**EPA WORKSHOP**

**ON**

**OPTICAL REMOTE SENSING TECHNOLOGIES**

# Executive Summary

A Workshop on Optical Remote Sensing Technologies was held in the
auditorium of the Environmental Protection Agency's (EPA) Environmental
Research Center in Research Triangle Park, NC on July 31, and August 1,
2001. The Workshop was convened by John Bosch of the Emissions
Monitoring and Analysis Division of EPA's Office of Air Quality Planning
and Standards, and sponsored in part by ARCADIS, an environmental
contractor supporting EPA's research on Optical Remote Sensing. Invited
participants were technology providers, regulators, end-users and
benefactors.

On the first day of the Workshop, the technology researchers/vendors
provided brief discussions of the current state of the technology, as
well as describing both commercially available instruments and
instruments in the developmental stage prior to commercial availability.
Generally, the presentations demonstrated that, while some areas
continue to require further development, many ORS technologies have
advanced well beyond their current level of deployment in the
marketplace. In other words, from a technical standpoint, ORS
technologies are capable of much broader application than that seen at
present. Vendor organizations expressed frustration at their inability
to move many technologies beyond the research phase into broader
application in the environmental market. Significant advancements and
improvements shown are in the following areas:

-   Temporal and spatial resolution

-   Range (distance) of measurements

-   Detection levels

-   Number of compounds detectable

-   Plume imaging

-   Cost effectiveness

A panel discussion, consisting of representatives of various
organizations within EPA, convened during the afternoon session to
address the direction of marketability for new technology, and its
importance in the industry. Panel participants were instructed to
emphasize incentives and impediments to the development and
implementation of new technologies. The panel's consensus was that
focusing technology development on areas of immediate concern and areas
where it was possible to implement new technologies to achieve reduced
costs (either for the Agency, or more importantly for the end users)
provides the best opportunity for future success. Important future needs
identified included improved capabilities for continuous monitoring of
Hazardous Air Pollutants (for potential cap and trade approaches), as
well as mercury and fine particulate matter monitoring.

A second panel discussion, consisting of representatives of prospective
end users of ORS technologies, was convened to kick off the second day
of the Workshop. Panel participants included staff from the Department
of Defense, EPA Regions, and various state environmental compliance
agencies. The presenters emphasized the need for technologies to address
specific needs in order to have the best chance of success. Several
presenters indicated that ORS does offer the potential to address
specific needs, but expressed concerns in regards to acceptance of data
by all relevant regulatory agencies.

A panel of representatives of funding organizations was convened next.
The panel included staff from the EPA, NASA, and various DOD groups.
Details of funding mechanisms were provided. A recurring emphasis was
cooperation and cofunding between industry and regulatory agencies.

The Workshop concluded with open discussion on how to build and maintain
momentum for application of ORS technologies. Approaches identified
included the following:

-   Increased cooperation and involvement between technology developers,
    regulators, and end users at the early stages of technology
    development

-   Improved focus on specific issues of immediate concern to the
    regulated community as opposed to attempting to cure all ills

-   Increased technology transfer through actions like additional
    workshops/presentations

The presence of participants in this workshop does not reflect
endorsement for any kind of technology or equipment. The purpose was to
bring together interested parties in the field and allow collaboration
for potentially expanding remote sensing technology. The workshop
represented an economical way to come together to address issues and to
learn more about the most current available technologies.

**SUMMARY OF TECHNICAL PAPERS** (in order of presentation)

## Ram A. Hashmonay, ARCADIS

Dr. Hashmonay was the chair of the technical session and the first
speaker of the day. Several references on how ORS technologies have
developed were presented. Reasons for the current limited applications
of remote sensing technologies were discussed. Premature "as is" use,
misinterpretation of the path integrated concentration data, disapproval
of regulatory agencies, and the use of dispersion modeling assumptions
were mentioned as a partial list of "what went wrong".

An overview of the current state of the art was given with emphasis on
the technology's maturity and improved capabilities. These advances in
detection levels and speed of measurement significantly increase the
feasibility of using multiple beams approaches to better account for
spatial and temporal variability of measured plumes. Simple multiple
beam and innovative tomography approaches developed by Dr. Hashmonay and
others caught the interest of the EPA as viable for directly analyzing
fugitive emissions of open area sources using ORS. The ability of ORS to
provide actual numbers on emissions to regulators, without applying
indirect inverse modeling approaches, is a step towards overcoming some
of the difficulties with ORS detailed previously.

