United States
Environmental Protection
Agency
Environmental Monitoring
and Support Laboratory
P.O. Box 15027
Las Vegas NV 89114
EPA-600/4-79-071
November 1979
Research and Development
5EPA
A Battery-Operated
Air Sampler for
Remote Areas
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad categories
were established to facilitate further development and application of environmental
technology. Elimination of traditional grouping was consciously planned to foster
technology transfer and a maximum interface in related fields. The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL MONITORING series.This series
describes research conducted todevelop newor improved met hods and instrumentation
for the identification and quantification of environmental pollutants at the lowest
conceivably significant concentrations. It also includes studies to deter mine the ambient
concentrations of pollutants in the environment and/or the variance of pollutants as a
function of time or meteorological factors.
This document is available to the public through the National Technical Information
Service, Springfield, Virginia 22161
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EPA-600/4-79-071
November 1979
A BATTERY-OPERATED AIR SAMPLER FOR REMOTE AREAS
by
K. W. Brown, G. B. Wiersma, and C. W. Frank
Monitoring Systems Research and Development Division
Environmental Monitoring and Support Laboratory
Las Vegas, Nevada 89114
ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
LAS VEGAS, NEVADA 89114
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DISCLAIMER
This report has been reviewed by the Environmental Monitoring and Support
Laboratory-Las Vegas, U.S. Environmental Protection Agency, and approved for
publication. Mention of trade names or commercial products does not consti-
tute endorsement or recommendation for use.
11
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FOREWORD
Protection of the environment requires effective regulatory actions
that are based on sound technical and scientific information. This infor-
mation must include the quantitative description and linking of pollutant
sources, transport mechanisms, interactions, and resulting effects on man
and his environment. Because of the complexities involved, assessment of
specific pollutants in the environment requires a total systems approach
that transcends the media of air, water, and land. The Environmental
Monitoring and Support Laboratory-Las Vegas contributes to the formation
and enhancement of a sound monitoring data base for exposure assessment
through programs designed to:
•develop and optimize systems and strategies for moni-
toring pollutants and their impact on the environment
• demonstrate new monitoring systems and technologies by
applying them to fulfill special monitoring needs of
the Agency's operating programs
This report presents an approach in solving some of the problems asso-
ciated with the development of a remote air monitoring system. To date,
many proposals have focused only on the selection of remote monitoring sites
pollutants to monitor, etc.; the real-world problems of how to monitor and
what equipment will best serve the objectives have not been considered.
The utilization and application of the equipment as described in this report
will be of value to those concerned with monitoring air in remote areas.
For further information on this equipment, contact the Pollutant Pathways
Branch of the Monitoring Systems Research and Development Division.
~^r^u-^yA-^~^
V
George B. Morgan
Director
Environmental Monitoring and Support Laboratory
Las Vegas
111
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SUMMARY
An air sampling system developed to evaluate air quality in biosphere
reserves or in other remote areas is described. The equipment consists of
a Dupont P-4000A pump and a specially designed battery pack containing Gates
batteries.
This air sampling system was tested in southern Utah and at 10 remote
sampling sites in the Great Smoky Mountains National Park. The equipment
was backpacked to the remote sampling sites, and was operated continuously
at full capacity for a maximum 8-day period. Except for tampering by curi-
ous hikers at one site, the equipment operated satisfactorily.
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CONTENTS
Foreword
Summary iv
Figures vi
Acknowledgment vii
1. Introduction 1
2. Conclusions 1
3. Recommendations for Future Research 2
4. Materials and Methods 2
5. Results and Discussion 3
References 6
v
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FIGURES
^Number Eage
1 Change of discharge voltage as a function of time for one
40 Ah power supply unit „ 4
2 Barbed wire enclosure constructed to prevent people and
animals from tampering with air sampling equipment 5
VI
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ACKNOWLEDGMENT
We appreciate the assistance of Mr. Gloyd Green of the U.S. Environ-
mental Protection Agency, Environmental Monitoring Support Laboratory-Las
Vegas, in selecting and constructing the power supply.
VII
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INTRODUCTION
Most air sampling equipment requires conventional electrical sources.
The majority of the techniques employed and the equipment presently in
operation are only satisfactory in suburban, rural, and/or industrialized
areas where a suitable power supply is available.
Sampling air in primitive and wilderness areas that are accessible
only by foot and pack animals has necessitated the need to design equipment
that is suitable for use in these remote locations. Transportation of equip-
ment by air in many remote regions is prevented by regulations prohibiting
low-altitude flying. Low-flying aircraft such as helicopters would also
tend to pollute the very areas being sampled.
