in a bistatic configuration
(the UV source and detector on opposite ends of the
optical path). This project is the first time the UV-
DOAS instrument has been deployed by this group
for data collection. For this particular field campaign,
data from the UV-DOAS instrument were used to
provide additional information on benzene, toluene,
1-3
-------
Evaluation of Fugitive Emissions at a
and xylenes (BTX) concentrations. The UV-DOAS
instrument was used for BTX measurements because
it has a much lower minimum detection limit (MDL)
than the OP-FTIR for these compounds. Although the
strong, structured UV absorption features of mono-
cyclic aromatic hydrocarbons (i.e., BTX) have been
known for a long time, it only recently became
possible to use these properties for the reliable, sensi-
tive, and selective measurement of these compounds
by UV-DOAS. UV-DOAS measurements of BTX
and trace gases can be an extremely valuable comple-
ment to more traditional techniques like OP-FTIR.
Table 1-1 presents summary information on the ORS
instrumentation used in this study. The table lists the
analytes measured by each instrument during the
current study and instrument limitations such as
weather and interfering species.
Meteorological and survey measurements were also
made during the field campaign. A theodolite was
used to make the survey measurement of the azimuth
and elevation angles and the radial distances to the
mirrors, relative to the OP-FTIR sensor.
1.2.1 Horizontal RPM
The HRPM approach provides spatial information to
path-integrated measurements acquired in a horizon-
tal plane by an ORS system. This technique yields
information on the two-dimensional distribution of
the concentrations in the form of chemical concentra-
tion contour maps. This form of output readily
identifies chemical "hot spots," the locations of high
emissions. This method can be of great benefit for
performing site surveys before, during, and after site
remediation activities.
HRPM scanning is usually performed with the ORS
beams located as close to the ground as is practical.
This enhances the ability to detect minor constituents
emitted from the ground, since the emitted plumes
dilute significantly at higher elevations. The survey
area is typically divided into a Cartesian grid of n
times m rectangular cells. In some unique cases, the
survey area may not be rectangular due to obstruc-
tions, and the shape of the cells may be slightly
altered accordingly. A mirror is located in each of
these cells, and the ORS sensor scans to each of these
mirrors, dwelling on each for a set measurement time
(30 seconds in the present study). The system scans
to the mirrors in the order of either increasing or
decreasing azimuth angle. The path-integrated con-
centrations measured at each mirror are averaged
over several scanning cycles to produce maps of
time-averaged concentrations. Meteorological mea-
surements are made concurrent to the scanning
measurements.
Figure 1-3 represents a typical HRPM configuration.
In this particular case, n = m = 3. The solid lines
represent the nine optical paths, each terminating at
a mirror.
Table 1-1. Summary Information on the ORS Instrumentation Used in the Study.
Property OP-FTIR OP-TDLAS UV-DOAS
Wavelength Range Infrared (2-20 |im)
Target Analytes
Detection Limits
Methane, ammonia, gasoline,
VOCs
Parts per billion
Limiting Weather Heavy rain
Conditions
Interfering Species Carbon dioxide, water
Near Infrared (approx. 1.5 Ultraviolet (245-380
|im) nm)
Methane Benzene, toluene, xylene
Parts per billion
Heavy rain, fog
None
Parts per billion
Heavy rain, fog
Oxygen, ozone
1-4
-------
Brownfield Landfill in Ft. Collins, Colorado
One OP-FTIR instrument (manufactured by Uni-
search Associates) was used to collect Horizontal
RPM data during the field campaign.
150
0)
£ 100
0)
o
5
-------
Evaluation of Fugitive Emissions at a
define the performance criteria that limit the proba-
bilities of making decision errors by considering the
purpose of collecting the data, defining the appropri-
ate type of data needed, and specifying tolerable
probabilities of making decision errors.
Quantitative objectives are established for critical
measurements using the data quality indicators of
accuracy, precision, and completeness. The accep-
tance criteria for these data quality indicators (DQIs)
are summarized later in Table 5-2 of Section 5 of this
report. Accuracy of measurement parameters is
determined by comparing a measured value to a
known standard, assessed in terms of percent bias.
Values must be within the listed tolerance to be
considered acceptable.
Precision is evaluated by making replicate measure-
ments of the same parameter and by assessing the
variations of the results. Precision is assessed in
terms of relative percent difference (RPD), or relative
standard deviation (RSD). Replicate measurements
are expected to fall within the tolerances shown in
Table 5-2 of Section 5. Completeness is expressed as
a percentage of the number of valid measurements
compared to the total number of measurements taken.
Estimated minimum detection limits (MDL) of the
OP-FTIR instrument, by compound, are given in
Table 1-2. It is important to note that the values listed
in Table 1-2 should be considered first step approxi-
mations, as the MDL is highly variable, and depends
on many factors including atmospheric conditions.
Actual MDL are calculated in the quantification
software for all measurements taken. MDL for each
absorbance spectrum are determined by calculating
the root mean square (RMS) absorbance noise in the
spectral region of the target absorption feature. The
MDL is the absorbance signal (of the target com-
pound) that is five times the RMS noise level, using
a reference spectrum acquired for a known concentra-
tion of the target compound.
Table 1-2. Detection Limits for Target Compounds.
Compound
OP-FTIR Estimated Detection
Limit for Path Length = 100m,
1 min Average
(ppmv)
AP-42 Value ratioed to an
average methane concentra-
tion of 50 ppma
(ppmv)
1 ,4-Dichlorobenzene
2-Propanol
Acetone
Acrylonitrile
Butane
Chlorobenzene
Chloroform
Chloromethane
Dichlorodifluoromethane
Dimethyl sulfide
Ethane
Ethanol
Ethyl benzene
Ethyl chloride
0.012
0.0060
0.024
0.010
0.0060
0.040
0.012
0.012
0.0040
0.018
0.010
0.0060
0.060
0.0040
0.000021
0.0050
0.00070
0.00063
0.00050
0.000025
0.0000030
0.00010
0.0016
0.00078
0.089
0.0027
0.00046
0.00013
continued
1-6
-------
Brownfield Landfill in Ft. Collins, Colorado
Table 1-2. Detection Limits for Target Compounds (concluded).
Compound
Ethylene dibromide
Ethylene dichloride
Fluorotrichloromethane
Hexane
Hydrogen sulfide
Methane
Methanol
Methyl ethyl ketone
Methyl isobutyl ketone
Methyl mercaptan
Methylene chloride
Octane
Pentane
Propane
Propylene dichloride
Tetrachloroethene
Trichlorethylene
Vinyl chloride
Vinylidene chloride
Xylenes
OP-FTIR Estimated Detection
Limit for Path Length = 100m,
1 min Average
(ppmv)
0.0060
0.030
0.0040
0.0060
6.0
0.024
0.0015
0.030
0.040
0.060
0.014
0.0025
0.0080
0.0080
0.014
0.0040
0.0040
0.010
0.014
0.030
AP-42 Value ratioed to an
average methane concentra-
tion of 50 ppma
(ppmv)
0.00000010
0.000041
0.000076
0.00066
0.0036
N/Ab
N/A
0.00071
0.00019
0.00025
0.0014
N/A
0.00033
0.0011
0.000018
0.00037
0.00028
0.00073
0.000020
0.0012
a The AP-42 values represent an average concentration of different pollutants in the raw landfill gas. This is not comparable
to the detection limits for the OP-FTIR which is an average value for a path length of 100 meters across the surface of the
area source being evaluated. However, it does provide an indication of the types of pollutants and range of concentrations
associated with landfill gas emissions in comparison to the detection limits of the OP-FTIR.
b N/A = not available.
1.4 PrOJGCt SchGdlllG during September 2003. Table 1-3 provides the
One field campaign was completed for this study schedule of ORS work that was performed.
Table 1-3. Schedule of Work Performed at the Site.
Day Detail of Work Performed
Thursday, September 4 to Saturday, September 6 Travel to site
AM-Set-up
Sunday, September 7
J F PM-HRPM Survey of Areas C and D
continued
1-7
-------
Evaluation of Fugitive Emissions at a
Table 1-3. Schedule of Work Performed at the Site (concluded).
