EPA-600/1-76-034
October 1976
NITROGEN DIOXIDE TRENDS IN SELECTED
CHATTANOOGA COMMUNITIES
By
C.E. Decker and T.M. Royal
Research Triangle Institute
Research Triangle Park, N.C. 27711
Contract No. 68-02-1737
Project Officer
William F. Barnard
Exposure Assessment Branch
Population Studies Division
Health Effects Research Laboratory
Research Triangle Park, N.C. 27711
ft,
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
HEALTH EFFECTS RESEARCH LABORATORY
RESEARCH TRIANGLE PARK, N.C. 27711
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DISCLAIMER
This report has been reviewed by the Health Effects Research
Laboratory, U.S. Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily
reflect the views and policies of the U.S. Environmental Protection
Agency, nor does mention of trade names or commercial products
constitute endorsement or recommendation for use.
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FOREWORD
The many benefits of our modern, developing, industrial society are
accompanied by certain hazards. Careful assessment of the relative risk
of existing and new man-made environmental hazards is necessary for the
establishment of sound regulatory policy. These regulations serve to
enhance the quality of our environment in order to promote the public
health and welfare and the productive capacity of our Nation's population.
The Health Effects Research Laboratory, Research Triangle Park
conducts a coordinated environmental health research program in toxicology,
epidemiology, and clinical studies using human volunteer subjects. These
studies address problems in air pollution, non-ionizing radiation,
environmental carcinogenesis and the toxicology of pesticides as well as
other chemical pollutants. The Laboratory develops and revises air quality
criteria documents on pollutants for which national ambient air quality
standards exist or are proposed, provides the data for registration of new
pesticides or proposed suspension of those already in use, conducts research
on hazardous and toxic materials, and is preparing the health basis for
non-ionizing radiation standards. Direct support to the regulatory function
of the Agency is provided in the form of expert testimony and preparation of
affidavits as well as expert advice to the Administrator to assure the
adequacy of health care and surveillance of persons having suffered imminent
and substantial endangerment of their health.
In an effort to document the health effects attributable to atmospheric
nitrogen dioxide, the Health Effects Research Laboratory of the Environmental
Protection Agency established an aerometry network in Chattanooga, Tennessee.
This area was chosen because a point source for nitrogen oxides, a trinitro-
toluene, TNT, plant is located just beyond the northeastern fringes of the
city. As a by-product if the TNT production process, substantial atmospheric
concentrations of oxides of nitrogen are emitted and are generally channeled
between the ridges of the Appalachian foothills running north and south.
Because of local meteorological conditions and topography, and the frequency
of thermal inversions, the situation is often aggravated and the pollutants
become trapped in the valley.
This report describes the air monitoring program in Chattanooga from
June 1974 until June 1976. It discusses not only the sampling techniques but
presents data showing the reduction in the levels of N02-
Johfl H. Knelson, M.D.
Director,
Health Effects Research Laboratory
iii
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ABSTRACT
The objectives of this project were to operate air monitoring sta-
tions and collect air quality data in the Chattanooga, Tennessee area to
support epidemiological studies during the period June 15, 1974 to June 14,
1976. This ongoing project was begun in 1969 under the sponsorship of the
U.S. Environmental Protection Agency and was designed to gather air quality
data for use in studies relating health effects to ambient concentrations
of oxides of nitrogen. Initially, the aerometric program consisted of
particulate (high volume method) and nitrogen dioxide (CHESS bubbler meth-
od) measurements at ten stations located in and about the Chattanooga area.
In 1972 Research Triangle Institute upgraded the aerometric monitoring pro-
gram in Chattanooga through a joint project sponsored by the Environmental
Protection Agency and the Coordinating Research Council. Chemiluminescent
NO-NO -N00 analyzers and data acquisition systems were installed in environ-
X iiL
mentally-controlled shelters at seven of the nine monitoring sites operating
at that time. Research Triangle Institute has operated and maintained the
nine-station monitoring network and provided aerometric data to the Environ-
mental Protection Agency under Contract 68-02-1737 through May 1976.
iv
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TABLE OF CONTENTS
Page
ABSTRACT iv
LIST OF FIGURES vi
LIST OF TABLES vii
ACKNOWLEDGMENT viii
Section
1.0 INTRODUCTION 1
1.1 Background/Ob jective/Summary 1
1.2 Aerometric Measurement Program 2
2.0 SITE LOCATIONS 5
3.0 DESCRIPTION OF INSTRUMENTATION/FACILITIES 9
3.1 Shelters/Ambient Air Sampling System 9
3.2 Chemiluminescent NO-NO -N00 Analyzers 9
x 2 J
3.3 Calibration Technique/Apparatus 12
3.4 Data Acquisition Systems 14
4.0 OPERATIONAL PROTOCOL 17
5.0 PROCESSING OF FIELD DATA 19
6.0 DATA VALIDATION AND QUALITY CONTROL 23
7.0 SUMMARY OF NITROGEN DIOXIDE DATA (September 1972 to
June 1976) 25
7.1 Data Recovery 36
7.2 Observations and Conclusions 38
8.0 REFERENCES 41
Appendixes
A. OPERATING PROCEDURES FOR CHEMILUMINESCENT ANALYZERS AND
DATA ACQUISITION SYSTEMS 43
B. DETAILED CALIBRATION PROCEDURES (BENDIX NO-NO -N09
ANALYZER) x. 51
C. DETAILED MAINTENANCE PROCEDURES (BENDIX NO-NO -NO,
ANALYZER) X. / 55
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LIST OF FIGURES
Figure Page
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Site locations
Shelter exterior
Shelter interior
Schematic diagram of Bendix NO-NO -N09 analyzer and data
acquisition scheme
Gas phase titration system for calibrating NO-NO -NO
analyzers
Photograph of Metrodata DL-630-3 data logger and remote
control unit
Functional diagram of Metrodata DL-630-3 and remote
control unit
Data processing flow chart
Hourly and 24-hour average data printout
Graphical presentation of quarterly mean NO- concentrations
for site 0621
Graphical presentation of quarterly mean NO- concentrations
for site 0622
Graphical presentation of quarterly mean N0« concentrations
for site 0631
Graphical presentation of quarterly mean NO- concentrations
for site 0632
Graphical presentation of quarterly mean NO- concentrations
for site 0633
Graphical presentation of quarterly mean NO- concentrations
for site 0634
7
10
11
12
13
15
16
20
21
29
30
31
32
33
34
16 Graphical presentation of quarterly mean N0~ concentrations
for site 0641 35
vi
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LIST OF TABLES
Table Page
1 Sampling site locations and coordinates 6
2 Annual NO arithmetic means 26
3 Ratio of annual NO arithmetic means 27
3
4 Quarterly mean N09 concentrations (yg/m ) 28
3
5 Ratio of quarterly mean NO. concentrations (ug/m ) .... 36
6 Percent of valid NO data by year 37
vii
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ACKNOWLEDGMENTS
The work on this project was performed by personnel in the Environ-
mental Measurements Department, Systems and Measurements Division, Re-
search Triangle Institute for the U.S. Environmental Protection Agency
under Contract 68-02-1737 during the period June 15, 1974 to June 14,
1976. Mr. C. E. Decker, Manager, Environmental Measurements Department,
was the Project Leader and responsible for the coordination and conduct
of the program. Mr. T. M. Royal, Mr. R. W. Murdoch, and Mrs. B. A. Grimes
participated in the data acquisition program in Chattanooga. Mr. Royal
provided technical support for calibration and operation of instrumentation,
data processing and validation; Mr. Murdoch performed field calibrations
and repaired instrumentation; and Mrs. Grimes served as the RTI coordina-
tor, on-site in Chattanooga and supervised the day-to-day operations of
the network.
The Research Triangle Institute acknowledges the cooperation and
assistance of Messrs. F. B. Benson, Jr., W. B. Steen, R. C. Dickerson,
W. F. Barnard, and K. D. Kyle—Health Effects Research Laboratory, Environ-
mental Protection Agency; Messrs. J. B. Cole and W. H. Pope—Chattanooga
State Technical Community College; and the citizens and organizations in
Chattanooga that provided the sites for the aerometric program.
viii
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1.0 INTRODUCTION
1.1 Background/Objectives/Summary
The following technical report describes the efforts and activities
for operating an air monitoring program in Chattanooga, Tennessee, during
the period June 15, 1974, through June 14, 1976. The ongoing project was
begun in 1969 under the sponsorship of the U.S. Environmental Protection
Agency (EPA) and was designed to gather air quality data in the Chattanooga
area and examine health effects attributable to atmospheric oxides of nitro-
1 2/
gen.—*— This study was designed to investigate the effects of atmospheric
NO. in a community exposed to a large stationary source (i.e., Volunteer
Army Munitions Plant). Initially, the aerometric monitoring program con-
sisted of particulate (high volume method) and nitrogen dioxide (NO.)