Remoteness also compounds problems encountered with equipment calibra-
tion and repair. Problems of this nature, especially for remote long-term
air sampling studies, can seriously affect the outcome of the monitoring
program.
A cooperative pollutant monitoring study between the U.S. Environmental
Protection Agency's (EPA) Environmental Monitoring and Support Laboratory-
Las Vegas (EMSL-LV) and the U.S. Park Service in the Great Smoky Mountains
National Park required sampling air in remote regions of this biosphere
reserve (UNESCO, 1971). Data collected from previous studies in this area
(Wiersma et al., 1978) showed that particular emphasis should be given to
the sampling and characterization of airborne particulates. The sampling
scheme described in this article details the equipment used to complete this
task.
CONCLUSIONS
1. The construction of a low-cost and accurate air pollutant monitor-
ing system is a critical need in the overall development of a remote air
monitoring system.
2. The use of this air monitoring system in remote areas has shown it
to be an extremely efficient and dependable air sampling device.
3. Air sampling studies conducted in remote areas and/or on biosphere
reserve sites will enhance the development of a uniform, efficient, and
cost-effective pollutant monitoring program.
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RECOMMENDATIONS FOR FUTURE RESEARCH
1. The development of monitoring equipment and methodology for
assessing pollutant levels in remote areas should be pursued.
2. A remote monitoring program should be initialed with intermediate
results being disseminated as soon as possible.
3. Developed equipment should be used and tested under a variety of
remote environmental conditions.
MATERIALS AND METHODS
Prime considerations of design were weight, durability, no required
maintenance, and a need to operate at full-capacity for a minimum of 8 days.
The pump selected for this air sampling system was the Dupont constant Flow
Air Sampler P-4000A. It is a 4-cylinder diaphragm-type pump weighing 840
grams (g). The pump is capable of flow rates from 500 to 4,000 cubic centi-
meters per minute (cm3/min) and is guaranteed to run within -5% of the se-
lected flow rate. This is accomplished by electronic control circuits which
automatically adjust the motor speed to pump at a constant flow rate regard-
less of changes in pressure and temperature during the sampling period
(Dupont, 1978).
The pump comes equipped with two internal rechargeable nickel-cadmium
(Ni-Cd) batteries. These batteries were removed prior to the pump's use
because they do not provide sufficient power for operating the pump over
extended periods of time as required for remote air sampling. Also the
remoteness of the sampling sites prevented the possibility of recharging the
Ni-Cd batteries on a daily basis as intended by the manufacturer.
The pump draws a minimum of 125 milliamperes (mA) during free-flow con-
ditions, and a maximum of 400 mA during restricted flow. Because of the
current required and the length of operating time, a power supply that pro-
vided an average of 200 mA current over a 2-week period was needed. At this
level a power supply of 67.2 ampere-hours (Ah) was necessary. As the envi-
ronmental conditions under which the equipment would be required to operate
might be adverse, it was decided to add a power reserve of 12.8 Ah.
The power supply consisted of Gates rechargeable sealed acid batteries.
Packs of six individual cells are rated at 6 volts and 10 Ah. Their
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relatively small size (13.7 cm x 9.1 cm x 8.0 cm) and weight (2445 g per pack)
were important in their selection.
To provide the required 80 Ah rating, eight battery packs were needed.
However, due to the total bulk and weight of eight packs, only four were
connected together. Four packs were placed in individual carrying cases for
transportinq. Each case weighed 2010 g and was constructed from 1.2-cm thick
/B\
Plexiglas measuring 30.0 cm x 20.8 cm x 11.3 cm. The four-pack power sup-
ply units were constructed to enable parallel connection. Two power units
were used per site to satisfy the necessary 80 Ah requirement. Additional
power supply units could be paralleled to provide longer equipment operation
if required.
Figure 1 shows the discharge voltage as a function of time under labora-
tory operating conditions for one power supply unit of 40 Ah. The discharge
was fairly constant for 6 days. However, on the seventh day a sharp decrease
was noted. During the seventh and ninth days, even though the voltage was de-
creasing, the pump maintained a 4000 cm3/min flow rate. In most battery-
powered systems, the capacity per cycle increases as the temperature in-
creases; therefore, precautions in calculating the operating time should be
taken in adverse temperature conditions.
The air flow through the filters was controlled by Visi-Float® flow-
meters. Latex laboratory tubing, with an inside diameter of 5.0 millimeters
and a wall thickness of 2.0 millimeters, was used for all inlet and discharge
piping from the pump and filter holders to the flowmeters. The pump was
placed 2 m from the filter holder which was a 37-millimeter-diameter Milli-
pore ® aerosol monitor. The aerosol monitor included an aerosol filter mem-
brane with a pore size of 0.45 micrometer (pm). The monitors were conve-
nient to use under field conditions because of their ease in changing and
because contamination of the membrane was easily avoided.