Day Detail of Work Performed
AM-HRPM Survey of Area B
Monday, September 8
PM-VRPM Survey
AM-HRPM Survey of Area A
Tuesday, September 9
PM-VRPM Survey
Wednesday, September 10 Travel from site
-------
Brownfield Landfill in Ft. Collins, Colorado
Chapter 2
Test Procedures
The following subsections describe the test proce-
dures used at each of the four survey areas, which are
designated as Area A through Area D. Refer to Figure
1-1 for the geographical orientation of each area. The
survey areas were chosen to ensure that the study
investigated the maximum amount of surface area at
the site. Another factor in selecting the survey areas
was the location of key areas of interest at the site,
including playgrounds and soccer fields. The bound-
aries of each survey area were determined based on
the location of physical barriers such as buildings and
trees. HRPM was performed in each area to produce
surface concentration maps and to locate any surface
hot spots. In addition, VRPM was performed in Area
A to obtain an emission flux rate of methane, ammo-
nia, and gasoline from the site. Refer to Figure 1 -2 for
the geographical orientation of the VRPM configura-
tions. VRPM was not performed in the other areas
due to limitations in the size of the areas, and the
presence of physical barriers. Each section includes a
figure that details the position of the mirrors used in
the FIRPM surveys. The coordinates of the mirrors
used in each configuration are presented in Appendix
A of this report.
OP-FTIR data were collected as interferograms. All
data were archived to CD-ROMs. After archiving,
interferograms were transferred to ARC ADIS person-
nel who performed the transformations to absorbance
spectra and then calculated concentrations using
Non-Lin (Spectrosoft) quantification software. This
analysis was done after completion of the field
campaign. Concentration data were then matched with
the appropriate mirror locations, wind speed, and
wind direction. The ARCADIS RPM software was
used to process the data into horizontal plane concen-
tration maps or vertical plane plume visualizations,
as appropriate.
Meteorological data including wind direction, wind
speed, temperature, relative humidity, and barometric
pressure were continuously collected during the
measurement campaign with a Climatronics model
101990-G1 instrument. The Climatronics instrument
is automated. It collects real-time data from its
sensors and records time-stamped data as one-minute
averages to the computer used for data collection.
Wind direction and speed-sensing heads were used to
collect data at the surface during the HRPM surveys,
and at heights of 2 and 10 meters during the VRPM
survey. The 10 meter sensor was placed on top of the
scissors jack. The sensing heads for wind direction
incorporate an auto-north function (automatically
adjusts to magnetic north) that eliminates the errors
associated with subjective field alignment to a
compass heading. After collection, a linear interpola-
tion between the two sets of data is done to estimate
wind velocity as a function of height.
Once the concentrations maps and wind information
are processed, the concentration values are integrated
incorporating the wind speed component normal to
the plane at each height level to compute the flux
through the vertical plane. In this stage, the concen-
tration values are converted from parts per million by
volume to grams per cubic meter considering the
molecular weight of the target gas and ambient
temperature. This enables the direct calculation of
the flux in grams per second using wind speed data
in meters per second.
In reporting the average calculated flux, a moving
2-1
-------
Evaluation of Fugitive Emissions at a
average is used in the calculation of the average flux
values to show temporal variability in the measure-
ments. A moving average involves averaging flux
values calculated from several different consecutive
cycles, which are defined as data collected when
scanning one time through all the mirrors in the
configuration. For example, a data set taken from 5
cycles may be reported using a moving average of 4,
where values from cycles 1 to 4, and 2 to 5 are aver-
aged together to show any variability in the flux
values.
Section 3 of the report contains a figure depicting the
reconstructed gasoline plume map and calculated
gasoline flux generated from the collected data using
the VRPM method. It should be noted that the shape
of the plume maps generated by this method is used to
give information on the homogeneity of the plume
and do not affect the calculated flux values. The shape
of the maps generated represents the best fit of the
limited data to a symmetric Gaussian function, and
this fit may drive the plume shape outside of the
configuration.
2.1 Area A
Area A was located in the northwestern section of the
site. The area was bounded on the north by the Cache
La Poudre River, on the west by a set of railroad
tracks, and on the south by a recreational building at
the site. Figure 2-1 shows a schematic of the HRPM
configuration used in Area A, and Figure 2-2 shows
a partial picture of the configuration. The area was
divided into nine cells, and the OP-FTIR/scanner was
placed in the southwestern corner of the area.
2.2 Area B
Area B was located in a central location at the site.
The area consisted primarily of a large playground
and land directly adjacent to the playground. The area
was bounded on the west by a large parking lot and
recreation building and on the east by another parking
lot. Figure 2-3 shows a partial picture of the HRPM
configuration used in the area. The area was divided
into eight cells, and the OP-FTIR/scanner was placed
along the southern boundary of the area.
Ft. Collins Area A Geometry
110
40
60 80 100
x Distance (meters)
120
140
160
Figure 2-1. Schematic of the HRPM
Configuration Used in Area A.
Figure 2-2. Partial Picture of the HRPM
Configuration Used in Area A.
2.3 Area C
Area C was located in a central location at the site.
The area was bounded on the west by the large
playground in Area B, on the east by the United Way
building at the site, and on the north by the Cache La
Poudre River. A small ravine running north to south
bisected the area. Figure 2-4 shows a partial picture
of the HRPM configuration used in the area. The
area was divided into eight cells, and the OP-FTIR/
scanner was located along the southern boundary of
2-2
-------
Brownfield Landfill in Ft. Collins, Colorado
Figure 2-3. Partial Picture of the HRPM
Configuration Used in Area B.
Figure 2-4. Partial Picture of the HRPM
Configuration Used in Area C.
the area.
2.4 Area D
Area D was located in the southeastern corner of the
site. The area was bounded on the east by the Cache
La Poudre River, on the west by an industrial area,
and on the north by a playground on the southern side
of the United Way Building. Figure 2-5 shows a
partial picture of the HRPM configuration used in the
area. The area was divided into eight cells, and the
Figure 2-5. Partial Picture of the HRPM
Configuration Used in Area D.
OP-FTIR/scanner was set up along the southwestern
boundary of the area.
2.5 VRPM Measurements
The VRPM survey was conducted in Area A using
two monostatic OP-FTIR instruments and two
scissors jacks. The configuration formed two vertical
planes, one upwind and one downwind. The upwind
plane was located near the eastern boundary of Area
A, and the downwind plane was located along the
western boundary of the site (Figure 1-2). Each plane
consisted of three mirrors placed along the surface
and two mirrors placed on the scissors jack. Figure
2-6 shows a partial picture of the VRPM configura-
tion used in the study.
2.6 OP-TDLAS Measurements
The OP-TDLAS system was deployed during each
day of the field campaign to provide additional
information on methane concentrations at the site.
The OP-TDLAS is a more cost-effective instrument
for collecting measurements of specific target com-
pounds, such as methane. The methane measure-
ments from the OP-TDLAS served as a validation of
methane measurements taken with the OP-FTIR.
Figure 2 7 shows a picture of the OP-TDLAS system.
The OP-TDLAS collected data along the surface in
Areas C and D on September 7 and in Areas A and B
on September 8. On September 9, the instrument was
2-3
-------
Evaluation of Fugitive Emissions at a
Figure 2-6. Partial Picture of the VRPM
Configuration Used at the Site.
Figure 2-7. OP-TDLAS System.
set up in Area A and collected data using surface and
vertical beam paths. In most cases, the optical config-
urations used with the OP-TDLAS were very similar
to the configurations used with the OP-FTIR instru-
ment. The distance of the path lengths used in each
OP-TDLAS configuration are presented in Appendix
Figure 2-8. UV-DOAS Instrument.
B of this report.
2.7 UV-DOAS Measurements
The UV-DOAS instrument was deployed at the site
by a representative of OPSIS, Inc. to provide supple-
mental data on BTX concentrations at the site. The
instrument collects continuous measurements and
reports one-minute, path-averaged concentrations.
Figure 2-8 shows a picture of the UV-DOAS instru-
ment.
On September 9, the instrument was set up along the
western boundary of Area A. The UV-DOAS config-
uration in Area A was approximately parallel to the
path of mirror 3 from the VRPM survey done in this
area with the OP-FTIR instrument. The UV-DOAS
instrument collected data on this day for approxi-
mately three hours.