(CHESS bubbler method) measurements at 10 monitoring sites located in
and about the Chattanooga area. Continuous NO. measurements were recorded
at two stations using the Technicon Air Monitor II (Saltzman Method).
Operation of the air monitoring network was conducted for EPA by the
Chattanooga State Technical Community College.
In September 1972 Research Triangle Institute participated in a
joint EPA-Coordinating Research Council (CRC) program to upgrade the
aerometric monitoring program by incorporation of chemiluminescent NO-NO -NO
analyzers and data acquisition systems in shelters at seven of the nine
monitoring sites operating at that time in Chattanooga.— The motivating
factor behind this program involved questions raised with respect to the
accuracy and validity of NO. data collected over the past decade by the
Federal Reference Method for monitoring NO in ambient air (i.e., modified
Jacob-Hochheiser Method). Investigations conducted by EPA and by various
organizations ' had shown that the reference method possessed inherent
deficiencies. The major objections to the reference method were the low
and variable collection efficiency and the interference of nitric oxide
with the measurement. Research Triangle Institute obtained and provided
N02 data using chemiluminescent NO analyzers to EPA under this program
from September 1972 until December 14, 1973. On December 15, 1973,
Research Triangle Institute was contracted by the Health Effects Research
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Laboratory, EPA, Research Triangle Park, North Carolina, to assume the
responsibility for the coordination and operation of the entire Chatta-
nooga aerometric monitoring program. Funding for 6 months for the air
monitoring program was provided to Research Triangle Institute under EPA
Contract No. 68-02-0335, "Effects of Nitrogen Oxide Levels on Health
Characteristics of Persons in Chattanooga, Tennessee."
On June 15, 1974, Contract No. 68-02-1737 was awarded to Research
Triangle Institute to continue to operate and maintain air monitoring
stations and collect air quality data in the Chattanooga area. Data
acquisition was concluded on May 31, 1976. The aerometric network was
dismantled, and all equipment was returned to Research Triangle Park,
North Carolina, by June 14, 1976. This final report summarizes all
activities related to the operation of the air monitoring program in
Chattanooga under Contract No. 68-02-1737 during the period June 15,
1974, through June 14, 1976. To provide continuity, all relevant
activities and chemiluminescent N02 data collected during the years
1973, 1974, 1975, and part of 1976 have been included in subsequent
discussions.
1.2 Aerometric Measurement Program
The aerometric measurement program for the Chattanooga Health Effects
Study as it existed in April 1972 consisted of NO and particulate meas-
urements from 10 monitoring sites located in and about the Chattanooga
area. Twenty-four-hour integrated N02 and suspended particulate samples
were collected at these stations using the CHESS modification of the
Jacobs-Hochheiser Method and the High Volume Sampler Method. Continuous
NO measurements were recorded at two stations using the Technicon Air
Monitor II (Saltzman Method). During the third quarter of 1972 the mon-
itoring program was upgraded to include chemiluminescent NO-NO -NO
X £,
monitoring instrumentation and data acquisition systems in shelters
equipped to maintain the environment necessary to insure proper operation
of the monitoring equipment at seven of the nine monitoring sites in Chat-
tanooga. Sites were selected to include upgraded NO monitoring facilities
in high, medium, and low N0? exposure areas. The aerometric measurement
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program was again modified in December of 1973. The major changes included
the deletion of the Technicon Air Monitor II (continuous NCL measurements
by the Saltzman Method) at stations 0632 and 0633 and the addition of RSP
samplers at all nine sites.
Site locations and a description of the instrumentation and facilities
are described in sections 2.0 and 3.0, respectively. The operational pro-
tocol and procedures used to obtain N02 and particulate data, computer pro-
grams used to process the field data, and data validation and quality
control procedures used to insure the collection of quality data are
presented in sections 4.0, 5.0, and 6.0. Although the Scope of Work
for Contract 68-02-1737 required only that aerometric data (N0? and
particulate) be collected and provided to the Environmental Protection
Agency in computer-compatible format, Research Triangle Institute decided
that a preliminary summary of the NO data obtained during the program
was warranted. A graphical presentation and description of chemilumines-
cent NO data obtained during the calendar years of 1973, 1974, 1975, and
the first 5 months of 1976 are presented in section 7.0. Detailed operating,
calibration, and maintenance procedures used in this program are presented
in Appendixes A, B, and C, respectively. Hardcopy printouts and magnetic
tapes containing formatted hourly and 24-hour average chemiluminescent
NO data for the entire program have been provided to the project officer.
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2.0 SITE LOCATIONS
To provide continuity for the measurement program, EPA decided to
retain the reference sampling site locations used in the original NO
I/
study,— when upgraded facilities (i.e., 2.4-m by 3.7-m shelters, chemi-
luminescent NO-NO -N07 analyzers, and data acquisition systems) were
X £*
installed at seven sites selected by the EPA project officer from the
nine permanent monitoring sites operating in Chattanooga during the
fourth quarter of 1972. Two of the nine sampling sites used 3- by 4-m
shelters and contained high volume, RSP, and bubbler samplers. The
addresses of the nine sampling sites and location coordinates obtained
from U.S. Department of Interior Geological Survey Contour Maps are
presented in table 1. The locations of the sampling sites with respect
to the Volunteer Army Munitions Plant and the city of Chattanooga are
shown in figure 1.
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Table 1. Sampling site location and coordinates
Site No.
0621*
0622*
0631*
0632*
0633*
0634*
0635
0641*
0642
Address
Children's Home
421 Gillespie Avenue
Chattanooga, Tennessee
Jewish Community Center
5326 Lynneland Terrace
Chattanooga, Tennessee
Clark Road
Harrison, Tennessee
3729 Briarwood Drive
Chattanooga, Tennessee
2708 Hickory Valley Road
Chattanooga, Tennessee
Loret Villa, Highway 58N
5 Miles Northeast of
Chattanooga, Tennessee
4409 Murray Hills Drive
Chattanooga, Tennessee
3319 Dayton Boulevard
Red Bank, Tennessee
Santeelah Road
Red Bank, Tennessee
Coordinates
Latitude
35°01'47"
35°0'21"
35°06'37"
35°05'05"
35°03'40"
35°08'21"
35°05'12"
35°06'37"
35007'41"
Longitude
85°14'42"
85°13'14"
85°08'46"
85°11'27"
85°09'22"
85°07'25"
85°12'26"
85°17'44"
85°17'00"
t
Upgraded facility (2.3- x 3.7-m shelters, chemiluminescent NO-NO -NO.
analyzer, data acquisition system).
Obtained from U.S. Department of Interior Geological Survey Contour
Maps.
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3.0 DESCRIPTION OF INSTRUMENTATION/FACILITIES
3.1 Shelters/Ambient Air Sampling System
The shelter used to house the instrumentation in seven of the nine
air monitoring stations was a 2.3- x 3.7- x 2.3-m factory-assembled,
aluminum-sided building. The building included an automatic switching
18,000 Btu heating/cooling unit, an electrical system to accommodate
240 V, single-phase service for the heating and cooling unit, 120 V
circuits for fluorescent lights and wall receptacles inside and outside,
an 8-ft instrument table and 5-ft workbench, and an air-sampling Pyrex
glass manifold system. Pictures of the shelter exterior and interior
complete with instrumentation are shown in figures 2 and 3.
The ambient air sampling system consisted of a cane (to prevent
moisture and particulates from settling into the inlet), a particulate
trap (glass bottle) to remove large suspended particulates, three 4-m
sections of 3.8 cm o.d. glass manifold (one section having four sampling
ports), and a blower. Ambient air was aspirated through the manifold by
the blower at a rate of approximately O.lm /min. Sampling ports made
of 12/5 ball and socket joints were used for easy hookup of instrument
inlet lines.
3.2 Chemiluminescent NO-NO -NO„ Analyzers
X £.