## Robert H. Kagann, EDO-AIL

Dr. Kagann discussed the use and history of Open Path Fourier Transform
Infra Red Spectroscopy (OP-FTIR) for emissions characterization. A basic
set-up for making OP-FTIR measurements was presented. The very high
efficiency of OP-FTIR was emphasized and the advantages were enumerated
as follows:

-   Fast measurements -- a 1 minute measurement interval provides a good
    instrument sensitivity along a 100 meter measurement path-length

-   Remote sensing - can take measurements in inaccessible areas

-   Area coverage -- typical data is path-integrated concentration.
    Tomographic techniques, as earlier presented by Dr. Hashmonay, can
    provide direct measurement of fugitive emission fluxes

-   Near real time - a calibration check in the field using TO16 EPA
    method is needed

This technology was first applied in the laboratory in the late 70's.
Since its inception, the Clean Air Act Amendment has promoted more
serious requirements. Availability of commercial instruments arose. The
compendium TO16 Method was developed, and the Europeans followed suit in
developing and promoting optical remote sensing technologies.

## Harold Schiff, Unisearch Associates

Dr. Schiff represented Unisearch Associates, which manufactures all
types of spectroscopic instrumentation. His presentation focused mainly
on Tunable Diode Laser Systems (TDLS).

Laser wavelength depends on the crystal composition and the width of
laser line is very narrow, essentially eliminating any interferences.
The advantages of using an open path diode laser include:

-   Telecommunications spectral range -- the instrument can easily be
    connected with fiber optic cable and be located anywhere

-   Can carry out measurements from different locations simultaneously

-   System has automatic calibration

Optical sensing using TDLS gives the option of multiplexing combined
with high sensitivity. This allows a fast measurement of many beams in
few seconds and can apply the tomographic approaches previously
discussed. Generally, one laser is utilized for each gas to be measured.
However, several lasers can be combined in one unit if required. TDLS is
the best way to measure one or a limited number of gases, with higher
sensitivity results, quick response time and lack of interference.
Several examples of open path TDLS applications along with an example of
a hybrid TDLS/DOAS system for fast multiple compound measurements, were
presented.

## N. Scott Higdon, ITT Industries

Mr. Higdon presented a number of ITT's custom systems that are under
various stages of development, including the following:

-   LIDAR for detecting particulates or dust (fully developed); this
    eye-safe aerosol system developed for Hampton University is a
    powerful mapping tool

-   Differential Absorption LIDAR (DIAL) for detection of gases and
    chemical agents over unprecedented long ranges via receiving signals
    from distant hard targets. Applying radial tomography will achieve
    large-scale plume mapping

-   Raman Scattering to detect surface molecular contamination and
    biological agents, most applications being in support of the
    military

-   Hg measurement using the DIAL techniques, including plume mapping

## John Otten, Kestrel Corporation

Kestrel Corporation focuses on spectral imaging technology, according to
Dr. Otten. The airborne applications are mostly in support of the
military (surreptitious surveillance and rocket launching). Leak
detection of rocket plumes during testing is very crucial to
identify/pinpoint any problem prior to rocket launching, thus averting
any catastrophic accidents. These FTIR-based imaging systems may be
modified into a simultaneous multiple beam OP-FTIR system that can apply
tomographic approaches.

[Wynn L. Eberhard, Environmental Technology Laboratory, National Oceanic
and Atmospheric Administration]{.underline}

Currently, ETL has 6 aerosol, 3 Doppler, and 2 Ozone Lidar measurement
systems in place. Furthermore, ETL is involved in research areas
attempting to advance Lidar technology for use in new scientific
applications. Issues in air quality in the U.S. and Europe are prompting
the research and development of optical methods to better measure
ammonia. ETL has developed and demonstrated NH~3~ plume measurement
capability with DIAL.

[Ting I Wang, Optical Scientific Inc]{.underline}.