2-4
-------
Brownfield Landfill in Ft. Collins, Colorado
Chapter 3
Results and Discussion
The results from the ORS-RPM data collected at the
site are presented in the following subsections. The
HRPM results from Areas B, C, and D are not pre-
sented because no significant hot spots of methane or
VOC were detected in these areas. Data from the
VRPM surveys were collected only in Area A.
VRPM surveys in Areas B, C, or D were not neces-
sary because the HRPM surveys in these areas
indicated that there were no significant methane or
VOC hot spots to contribute to a significant emis-
sions flux. Moreover, physical and geographical
barriers in Areas B, C, and D would have precluded
VRPM measurements. It should be noted that the
concentration values reported in the following sec-
tions have not been corrected to standard atmospheric
conditions.
3.1 Area A
Data from HRPM and VRPM surveys using the OP-
FTIR instrument were collected for Area A, In
addition, the OP-TDLAS collected methane emission
data to validate the OP-FTIR measurements, and the
UV-DOAS collected supplemental BTX data.
3.1.1 HRPM Results
A HRPM survey was performed in Area A to identify
possible hot spots of methane and VOCs. Table 3 1
presents the average methane concentrations detected
along each beam path in the configuration. The
locations of the mirrors used in this configuration are
presented in Appendix A of this report.
Table 3-1. Average Methane Concentrations Measured During the HRPM Survey of Area A.
Loop
Mirror 1
1
2
3
4
5
6
7
8
9
10
.81
.81
.80
.79
.79
.79
.78
.78
.80
.77
Methane Concentrations
(ppm)
Mirror 2
1.83
1.83
1.82
1.82
1.81
1.81
1.80
1.80
1.79
1.79
Mirror 3 Mirror 4
1.81
1.81
1.78
1.80
1.78
1.78
1.78
1.78
1.78
1.77
.81
.81
.79
.80
.79
.76
.77
.77
.77
.77
Mirror 5
1.81
1.82
1.80
1.80
1.79
1.79
1.79
1.78
1.77
1.78
Mirror 6 Mirror 7
1.81
1.80
1.79
1.78
1.78
1.77
1.77
1.71
1.76
1.76
.86
.84
.83
.83
.83
.83
.82
.82
.82
.83
Mirror 8
1.83
1.81
1.80
1.80
1.79
1.79
1.78
1.78
1.78
1.78
Mirror 9
1.83
1.82
1.79
1.80
1.78
1.78
1.79
1.78
1.78
1.78
continued
3-1
-------
Evaluation of Fugitive Emissions at a
Table 3-1. Average Methane Concentrations Measured During the HRPM Survey of Area A
(concluded).
Methane Concentrations
Loop (ppm)
Mirror 1 Mirror 2 Mirror 3 Mirror 4 Mirror 5 Mirror 6 Mirror 7 Mirror 8 Mirror 9
11
12
13
14
15
.77
.78
.78
.78
.77
Mean 1.79
DOT °-°14
1.79
1.80
1.79
1.80
1.79
1.80
0.015
1.78
1.78
1.77
1.77
1.78
1.78
.78
.78
.78
.78
.78
.78
0.013 0.014
1.80
1.79
1.78
1.79
1.78
1.79
0.013
1.77
1.77
1.77
1.77
1.76
1.77
.81
.83
.81
.82
.81
.83
0.022 0.012
1.78
1.80
1.79
1.78
1.78
1.79
0.014
1.78
1.79
1.77
1.77
1.78
1.79
0.016
The survey did not detect the presence of any meth-
ane hot spots along the surface in Area A. This is
supported by the relatively small standard deviations
of measured methane concentrations for each beam
path in the configuration (Table 3-1). Average meth-
ane concentrations measured along each beam path
were very close to ambient background levels.
The HRPM survey detected the presence of gasoline
(primarily octane) in Area A. Figure 3-1 presents the
reconstructed map of surface gasoline concentrations
(in parts per billion) measured in Area A. The figure
shows the presence of one hot spot with an average
concentration over 81 ppb and a maximum concentra-
tion of about 100 ppb located in the southern corner
of Area A. The MDL of the OP-FTIR instrument is
15 ppb for gasoline.
Ft. Collins Area A Gasoline Source Location
110
100
90
ffi" 80
-------
Brownfield Landfill in Ft. Collins, Colorado
3.1.2 VRPM Results
The VRPM survey of the site detected methane,
ammonia, and gasoline on the downwind VRPM
configuration (Figure 1-2). Figure 3-2 shows a time
series of methane and ammonia concentrations
measured along beam path #5 of the VRPM down-
wind survey (which extended from the OP-FTIR
instrument to the mirror placed at the top of the
scissors] ack), and observed wind direction during the
period of data collection. The methane and ammonia
concentrations are well-correlated, indicating that the
measured concentrations probably came from the
same source. The peak concentrations of methane and
ammonia occur during periods that the wind direction
is around -20° from normal to the plane of the config-
uration (approximately 123° from due north). Since
methane and ammonia hot spots were not detected
during the FtRPM survey of Area A, and methane and
ammonia were detected on the downwind VRPM
configuration when the winds shifted to a more
easterly direction, it is likely that the source of the
methane and ammonia detected is located outside of
Area A across the river.
Figure 3-3 is a vertical map of the reconstructed
gasoline plume from the downwind VRPM survey
showing contours of gasoline concentrations in parts
per million. The average calculated gasoline flux
from this survey was 0.87 g/s. The reconstruction
shows that the shape of the plume is very broad both
horizontally and vertically, indicating that the source
of the plume is relatively far from the configuration.
This is consistent with the location of the gasoline hot
spot found in the FtRPM survey of this area. No
vertical gasoline plume was detected on the upwind
VRPM configuration, but low levels of gasoline were
detected on the surface beam paths of the upwind
VRPM configuration. This is probably due to the
gasoline hot spot located close to the axis of the
upwind VRPM configuration (Figures 1-1 and 1-2).
10
-35
Wind Direction
yy^ry^yv
20.00
•S 1-2.00
0.00
12345678 910111213141516171819202122232425262728
Cycle Number
Figure 3-2. Time Series of Wind Direction and Concentrations of Methane
and Ammonia Measured on Beam Path #5 of the VRPM Downwind Survey.
3-3
-------
Evaluation of Fugitive Emissions at a
Concentrations are in ppm
Flux = 0.87 g/s
40 60 80
Crosswind Distance (meters)
100
120
Figure 3-3. Reconstructed Gasoline Plume Map from the Downwind
VRPM Survey.
Figure 3-4 presents a time series of gasoline, meth-
ane, and ammonia fluxes measured during the down-
wind VRPM survey. The average flux values were
calculated using a moving average of 4 cycles. The
well-correlated methane and ammonia fluxes ap-
peared during the second half of the survey when
wind shifted slightly to the east. These flux values are
probably a significant underestimation of the emis-
sion rate of the methane and ammonia source because
only a small portion of the plume was captured by the
measurement configuration. However, the gasoline
flux values are significant throughout the measure-
ment period. The gasoline flux values are probably a
slight underestimation of the source emission rate
since the detected hot spot is located approximately
100 meters away from the downwind VRPM configu-
ration. The highest gasoline flux values occurred
during periods when the observed wind direction was
close to perpendicular to the downwind VRPM
configuration (see Figure 3-2 for a time series of
observed wind directions during this period).
1 2345678 9101112131415161718192021222324
Cycle Number
Figure 3-4. Gasoline, Methane, and Ammonia
Fluxes Measured during the Downwind VRPM
Survey.
3.1.3 UV-DOAS Results
The UV-DOAS instrument was set up along the
3-4
-------
Brownfield Landfill in Ft. Collins, Colorado
surface approximately parallel to the downwind
VRPM configuration on September 9. Table 3-2
presents the average concentrations of benzene,
toluene, and p-xylene (in parts per billion) measured
by the UV-DOAS instrument during the same time
period as the VRPM run. The MDL of the UV-DOAS
instrument was 1 ppb for benzene, toluene, and
p-xylene.
Table 3-2. Average Concentration of BTX Com-
pounds Measured by the UV-DOAS Instrument.
