United States Office of Air Quality EPA-450/4-79-007
Environmental Protection Planning and Standards OAQPS No. 1.2-114
Agency Research Triangle Park NC 27711 February 1979
Air
Guideline Series
Guidance for Selecting
TSP Episode Monitoring
Methods
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I EPA-450/4-79-007
(OAQPS No. 1.2-114)
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- Guidance for Selecting TSP
1 Episode Monitoring Methods
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_ Monitoring and Data Analysis Division
Office of Air Quality Planning and Standards
and
Environmental Monitoring and Support Laboratory
Office of Research and Development
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Office of Air Quality Planning and Standards
Research Trianale Park. North Carolina 27711
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U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air, Noise, and Radiation
3 of Air Quality Planning and Stand
Research Triangle Park, North Carolina 27711
February 1979
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OAQPS GUIDELINE SERIES
The guideline series of reports is being issued by the Office of Air Quality Planning and Standards (OAQPS) to
provide information to state and local air pollution control agencies; for example, to provide guidance on the
acquisition and processing of air quality data and on the planning and analysis requisite for the maintenance of _
air quality. Reports published in this series will be available -as supplies permit-from the Library Services Office
(MD-35), US. Environmental Protection Agency, Research Triangle Park, North Carolina 27711; or, for a
nominal fee, from the National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia
22161
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Publication No EPA-450/4-79-007
(OAQPS No. 1.2-1 14) I
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PREFACE
The Reference Method for the Determination of Suspended Particulates
in the Atmosphere (High Volume Sampler Method) specifies a twenty-four
hour sampling interval. However, the use of particulate monitors which
provide data at much shorter time intervals than twenty four hours is
necessary during air pollution episodes and for purposes of daily report-
ing of an index of air quality. As a result, revised monitoring regulations
have been proposed (Appendix C of 40 CFR 58, Aug. 7, 1978) that allow the
use of short term particulate monitors. Consequently, this guideline
was prepared to describe the two modified versions of the Reference
Method for Particulates that are permitted to be used during air pollution
episodes and for purposes of daily air quality index reporting. In
addition, the guideline explains the procedure for establishing a site
and season-specific relationship between the high volume method and
particulate methods other than the two modified high volume methods.
Criteria are included in this guideline for use by Regional Offices,
State,and local agencies in determining if such a relationship is
satisfactory for use during particulate episodes. Example calculations
showing the detailed steps are also included.
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ACKNOWLEDGMENT
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This guideline is based on a report furnished to the Environmental
Protection Agency by Frank Smith of the Research Triangle Institute, J
Research Triangle Park, North Carolina in fulfillment of a project
assignment under Contract No. 68-02-2714. Through the primary efforts
of George Manire of the Monitoring and Reports Branch, Monitoring and
Data Analysis Division, Office of Air Quality Planning and Standards,
Environmental Protection Agency, the report was reviewed and rewritten *
in guideline series format. Technical assistance and review were
provided by Alan Hoffman, William Cox, and Stanley Sleva of the Office of I
Air Quality Planning and Standards and Frank McElroy and Larry Purdue _
of the Environmental Monitoring and Support Laboratory, Research Triangle |
Park.
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I. INTRODUCTION
TABLE OF CONTENTS
Page
1
A. Purpose and Scope 1
B. Rationale
for the Revised Episode Regulations 2
II. USE OF MODIFIED REFERENCE METHODS 3
A. Short-Time
B. Staggered
Interval High Volume Sampling 3
High-Volume Sampling 5
III. USE OF OTHER METHODS 6
A. Test Condi
B. Evaluation
C. Method for
IV. REFERENCES
APPENDIX A - Method
tions for Establishing the Relationship 6
Procedure 7
Displaying the Relationship 8
9
for the Determination of Total
Suspended Parti culates in the Atmosphere
Over Short Sampling Times
APPENDIX B - Example
Calculations
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GUIDANCE FOR SELECTING TSP EPISODE MONITORING METHODS
I. INTRODUCTION
The EPA requirements which are prescribed in Title 40 Code of
Federal Regulations (40 CFR) Part 51 for ambient air quality monitoring
for purposes of State Implementation Plans (SIPs) are being revised.