Dr. Wang described two path-integrated flow meters. These optical
anemometers, which utilize a pair of parallel laser beams and receivers,
measure the scintillation from one receiver to the next. Determining the
temporal correlation between the two signals is related to the wind
speed. In the long path instrument, the air velocity along a 200-900 m
long path, such as in an aluminum smelter pot room roof vent, can be
measured. Optical flow sensing was approved as an equivalent Method 14
technology for compliance with the USEPA MACT rules. The EPA has applied
the optical anemometer technology for other environmental airflow.

The Optical Flow Sensor (OFS) measures airflow in a stack or exhaust
duct. The OFS is installed at one level and measures through glass
windows across the stack or duct. The data are verified by testing at
the NIST Wind Tunnel. The OFS affords advantages, which the other
methods do not offer, including:

-   Non-intrusive, not directly exposed to the stack flow

-   Path averaged measurement for more representative results

-   Simple, non-angled installation which lowers cost vs. ultrasonic

-   Result independent of temperature and pressure

-   Direct cross-stack velocity measurement

-   No moving parts, solid-state construction

## Cary Secrest, EPA Office of Enforcement and Compliance Assurance

UV/DOAS is the simplest application of remote sensing, yet it can yield
powerful results. From a regulatory standpoint open path can help with
enforcement and lower costs. Measurement comparisons between UV/DOAS and
FTIR were in agreement and demonstrate the utility of using multiple
beams to promote better understanding of measured data.

## Tom Reichardt, Sandia Labs

Sandia Labs is currently developing a laser-based imaging system for
detection of fugitive emissions from refineries. They have also worked
on topographical LIDAR. Active Laser-IR is better than conventional leak
detection methods (hand-held sniffer). It allows rapid broad range area
coverage for easy recognition and source location of plumes. It
accelerates the leak detective process, which may decreases costs for
environmental compliance.

There are currently several technologies in development. Gas can be seen
regardless of temperature because active imaging is not temperature
dependent unlike the passive imaging. The disadvantage of the active
imaging is it needs a reflective source. Smaller portable systems are
necessary. Compliance monitoring will drive future further
marketability. The petroleum industry may be first in line to decrease
their compliance costs.

## Bob Hinnricks, Pacific Advantage Technologies

Their group is working on a gas detection spectrometer primarily
applicable to underground leak testing. Infrared imaging can easily
detect underground methane leaking to the atmosphere. The flow is not
accurate at this time, but good results demonstrated that even low level
leaks could be detected. The technique can also be applicable to the
propane industry. Propane, other gases and hydrocarbon soots were
identified as well. Another application of this technique is for tank
leak detection. The instrument may be available by mid-2002.

[David Green, Physical Sciences, Inc.]{.underline}

Their company has worked with the EPA/SBIR Program on a tunable diode
laser. The goal is to develop a portable device that is affordable and
practical. This is very useful in methane detection or any gas leak
detection survey. Its sensitivity is in the ppm range. It only weighs 9
pounds and is rugged. To date, 70 devices have been delivered. Passive
imaging instrument has been developed as well. The cost is about
\$10,000 per unit and will be available in 18 months.

## Michael Calidonna, US Air Force

Lt. Calidonna discussed a project for opacity test method development.
The current method for opacity test is based on EPA Method 9, which is
an eyeball calibration. The EPA method is tiring, time consuming,
non-reproducible and subjective. The new test method offers a better way
of measuring opacity in a smoke stack. It is a digital camera-based
method, involving a simple point and click operation after a 10-minute
set-up. It has built-in algorithms that are tamper-proof. The results
are permanent and reproducible. Litigation costs and fines, etc. can be
avoided with this technology. In two to three years time, this new
technology will need method validation, which will be followed by a six
months certification process. The cost is approximately \$5,000 per
unit.

EXPERT PANEL FOR NATIONAL REGULATORY PROGRAMS AND POTENTIAL APPLICATIONS

David Mobley, Director of the Emissions, Monitoring and Analysis
Division of EPA's Office of Air Quality Planning and Standards (OAQPS)

Introduced the panel and provided an overview of the subsequent
discussion. The subjects were incentives and impediments encountered in
balancing the need and the desire to develop and use new technologies.

## Barrett Parker, Emissions Measurement Center, OAQPS

Mentioned incentives for increased measuring, such as Title V and CAM
rules and maximum standards. MACT standards expansion will also drive
monitoring needs. Residual risk determinations will also require ambient
air toxics measurement. Many sources are apprehensive when it comes to
using an advanced monitoring system for fear that the results may be
used against them. There is a need for user-friendly instruments that
have on-going calibration capability.