Compound
Concentration
(ppb)
Average
Range
Std. Dev.
benzene
toluene
p-xylene
2.6
21
4.9
0.91 to 7.2
5. 6 to 27
3.8 to 7.6
1.8
5.8
0.95
Figure 3-5 presents a time series of gasoline concen-
trations (in parts per billion) collected with the
OP-FTIR instrument along beam path #3 (which
extended along the surface from the OP-FTIR instru
ment to the base of the scissors jack), and BTX
concentrations (in parts per billion) collected with the
UV-DOAS instrument. The time period depicted in
the figure represents times that the two instruments
were concurrently collecting data. The figure shows
that the concentrations of toluene and gasoline
correlate well although they were collected with
different instruments, indicating that the detected
gasoline plume contains BTX compounds below the
detection levels of the OP-FTIR (MDL of 90 ppb for
benzene, 40 ppb for toluene, and 37 ppb for
p-xylene).
3.1.4 Summary of Results from Area A
Figure 3-6 presents a summary of the results of the
gasoline surface concentration map from the HRPM
survey in Area A showing a hot spot in the southern
corner of the area. The figure also shows the sus-
pected location of the source of methane and ammo-
nia measured on the VRPM downwind plane. The
location of this source is based on wind data and the
fact that methane and ammonia plumes were not
JJJJJJJJJJJjpjtA
<" &
-------
Evaluation of Fugitive Emissions at a
Figure 3-7 presents a time series of measured metha-
nol concentrations.
3.3 OP-TDLAS Measurements
The OP-TDLAS measured methane concentrations in
Areas A, B, C, and D. As mentioned previously, the
configurations used by the OP-TDLAS were often
similar to the configurations used with the OP-FTIR
instruments. Data from the survey of Area C were
unavailable due to a software malfunction. Table 3-4
presents the average methane concentrations (in parts
per million) measured at the site by the OP-TDLAS
system. The table also includes information on the
average methane concentrations measured by the
OP-FTIR instrument for cases that the OP-FTIR
beam paths were similar to those of the OP-TDLAS.
The methane concentrations measured by the
OP-TDLAS did not show much variability between
areas. In fact, most of the measured concentrations
were only slightly above ambient methane levels,
reinforcing the findings of the HRPM surveys.
Concentrations measured with the OP-TDLAS
ranged from 1.83 to 2.09 ppm. The methane concen-
trations measured with the OP-TDLAS system were
almost always slightly higher than concentrations
measured with the OP-FTIR instrument along similar
optical paths.
Cache
la Poudre
River
Downwind Sensor
Configuration.
Upwind Sensor
Configuration I
\
„-'""— \ \
i *^ Tb
Figure 3-6. Results Summary Map from Area A Measurements.
3-6
-------
Brownfield Landfill in Ft. Collins, Colorado
Table 3-3. Average Methane Concentrations Found during the HRPM Surveys of Areas B, C, and D.
Area
Concentration
(ppm)
A
B
C
Mirror 1
1.89±0.027
1.80±0.011
1.80±0.020
Mirror 2
1.81±0.008
1.76±0.011
1.75±0.020
Mirror 3
1.89±0.012
1.75±0.012
1.73±0.017
Mirror 4
1.81±0.009
1.73±0.010
1.77±0.018
Mirror 5
1.92±0.012
1.73±0.011
1.73±0.018
Mirror 6
1.82±0.005
1.74±0.011
1.75±0.018
Mirror 7
1.81±0.009
1.74±0.010
1.72±0.017
Mirror 8
1.89±0.009
1.78±0.011
1.71±0.017
10:08 10:12 10:16 10:21 10:25 10:29 10:33 10:38 10:42 10:46 10:51 10:55 10:59 11:04 11:08
Local Time (AM, rounded to minutes)
Figure 3-7. Time Series of Methanol Concentrations Measured
along Beam Path #3 of the Area B HRPM Survey.
3-7
-------
Evaluation of Fugitive Emissions at a
Table 3-4.Comparison of Methane Concentrations Measured with the OP-TDLAS and OP-FTIR
Instruments.
Methane Concentration
(ppm)
Mirror
No.
Area A
09/08/03
OP-
TDLAS
1
2
3
4
5
6
7
8
Avg.
Std. Dev.
Avg.
Std. Dev.
Avg.
Std. Dev.
Avg.
Std. Dev.
Avg.
Std. Dev.
Avg.
Std. Dev.
Avg.
Std. Dev.
Avg.
Std. Dev.
1.91
0.02
1.99
0.08
2.08
0.05
2.05
0.04
2.06
0.05
2.09
0.03
2.09
0.02
2.06
0.02
OP-
FTIR
1.92
0.03
1.88
0.03
1.84
0.02
1.85
0.03
1.84
0.02
OP-
TDLAS
1.94
0.02
1.96
0.01
1.98
0.01
1.95
0.02
1.98
0.03
1.99
0.02
2.01
0.02
1.96
0.02
09/09/03
OP-
FTIR
1.78
0.01
1.78
0.01
1.77
0.02
1.79
0.02
OP-
TDLAS
1.96
0.05
1.83
0.12
2.03
0.05
2.03
0.05
2.03
0.04
2.07
0.06
2.04
0.05
2.04
0.04
OP-
FTIR
1.74
0.04
1.88
0.04
1.86
0.04
1.88
0.05
1.87
0.04
Area B
OP-
TDLAS
2.01
0.04
2.03
0.05
2.06
0.05
2.03
0.04
1.98
0.03
2.05
0.02
2.02
0.02
2.07
0.02
OP-
FTIR
1.81
0.01
1.81
0.02
1.82
0.02
1.81
0.02
Area D
OP-
TDLAS
2.03
0.12
1.93
0.18
1.90
0.24
1.98
0.12
1.94
0.12
1.95
0.15
1.99
0.13
1.97
0.15
OP-
FTIR
1.80
0.02
1.77
0.02
1.75
0.02
1.75
0.02
1.73
0.02
1.72
0.02
1.73
0.02
1.71
0.02
3-S
-------
Brownfield Landfill in Ft. Collins, Colorado
Chapter 4
Conclusion
This report presents the results from a field campaign
conducted in September 2003 at a former landfill site
in Fort Collins, Colorado. The study used measure-
ments from several ground-based ORS instruments
and the ORS-RPM method to characterize fugitive
emissions of methane, ammonia, and VOCs from the
site.
HRPM surveys of the site did not detect the presence
of any methane hot spots, and methane surface
concentrations at the site were essentially at ambient
background levels. The HRPM survey of Area A
detected a gasoline hot spot (average concentration
over 81 ppb, maximum concentration about 100 ppb)
in the southern corner of Area A (north of the large
playground adjacent to the gymnasium). The HRPM
survey of Area B detected the presence of methanol
along beam path #3, indicating a small hot spot south
of the large playground, within the fence line of the
property. The average methanol concentration mea-
sured during the survey was 21 ppb.
A VRPM survey was done in Area A to measure
fluxes of fugitive emissions. The VRPM survey
detected methane, ammonia, and gasoline in the
downwind configuration, along the fence line of the
site. The measured concentrations of methane and
ammonia correlated well temporally, suggesting the
source of the methane and ammonia emissions may
be the same. Looking at data on wind direction and
the lack of methane and ammonia concentrations
measured during the HRPM survey, it is concluded
that this source of ammonia and methane was located
outside of Area A, northeast of the survey area
(across the river). The calculated gasoline flux of
0.87 g/s was from the gasoline hot spot detected
during the HRPM survey of Area A. Since the loca-
tion of this hot spot is approximately 100 meters
upwind of the VRPM measurement configuration, it
is concluded that this flux is a slight underestimation
of the actual emission rate from the source because a
small portion of the plume may not have been cap-
tured by the measurement configuration. The above
conclusions are confirmed by the fact that the VRPM
survey did not detect any methane, ammonia, or
gasoline plumes along the upwind configuration.
The UV-DOAS instrument was deployed in Area A
to collect data concurrently with the OP-FTIR instru-
ment. The UV-DOAS detected the presence benzene,
toluene, and p-Xylene. The average measured con-
centrations of benzene, toluene, and p-Xylene were
2.6 ppb, 21 ppb, and 4.9 ppb, respectively. The
concentrations of toluene measured with the
UV-DOAS instrument correlated well with gasoline
concentrations measured with the OP-FTIR instru-
ment during the same time period, indicating that the
gasoline plume contains BTX compounds at levels
lower than the MDL of the OP-FTIR.