The revised requirements will appear in a new Part 58 entitled,
"Ambient Air Quality Surveillance," and will include revisions
to the emergency episode monitoring requirements now described in
40 CFR Part 51.17(c). The emergency episode guidance provided in
Federal Regulation Part 51.16 and Appendix L will be amended to reflect
the new requirements. The new regulations would permit the use of
two modified versions of Appendix B of 40 CFR, Part 50 - Reference
Method for the Determination of Suspended Particulates in the
Atmosphere (High Volume Method). The regulations will also permit
the use of non high-volume methods provided that specific site
relationships to the reference method have been determined and documented
and that these methods provide for short-term measurements.
A. Purpose and Scope
There are two purposes for this guideline. The first is
to explain the principles of operation of the two episode particulate
monitoring methods which are modifications of the reference method:
(1) high-volume sampling over short sampling time intervals; and (2)
staggered high-volume sampling. These methods may be used by an
agency in their TSP episode network without further testing in most
cases.
Secondly, a procedure is described for establishing a site-
and season-specific relationship between the high-volume method and
particulate methods other than the two mentioned above.
This guideline does not cover the criteria for emergency
episode station location or design, sampling frequency, mechanics of
becoming aware of an episode, or corrective actions to take in order
to minimize episodic conditions.
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B. Rationale for the Revised Episode Regulations
When the requirements described in 40 CFR Part 51.16 I
and 51.17(e) were promulgated, tape samplers were required in
order to monitor the ambient air during total suspended particulates
(TSP) episodes as a basis for initiating episode control actions. *
The tape sampler provided more frequent measurements at shorter time «
intervals then the reference method. I
Since the promulgation of this regulation, several
investigations have attempted to establish a relationship between |
the TSP as measured by the reference method in air and the optical
density or reflectance of particulate matter collected on paper
spots or tapes ~ .All such studies have shown that the
relationship is dependent on a number of factors which preclude
the method's general application as an index of TSP mass concentration.
The optical density, transmittance, or reflectance of the spot sample
is proportional to mass concentration only when the optical properties '
of the aerosol (e.g., particle size, shape, density, refractive index, _
color, size distribution, etc.) remain reasonably constant.
Several area- and site-specific empirical relationships
of mass concentration to reflectance or optical density have been p
calculated. Both linear3'5'13"16 and non-linear3'4'7"11 relation-
ships have been reported as suitable for specific sites and
conditions. However, there appears to be no universally con-
sistent relationship between the tape sampler and the hi-vol '
sampler measurements.
Because of this problem, the emergency episode monitoring
requirements are being revised by allowing the use of two modified
reference methods; by requiring that a specific site relationship _
be determined for methods not based on the reference method (such as |
the tape sampler) and by removing the specification in coefficient
of haze (COH ) for tape samplers from §51.16 and Appendix L of I
40 CFR Part 51.
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II. USE OF MODIFIED REFERENCE METHODS
Short-time interval high-volume sampling and staggered
high-volume sampling are two acceptable episode monitoring
methods. Because these methods are based on the reference method,
it is believed that they are applicable as monitoring methods
during an episode without having to determine a specific site
relationship. In areas where there is high humidity, oily
particulate, acidic particulate, or types of particulates for
which equilibration is not achieved in 2 hours, an agency should
establish a specific site relationship between the recommended
methods and the referenced hi-vol method. However, in most cases,
the recommended methods can be used without testing.
A. Short-Time Interval High Volume Sampling
The complete procedure for short-time interval high-volume
sampling is given in Appendix A, however, the major modifications
are: (a) a shorter sampling period (4 hours), and (b) different filter
equilibration conditions (2 hours).
The method is applicable to measurement of TSP concentrations
in ambient air during air pollution episode conditions, using a
4-hour sampling period and a 2 hour filter equilibration period.
That is, every 4 hours the loaded filter is replaced by a clean
filter. Thus, data are available 6 hours after the start of the
sampling. This method requires only one sampler; however, it may
be wise to have a second one in case the first one fails during an
episode. TSP values representing 4 hour averages for successive
sampling periods may be plotted or tabulated as they are received
in a fashion to facilitate the detection of a change in the ambient
TSP conditions.