Bendix Model 8101-B chemiluminescent NO-NO -N09 analyzers equipped
X ^
with teflon particulate filters (MACE FILTER) were used to monitor NO
concentrations at the seven stations indicated in section 2.0. The
principle of operation of the Bendix analyzer is based on the chemi-
luminescent gas phase reaction between nitric oxide (NO) and ozone (0.).
A schematic diagram of the gas flow and detection system of the Bendix
analyzer is shown in figure 4. The measurement of N0_ concentrations
by this instrument requires that NO be reduced to NO prior to the
reaction with 0«. The sum of the NO measurement plus that produced by
reducing N09 to NO is the nitrogen oxide (NO ) concentration. Subtraction
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of the previous NO measurement from the NO measurement gives the N0_ con-
centration. The chemiluminescent reaction is pressure dependent and the
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Figure 2, Shelter exterior.
10
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Figure 3, Shelter interior.
11
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maximum absolute operating pressure of the Bendix analyzer is approximately
17.8 cm of mercury. At this pressure the minimum detectable concentration
3
of the Bendix analyzer has been determined to be approximately 10 yg/m .
3.3 Calibration Technique/Apparatus
Due to problems associated with field use of NO- permeation tubes
and the need to determine periodically the efficiency of the heated carbon
converter (i.e., reduces N0,; to NO), the gas phase titration procedure was
used for routine dynamic calibration of the chemiluminescent NO-NO -NO
II
x
analyzers.— The gas phase titration technique is based upon application
CHARCOAL
Sample
Inlet
ANALYZER
INDICATOR
ANALYZER
SYSTEM
Figure 4. Schematic diagram of Bendix NO-NO -NO analyzer and
data acquisition scheme.
12
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of the rapid gas phase reaction between NO and 0, to produce a stoichio-
8 9/
metric quantity of NO..—1— Nitric oxide from a cylinder of NO in NO (100
ppm) was diuted with a constant flow of clean air to provide 0.5 ppm and
used to calibrate the NO and NO channels of the chemiluminescent NO-NO -NO
x x i
analyzer. By incorporation of a calibrated ozone generator in the calibra-
tion apparatus upstream from the point of NO addition, precise NO concen-
trations can be generated by oxidation of NO to NO with 0 . As long as a
slight excess of NO is present, the concentration of 0_ added is equivalent
to the concentration of NO consumed, and is equivalent to the concentration
of NO generated. A diagram of the gas phase titration apparatus used in
this program for calibration of the NO analyzers is shown in figure 5.
PEN
LAMP
CALIBRATION SYSTEM
ADJUSTABLE SLEEVE
^JrjOZ
>«ii-'ai!=ir n i (Ti r
Figure 5. Gas phase titration system for calibrating
NO-NO -NO, analyzers.
X i—
13
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Primary calibration of the NO concentration in the pressurized cylin-
ders containing nitrogen as a diluent was accomplished initially by gas
phase titration and later by reference to a primary standard of NO in
nitrogen (National Bureau of Standards SRM-1684). Once the NO concentra-
tion in a cylinder had been determined, the cylinder could be used over
its lifetime to provide a working standard for routine calibration;—
however, to insure validity of data, the NO concentration was reverified
at 2-month intervals.
3.4 Data Acquisition Systems
The Metrodata Model DL-630-3 data logger was used to acquire and
store data on magnetic tape. The data logger is a complete data acquisi-
tion system that records on magnetic tape 25 channels of analog data plus
a time code, station identification, and manual data entry. Data are
recorded on magnetic tape at 5-minute intervals. Manual data can be
entered immediately upon actuation of the switch on a manual data unit
(EC-22) which initiates the recording of one scan. A photograph of the
data logger with the remote control unit is shown in figure 6. The data
logger is shown without a cabinet (cabinets were installed on all units).
A functional diagram of the data logger system is shown in figure 7. The
system can be interrogated remotely from a control site through a voice
grade telephone line and standard telephone data couplers. The interro-
gation feature was utilized initially, but was deleted after the RTI
coordinator was located in Chattanooga in June of 1974.
14
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4.0 OPERATIONAL PROTOCOL
During the period of performance of Contract 68-02-1737 (June 15,
1974 to June 14, 1976), the following protocol was used to operate and
maintain the aerometric measurement program in Chattanooga. Chattanooga
State Technical Community College operators under the supervision of Mrs.
Bobbie Grimes, RTI coordinator in Chattanooga, performed the daily tasks
required to operate and maintain the aerometric measurement program. High
volume, RSP, and NO bubbler samples were collected on a daily basis and
forwarded to Rockwell International, Thousand Oaks, California, for analy-
sis. Maintenance procedures were implemented for samplers and equipment
as specified in the Operational Procedures supplied by EPA.
Daily procedures associated with operation of the chemiluminescent
analyzers and data acquisition systems included zeroing of the analyzer,
strip chart recorder annotation, data logger time/date check, and analyzer
log entry. Magnetic tapes for the data acquisition systems were replaced
and returned with tape logs and analyzer data sheets via air mail to RTI
for data processing on a weekly schedule. Oxygen cylinder pressure, in-
strument cell pressure, measurement range, and other operational status
checks were recorded on the analyzer data sheet to facilitate assessment
of instrument performance.
Chemiluminescent analyzers were zeroed daily and spanned once per
week. A multipoint calibration was performed on a routine basis every 3
weeks. Nonroutine calibrations were performed whenever a replacement
analyzer was set up or whenever testing was required to determine malfunc-
tions or questionable instrument performance. During each calibration
period, the converter efficiency (NO ->• NO) of the analyzer and span drift
from the previous calibration period were determined. Calibration data
were compared with previous data to determine long-term drift for data
quality control. Nitrogen dioxide data were also recorded on strip chart
recorders, which served as backup recording systems in case of failure of
the data acquisition systems. Data from the strip chart recorders were
also used for validation purposes to insure that the data integrity was
maintained throughout the data processing sequence of events.
17
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5.0 PROCESSING OF FIELD DATA
In this program, field data were recorded as digital voltages on
magnetic tape cassettes, which were forwarded to RTI weekly for process-
ing. Field data were translated by RTI personnel using EPA's Metrodata
Translator and temporarily stored on nine track magnetic tape for the
various processing phases required to convert digital voltages to concen-
3
tration units (yg/m ) and produce both a computer-compatible data tape
and a hardcopy printout. The flow diagram shown in figure 8 describes
the treatment of the data from the time magnetic tape cassettes were
received until a printout of data in various useful forms was obtained.
The tape translator extracts edited data records from logical records
on field tapes. The translator is programmed to count the number of char-
acters in each logical record in the tape-reading routine. The edit and
flag program verifies data within a given range, time, station identifica-
tion, and valid manual data entry codes. The transfer equation program
converts instrument voltage to the appropriate concentration units (i.e.,
ppm or yg/m ). The general form of the transfer function utilized in the
program was
Concentration = m(v - v ).
o
The output of this program was a tape and printout of 5-minute data.
The merge and average data program allows hourly averages from strip
chart records to be inserted as required and combined with existing data
to yield 24-hour average concentration values. A tape was generated in
this program for future use. A typical printout of the merge and average
program is shown in figure 9. Ten days of hourly averages are printed
per page for each site.
19
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CARD
INPUT
CALIBRATION
DATA
CARD INPUT
MISSING HOURLY
AVERAGES FROM
STRIP CHART
CASSETTES
TAPE TRANSLATOR
I/A IN. 4-TRACK TO
1/2 IN. 9-TRACK COMPUTES
COMPATIBLE TAPE
EDIT AND FLAG
PROGRAM
OLTAGE
WITH
GOOD DAT
TAINED
TRANSFER EQUATION
PROGRAM
5-MIN
DATA
PHYSICAL
UNITS
MERGE AND
AVERAGE DATA
PROGRAM
VOLTAGE
PRINTOUT
EC-2 2
CODE 999
VOLTAGE
PRINTOUT
-*/ EC-22
/ CODES OTHER
/ THAN 999
5-MIN
DATA
PHYSICAL
UNITS
EC-22 CODE 999
5-MIN
DATA
PHYSICAL
UNITS
EC-22 CODE
NOT 99
1-HOUR
AND
24-HOUR
AVERAGE
WITH
CASE COUNT
Figure 8. Data processing flow chart.
20
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"O O '^"J O '
*H »^ *-< cv
^*
g
'U
u
cr.
.u
c- e i- c. t--
o>. •
-o
e>o
". Cf\f«-i«-cvrt^{v:ir«ti*.