The OP-TDLAS system collected information on
methane concentrations in Areas A, B, C, and D. The
methane concentrations measured with the
OP-TDLAS were generally slightly higher (less than
10%) than concentrations measured with the
OP-FTIR instrument along similar optical paths.
4-1
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Evaluation of Fugitive Emissions at a
4-2
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Brownfield Landfill in Ft. Collins, Colorado
Chapter 5
Quality Assurance/Quality Control
5.1 Equipment Calibration
As stated in the ECPD Optical Remote Sensing
Facility Manual (U.S. EPA, 2004), all equipment is
calibrated annually or cal-checked as part of standard
operating procedures. Certificates of calibration are
kept on file. Maintenance records are kept for any
equipment adjustments or repairs in bound project
notebooks that include the data and description of
maintenance performed. Instrument calibration
procedures and frequency are listed in Table 5-1 and
further described in the text.
As part of the preparation for this project, a Category
III Quality Assurance Project Plan (QAPP) was
prepared and approved for each separate field cam-
paign. In addition, standard operating procedures
were in place during the field campaign.
5.2 Assessment of DQI Goals
The critical measurements associated with this
project and the established data quality indicator
(DQI) goals in terms of accuracy, precision, and
completeness are listed in Table 5-2. More informa-
tion on the procedures used to assess DQI goals can
be found in Section 10 of the ECPD Optical Remote
Sensing Facility Manual (U.S. EPA, 2004).
5.2.1 DQI Check for Analyte PIC Measure-
ment
The precision and accuracy of the analyte path-
integrated concentration (PIC) measurements was
assessed by analyzing the measured nitrous oxide
concentrations in the atmosphere. A typical back-
ground atmospheric concentration for nitrous oxide
is about 315 ppb, but this value may fluctuate due to
Table 5-1. Instrumentation Calibration Frequency and Description.
Instrument
Measurement
Calibration
Date
Calibration Detail
Climatronics Model 101990-G1
meteorological heads
Climatronics Model 101990-G1
meteorological heads
Topcon Model GTS-21 ID
theodolite
Topcon Model GTS-21 ID
theodolite
Wind speed in
miles/hour
Wind direction in
degrees from north
Distance
measurement
Angle
measurement
22 April 2003 APPCD Metrology Lab calibration records on
file
22 April 2003 APPCD Metrology Lab calibration records on
file
1 May 2003 Calibration of distance measurement:
Actual distance=50 ft.
Measured distance=50.6 ft. and 50.5 ft.
21 May 2003 Calibration of angle measurement:
Actual angle= 360°
Measured angle= 359°41' 18", and
359°59'55"
5-1
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Evaluation of Fugitive Emissions at a
Table 5-2. DQI Goals for Instrumentation.
Analysis Method
Measurement
Parameter
. n • • Detection „
Accuracy Precision . . Completeness
Analyte PIC OP-FTIR: Nitrous Oxide
Concentrations
Ambient Wind Climatronics heads met
Speed side-by-side comparison in the
field
Ambient Wind Climatronics heads met
Direction side-by-side comparison in the
field
Distance Theodolite- Topcon
Measurement
±25 %/15 %/10%a ±10% See Table 1 -2
±1 m/s ±1 m/s N/A
±10°
±lm
±10°
±lm
N/A
O.lm
90%
90%
90%
100%
The accuracy acceptance criterion of ±25% is for pathlengths of less than 50 m, ±15% is for pathlengths between 50 and 100 m, and ±10%
is for pathlengths greater than 100 m.
seasonal variations in nitrous oxide concentrations or
elevation of the site. The elevation of the site sur-
veyed in this field campaign is approximately 5,000
ft above sea level. At this elevation, the optical
density of a nitrous oxide concentration of 315 ppb
would be equivalent to a lower concentration of
nitrous oxide at sea level, due to the decreased air
density. To correct the background nitrous oxide
level for the effects of elevation, the measured
temperature and atmospheric pressure were ratioed to
standard temperature and pressure values. The
corrected background nitrous oxide concentration is
approximately 265 ppb.
The precision of the analyte PIC measurements was
evaluated by calculating the relative standard devia-
tion of each data subset. A subset is defined as the
data collected along one particular path length during
one particular survey in one survey sub-area. The
number of data points in a data subset depends on the
number of loops used in a particular survey.
The accuracy of the analyte PIC measurements was
evaluated by comparing the calculated nitrous oxide
concentrations from each data subsets to the cor-
rected background concentration of 265 ppb. The
number of calculated nitrous oxide concentrations
that failed to meet the DQI accuracy criterion in each
data subset was recorded.
Overall, 61 data subsets were analyzed from this field
campaign. Based on the DQI criterion set forth for
precision of ±10%, each of the 61 data subsets were
found to be acceptable. The range of calculated
relative standard deviations for the data subsets from
this field campaign was 0.57 to 11.7 ppb, which
represents 0.22% to 4.4% RSD.
Each data point (calculated nitrous oxide concentra-
tion) in the 61 data subsets were analyzed to assess
whether or not it met the DQI criterion for accuracy
of ±25% (265 ± 66 ppb) for path lengths less than 50
meters, ±15% (265 ± 40 ppb) for path lengths be-
tween 50 and 100 meters, and ±10% (265 ± 27 ppb)
for path lengths greater than 100 meters. All the 1136
data points that were analyzed met the DQI criteria
for accuracy. Based on the DQI criterion set forth for
accuracy and precision, all data points were found to
be acceptable, for a total completeness of 100%.
5.2.2 DQI Checks for Ambient Wind Speed
and Wind Direction Measurements
Section 10 of the ECPD Optical Remote Sensing
Facility Manual (U.S. EPA, 2004) states that the DQI
5-2
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Brownfield Landfill in Ft. Collins, Colorado
goals for precision and accuracy of the Climatronics
meteorological heads are assessed by collecting
meteorological data for 10 minutes with the two
heads set up side-by side. This was not done prior to
the current field campaign because this DQI proce-
dure had not been implemented at the time of the
study. However, the Climatronics heads were cali-
brated in April 2003 by the APPCD Metrology Lab
(see Table 5 2). Additionally, checks for agreement
of the wind speed and wind direction measured from
the two heads (2 m and 10m) were done in the field
during data collection. Although it is true that some
variability in the parameters measured at different
levels should be expected, this is a good first-step
check for assessing the performance of the instru-
ments. Another check is done in the field by compar-
ing the measured wind direction to the forecasted
wind direction for that particular day.
5.2.3 DQI Check for Precision and Accuracy
of Theodolite Measurements
Although this instrument was not calibrated immedi-
ately prior to the current field campaign, the theodo-
lite was originally calibrated by the manufacturer
prior to being received by the U.S. EPA. Addition-
ally, there are several internal checks in the theodolite
software that prevent data collection from occurring
if the instrument is not properly aligned on the object
being measured or if the instrument has not been
balanced correctly. When this occurs, it is necessary
to reinitialize the instrument to collect data.
The following DQI checks were performed on the
theodolite prior to the current field campaign. These
checks were performed during May 2003 at a field
site near Chapel Hill, NC. The calibration of distance
measurement was done using a tape measure to
compare the actual distance to the measured distance.
This check was duplicated to test the precision of this
measurement. The actual distance measured was
15.2m. The measured distance during the first test
was 15.4m, and the measured distance during the
second test was 15.4m. The results indicate the
accuracy (1.3% bias for test one and two) and preci-
sion (0% RSD) of the distance measurement fell well
within the DQI goals.
The check to test the precision and accuracy of the
angle measurement was done by placing two mirror
targets approximately 180 degrees apart. The theodo-
lite was placed in the middle of the imaginary circle
formed by the two mirrors. The actual angle was
360°. The angle measured during the first test was
359°41'18", and the angle measured during the
second test was 359°59'55". The results indicate the
accuracy and precision of the angle measurement fall
well within the DQI goals.
5.3 QC Checks of OP-FTIR Instrument
Performance
Several checks should be performed on the OP-FTIR
instrumentation prior to deployment to the field and
during the field campaign. More information on these
checks can be found in MOP 6802 and 6807 of the
ECPD Optical Remote Sensing Facility Manual. At
the time of the current field campaign, the procedures
and schedule of QC checks were still being devel-
oped. Consequently, QC checks were performed only
in the field on the Unisearch OP-FTIR.