Based on a coefficient of variation (relative standard
deviation) of approximately 5% for this method, successive differences
of less than 10% should not be interpreted as a significant change.
However, four or more TSP values, from successive sampling periods,
changing in the same direction should be interpreted as a trend.
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The disadvantages of this method over the staggered high- |
volume sampling are:
(a) Because acid gases affect a surface reaction on
alkaline filters and because six filters are needed
to determine a 24-hour TSP level, this method of
monitoring an episode could introduce a larger bias
in the TSP analysis;
(b) Because the filters have to be changed and the air
flow rate measured every four hours, beginning four _
hours after the first hour, there will be a greater |
chance for human error. However, based on a short-
term interval high-volume sampling study , the
established relative standard deviation (coefficient
of variation) for single operator (same sample, different I
samplers, and different day) variation for four hour
sampling and two hour equilibration periods is only 5.2
percent; and
(c) Because the filter has to be changed every four hours, the 24- M
hour TSP (yg/m3) values will be the average of six intermit-
tent TSP (yg/m3) values, thus not a true continuous 24-hr value.
The advantages of this method over the staggered high-volume |
sampling are:
(a) Provides a measure of the TSP over a very recent (four . I
hour)period of time; thus as a result, concentrations
are available 6 hours after the start of sampling; I
(b) Only one sampler is required, however, a second one is
recommended; ,
(c-) A lower probability that dense fog, high humidity, oily "
particulate, or excessive particulates collected during
an episode will severely reduce the air flow through
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the filter, which may reduce the precision and accuracy
of this method; and |
(d) The two hour equilibration may be more effective on a
four hour TSP sample than on a 24-hour TSP sampler. I
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B. Staggered High-Volume Sampling
This method is based upon the reference method modified
such that multiple monitors are used at the site and the filters
are weighed after 2 hours of equilibration, as described in
Appendix A, 7.2. The starting time of each high-volume monitor is
staggered by some constant time interval. For example, staggering
the starting time of each monitor by 4 hours would require 6 monitors
for continuous operation and would provide a 24-hour TSP average
value, after the first 26 hours and every 4 hours thereafter.
This method can be implemented with any desired time
increment between sampling start times. However, due to the number
of samplers required, increments of less than four hours would
probably not be practical.
The samplers should be placed on-site in a matrix such
that they will be sampling the same atmosphere but without inter-
ference with each other. The electrical power supply should be
capable of supporting the total number of samplers operating
simultaneously without varying appreciably in voltage as individual
samplers are taken off or put on line.
TSP values representing 24 hour averages for successive
sampling periods may be plotted or tabulated as they are recieved
in a fashion to facilitate the detection of a change in the ambient
TSP conditions.
Based on a coefficient of variation of 3.7 percent for the
reference method, successive differences less than about 7.4% should
not be interpreted as a significant change. However, four or more
TSP values, from successive sampling periods, changing in the same
direction should be interpreted as a trend.
The disadvantages of staggered high-volume sampling as
compared to the short-time interval high-volume sampling include:
(a) Increased equipment, power and labor requirements;
(b) The elapsed time from the start of sampling until
the first results are available is 26 hours;
(c) The high probability that dense fog, high humidity,
oily particulate, and excessive particulates collected
during an episode may severely reduce the air flow through
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the filter, thus reducing the precision and accuracy
of this method; and
(d) A 2 hour equilibration time may, not be long
enough to account for moisture on the 24-hour I
sample.
Advantages of using staggere^ high-volume sampling over the J
short-time interval high-volume sampling are:
(a) It measures for 24 hours, thus the results should be
a better indicator of the 24-hour TSP level; and
(b) It provides current 24-hour TSP behavior during an 8
episode condition.
III. USE OF OTHER METHODS *
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Whenever a method other than the two recommended methods is
to be useo for episode monitoring, a specific site relationship
between it and the reference hi-vol method must be established and
documented.