Karen Riggs, Batelle (representing EPA's ETV Program)

Focused on the EPA's Environmental Technology Verification (ETV)
program. There are about 100 stakeholders of which there are no vendors.
The stakeholders advise ETV on how to run the program, what monitoring
technology is needed, and which of the technologies are important to be
verified. ETV's focus is primarily on field technology. Of importance
are mercury contaminants emissions monitoring, multi-metal monitoring
and open path systems. ETV is involved in the technology verification
but not in technology approval.

## Tom Pace, Emission Factor and Inventory Groups, OAQPS

Emission inventories are the fundamental building blocks for doing air
quality management. It is impossible to measure everywhere, so some
sources are measured and emission factors developed. Open path
technologies will be helpful in monitoring emissions from open sources,
fugitive dusts, ammonia, all kinds of fires and mobile sources for
pollutants. The incentive is to get better information, which with more
accurate planning will help avoid repetition that costs time and money.

## Cary Secrest, EPA/OECA 

EPA faces an impediment to using ORS technology in that there are only
minimal funding resources set aside and even less time is available.
Legal issues may impede industry from utilizing ORS technologies.

Dan Powell, Technology Innovation Office, EPA's Office of Solid Waste
and Emergency Response (EPA/OSW)

While admittedly focusing on cleanup of water and soil, Mr Powell
indicated that there should be incentives for employing new technologies
and dealings with some of the impediments in trying to develop more
defensible data/information. Performance-based measurements could be
included in site assessment and site activity.

## Barry Lesnik, Economics, Methods and Risk Analysis Division, EPA/OSW

He stressed that EPA SW846 methodologies were not reference methods and
could be modified to fit specific applications

## J. D. Bachmann, Senior Science Advisor, EPA/OAQPS

He introduced the idea that ORS technologies could play a role in
enabling the development of a "cap and trade" approach for air toxics
similar to the one that has been successfully employed in the Acid Rain
Program. Continuous monitoring methods are the cornerstone for such a
program and ORS offers a unique approach. He was very interested in the
concept of facility-wide measurements.

**END-USER PERSPECTIVES**

## Rochelle Williams, U. S. Army Forces Command, Atlanta, GA

There is a need for a defensible data for DOD to demonstrate compliance
during training activities. It must be done right and scientifically.
The U. S. Army does a lot of testing for emission characterization from
munitions and artillery and there are limited in what they can
adequately measure. At this time, they are unable to characterize a
3-dimensional plume effectively. This 3-D mapping could help in
dispersion models for risk assessment based on these air emissions.

Additional needs for characterization include fog oils and other
obscurants which have been perceived as potentially hazardous by some
state environmental organizations. She added that whatever technologies
are developed, it is important that they be "idiot proof" to allow them
to be used by enlisted personnel with a minimum of training.

## Dennis Goodenow, California Air Resources Board

CARB routinely does two types of air monitoring as follows:

-   ambient air quality monitoring (ongoing projects)

-   special purpose air quality

He felt that ORS could be an important tool for the latter. CARB is
concerned about monitoring impacts to high-risk populations (e.g.,
schools, hospitals, etc.). Some current areas of concern that may offer
applications for ORS include:

-   children's emissions initiative -- monitoring emissions in homes and
    playground, etc. to check what chemicals are the children exposed
    to.

-   Pesticide monitoring

-   Toxics' control identification -- there are 188 HAPS that need to be
    identified

-   Controlled burns in military bases

-   Emergency response (toxic spills, tire fires)

## Van Shrieves, EPA Regional Office IV, Atlanta, GA

Region IV currently has two DOAS instruments in use for monitoring and
they have conducted some special studies. He would like to see
additional information exchange to better spread the word about ORS
capabilities.

## Rick Taylor, Missouri State Environmental Protection Agency

He has successfully applied ORS methods and believes they word well when
applied correctly. In 1995, Missouri was able to identify only 6
analytes with the OP-FTIR. This number has greatly increased to 76
identified compounds with the current technology. ORS methods have been
or will be applied at sites such as swine farms, landfills, and
wastewater treatment plants. Multiple optical measurements (tomography)
are non-biased and offer temporal resolution, providing a huge advantage
over conventional, "grab" sampling methods such as SUMMA canisters.
Furthermore, computerized samples are non-degradable and therefore have
better sample integrity.