On the first day of the field campaign (September 7),
the single beam ratio, electronic noise, saturation,
linearity, baseline stability, and random baseline
noise tests were performed. The results of the satura-
tion test indicated that some saturation was occurring
in the detector of the instrument. In response to this,
the instrument detector response was adjusted slightly
to correct this problem. The results of the other tests
indicated that the instrument was operating within the
acceptable criteria range.
On September 8, the signal-to-noise, and single beam
ratio tests were performed on the Unisearch
OP-FTIR. The results of these tests indicated that the
instrument was operating within the acceptable
criteria range.
In addition to the QC checks performed on the
OP-FTIR, the quality of the instrument signal (inter-
ferogram) is checked constantly during the field
5-3
-------
Evaluation of Fugitive Emissions at a
campaign. This is done by ensuring that the intensity
of the signal is at least five times the intensity of the
stray light signal (the stray light signal is collected as
background data prior to actual data collection and
measures internal stray light from the instrument
itself). In addition to checking the strength of the
signal, checks are done constantly in the field to
ensure that the data are being collected and stored to
the data collection computer. During the campaign, a
member of the field team constantly monitors the
data collection computer to make sure these checks
are completed.
5.4 Validation of Concentration Data
Collected with the OP-FTIR
During the analysis of the OP-FTIR data, a validation
procedure was performed to aid in identifying the
presence of gasoline and ammonia in the dataset. This
validation procedure involves visually comparing an
example of the measured spectra to a laboratory-
measured reference spectrum.
Figure 5-1 shows an example of a validation done
using a spectrum collected at the site. Gasoline was
detected in this particular spectrum. The reference
spectrum used to quantify gasoline concentrations is
an actual laboratory-measured spectrum of Exxon
87-octane gasoline. The gasoline features can be seen
in the measured field spectrum (green trace). Classi-
cal Least Squares (CLS) analysis performed on this
spectrum resulted in determinations of 55.1 ± 3.0 ppb
of gasoline. The uncertainty value is equal to three
times the standard error in the regression fit of the
measured spectrum to a calibrated reference spec-
trum, propagated to the concentration determination.
Figure 5-2 shows a validation done for an ammonia
spectrum collected at the site. The ammonia features
can be clearly seen in the measured field spectrum
(blue trace). Classical Least Squares (CLS) analysis
performed on this spectrum resulted in determina-
tions of 17.4 ± 0.97 ppb of ammonia.
5.5 Internal Audit of Data Input Files
An internal audit was performed by the ARCADIS
Figure 5-1. Comparison of a Gasoline Spectrum
Measured at the Site (Green Trace) to Reference
Spectra of Gasoline (Red Trace).
Figure 5-2. Comparison of an Ammonia Spec-
trum Measured at the Site (Blue Trace) to Ref-
erence Spectra of Ammonia (Red Trace).
Field Team Leader on a sample of approximately
10% of the data from the field campaign. The audit
investigated the accuracy of the input files used in
running the radial plume mapping (RPM) programs.
The input files contain analyzed concentration data,
mirror path lengths, and wind data. The results of this
audit found no problems with the accuracy of the
input files created.
5-4
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Brownfield Landfill in Ft. Collins, Colorado
5.6 OP-TDLAS Instrument
At the time of the field campaign, the OP-TDLAS
system had only recently been acquired by EPA.
Consequently, standard operating and calibration
procedures were still being developed. Many im-
provements have been made to the QA process since
this field campaign. Some of these improvements
include the development of calibration cells and the
development of a standard operating procedure for
collecting emissions measurements with the
OP-TDLAS (see MOP 6811 of the ECPD Optical
Remote Sensing Facility Manual).
The comparison of methane concentrations measured
with the OP-TDLAS system to methane concentra-
tions measured with the OP-FTIR is a good valida-
tion of the OP-TDLAS. Table 3-4 shows that there is
reasonable agreement between the concentrations
measured with the two instruments, although the
methane concentrations measured with the
OP-TDLAS system were generally slightly higher
(within 10%) than concentrations measured with the
OP-FTIR instrument along similar optical paths. The
data from Table 3-4 also indicates that the precision
of the data collected with the OP-FTIR is better than
the precision of the OP-TDLAS data. This is espe-
cially true of data collected in Area D, where the
standard deviation of the OP-TDLAS data is as high
as 0.24 ppm.
An experiment performed in January 2004 compared
methane concentrations measured with the
OP-TDLAS system and the IMACC OP-FTIR. The
experiment collected methane measurements at a
wide range of concentrations. Figure 5-3 shows the
results of this experiment. The results show that there
is very good agreement in methane concentrations
measured with both instruments. However, a closer
inspection of this dataset found that the precision of
the OP-TDLAS data was not favorable at methane
concentrations close to ambient background levels.
This is consistent with the findings of the current
study.
Despite the issue of precision of the OP-TDLAS
1000 2000 3000 4000
FUR-Measured PIC (ppn-m)
5000
Figure 5-3. Post-Fort Collins Comparison of
Methane Concentrations Measured with the
OP-TDLAS and OP FTIR Instruments.
instrument at low concentrations, it is apparent from
the data presented in Figure 5-3 that methane concen-
trations measured with the OP-TDLAS and OP-FTIR
instruments are comparable for area emissions
monitoring when a wide range of concentrations are
measured.
5.7 UV-DOAS Instrument
Data from the UV-DOAS instrument were collected
and analyzed by a representative of OPSIS, Inc. The
following QC summary was created using informa-
tion provided to ARCADIS by OPSIS, Inc.
• The UV-DOAS AR500 emitter and receiver were
placed on a stable foundation in order to provide
a high and stable light signal input to the spec-
trometer.
• The AR500 provides a system check function that
performed a complete check of the integrity of
the spectrometer.
• A zero and span calibration check was performed
for all gases involved when the system was
installed at the site.
• Monitored data, including the stored concentra-
5-5
-------
Evaluation of Fugitive Emissions at a
tion, deviation, and light level values, were
reviewed. Data that was sampled with light level
values below minimum threshold were invali-
dated. A few of the data points collected were
invalidated due to loss of light signal.
Spectral validation of the detected compounds
(similar to validation provided for the OP-FTIR
data in Section 5.4) was not provided. This is
recommended for future studies using the
UV-DOAS instrument.
In the application of BTX measurements using
the standard resolution spectrometer, the effect of
oxygen in the monitoring path was compensated
for. This was done in the oxygen reference cali-
bration procedure. This procedure was performed
for each specific optical path length that the
system operated on. Some of the data were cor-
rected in offset levels. The origin of offset con-
centration was due to the fact that only one
oxygen reference was performed during the
project.
The MDL for benzene, toluene, and p-xylene was
1 ppb. The precision and accuracy of the mea-
surements is 1%, as reported by OPSIS, Inc.
5-6
-------
Brownfield Landfill in Ft. Collins, Colorado
Chapter 6
List of References
Hashmonay, R.A., M.G. Yost, D.B. Harris, and E.L. Thompson (1998), Simulation study for gaseous fluxes
from an area source using computed tomography and optical remote sensing, presented at SPIE Conference
on Environmental Monitoring and Remediation Technologies, Boston, MA, Nov., 1998, in SPIE Vol. 3534,
pp. 405-410.
Hashmonay, R.A., and M.G. Yost (1999), Innovative approach for estimating fugitive gaseous fluxes using
computed tomography and remote optical sensing techniques, J. Air Waste Manage. Assoc., 49:8, pp. 966-972.
Hashmonay, R. A., M.G. Yost, and C. Wu (1999), Computed tomography of air pollutants using radial scanning
path-integrated optical remote sensing, Atmos. Environ., 33:2, pp. 267-274.
Hashmonay, R.A., D.F. Natschke, K.Wagoner, D.B. Harris, E.L.Thompson, and M.G. Yost (2001), Field
evaluation of a method for estimating gaseous fluxes from area sources using open-path Fourier transform
infrared, Environ. Sci. Technol., 35:11, pp. 2309-2313.
Hashmonay, R.A., K. Wagoner, D.F. Natschke, D.B. Harris, and E.L. Thompson (2002), Radial computed
tomography of air contaminants using optical remote sensing, presented June 23-27, 2002 at the AWMA 95th
Annual Conference and Exhibition, Baltimore, MD.