The disadvantage of using other methods over the recommended
methods is that the recommended methods are based on the same |
principle as the reference method and in most cases, the specific
site relationship need not be determined, thus reducing the testing g
time, testing cost, and the need perhaps for skilled personnel or
expensive equipment. I
The advantage of other methods over the recta-mended methods
may be the advantage of automation which could minimize the loss
of time between air samples and important strategy decisions.
This section describes the procedures which should be followed fl
to develop the specific site relationship.
A. Test Conditions for Establishing the Relationship
The reference method is the Federal Register hi-vol reference _
method and should be operated according to the method specification except I
that the sampler need not be operated from midnight to midnight, any given
24 hours of continuous operation is acceptable. The method (candidate method) |
for which the specific site relationship is to be established should be
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operated and calibrated, if needed, according to the applicable
operation manuals.
At least ten (10) ambient air measurements should be made
simultaneously by the candidate and the reference hi-vol methods.
The air samples should be taken simultaneously in the same area
(i.e., within 2-3 meters of each other) without interference
between samples or instruments.
These measurements should be made on ambient air containing
TSP concentrations in the range that the candidate method will be
subjected to during an episode. To accomplish this, the measurements
could initially be performed in non-episodic (normal) atmospheric
conditions, to establish the relationship, but resumed during an
episode to determine if the established relationship changes signifi-
cantly. The relationship may be a function of the pollutant source,
such as coal combustion, dust storms, or fuels used. If such is the
case, then that particular pollutant source specific relationship
should be used.
If the candidate method has a shorter measuring time
interval than the reference hi-vol method, a sufficient number of sequen-
tial interval measurements should be made to equal the time period
of the reference hi-vol method. The TSP concentration as determined
by the reference hi-vol method and the TSP concentration determined
by the candidate method (or the mean of sequential determinations by
the candidate method) are considered a "test pair."
All records, test data, procedural description and details,
and other documentation obtained from (or pertinent to) tests made
for the purpose of testing a candidate method should be identified,
dated, and signed by the tester.
B. Evaluation Procedure
The test pairs are used to estimate the functional rela-
tionship between the candidate and the reference methods. Graphical
or regression techniques are useful in estimating the form of the
regression equation between the candidate method (y) and the reference
hi-vol method (x). If the relationship appears to be reasonably linear
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over the range of interest; then? standard linear regression techniques can I
be used to estimate and test the significance of the relationship. Appendix B
contains a worksheet which illustrates the basic calculations when
a linear relationship appears suitable. Agencies are not advised
to use a candidate method whenever the linear coefficient of correlation M
is less than 0.7. I
These calculations are based on the assumption that measurements
obtained using the reference method have little measurement error |
compared to measurements errors in the candidate method. Thus, the
reference method is treated as the independent variable (X) in
estimating the least squares regression line which relates the two
m easurements. Other estimation techniques * are available for
situations where both variables are subject to substantial errors.
C. Other Relationships
In cases where the relationship does not appear to be linear
over the entire range of interest, other techniques for relating the M
two measuring systems may be used. For example, some agencies have
found that a piece-wise linear function is superior to a single linear
function. Tests of significance are not as straightforward as for |
the linear case and require care in interpretation. Often, it is
possible to linearize a non-linear relationship by transformation of I
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variables (e.g., yX, log X, etc). In such cases, the procedures outlined
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in Appendix B may be applied to the transformed variables. In some rare
cases, it may be necessary to use non-linear regression techniques
to properly fit the measured data.
D. Methods for Displaying the Relationship
Because of the need to quickly assess the quality of the ambient
air during a TSP episode, it is recommended that a method be devised
to aid in the rapid interpretation of the data. Methods such as the
use of a graph, table of corresponding values, or the equation of the |
relationship could be used to obtain a rapid interpretation of the data.
In any event, regardless of the method chosen, it should be readily
accessible to the instrument operator or data user.
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IV. REFERENCES
1. R.S.C. Rogers, and F. Smith. An Evaluation of the High Volume
Method for Determining Total Suspended Partlculates Over Short
Sampling Times, EPA Contract No. 68-02-0294, Task 15, Research
Triangle Institute, Research Triangle Park, North Carolina 27709,
November 1974.