# 

# ACTIONS NEEDED TO CREATE AND SUSTAIN MOMENTUM

## Bill Vaughn, Chairman of the AWMA Division on Remote Sensing

AWMA's mission is to assist in professional development and critical
environmental decision making to benefit society. AWMA's purpose is to
enhance knowledge and provide quality information on which to base
environmental decisions. The technologies can provide real time data on
multiple pollutants to inform regulators and the public.

## Jim Gallup -- EPA manager of Small Business Innovative Research (SBIR) programs

SBIR funding is available to companies with less than 500 employees.
There is a 1 in 10

approval. There are two phases in the funding program as follows:

-   Phase I - \$70,000 grant money for six months to prove the
    feasibility of the technology

-   B\) Phase II -- can be as much as \$750,000. Open to competition
    among companies

The program does a lot of SBIR National Meetings across the country
where companies will listen to what is being offered at all agencies.
Most of the proposals seen in the measurement or monitoring areas are
from companies that have worked with Department of Defense and National
Aeronautic Space Administration.

Bob Holst, DOD Manager for SERDP/ESCTP involving environmental
compliance projects

This is a 3-Agency partnership (DOD-DOE-EPA). DOD solicitations include
basic and applied research/advanced development (SERDP) and
demonstration/validation (ESCTP).

Four thrust areas in SERDP include:

-   clean-up -- cleaning up of unexploded materials

-   conservation -- to locate endangered species, maintenance and
    restoration

-   compliance area -- ensuring that DOD activities meet environmental
    standards

-   HAPS substitution

Fine PM and dust are considered to be major issues looming on the
compliance horizon.

## Bill Grant, Lidar Applications Group, NASA Langley Research

NASA has interest in the global troposphere and stratosphere. They are
mainly interested in the chemistry and dynamics of the radiation budget
of the atmosphere. Global airborne measurements characterize background
atmosphere at different parts of the world. Asian emissions are being
checked out due to increasing concerns. Sea transport is fairly
efficient in this part of the world. NASA has no need for further remote
sensing, but this is an opportunity for coordination with other EPA
groups, NOAA type programs in the US.

NASA is interested in technology/instrument capable of hydrazine
detection at the ppb level. At this time, it is very difficult to detect
hydrazine leaks from containers at the Cape. Detection of hydrogen leaks
from shuttle engines is also of interest to NASA.

Larry Jones -- Chief, EPA/ORD/NRMRL/APPCD Emissions Characterization and
Prevention Branch

He gave an overview of what his branch does and the technology used.
They have used OP-FTIR in radial tomography configuration as earlier
presented by Dr. Hashmonay, to measure emission fluxes from animal waste
operations (swine regulations and looking into poultry as well).

## Susan Thornloe -- Scientist, EPA/ORD/NRMRL/APPCD Atmospheric Protection Branch

ORD is looking for better methods for emissions measurements. Joint
ventures with industry are highly recommended due to funding restraints.
One ongoing project involves a new type of landfill technology.
Bioreactors enhance decomposition processes within landfills and produce
landfill gas at faster rates, making energy recovery from landfills more
cost effective. Increased fugitive emissions are of concern.
Applications of the new tomographic approaches are under consideration
to address the issue. Other pollutants like mercury should be better
understood to determine whether they are an issue for human or ecosystem
health. The status of current knowledge is outdated. Partnership with
industry is the best way to move forward

## Michael Calidonna -- Project Manager, USAF Research Laboratory, Tyndall AFB, FL

The USAF has worked on numerous occasions with other governmental
organizations. NASA has provided some seed money, and USAF has
coordinated partnerships with DOD and EPA. One difficulty discussed was
the issues related to getting buy in for technologies from federal and
state regulators. This can cost the vendor a lot of invested time. One
successful approach involves getting together with regulators in advance
to discuss potential issues. Funding for development is available
through numerous different channels. Lt. Calidonna expressed his concern
that EPA's perceived convoluted chain of command often slows approval
processes. It is important for vendors to understand the DOD needs, and
to routinely follow up with contacts in order to address the issues. One
particular need he expressed involved sensing biochemical and biological
hazards to prevent military casualties.