Platt, U. (1994), Differential optical absorption spectroscopy (DOAS), In: Air Monitoring by Spectroscopic
Techniques, Chemical Analysis Series, Vol. 127, John Wiley & Sons, Inc. pp. 27-84.
U.S. EPA QA/G4 (2000), Guidance for the Data Quality Objectives Process, EPA-600/R-96/055, Office of
Environmental Information, U.S. EPA, Washington, DC. Also at
http://www.epa.gov/quality/qs-docs/g4-fmal.pdf (accessed April 2005).
U.S. EPA (2004), ECPB Optical Remote Sensing Facility Draft Facility Manual, approved April.
Wu, C., M.G. Yost, R.A. Hashmonay, and D.Y. Park (1999), Experimental evaluation of a radial beam
geometry for mapping air pollutants using optical remote sensing and computed tomography, Atmos. Environ.,
33:28, pp. 4709-4716.
6-1
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Evaluation of Fugitive Emissions at a
6-2
-------
Brownfield Landfill in Ft. Collins, Colorado
Appendix A
OP-FTIR Mirror Coordinates
Table A-1. Standard Distance and Horizontal
Coordinates of Mirrors Used in the HRPM Survey
of Area A.
Table A-3. Standard Distance and Horizontal
Coordinates of Mirrors Used in the HRPM Survey
of Area C.
Mirror
Number
1
2
3
4
5
6
7
8
9
Standard
Distance
(m)
125
87.3
149
179
117
149
49.8
86.2
121
Horizontal Angle
from North
(degrees)
76
82
88
97
99
105
110
116
120
Table A-2. Standard Distance and Horizontal
Coordinates of Mirrors Used in the HRPM Survey
of Area B.
Mirror
Number
1
2
3
4
5
6
7
8
Standard
Distance
(m)
42.4
83.7
37.9
79.1
38.2
77.2
82.8
45.2
Horizontal Angle
from North
(degrees)
353
1
10
15
25
29
50
54
Mirror
Number
1
2
3
4
5
6
7
8
Standard
Distance
(m)
50.0
69.7
93.2
139
129.1
92.7
68.3
37.9
Table A-4. Standard
Coordinates of Mirrors
of Area D.
Mirror
Number
1
2
3
4
5
6
7
8
Standard
Distance
(m)
52.2
84.9
107
52.5
87.5
50.0
88.2
126
Horizontal Angle
from North
(degrees)
68
62
61
59
40
30
29
20
Distance and Horizontal
Used in the HRPM Survey
Horizontal Angle
from North
(degrees)
286
290
292
309
310
341
335
329
A-1
-------
Evaluation of Fugitive Emissions at a
Table A-5. Standard Distance and Horizontal
Coordinates of Mirrors Used in the VRPM Survey.
Mirror
Number
1
2
3
4
5
1
2
3
4
5
Standard
Distance
(m)
36.9
68.7
110
113
113
44.9
89.9
117
118
118
Horizontal
Angle from
North
(degrees)
Upwind
65
70
70
70b
69b
Downwind
48
51
53
53
53
Vertical Angle3
(degrees)
0
0
0
1
5
0
0
0
2
6
a Vertical angle shown is the angle from horizontal (positive values
indicate elevation from the horizontal, negative values indicate
descent from the horizontal).
b Although Mirrors 4 and 5 were on the same scissors jack, Mirror 5
was not directly above Mirror 4.
A-2
-------
Brownfield Landfill in Ft. Collins, Colorado
Appendix B
OP-TDLAS Configuration Path Length Distances
Table B-1. Standard Distance of Path Lengths Used in OP-TDLAS Configurations.
Area A
Mirror Number
1
2
3
4
5
6
7
8
09/08/03
(m)
41.0
76.3
118
119
119
173
203
195
09/09/03
Surface
(m)
136
146
174
143
114
156
193
105
Vertical
(m)
48.1
83.6
119
120
120
156
194
106
Area B
(m)
82.4
80.9
79.6
79.3
79.3
80.6
87.1
153
Area D
(m)
52.2
52.5
50.0
84.9
87.5
88.2
107
126
B-1
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Evaluation of Fugitive Emissions at a
B-2
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Brownfield Landfill in Ft. Collins, Colorado
Appendix C
Methane Concentrations
Table C-1. Methane Concentrations Found during the Area A HRPM Survey.
Loop
Methane Concentration
(ppm)
Mirror 1 Mirror 2 Mirror 3 Mirror 4 Mirror 5 Mirror 6 Mirror 7 Mirror 8 Mirror 9
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
.81
.81
.80
.79
.79
.79
.78
.78
.80
.77
.77
.78
.78
.78
.77
.83
.83
.82
.82
.81
.81
.80
.80
.79
.79
.79
.80
.79
.80
.79
.81
.81
.78
.80
.78
.78
.78
.78
.78
.77
.78
.78
.77
.77
.78
.81
.81
.79
.80
.79
.76
.77
.77
.77
.77
.78
.78
.78
.78
.78
.81
.82
.80
.80
.79
.79
.79
.78
.77
.78
.80
.79
.78
.79
.78
.81
.80
.79
.78
.78
.77
.77
.71
.76
.76
.77
.77
.77
.77
.76
.86
.84
.83
.83
.83
.83
.82
.82
.82
.83
.81
.83
.81
.82
.81
.83
.81
.80
.80
.79
.79
.78
.78
.78
.78
.78
.80
.79
.78
.78
.83
.82
.79
.80
.78
.78
.79
.78
.78
.78
.78
.79
.77
.77
.78
C-1
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Evaluation of Fugitive Emissions at a
Table C-2. Methane Concentrations Found during the Area B HRPM Survey.
Loop
Methane Concentration
(ppm)
Mirror 1 Mirror 2 Mirror 3 Mirror 4 Mirror 5 Mirror 6 Mirror 7 Mirror 8
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
.90
.91
.89
.90
.90
.85
.90
.89
.89
.89
.90
.89
.83
.84
.92
.81
.81
.82
.81
.81
.82
.80
.80
.80
.80
.81
.80
.81
.80
.82
.90
.89
.89
.90
.89
.90
.89
.88
.87
.89
.89
.90
.89
.90
.92
.83
.82
.82
.83
.80
.81
.82
.80
.81
.81
.81
.82
.81
.81
.82
.92
.94
.93
.92
.91
.92
.92
.92
.92
.90
.89
.92
.91
.90
.92
.83
.82
.82
.82
.82
.81
.82
.82
.81
.81
.81
.81
.81
.82
.82
.82
.82
.81
.81
.81
.82
.80
.81
.80
.81
.80
.80
.81
.83
.82
.88
.90
.89
.89
.90
.88
.88
.88
.88
.88
.88
.80
.89
.91
.89
Table C-3. Methane Concentrations Found during the Area C HRPM Survey.
Methane Concentration
Loop (PPm)
Mirror 1 Mirror 2 Mirror 3 Mirror 4 Mirror 5 Mirror 6 Mirror 7 Mirror 8
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
.78
.78
.78
.79
.79
.78
.79
.80
.80
.80
.81
.81
.80
.81
.81
.80
.74
.74
.75
.76
.75
.76
.76
.76
.76
.76
.77
.77
.76
.77
.77
.77
.73
.72
.73
.75
.73
.75
.74
.75
.74
.76
.76
.76
.75
.76
.76
.75
.71
.71
.71
.72
.73
.73
.72
.73
.73
.74
.74
.73
.73
.74
.74
.74
.71
.71
.72
.73
.72
.73
.73
.73
.73
.74
.74
.73
.74
.74
.73
.74
.72
.72
.73
.74
.74
.74
.74
.74
.75
.76
.76
.75
.75
.75
.75
.76
.73
.73
.73
.74
.74
.74
.74
.74
.75
.75
.76
.75
.75
.75
.75
.75
.76
.77
.77
.78
.78
.78
.78
.79
.79
.80
.79
.79
.79
.79
.79
.80
C-2
-------
Brownfield Landfill in Ft. Collins, Colorado
Table C-4. Methane Concentrations Found during the Area D HRPM Survey.