12. American Society for Testing and Materials, "Standard Method
of Test for Parti cul ate Matter in the Atmosphere (optical density
of filtered deposit)", ASTM Designation D 1704-61, 1969.
3. Pedace, E.A. and E.B. Sansone. "The Relationship Between
'Soiling Index1 and Suspended Particulate Matter Concentrations,"
J. Air Poll. Control Assoc. , 22_, 348, 1972.
4. Ingram, W.T. and J. Golden. "Smoke Curve Calibration,"
J. Air Poll. Control Assoc., 23_, 110, 1973.
5. Lisjak, G.J. "Comparison of High Volume and Tape Sampler Data,"
Allegheny County (PA.) Health Department, Bureau of Air Pollution
Control, Pittsburgh, PA, 1977..
6. West, P.W. "Chemical Analysis of Inorganic Air Pollutants," in
Air Pollution, V.II, 2i
Press, New rork, 1953.
7. Waller, R.E. "Experiments on the Calibration of Smoke Filters,"
J. Air Poll. Control Assoc., 1_4_:323, 1964.
Air Pollution, V.II, 2nd Edition, A.C. Stern, Editor, Academic
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8. Sullivan, O.L. "The Calibration of Smoke Density," J. Air Poll.
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Control Assoc., 1_2:474, 1962.
Kerreny, E. "The Determination of Gravimetric Pollution
Concentrations by Means of Filter Papers," J. Air Poll . Control
Assoc., 11:273, 1962.
| 10. Sanderson, H.P. and M. Katz. "The Optical Evaluation of Smoke
cr Parti 0.1 ate Matter Collected on Filter Paper," J. Air Poll.
. Control Assoc., j_3_:476, 1963.
11. Katz, M.H., H.P. Sanderson, and M.B. Ferguson. "Evaluation of
I Air-Borne Parti cul ates in Atmospheric Pollution Studies,"
Anal. Chsn., 3_Q_:1172, 1953.
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12.
13.
14.
15.
16.
17.
18.
19.
10
Coulson, J. and J. McK. Ellison. "A Calibration of the Filter
Paper Method of Estimation of Smoke," Brit. J. Anpl . Phys.,
14:899, 1963.
Cholak, J., L.J. Schaffer, ' .J. Younker, and D.W. Yeager. "The
Relationship Betv/een Sulfu Dioxide and Particulate Matter in
the Atmosphere," Amer. Ind. Hyq. Assoc. J., 19:371, 1953.
Hall, S.R. "Evaluation of Particulate Concentrations with
Collecting Apparatus," Anal. Cham., 24:995, 1952.
Rondia, D. "L1 estimation do la densite des fumees1 dans 1'air,"
Int. J. Air Wat. Poll., 6:353, 1962.
Stalker, W.W., R.C. Dickerson, and G.D. Kramer. "Atmospheric
S Ifur Dioxide and Particulate Matter: A Comparison of Methods
ar-d Measurements," Amer. Ind. Hyq. Assoc. j'. , 24:68, 1963.
Daniels Cuthbert, Wood, Fred S. Fitting Equations to Data,
Wiley-Interscience. 1971.
National Bureaus of Stnadards, Experimental Statistics, Handbook 91,
Washington, 1963 (Edited by M.G. Natrella).
Acton, Formon S., Analysis of Straight-Line Data, John Wiley and
Sons, New York, 1959.
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APPENDIX A
| METHOD FOR THE DETERMINATION
OF TOTAL SUSPENDED PARTICIPATES IN THE ATMOSPHERE
OVER SHORT SAMPLING TIMES,
* (HIGH VOLUME METHOD)
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APPENDIX A |
METHOD FOR THE DETERMINATION
OF TOTAL SUSPENDED PARTICULATES IN THE ATMOSPHERE
OVER SHORT SAMPLING TIMES,
(HIGH VOl'JME METHOD) .
1.0 PRINCIPLE AND APPLICABILITY
1. Air is drawn into a covered housing and through a filter by means |
3
of a high-f.low-rate blower at a flow rate (1.70 to 1.98 m /min; 60 to 70
ft /min) that allows suspended particles having diameters of less than 100
ym (Stokes equivalent diameter) to pass to the filter surface (ref. 1).