RESULTS AND DISCUSSION
Installation of the sampling equipment in the field took approximately
20 minutes per site. The power supply units, pump, and flowmeters were
placed on the ground. The pump and flowmeters were put in a plastic bag to
protect them from the frequent rain storms. At eight sites, the aerosol mon-
itors were placed approximately 1.7 m above the ground, attached by wire ties
to the trunks of suitable trees. At the remaining two sites they were at-
tached to the top of a barbed wire enclosure. The enclosure as shown on
Figure 2 was constructed from one-half-inch conduit pipe measuring 2.0 x 2.0
meters square at the base. It resembled a pyramid in design having a peak
height of 2.6 m. Barbed wire was strung around the base to a height of 1.2 m
to prevent bears from damaging the sampling equipment.
Four aerosol monitors were used per pump due to the analytical require-
ments. One filter was analyzed by scanning electron microscopy, another by
atomic absorption, and a third by x-ray fluorescence spectrometry. The fourth
filter was kept as a replacement in case of damage or loss to one of the
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10
Time (days)
Figure 1. Change of discharge voltage as a function of time for one 40 Ah power supply unit.
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Figure 2. Barbed wire enclosure constructed to prevent
people and animals from tampering with air
sampling equipment.
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other three, or in case a more extensive analytical examination was re-
quired.
The operational time at each sampling site varied from 4 to 8 days. The
flow rate through each filter at all of the sites was 1,000 cm3/min. None of
the air monitoring sites were visited after the initial installation until
they were dismantled.
At the end of the sampling period, the flow rates were noted and record-
ed. At 8 of the 10 sites the monitoring equipment was operating normally.
At one site the flow rate through each filter had dropped to 800 cm3/min.
As far as could be determined, this pump and the other associated equipment
were operating properly. The reason for the drop in flow rate is not known.
At the remaining site, the equipment was not operating. It was obvious that
the gear had been tampered with, probably by local hikers. Also, at one of
the enclosed sites, a bear cub had gotten through the barbed wire and over-
turned the batteries and pump. However, the equipment at this site, even
though subjected to this abuse, continued to operate properly.
The use of this air sampling equipment has also been tested and operated
at five sites in southern Utah. The length of operation at each site was for
a 40-hour period. During these operations, no malfunctions or drop in flow
rates occurred at any of the sampling sites.
This air sampling system has proved to be an effective and efficient
field instrument for sampling air in remote areas especially where back or
horse packing are the only means of access. It also provides dependable air
monitoring capabilities in areas without conventional power sources.
REFERENCES
1. Dupont, 1978. Dupont Constant Flow Sampler. E. I. du Pont de Nemours and
Company, Inc. Applied Technology Division, Wilmington, Delaware, E-16146.
p. 21.
2. UNESCO. 1971. International Coordinating Council of the Programme on
Man and Biosphere. UNESCO MAB Final Report, First Session Paris, p. 65.
3. Wiersma, G. B., K. W. Brown, and R. Herrmann. 1978. Great Smoky Moun-
tains Preliminary Study for Biosphere Reserve Pollutant Monitoring.
Environmental Monitoring and Support Laboratory, Office of Research and
Development, U.S. Environmental Protection Agency, Las Vegas, Nevada
(in press).
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/4-79-071
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
A BATTERY-OPERATED AIR SAMPLER
FOR REMOTE AREAS
5. REPORT DATE
November 1979
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
K. W. Brown, G. B. Wiersma and C. W. Frank
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Monitoring and Support Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Las Vegas, Nevada 89114
10. PROGRAM ELEMENT NO.
1HD620
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency-Las Vegas, NV
Office of Research and Development
Environmental Monitoring and Support Laboratory
Las Vegas, Nevada 89114
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/600/07
15. SUPPLEMENTARY NOTES
16. ABSTRACT
An air sampling system developed to evaluate air quality in biosphere reserves
or in other remote areas is described. The equipment consists of a Dupont P-4000
pump and a specially designed battery pack containing Gates batteries.
This air sampling system was tested in Southern Utah and at 10 remote sampling
sites in the Great Smoky Mountains National Park. The equipment was backpacked
to the remote sampling sites, and was operated continuously at full capacity
for a maximum 8-day period. Except for tampering by curious hikers at one site,
the equipment operated satisfactorily.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Site survey
Pollution
Air monitoring
Sampling equipment
Biosphere reserves
Great Smoky Mountains
14D
68Q
18. DISTRIBUTION STATEMEN1
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
16
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
ŁU.S. GOVERNMENT PRINTING OFFICE 1979-683-091/2206
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