Methane Concentration
Loop (PPm)
Mirror 1 Mirror 2 Mirror 3 Mirror 4 Mirror 5 Mirror 6 Mirror 7 Mirror 8
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
1.78
1.77
1.78
1.79
1.78
1.78
1.78
1.78
1.77
1.78
1.78
1.79
1.78
1.78
1.79
1.80
1.81
1.81
1.85
1.82
1.83
1.82
1.82
1.80
1.80
1.80
1.80
1.80
1.82
1.81
1.73
1.74
1.73
1.73
1.74
1.74
1.73
1.73
1.74
1.73
1.74
1.75
1.74
1.75
1.75
1.75
1.74
1.82
1.77
1.77
1.77
1.77
1.79
1.76
1.75
1.76
1.77
1.78
1.77
1.76
1.71
1.72
1.72
1.71
1.72
1.71
1.72
1.71
1.71
1.71
1.72
1.72
1.71
1.72
1.73
1.73
1.74
1.77
1.73
1.75
1.75
1.75
1.75
1.73
1.74
1.70
1.75
1.76
1.75
1.74
1.75
1.76
1.76
1.75
1.76
1.76
1.75
1.76
1.75
1.76
1.77
1.76
1.77
1.76
1.77
1.78
1.79
1.78
1.78
1.81
1.79
1.80
1.78
1.77
1.78
1.77
1.79
1.80
1.81
1.78
1.72
1.71
1.71
1.72
1.72
1.72
1.72
1.72
1.71
1.72
1.73
1.72
1.73
1.73
1.74
1.74
1.76
1.73
1.75
1.76
1.75
1.76
1.74
1.74
1.73
1.73
1.76
1.77
1.75
1.74
1.73
1.74
1.73
1.73
1.73
1.74
1.73
1.73
1.72
1.73
1.73
1.73
1.73
1.73
1.74
1.75
1.76
1.76
1.77
1.79
1.77
1.78
1.77
1.76
1.76
1.75
1.76
1.77
1.77
1.76
1.70
1.71
1.70
1.70
1.69
1.70
1.70
1.71
1.70
1.70
1.70
1.71
1.71
1.71
1.71
1.72
1.73
1.73
1.74
1.74
1.73
1.74
1.72
1.72
1.72
1.73
1.73
1.75
1.74
1.72
1.69
1.70
1.69
1.70
1.70
1.69
1.70
1.69
1.69
1.70
1.70
1.70
1.71
1.71
1.71
1.73
1.73
1.73
1.74
1.73
1.73
1.74
1.72
1.72
1.72
1.73
1.73
1.74
1.73
1.73
C-3
-------
Evaluation of Fugitive Emissions at a
Table C-5. Methane Concentrations Found during the Downwind VRPM Survey Run 1.
Methane Concentration
Loop (PPm)
Mirror 1 Mirror 2 Mirror 3 Mirror 4 Mirror 5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
1.92
1.91
1.90
1.97
1.97
1.91
1.85
1.89
1.90
1.91
1.90
1.91
1.92
1.91
1.94
1.92
1.92
1.93
1.91
1.95
1.92
1.90
1.93
1.95
1.92
1.93
1.93
1.94
1.99
2.00
1.87
1.86
1.87
1.92
1.88
1.84
1.84
1.83
1.86
1.86
1.85
1.86
1.88
1.86
1.89
1.87
1.86
1.89
1.87
1.88
1.86
1.89
1.91
1.90
1.88
1.87
1.87
1.91
1.92
1.94
1.82
1.81
1.84
1.83
1.81
1.80
1.79
1.81
1.81
1.82
1.81
1.83
1.85
1.84
1.84
1.82
1.85
1.84
1.84
1.85
1.82
1.87
1.86
1.85
1.84
1.84
1.84
1.88
1.87
1.88
1.83
1.83
1.86
1.81
1.81
1.82
1.81
1.86
1.83
1.83
1.83
1.87
1.86
1.85
1.87
1.83
1.90
1.84
1.87
1.88
1.84
1.90
1.88
1.87
1.88
1.87
1.84
1.87
1.89
1.88
1.81
1.84
1.87
1.81
1.80
1.80
1.79
1.85
1.81
1.81
1.82
1.86
1.83
1.84
1.84
1.84
1.88
1.85
1.84
1.82
1.84
1.86
1.88
1.87
1.86
1.85
1.85
1.85
1.85
1.85
C-4
-------
Brownfield Landfill in Ft. Collins, Colorado
Table C-6. Methane Concentrations Found during the Downwind VRPM Survey Run 2.
Methane Concentration
Loop (PPm)
Mirror 1 Mirror 2 Mirror 3 Mirror 4 Mirror 5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
1.70
1.71
1.72
1.70
1.70
1.70
1.70
1.70
1.71
1.71
1.72
1.70
1.70
1.71
1.73
1.73
1.74
1.75
1.77
1.77
1.81
1.80
1.80
1.79
1.78
1.78
1.78
1.84
1.85
1.85
1.84
1.85
1.84
1.83
1.84
1.85
1.85
1.85
1.84
1.84
1.85
1.86
1.88
1.87
1.90
1.90
1.93
1.95
1.95
1.94
1.93
1.92
1.93
1.92
1.83
1.83
1.82
1.82
1.82
1.83
1.82
1.82
1.83
1.84
1.83
1.82
1.82
1.84
1.85
1.85
1.86
1.88
1.88
1.92
1.92
1.92
1.92
1.90
1.90
1.89
1.90
1.85
1.82
1.84
1.83
1.84
1.84
1.83
1.86
1.86
1.86
1.84
1.84
1.84
1.86
1.91
1.86
1.89
1.91
1.90
1.97
1.94
1.94
1.94
1.93
1.92
1.95
1.96
1.84
1.84
1.84
1.83
1.84
1.83
1.83
1.84
1.84
1.85
1.84
1.83
1.84
1.85
1.86
1.87
1.87
1.90
1.91
1.94
1.93
1.92
1.92
1.90
1.91
1.90
1.91
C-5
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/R-05/042
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Evaluation of a Former Landfill Site in Fort Collins, Colorado
Using Ground-Based Optical Remote Sensing Technology
5. REPORT DATE
April 2005
6. PERFORMING ORGANIZATION CODE
7. AUTHORS
Mark Modrak, Ram A. Hashmonay, Ravi Varma, and Robert
Kagann
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
ARCADIS G&M, Inc.
4915 Prospectus Dr., Suite F
Durham, NC 27713
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-C99-201, WA 0-025
12. SPONSORING AGENCY NAME AND ADDRESS
U. S. EPA, Office of Research and Development
Air Pollution Prevention and Control Division
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final; 09/2003-09/2004
14. SPONSORING AGENCY CODE
EPA/600/13
15. SUPPLEMENTARY NOTES
The EPA Project Officer is Susan A. Thorneloe, Mail Drop E305-02, Phone (919) 541-2709, e-mail
thorneloe.susan@epa.gov
16. ABSTRACT
The report describes an assessment of fugitive landfill gas emissions of methane and VOCs at a former
landfill site in Fort Collins, Colorado. Before initiating any additional development of the property under the
city's Brownfields program, the city of Ft. Collins requested assistance from the EPA to search for any
fugitive gas emissions from the former landfill site. This assessment was necessary due to the potential
adverse health effects associated with exposure to landfill gas. An open-path Fourier transform infrared
spectrometer, open-path tunable diode laser absorption spectroscopy, and an ultra-violet differential optical
absorption spectrometer were used to make the assessment survey. The survey did not detect any surface
methane hot spots at the site, and the highest methane concentrations detected at the site were only
slightly above ambient background levels. However, the survey detected a gasoline hot spot (average
concentration over 81 ppb, with a maximum concentration of about 100 ppb) located in the vicinity of a
recreational building at the site; the average calculated gasoline flux was 0.87 g/s. In addition to gasoline,
the survey detected methane and ammonia downwind from the site. The methane and ammonia
concentrations were well-correlated, indicating that they probably came from the same source. Wind data
collected indicated that the source of the methane and ammonia is across a river adjacent to the site.
17.
KEYWORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Earth Fills (Landfill)
Emissions
Organic Compounds
Methane
Ammonia
Gasoline
Pollution Control
Stationary Sources
13B
13C
14G
07C
07B
21D
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
52
Release to Public
20. SECURITY CLASS (This Page)
Unclassified
22. PRICE
C-6
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