Particles within the size range of 0.1 to 100 ym diameter are ordinarily
collected on fiberglass filters. The mass concentration of total suspended par-
3
ticulate^ in the ambient air (yg/m ) is computed by measuring the mass of
collected particulates and the volume of air sampled.
2. This method is applicable to measurement of 4-hour average mass
concentrations of total suspended particulates in ambient air. To assure meas-
urements of acceptable precision, this method should not be used to measure _
average concentrations of less than about 30 yg/m (this yields 4-hour samples |
of approximately 20 mg). The size of the sample collected is usually adequate
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for other analyses. Concentrations as low as 10 yg/m can be measured; how-
ever, the relative error would probably be larger than that given in section 4.0.
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2.0 RANGE AND SENSITIVITY
Weights are determined to the nearest 0.1 mg, airflow rates are deter-
mined to the nearest 0.1 m /min, times are determined to the nearest minute,
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and mass concentrations are reported to three significant digits, e.g., 102
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yg/m and 50.6 yg/m .
3.0 INTERFERENCES I
1. Particulate matter that is oily, such as photochemical smog or wood
smoke, may b\ock the filter and cause a rapid drop in airflow at a nonuniform
rate. Dens., fog or high humidity in conjunction with certain types of par-
ticulates may severely reduce the airflow through the filter.
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A-3
2. Fiberglass filters are comparatively insensitive to changes in
relative humidity but collected particulates can be hygroscopic (ref. 2).
3. Acid gases in the sample air,may be converted to particulate matter
on the surface of alkaline filters (refs. 3, 4).
4.0 PRECISION, ACCURACY, AND STABILITY
4.1 Precision
Based on the Short-term High Volume Study, the estimated relative stan-
dard deviation (coefficient of variation) for single operator (same sample,
different samplers, and different day) variation for 4-hour sampling and
2-hour equilibration periods is 5.2 percent.
4.2 Accuracy
The accuracy with which the sampler measures the true average concentra-
tion cannot be quantitatively determined. Measured values higher than the
true values may result when alkaline filters are used. A functional analysis
of the method indicates that other large biases should not normally occur in
short-term sampling (ref. 5).
5.0 APPARATUS
5.1 Sampling
5.1.1 Sampler. The sampler consists of three units: 1) the faceplate and
gasket, 2) the filter adapter assembly, and 3) the motor unit. Figure A-l
shows an exploded view of these parts, their relationship to each other, and
how they are assembled. The sampler must be capable of passing environmental
2 2
air through a 406.5 cm (63 in. ) portion of a clean 20.3 by 25.4 cm (8 by
10 in.) fiberglass filter at a rate of at least 1.70 m /min (60 ft /min).
The motor must be capable of continuous operation for 4-hour periods with
input voltages ranging from 110 to 120 volts, 50-60 cycles alternating cur-
rent and must have third-wire safety ground. The housing for the motor unit
may be of any convenient construction so long as the unit remains airtight
and leak free.
5.1.2 Sampler Shelter. It is important that the sampler be properly installed
in a suitable shelter. The shelter is subjected to extremes of tempera-
ture, humidity, and all types of air pollutants. For these reasons the
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ADAPTED
MOUNTING MOTOR
PLATS "
0^«« HOUp.
g%«T. "^
17^
BASKET
SOTAMETEH
CONDENSER
ANOCLIP
-TUBINS
Figure A-l. Exploded view of typical high-volume air sampler parts.
materials of the shelter must be chosen carefully. Properly painted exterior
plywood or heavy gage aluminum serve well. The sampler must be mounted verti-
cally in the shelter so that the fiberglass filter is parallel with the ground.
The shelter must be provided with a roof so that the filter is protected from
precipitation and debris. The internal arrangement and configuration of a
suitable shelter with a gable roof are shown in figure A-2. The clearance
area between the main housing and the roof at its closest point should be
2 2
580.5 + 193.5 cm (90 + 30 in. ). The main housing should be rectangular, with
dimensions of about 29 by 36 cm (11-1/2 by 14 in.).