C "> -D "> .-_ T» ^> O O U -O 3 O ^ O "3 C-> J 'J> 'O ^>
. cv'tx. o
21
-------
6.0 DATA VALIDATION AND QUALITY CONTROL
In order to achieve and maintain a high level of data confidence, it
was essential to routinely monitor as many instrument parameters as feasi-
ble and to maintain appropriate records. Quality control for this program
included verification of calibration cylinder concentrations, performing
dynamic calibration at specified intervals, maintaining adequate records
that describe instrument performance, and thorough training of field
operators. Equipment deficiencies and failures were promptly corrected,
and new operational parameters were added when feasible to alert field
operators for degradation of performance.
Calibration data were examined for excessive zero and span drift.
3
If the zero drift exceeded ± 1 percent of full scale (±9.4 yg/m N02)
per 24-hour period, the data of the preceding 24-hour period were of
questionable validity and action was taken to determine the cause. Span
drift was determined from span calibration data each week. Span drift
exceeding ± 10 percent of full scale per week was usually associated with
instrument malfunction, and the previous week's data were invalidated.
Quality assurance performance audits were conducted periodically at
each station during the reporting period by EPA and an independent RTI
auditing team. The results of these audits have been documented in the
quarterly reports submitted to the project officer. All audit results
were satisfactory (i.e., analyzer response was within 10 percent of the
audit concentration. No data were invalidated due to results of any per-
formance audit. National Bureau of Standards SRM (NO in nitrogen, NO-
permeation tubes) and gas phase titration were used to generate reference
concentrations of NO and NO.,.
To verify data logger accuracy, a constant voltage data input stand-
ard was recorded every 5 minutes in conjunction with the NO analog data.
It was not necessary to delete any ambient air data due to analog-to-
digital conversion errors.
At the completion of each computer program set, the processed data
were compared with strip chart data for selected periods. More intensive
data checks were performed against strip chart and operational records
23
-------
after the hourly averages program. A typical check included comparison
of computer-processed data and strip chart data for two selected 1-hour
averages per day. The recorded data on strip charts were edited for signs
of equipment malfunctions, excessive pollutant levels, or unusual diurnal
patterns.
Data quality is a function of instrument and operator errors plus
small additional inaccuracies in the calibration system. The maximum
error resulting from the calibration procedures was estimated to be less
than ± 7 percent.
Data confidence near zero pollutant level is estimated to be in error
3 3
by less than ±9.4 yg/m , while at levels greater than 50 yg/m the error
was estimated to be less than 5.0 percent of the measurement level.
24
-------
7.0 SUMMARY OF NITROGEN DIOXIDE DATA (January 1973 to June 1976)
The Scope of Work for contract 68-02-1737 required only that NO
data be collected by the chemiluminescent method and provided in hard
copy and computer-compatible format to the Environmental Protection
Agency. Therefore, computer programs were written only to routinely
process NO data, as shown in figure 9. However, certain observations
and analyses were performed manually, using N0? data obtained from January
1973 to May 1976, and are as follows:
1. Annual arithmetic means (1973, 1974, 1975, January-May 1976),
2. Ratio of arithmetic means,
3. Quarterly means,
4. Ratio of quarterly means, and
5. Percent data recovery by station (1973, 1974, 1975, January-
May 1976).
These observations and results are summarized in the following paragraphs.
Whenever appropriate, results are shown graphically as well as in tabular
form.
Annual arithmetic means were computed for each monitoring station and
are presented in table 2 for 1973, 1974, 1975, and January-May 1976. These
data show a substantial reduction in NO exposure levels in the Chattanooga
areas where the sampling sites are located when compared to the mean NO
I/
data reported in the original 1968-1969 Chattanooga Study.— Mean NO con-
centrations decreased approximately 36 percent in sector I, approximately
56 percent in sector II, and approximately 68 percent in sector III when
data for 1973 were compared with data reported for the original study.
The most dramatic decrease in mean NO- concentration occurred at site 0631
located nearest the Volunteer Army Munitions Plant. The significant de-
crease in N0« concentration at site 0631 from 1974 to 1975 can be corre-
lated with a slowdown in TNT production and installation of control equip-
ment at the Volunteer Army Munitions Plant. The lowest annual mean was
observed during all years at site 0634. Site 0634 was located in a rural
area northeast of Chattanooga and used as a control site. The data pre-
sented in table 2 clearly indicate that the NO ambient air quality standard
25
-------
3
Table 2. Annual N09 arithmetic means (yg/m )
o
Annual N(>2 Arithmetic Mean (yg/m )
Site No.
0621
0622
0631
0632
0633
0634
0641
1973
42.9
63, .8
58. 0"1"
43 ..2
37.9
33,5
54.9
1974
42.7
49.4
76.3
45.9
39.1
34.9
45.8
1975
35.6
46.1
40.5
32.5
26.6
23.2
40.4
1976*
41.5
46.2
38.9
37.8
31.2
23.8
46.9
*5-month mean (January 1-May 30, 1976)
Volunteer Army Munitions Plant on strike (January-March 1973)
3
of 100 pg/m was not approached at any monitoring station during any of
these reported years. In general, NCL concentrations have remained almost
constant at site 0621; have decreased at site 0622 in 1974, 1975, and 1976;
have decreased substantially from 1973 to 1976 at sites 0631, 0632, 0633,
and 0634 (these four sites are directly affected by emissions from the VAM
Plant); and have decreased slightly at site 0641. Sites 0622 and 0641 are
both located near busy roadways and should correlate with and be affected
by local traffic.
Ratios of arithmetic means between sites for each year are presented
in table 3. The ratios presented in this matrix allow the reader to quick-
ly compare mean values between respective sites.
Quarterly mean N0? concentrations were computed for each site for
1973, 1974, 1975, and January-May 1976 and are presented in table 4.
These data are also presented in graphical form in figures 10-16. Data
for the fall quarter of 1972 were retrieved and are included to show the
26
-------
Table 3. Ratio of annual NO- arithmetic
means
Site No.
0621
0622
0631
0632
0633
0634
0641
Year
1973
1974
1975
1976*
1973
1974
1975
1976*
1973
1974
1975
1976*
1973
1974
1975
1976*
1973
1974
1975
1976*
1973
1974
1975
1976*
1973
1974
1975
1976*
0621 0622 0631 0632
1.00 1.49 1.35 1.01
1.00 1.16 1.78 1.07
1.00 1.29 1.13 0.91
1.00 1.35 0.94 0.91
1.00 0.90 0.67
1.00 1.54 0.93
1.00 0.88 0.70
1.00 0.69 0.67
1.00 0.75
1.00 0.60
1.00 0.80
1.00 0.97
1.00
1.00
1.00
1.00
0633
0.88
0.91
0.75
0.75
0.59
0.79
0.58
0.55
0.65
0.51
0.66
0.80
0.87
0.85
0.82
0.82
1.00
1.00
1.00
1.00
0634
0.78
0.82
0.65
0.57
0.52
0.71
0.50
0.42
0.58
0.46
0.57
0.61
0.78
0.76
0.71
0.63
0.88
0.89
0.87
0.76
1.00
1.00
1.00
1.00
0641
1.28
1.07
1.13
1.13
0.86
0.92
0.88
0.83
0.95
0.60
1.00
1.20
1.27
1.00
1.24
1.24
1.45
1.17
1.52
1.50
1.63
1.31
1.74
1.97
1.00
1.00
1.00
1.00
5-month mean (January 1-May 30, 1976).
27
-------
effect of the shutdown of the VAM Plant on certain stations. Ratios of
quarterly mean NO. concentrations between stations were also calculated
and are presented in table 5. All ratios presented in table 5 were cal-
culated in relation to the quarterly mean for site 0621. The effect or
influence of the VAM Plant shutdown can be seen in table 4 (i.e., site
3
0631 quarterly mean of 22.2 \..g/m for the first quarter of 1973) and in
Table 4. Quarterly mean N0~ concentrations (yg/m )
Year
1973
1974
1975
1976
Quarter*
1
2
3
4
1
2
3
4
1
2
3
4
1
2t
Site No.
0621 0622 0631 0632 0633 0634 0641
40.2 59.3 22.2$ 36.4 26.2 23.4 53.4
38.3 64.0 63.0 45.2 28.5 32.4 66.2
51.3 70.5 65.3 39.6 43.1 42.2 49.2
41.7 61.4 81.7 51.4 53.7 35.8 50.7
49.5 61.1 90.7 48.7 42.7 45.3 51.7
39.4 54.4 71.2 37.6 34.0 30.6 49.7
36.5 45.3 70.0 44.0 37.0 28.6 44.7
45.2 37.4 71.6 52.0 42.6 33.4 36.9
31.9 38.0 38.1 21.9 27.2 25.4 36.5
39.9 55.6 44.3 35.6 28.2 22.9 43.0
34.7 44.9 33.6 34.5 21.4 15.2 35.8
35.5 45.4 45.6 37.4 31.0 23.2 45.3
40.6 56.4 37.4 40.1 35.0 24.6 46.4
42.4 56.0 40.3 35.4 27.4 22.9 47.3
Quarter 1 - January-March.; Quarter 2 - April-June; Quarter 3 - July-
September; Quarter 4 - October-December.
April-May data only.
Plant Shutdown.
28
-------
lOOr
e
oo
90 -
80 -
t-i
4-1
-3 70 - a
4-J
VJ ^
t: 60 . c
s s
c ^
° 50 - ^ nvVV vv
i^~\ ,
2 30 :• :::::::::
1 — ' l
-------
0)
ro
100
90
E
"M 80
(-1
4-1
w
o
"O
4-1
3
C/5
tfl
5 /u - - i-vv-
2 5 iiiiiii
S 60 - miliiiiiiiiiiiiiiii:
r-1 ^^^^^^J' '
5 ';:::: ::1; ;;;;; ;:::::;;:;;;;;;;;;
§ 50 i^iiiii;iiiiiNiiiii;Miiiiiiii
o •.'•• •'••'•'•'••:'.•'.'. :::::: :::;:
o"4o i|;iii!;;iiii;iiii;;iiii iiiiiiiii.
S 30 iiiiii:!;; ii; iiiiiiiilii! ! iii
5 20 i'iiiiiiiiiiiiiiiiiiiiiiiiiiiiiii^
a) :::::;::
S 10 i-iiiiiiiiiiiiiiiiiiiiiiiii iiiiii;
3 :::::::;:::; :i ::; iiiiii iiii ;i: : : ::
1 i ¥
rters 4123
rs 1972 1973
» i-
ilii! iiiiiiiiffl
iiiiii iii-iiiiiiiiiiiii iiiiiii iiiiii ::::::;::;::::::::
iiiiii iiiiiiiii iiiiiii i^'i^ :::::::: i : i ii ii i : : : ii : : i: :i i i ii i i i:
iiiii iiiiiiiiiiiiiiiii: iiiiiiii iiiiiii iiiiiii iiiiiiii iiiiiii ii
1 V V
41234123
1974 1975
iiiiii iiiiiiiiiiiiiiii
iiiii: iiiiiiiiiiiiiiii:
iiiiii iiiiiiiiiiiiiiiii
412
1976
Figure 11. Graphical presentation of quarterly mean NO
concentrations for site 0622.
30
-------
f) : : ...,...;
B ;; \ ':'':':':'::
M 80 ';;;: '"':"' •:::::::!
C ' : : ' : -H :':::;: : • ••'
O 7Q i VJ ';':::: •'::.•:'
4J : cr> ....... . .
to • — " "" :
C : : ' O :: : :: v ': ::: : :': :: ::: ::
0) .... ng !••••; : ::::::
O 4-> ::.:::• '::::'::
C cn ,, 3 :: ::: •;::;•:•:: .::::::
0 DU ; ^ ::::.:.;;::.::;:;:;:;• ;
U :::::: co ::•:.::::::::::•::::::: ::::::
cs ' ' • 4-1 • • •: : ' " " : ' :
O 40 " C ::::':;: ":•::::::::•'• : : ' :' •;
Z • ' cfl ' ' '.•'. '..'.'.','.''' i:. .',:".'::
$ 30 ,;::: : X ]\ '^ ::.:. :::":':•'>: :. >:>:>••
S : : <3 y '.".'.: :\\': : :
>, ' y 1 ' . :::::::: : :: :" ':';"."
M 20 '-':::' M|H| ::y\::':]yyyyyyyy y::yy
OJ :••: t • • •• ;• .:.':••::' ' :::':'
4J • . ...•.'.' ; : :::::•:':: •;::::
l-i ::':':::•::•:• •:;:•::::•.•::•;: •;•••;:
3 10 !^;;:;; 'yyy' y^\y,^:.yy::' :"':y': [\\l\\\
0 ......I ............ ..............1....... ........
ill i
Quarters 412341
Years 1972 1973
o
4-1
O
O
0
•H
4J T3
U
-------
lOOi-
Quarters 4
Years 1972
Figure 13. Graphical presentation of quarterly mean NO,.
concentrations for site 0632.
32
-------
oncentration (yg/m )
M
Ui <^ ~J 00 vO O
O O O O O O
1 1 1 1 1 1
U ::::.
Cs| • • • • •
§ 40 >'::::
a :::::
cd :::::.
£ 30 iiiii
£ 20 ''•'-'•'••
0) iu :::::
5 10 ii:::ii
CX ::::::
0 ""'
Quarters 4
Years 1972
1973
"1 B|))||))
lillilllll 1 liilill
ii;!i;|iiMiiiiii:iiiiiiii'iijiiii:iiiiiiiiiiiiiiiii iiiiii iiiiii -iii!
::;j[: :;:;; :;;;;:::;;•: J] ;
II II
2341 23412
1974 1975 1976
Figure 14. Graphical presentation of quarterly mean NO
concentrations for site 0633.
33
-------
3
- Concentration (yg/m )
h-"
Ln ON ^j oo vo O
O O O O O O
1 1 1 1 1 1
§ 40 -
TO :
S 30 ':
M 20 -
01 u : ::
4-1 : •:
3 10 i-
O- :::
Quarters
Years 19
t Shutdown/Strike
... :::::::. :::::::: ; . .:
i
4123
72 1973
: — ' .:::.:.: ::....::,!::!! :::::
• : : :::;:;:::::;
l II
41 23412 34 12
1974 1975 1976
Figure 15. Graphical presentation of quarterly mean NO-
concentrations for site 0634.
34
-------
a
—
M
a.
100
90
«n
80
C 4J
•3 70 " £
4J i-l
n) (X, ii " ;
1 60 " 3 |M:;
o __ _ : : !:
C : : : !:
o sn - i •
u :••'::::
i 40 'i:iii: :ii::: '• :::i: :::::iiiii
C : :::•: -
« ;;;:;;; :•:::.; ::ii:ii iiiiiiiiii
S 30 ;-:::;: ;i;;;:; i;:;:;; ;:;;
>, ;;: ii:i iiiii iii;:!
« 20 iiii^ ^^i iiiiiii ;;;;!;;;;!
c8 ::::::: :;:::: ::::::::::;::::
<§• 10 >;;;:i :;!;;!; : i; ;; ;;;•;;;;:;;
0 -i-iii ii ii i ; ; ii;ii;:j;'i
Quarters 4123
Years 1972 1973
::::, :::::::::::::::::: ::::: : ' :. ::::•: •'•'•'•'-
::: :::::;:::::::: :::::::: ::::::: ::; ::: ::
• • • • • • • • : ; • • • • • • • • : : ' ; : :::;:;;: ::;:::; :::'::: ::::::::: : : ' :
41234123
1974 1975
i:::.:::::::::::: :.:.:::
::::::::::::::::::::::::
412
1976
Figure 16. Graphical presentation of quarterly mean N0«
concentrations for site 0641.
35
-------
table 5 in the ratio of means for the first quarter of 1973. Also, the
ratio of quarterly means for site 0631 compared to site 0621 is now run-
ning below 1.00 for the first 5 months of 1976.
7.1 Data Recovery
The percentage of valid N0_ data recovery achieved during each year
of this program is summarized in table 6. These records show that signifi-
cant improvements in the percentage of data recovery occurred from year to
Table 5. Ratio of quarterly mean NO™ concentrations
(yg/m3)
Year
1973
1974
1975
1976
Quarter*
1
2
3
4
1
2
3
4
1
2
3
4
1
2§ ,
t
Site No.