5.1.3 Rotameter. A rotameter marked in arbitrary units, frequently 0 to 70,
and capable of being calibrated is acceptable for measuring sample flow rates.
Other devices of at least comparable accuracy may be used (see addendum A).
5.1.4 Orifice Calibration Unit. Consisting of a metal tube 7.6 cm (3 in.)
ID and 15.9 cm (6-1/4 in.) long with a static pressure tap 5.1 cm (2 in.) from
one end. See figure A-3. The tube end nearest the pressure tap is flanged
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Figure A-2. Assembled sampler and shelter.
ORIFlCg
RESISTANCE PLATES
Figure Ar3. Orifice calibration unit.
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to about 10.8 cm (4-1/4 in.) OD with a male thread of the same size as the
5.1.6 Positive Displacement Meter. Calibrated in cubic meters or cubic
feet, to be used as a primary standard.
6.0 REAGENTS
6.1 Filter Media
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inlet end of the high-volume air sampler. A single metal plate 9.2 cm
(3-5/8 in.) in diameter and 0.24 cm (3/32 in.) thick with a central orifice *
2.9 cm (1-1/3 in.) in diameter is held in place at the air inlet end with a
female threaded ring. The other end of the tube is flanged to hold a loose
female threaded coupling, which screws onto the inlet of the sampler. An _
18-hole metal plate, an integral part of the unit, is positioned between the |
orifice and sampler to simulate the resistance of a clean fiberglass filter.
An orifice calibration unit is shown in figure A-3. I
5.1.5 Differential Manometer. Capable of measuring to at least 40 cm (16 in.)
of water.
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5.1.7 Barometer. Capable of measuring atmospheric pressure to the nearest
mm of Hg.
5.2 Analysis
5.2.1 Filter Conditioning Environment. Balance room or desiccator maintained
at approximately 25 °C and less than 10-percent relative humidity. A desiccator
with fresh desiccant such as Drierite maintained in an air-conditioned room
provides a satisfactory conditioning environment.
5.2.2 Analytical Balance. Equipped with a weighing chamber designed to
handle unfolded 20.3 by 25.4 cm (8 by 10 in.) filters and having a sensitivity
of 0.1 mg.
5.2.3 Light Source. Frequently a table of the type used to view X-ray films.
5.2.4 Number Device. Capable of printing identification numbers on the filters.
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Neutral fiberglass filters having a collection efficiency of at least 99 per-
cent for particles of 0.3 ym diameter, as measured by the DOP test, are suitable
for the quantitative measurement of concentrations of total suspended particu-
lates (ref. 6), although some other medium, such as paper, may be desirable for
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some analyses. If a more detailed analysis is contemplated, care must be
exercised to use filters that contain low background concentrations of the
pollutant being investigated. Careful quality control is required to deter-
mine background values of these pollutants.
7.0 PROCEDURE
7.1 Sampling
7.1.1 Filter Preparation. Expose each filter to the light source and inspect
for pinholes, particles, or other imperfections. Filters with visible Imper-
fections should not be used. A small brush is useful for removing particles.
Print an identification number using the numbering device on the outer edge of
the filters. Equilibrate the filters in the filter-conditioning environment
(section 7.2) for 2 hours. Weigh the filters to the nearest 0.1 mg; record
tare weight and filter identification number. Do not bend or fold the filter
before collection of the sample.
7.1.2 Sample Collection. Open the shelter, loosen the wing nuts, and remove
the faceplate from the filter holder. Install a numbered, preweighed, fiber-
glass filter in position (rough side up), replace the faceplate without dis-
turbing the filter, and fasten securely. Undertightening will allow air
leakage; overtightening will damage the sponge rubber faceplate gasket. A
very light application of talcum powder may be used on the sponge rubber face-
plate gasket to prevent the filter from sticking. During inclement weather
the sampler may be removed to a protected area for filter change. Close the
roof of the shelter, run the sampler for about 5 minutes, connect the rotameter
to the nipple on the back of the sampler, and read the widest part of the
rotameter float with the rotameter in a vertical position. Estimate to the
nearest whole number. If the float is fluctuating rapidly, tip the rotameter
and slowly straighten it until the float gives a constant reading. Disconnect
the rotameter from the nipple; record the initial rotameter reading, the
starting time, and the date on the filter or other suitable form folder. (The
rotameter should never be connected to the sampler except when the flow is
being measured.) Sample for 4 hours and take a final rotameter reading.