0621 0622 0631 0632 0633 0634 0641
1.00 1.48 0.55* 0.91 0.65 0.58 1.32
1.00 1.67 1.64 1.18 0.74 0.85 1.73
1.00 1.37 1.27 0.77 0.84 0.82 0.96
1.00 1.47 1.96 1.23 1.29 0.86 1.22
1.00 1.23 1.83 0.98 0.86 0.92 1.04
1.00 1.38 1.80 0.95 0.86 0.77 1.26
1.00 1.24 1.92 1.21 1.01 0.78 1.22
1.00 0.83 1.58 1.15 0.94 0.74 0.82
1.00 1.19 1.19 0.69 0.85 0.79 1.14
1.00 1.39 1.11 0.89 0.71 0.57 1.08
1.00 1.29 0.96 0.99 0.62 0.44 1.03
1.00 1.28 1.28 1.05 0.87 0.65 1.28
1.00 1.39 0.92 0.99 0.86 0.61 1.14
1.00 1.32 0.95 0.83 0.65 0.54 1.12
Quarter 1 - January-March; Quarter 2 - April-June; Quarter 3 - July-
September; Quarter 4 - October-December.
1 Ratio
Site mean
Site 0621 mean
^Volunteer Army Munitions Plant on strike.
§April-May data only.
36
-------
Table 6. Percent of valid N02 data by year
Site No.
0621
0622
0631
0632
0633
0634
0641
Year
1973
1974
1975
1976*
1973
1974
1975
1976*
1973
1974
1975
1976*
1973
1974
1975
1976*
1973
1974
1975
1976*
1973
1974
1975
1976*
1973
1974
1975
1976*
Operational Period
(days)
365
365
365
152
365
365
365
152
365
365
365
152
365
365
365
152
365
365
365
152
365
365
365
152
365
365
365
152
Valid N02 Data
(days)
259
316
347
151
296
343
344
148
302
331
343
90
344
311
357
151
319
352
264
131
235
321
277
151
207
269
314
148
Data Recovery
(%)
71.0*
86.6
95.1
99.3
81. 01"
94.0
94.2
97.3
82. 7f
90.7
94.0
59.2
94.2
85.2
97.8
99.3
87.3
96.4
72.3
86.2
64.4
87.9
75.6
99.3
56. 7t
73.7
86.1
97.3
January-May
^Single operator error accounted for 12.0 percent of instrument downtime at
0621; 10.8 percent at 0622; 15 percent at 0631; and 11 percent at 0641.
37
-------
year. Notable exceptions include 1976 at site 0631; 1975 at 0633; 1975 at
0634; and 1974 at site 0641. The best percentage data recovery occurred
during the first 5 months of 1976. With the exception of site 0631,
better than 97 percent valid data were recovered from the network. The
overall data recovery averaged over all sites for each year are as follows:
70.7 percent for 1973; 87.8 percent for 1974; 87.9 percent in 1975; and
91.1 for the first 5 months of 1976.
Logical explanations can be given to account for the improvement or
lack thereof in percent data recovery and are as follows:
1. The main reason for the improvement in percent data recovery
resulted from RTI locating a field coordinator in Chattanooga to super-
vise the local operators supplied by Chattanooga State Technical Community
College; considerable data were lost during 1973 due solely to local oper-
ator errors.
2. The primary reason for loss of data was due to failure of the
NO analyzers, which caused 99 percent of downtime (i.e., loss of data).
Less than 1 percent of lost data could be attributed to failure of the
dual recording systems (i.e., data acquisition and stripchart recorders).
Insufficient N09 analyzers were available for use on this program (i.e.,
eight analyzers were provided by EPA to operate seven stations). In 1976
two additional analyzers were provided by EPA for use on the program and
better than 97 percent valid data were recovered at all sites, except
sites 0631 and 0633.
7.2 Observations and Conclusions
Certain observations and conclusions can be drawn from the limited
amount of data presented in the previous paragraphs. These are as follows
and are by no means intended to be all inclusive:
1. Mean N0_ concentrations in Chattanooga have decreased significantly
in all three study sectors (figure 1 of this report) when compared to the
mean NO data reported for each section in the original 1968-1969 Chattanooga
Study. Mean NO concentrations in 1973 have decreased 36 percent in sector
I, 56 percent in sector II, and 68 percent in sector III. Year-to-year
decreases have continued for all sites in all sectors. The reader is
cautioned that percentage decreases are approximate, since the numbers used
38
-------
to compute the decrease in NO- levels for each sector were obtained using
different methods (i.e., the CHESS modification to the Jacobs-Hochheiser
Method in the 1968-69 Study and the chemiluminescent method in the 1972-
1976 Study). Inaccuracies inherent in the measurement method used to obtain
each set of data for the three sectors will influence the absolute percentage
decrease. In addition, the sampling sites presently used in Chattanooga
are not necessarily the same as those used in the original 1968-1969
Chattanooga Study— ; however, all sites used in the comparison are located
within the same sectors.
2. The slowdown in TNT production at the Volunteer Army Munitions
Plant and gradual installation of control equipment have been accompanied
by a decrease in NO concentration for the sector III study area. The
3
data show that the ambient air quality standard of 100 yg/m was not
approached at any site in sector III during the measurement period. The
3
highest annual mean was 76.3 yg/m at site 0631 in 1974 (site nearest the
3
point source) and the lowest mean was 23.2 yg/m at site 0634 (control site).
3. Based on the data and prevailing wind patterns for this area,
emissions from the TNT plant appear to be the major source of NO- in the
high NO exposure area (sector III) . The influence or effect of the TNT
plant contribution on the NO levels measured at each of the four sites
in section III can be correlated with wind direction from the TNT plant
to the site. The TNT plant was shut down by a strike during the first
calendar quarter (January-March 1973) and its impact on the quarterly mean
for each of the surrounding sites was apparent. The quarterly mean for
site 0631 located adjacent to and generally downwind of the TNT plant
decreased 47 percent, and for site 0634 decreased 38 percent. The quarterly
mean for sector III (i.e., average mean for sites 0631, 0632, 0633, and
3
0634) for the first calendar quarter of 1973 was 27 yg/m as opposed to
3 3
57 yg/m for the fourth quarter of 1972 and 42 yg/m for the second quarter
of 1973. Mean nitrogen dioxide concentrations at site 0631 in 1975 and
1976 were significantly lower than for previous years and approximate N0_
levels observed at other sites not influenced by the VAM Plant. These
data indicate that control equipment installed at the VAM Plant has been
effective.
39
-------
4. Based on the data obtained during this period of time (table 2) ,
there does not appear to be significant difference in NO exposure between
the health study areas (i.e., sectors I, II, or III); however, a significant
difference in exposure within sector III existed until the end of 1974.
This observation can readily be seen by examining data presented in table 2.
Sector III is comprised of sites 0631, 0632, 0633, and 0634.
3
In summary, the ambient air quality standard of 100 yg/m (annual
arithmetic mean) was not exceeded nor closely approached during the measure-
ment program at any of the seven monitoring sites, where chemiluminescent
NO analyzers were located. Short-term maximum hourly average concentra-
3
tions did occur at site 0631 in excess of 1,000 yg/m , but the overall mean
for site 0631 has decreased by more than 50 percent since 1973. In general,
mean NO concentrations measured in the Chattanooga area have decreased
significantly from those levels measured during the 1968-1969 Chattanooga
study. Slowdown in TNT production and installation of control equipment
at the VAM Plant have been accompanied by a decrease in NO concentrations
at sites located in sector III near the point source.
40
-------
8.0 REFERENCES
1. Shy, C. M., J. P. Creason, M. E. Pearlman, K. E. McClain, F. B. Bensen,
and M. Y. Young, "The Chattanooga School Children Study: Effects of
Community Exposure to Nitrogen Dioxide: Methods, Description or
Pollutant Exposure, and Results of Ventilatory Function Testing,"
Journal Air Pollution Control Association 20 (1970):539.
2. Pearlman, M. E., and J. P. Finklea, "Nitrogen Dioxide in Lower
Respiratory Illness," Ecological Research Branch, DHER, National Air
Pollution Control Administration (1970).
3. Decker, C. E., T. M. Royal, and J. B. Tommerdahl, "Program for
Upgrading the Instrumentation Employed in the 1972 Chattanooga N0?
Exposure Study," Final Report, Research Triangle Institute, CRC-APRAC
Project No. CAPM-10-71, May 1973.
4. Purdue, L. J., J. E. Dudley, J. B. Clements, and R. J. Thompson,
"Reinvestigation of the Jacobs-Hochheiser Procedure for Determining
Nitrogen Dioxide in Ambient Air," Environmental Science and Technology
6(1972):152.
5. Merryman, E. L. , C. W. Spicer, and A. Ling, "A Reevaluation of the
Jacobs-Hochheiser Procedure: Effects of NO, CO , CH , HO, and
Sodium Arsenite on NO Analysis." In Proceedings of 2nd Conference on
Natural Gas Research and Technology, AGA, Atlanta, Ga., June 5-7, 1972.
6. Hauser, T. J., and C. M. Shy, "Position Paper: NO Measurement,"
Environmental Science and Technology 6 (1972):890.
x
7. U. S. Environmental Protection Agency, "Ambient Air Quality Standards:
Reference Method for Determination of Nitrogen Dioxide, Federal
Register 38, No. 110 (June 8, 1973).
8. Hodgeson, J. A., R. E. Baumgardner, B. E. Martin, and K. A. Rheme,
"Stoichiometry in the Neutral lodometric Procedure for Ozone by Gas-
Phase Titration with Nitric Oxide," Analytical Chemistry 43 (1971):1123.
9. Rheme, K. A., B. E. Martin, and J. A. Hodgeson, "The Application of
Gas Phase Titration in the Simultaneous Calibration of NO, NO-, NO ,
and 0. Atmospheric Monitors." Paper presented at the 164th ACS Meeting,
New York, September 1972.
41
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APPENDIX A
OPERATING PROCEDURES
(As SUPPLIED TO CHATTANOOGA STATE
TECHNICAL COMMUNITY COLLEGE OPERATORS)
-------
APPENDIX A
OPERATING PROCEDURES TOR QEMILJUPlIFESCEOT ANALYZERS
AND DATA ACQUISITION SYSTEMS
A. DAILY OPERATING PROCEDURES
1. Indicate date, time, and station number on strip chart recorder
replace paper at end of roll and mail to RTI. Chart paper box
should be labeled with start and stop date and time and
station I.D.
2. Instrument Status
a) Check status of power, pump, ozone generator lights
(should be on).
b) Note 0~ pressure (20 psi, reset if not 20 psi).
c) Note range for NO, N09, NO (should be identical).
^ X
d) Read oxygen cylinder pressure (psi) (outside dial scale
nearest cylinder valve).
e) If #1, 2, 3 are correct, operational status of instrument
is okay.
f) Turn ozone generator on zero module ON.
3. Operational Status Data Logger System
a) Check date and time* - if date and time do not agree
with clock or wristwatch - correct date and time must
be entered using time preselect digits and time preset
switch (green button).
b) Check channel 18 for reading of 500; if value changes
+ 50, replace battery.
4. Enter operational status of Bendix analyzer on tape using
EC-22 switch. Leave switch in up position at least 3 seconds
each time. If operational status is sampling, enter _9 as
third digit; if status is inoperative, enter 7_ as third digit
(see code definitions for manual data inputs).
45
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Example Channel // Instrument ID Number Status (if sampling)
NO 8 12 129
Bendix NO 9 13 139
NO 21 25 259
X
Technicon N02 22 26 269
*
if inoperative, enter
N02 127
Bendix N02 137
NO 257
X
Technicon N02 267
5. Instrument Zero Procedure
a) Switch instrument mode switch to zero.
b) Enter code using EC-22 unit
NO - 128* - scan
N02 - 138 - scan
NO - 258 - scan
x
*
This means analyzer is stabilizing on zero air
c) After 10 minutes check zero voltages on channels 8, 9, 21;
enter millivolt readings on analyzer data sheet. Enter
code on tape using EC-22 unit;
NO - 120 - scan
N02 - 130 - scan
NO - 250 - scan
x
If "zero" reads 0.0 + 10 millivolt do not adjust. If zero exceeds
limit, readjust zero using zero control potentiometer located on meter.
Signify adjustment for NO, N09, NO by appropriate code.
L. X
NO - 128 -> perform zero adjust -> NO - 123
N02 - 135 -> perform zero adjust -> N02 - 133
NO - 258 ->• perform zero adjust -> NO - 253
X X
46
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d) Switch instrument input back to ambient and enter 128,
138, 258 on EC-22 and note "zero period" on strip chart.
If adjustment is made state zero "adjusted" for N0? on
strip chart.
e) After analyzer has sampled ambient air for two minutes,
turn off ozone generator and enter on EC-22, 129, 139,
259, if instrument is operating properly. If instrument
is not operating properly, enter the following codes:
NO - 127 - scan
N02 - 137 - scan
NO - 257 - scan
x
f) Place EC-22 unit digits to 999 and initiate scan prior to
leaving station. If any difficulty is experienced, call
RTI for instructions. (919)549-8311 Ext. 671 - C. E. Decker
Ext. 588 - Tom Royal
B. WEEKLY OPERATING PROCEDURES
1. Change magnetic tapes on data acquisition system at seven (7) day
intervals (on Friday). Mark date and time on tape logs and mail
tapes to RTI on Friday.
2. Magnetic Tape Change Procedures
a) Place data logger in STAND-BY MODE
b) Remove tape from recorder; place tape and tape log inside
carton.
c) Place new tape on recorder being careful not to crimp tape;
check to see that tape drive pins are inserted into tape
cirive w!>ee's.
d) Close elastic door.
e) Tape itiould ad",t!V e to start position - (i.e., aluminum strip
should be seated just past tape head - EOT/EOT light will
stop flashing), : f *ape does not advance, manual tape advance
may be accompli sued :-v using EOT/EOT button until aluminum
arrip Is properly located.
f) Place data logger in RECORD mode.
g) Check to see that recorder scans at five (5) minute intervals.
47
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h) Magnetic Tape Log Instructions
1. Note start, date and time for tape on tape log,
cassette number, data logger ID, and station number.
2. Note power failures on tape log.
3. Indicate stop date and time off.
4. If problems develop and unit will not work - call
T. M. Royal or C. E. Decker (919)549-8311 for
further instructions.
C. CODE DEFINITIONS FOR MANUAL DATA INPUTS
1. Identify environmental sensors with first and second digits of
the EC-22.
2. Identify operational mode of sensors with third digit of the
EC-22.
SENSOR IDENTIFICATION
Nitrogen Oxide (NO) (Bendix) / 1 / 2 /
Nitrogen Dioxide (NO,-,) (Bendix) / 2 / 3 /
Oxides of Nitrogen (NO ) (Bendix) / 2 / 5 /
X "
DATA INPUT STANDARD / 2 / 2 /
Nitrogen Dioxide (N0,?) (Technicon) / 2 / 6 /
OPERATIONAL MODE
Zero / / / 0 /
Span / / / 1 /
Calibrate / / / 2 /
Adjusted Zero / / / 3 /
Adjusted Span / / / 4 /
Mistake Made / / / 5 /
Spare / / / 6 /
Inoperative / / 111
Stabilizing (Transition Period) / / / 8 /
Ambient Sampling / / 9 /
48
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D. DATA LOGGER SAMPLING SEQUENCE
Channel
Number
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
DAY - JULIAN DATE
1st and 2nd Digit - Hours
3rd Digit - Tens of Minutes
1st Digit - Units of Minutes
2nd and 3rd Digit - Seconds
STATION IDENTIFICATION NUMBER
MANUAL DATA ENTRY
Nitric Oxide (NO) (Bendix)
Nitrogen Dioxide (NO™) (Bendix)
DATA INPUT STANDARD (Test Voltage)
Oxides of Nitrogen (NO ) (Bendix)
X
Nitrogen Dioxide (NO-) (Technicon)
Calibration Value Multiplier
+ 15 Volts
Calibration Values (ppm)
49
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APPENDIX B
DETAILED CALIBRATION PROCEDURES
(BEND IX NO-NOX-N02 ANALYZER)
51
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APPENDIX B
DETAILED CALIBRATION PROCEDURE (BENDIX NO-NO^ ANALYZER)
1. Turn on ozone generator and Hastings mass flow meter and allow them
to warm up for approximately 30 minutes.
2. Connect instrument inlet line to manifold of calibration apparatus.
Connect compressed air cylinder to calibration apparatus and allow
zero air (air filtered through charcoal) to flow through system.
Connect NO/N- gas regulator to cylinder and evacuate with pump to
prevent the formation of N0» in the regulator.
3. Allow analyzer to sample zero air for 5-10 minutes. Average zero
output for NO, NO , and N09 channels for at least 5 cycles (i.e.,
X j£
5 minutes). If instrument zero deviates from zero by more than
+ 10 mV, readjust to zero. Indicate proper entry codes for zero
and/or zero adjust on magnetic tape using EC-22 unit.
4. Prepare 0.1 ppm NO concentration by metering sufficient NO in
nitrogen into 5 liter/min diluent stream. Allow 10 minutes for
system and analyzer to equilibrate at that concentration and then
average the instrument output for at least 5 cycles. Enter proper
codes on magnetic tape with EC-22 unit. Enter calibration concen-
tration on magnetic tape using 10-turn potentiometer. Both NO and
NO channels are calibrated simultaneously.
5. Proceed to next calibration concentration and repeat Step No. 4 (i.e.,
0.1, 0.2, 0.4, 0.5 ppm NO, etc).
6. After completing the multipoint calibration with NO, generate N0~
concentrations as described in the previous discussion. Enter
proper codes and calibration concentrations on magnetic tape using
mode switches and 10-turn potentiometer. Repeat for additional
calibration points for N02 channel (i.e., 0.1, 0.2, 0.4, 0.5 ppm
N02> etc).
7. Return sample inlet line to sample manifold.
53
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APPENDIX C
DETAILED MAINTENANCE PROCEDURES
(BENDIX NO-NOX-N02 ANALYZER)
55
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APPENDIX C
DETAILED WIM1BMNCE PROCEDURES (BHNDIX NO-NOX-N02 ANALYZER)
1.0 AMBIENT AIR FILTER (TEFLON) REPLACEMENT
The ambient air filter contains a Teflon element. This element should
be inspected weekly and replaced as required. Frequent replacement will be
necessary in a dirty or high particulate concentration area. Replace the
element as follows:
a. Place the PUMP switch and the POWER switch in the off
position (down).
b. Loosen the wingnuts and open the filter assembly.
c. Remove the Teflon filter element.
d. Install the new filter element, close the assembly and
tighten the wingnuts.
2.0 EXHAUST FILTER (CHARCOAL) REPLACEMENT
The charcoal in the exhaust filter should be replaced on a monthly
basis. Replace the charcoal as follows:
a. Place the PUMP switch and the POWER switch in the off
position (down).
b. Reposition the instrument to gain access to the filter
which is mounted on the back panel. Exercise caution
to avoid applying excessive strain to the tubing
connections.
c. Disconnect the input and output lines from the filter.
d. Loosen the mounting brackets and remove the filter holder.
e. Unscrew the top portion of the filter.
f. Empty the charcoal and make sure the glass wool in the
bottom of the filter holder is in place before refilling.
g. Refill the filter holder using no. 10 mesh charcoal.
h. Reinstall the filter and reapply power.
i. Recheck the calibration.
57
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3.0 OXYGEN FILTER (SINTERED)
The oxygen filter is a sintered stainless steel mesh element that is
housed within a 1/8-in. tubing connector on the input of the capillary. The
element should be replaced when the oxygen cylinder is changed or when
the particulate buildup restricts the oxygen flow from the output of the
3
capillary to less than 30 cm per minute with OXYGEN pressure gage
2
reading of 20 Ib/in . Replace the filter element as follows:
a. Shut off the oxygen cylinder.
b. Place the PUMP switch and the POWER switch in the
off position (down).
c. Remove the four (4) screws from the top cover of
the instrument and lift the cover from the unit.
d. Loosen the fitting from the input end of the
capillary in the oxygen line.
e. Remove the stainless steel mesh filter from within
the fitting.
f. Install a new element and reconnect the fitting.
g. Replace the top cover and reapply power.
h. Recheck the calibration.
4.0 OXYGEN CYLINDER REPLACEMENT
The oxygen cylinder should be replaced when the cylinder pressure
2
decreases to 100 Ib/in g. The procedure for cylinder replacement is
presented below:
a. Place the PUMP, switch and the POWER switch in the off
position (down).
b. Close the oxygen cylinder valve.
c. Turn the two-stage regulator adjustment fully
counterclockwise.
d. Remove the two-stage regulator from the cylinder.
e. Replace the oxygen cylinder (verify that the new
cylinder contains welding grade or better oxygen).
58
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f. Connect the two-stage regulator to the cylinder.
g. Open the cylinder valve.
2
h. Adjust the two-stage regulator to 30 Ib/in g.
i. Place the POWER switch and the PUMP switch in the
ON position.
j. Allow 10 minutes for any air to be purged from the
system.
k. Perform the calibration procedure.
5.0 EVACUATION PUMP MAINTENANCE
The evacuation pump used in the Bendix NO-NO -NO analyzer is a
A £•
two-stage diaphragm-type vacuum pump. The pumping element and motor
require no lubrication and should not be dismantled in the field. However,
if the pump performance degrades to the point that it will not maintain a
vacuum of 23 in. Hg, the cause may be foreign particles under the reed
valves or a ruptured diaphragm. Correcting either of the aforementioned
problems may be accomplished as follows:
a. Place the PUMP switch and the POWER switch in the off
position (down).
b. Disconnect the pump power cord from the jack on the
rear panel of the instrument.
c. Disconnect the Teflon tubing from the pump intake and
the polyethylene tubing from the pump exhaust. The
copper tubing remains connected between the two heads.
d. Remove the eight (8) screws from the two heads (four
in each head) and remove the two heads.
e. The reed valve assemblies are mounted in the head. Note
the orientation of the reed valves with respect to the
input and output of each head.
f. Remove the reed valve assembly from each head by
removing the four (4) Phillips head screws attaching
the assembly to the head.
59
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g. Remove the two (2) screws that secure the reed valves
to each assembly. Use caution to prevent distorting
the reeds.
h. Wipe the reeds and the assemblies with a clean, lint-
free cloth.
i. Reassemble the reed valve assemblies utilizing the screws
removed in step g.
j. Reinstall the reed valve assemblies in the heads utilizing
the screws removed in step f. Insure that the proper
orientation of the reed valves is observed, as noted in
step e.
k. Inspect each diaphragm for evidence of deterioration or
holes. Remove any foreign matter from the diaphragm.
1. If either or both diaphragms require replacement, remove
the four (A) Phillips head screws that attach the diaphragm
to the piston and replace the diaphragm.
m. Install a new diaphragm utilizing the screws removed in
step 1.
n. Reinstall the heads on the pump utilizing the screws
removed in step d. Insure that the diaphragms are properly
seated in the grooves of the pump body prior to installing
the heads.
o. Reinstall the tubing removed in step c and reconnect the
pump power cord.
p. Service the exhaust filter (charcoal) in accordance with
paragraph 2.0.
q. Apply power to the instrument and pump and recheck the
pump vacuum.
r. Recheck the calibration.
60
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TECHNICAL REPORT DATA
i "lease ;-fad fnunictions on the reicrse before completing/
1. REPORT NO.
EPA-600/1-76-034
3. RECIPIENT'S ACCESSI OV NO.
4. TITLE AND SUBTITLE
Nitrogen Dioxide Trends in Selected Chattanooga
Communities
5. REPORT DATE
October 1976
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
C.E. Decker and T.M. Royal
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Research Triangle Institute
Research Triangle Park, N.C. 27709
10. PROGRAM ELEMENT NO.
1AA601
11. CONTRACT/GRANT NO.
68-02-1737
12. SPONSORING AGENCY NAME AND ADDRESS
Health Effects Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, N.C. 27711
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA-ORD
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The objectives of this project were to operate air monitoring stations and
collect air quality data in the Chattanooga, Tennessee area to supportepidemiological
studies during the period June 15, 1974 to June 14, 1976. This ongoing project was
begun in 1969 under the sponsorship of the U.S. Environmental Protection Agency
and was designed to gather air quality data for use in studies relating health
effects to ambient concentrations of oxides of nitrogen. Initially, th2 aerometric
program consisted of particulate (high volume method) and nitrogen dioxide (CHESS
bubbler method) measurement at ten stations located in and about the Chattanooga
area. In 1972 the Research Triangle Institute upgraded the aerometric monitoring
program in Chattanooga through a joint project sponsored by the Environmental
Protection Agency and the Coordinating Research Council. Chemiluminescent NO-NOX-N02
analyzers and data acquisition systems were installed in environmentally-controlled
shelters at seven of the nine monitoring sites operating at that time. The
Research Triangle Institute has operated and maintained the nine-station
monitoring network and provided aerometricdata to the Environmental Protection
Agency under contract 68-02-1737 through May 1976.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field.'Group
Nitrogen oxides
Nitrogen dioxide
air pollution
analyzers
monitors
13 B
14 B
13. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisRepoit)
UNCLASSIFIED
21. NO. OF PAGES
69
20. SECURITY CLASS (Tnis pagej
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
61
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