Record the final rotameter reading, ending time, and date on the filter folder
or other suitable form. Remove the faceplate as described above and carefully
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A-8
8.0 CALIBRATION
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remove the filter from the holder, touching only the outer edges. Fold the
filter lengthwise so that only surfaces with collected particulates are in
contact, and place in a manila folder. Record on the folder or other suit-
able form the filter number, location, and any other factors, such as
meteorological conditions or razing of nearby buildings, that might affect the _
results. If the sample is defective, void it at this time. In order to obtain |
a valid sample, the flow rate of a high-volume sampler must be measured with
the same rotameter and tubing that were used during its calibration.
7.2 Analysis
Equilibrate the exposed filters for 2 hours in a low relative humidity |
(< 10 percent) and room temperature environment, then weigh to the nearest
0.1 mg. After they are weighed, the filters may be saved for detailed chem-
ical analysis.
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7.3 Maintenance
7.3.1 Sampler Motor. Replace brushes before they are worn to the point where
motor damage can occur.
7.3.2 Faceplate Gasket. Replace when the margins of samples are no longer
sharp. The gasket may be sealed to the faceplate with rubber cement or
double-sided adhesive tape. _
7.3.3 Rotameter. Clean as required, using alcohol.
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8.1 Purpose _
Since only a small portion of the total air sampled passes through the |
rotameter during measurement, the rotameter must be calibrated against actual
airflow with the orifice calibration unit. Before the orifice calibration g
unit can be used to calibrate the rotameter, the orifice calibration unit
itself must be calibrated against the positive displacement primary standard.
8.1.1 Orifice Calibration Unit. Attach the orifice calibration unit to the
intake end of the positive displacement primary standard and attach a high-
volume motor blower unit to the exhaust end of the primary standard. Connect
one end of a differential manometer to the differential pressure tap of the
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A-9
orifice calibration unit and leave the other end open to the atmosphere.
Operate the high-volume motor blower unit so that a series of different, but
constant, airflows (usually six) are obtained for definite time periods.
Record the reading on the differential manometer at each airflow. The dif-
ferent constant airflows are obtained by placing a series of loadplates, one
at a time, between the calibration unit and the primary standard. Placing
the orifice before the inlet reduces the pressure at the inlet of the primary
standard below atmospheric; therefore, a correction must be made for the
increase in volume caused by this decreased inlet pressure. Attach one end
of a second differential manometer to an inlet pressure tap of the primary
standard and leave the other open to the atmosphere. During each of the con-
stant airflow measurements made above, measure the true inlet pressure of the
primary standard with this second differential manometer. Measure atmospheric
pressure and temperature. Correct the measured air volume to true air volume
as directed in subsection 9.1.1, then obtain true airflow rate, Q, as directed
in subsection 9.1.3. Plot the differential manometer readings of the orifice
unit versus Q.
*
8.1.2 High-volume Sampler. Assemble a high-volume sampler with a clean filter
in place and run for at least 5 minutes. Attach a rotameter, read the float,
adjust so that the float reads 65, and seal the adjusting mechanism so that
it cannot be changed easily. Shut off motor, remove the filter, and attach
the orifice calibration unit in its place. Operate the high-volume sampler at
a series of different, but constant, airflows (usually six). Record the
reading of the differential manometer on the orifice calibration unit and
record the readings of the rotameter at each flow. Measure atmospheric pres-
sure and temperature. Convert the differential manometer reading to m /min,
Q, then plot rotameter reading versus Q.
8.1.3 Correction for Differences in Pressure or Temperature. See Addendum B,
9.0 CALCULATIONS
9.1 Calibration of Orifice
9.1.1 True Air Volume. Calculate the air volume measured by the positive
displacement primary standard.
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A-10
where
9.1.3 True Airflow Rate
V
Q -
V
where
3
Q = Flow rate, m /min
T = Time of flow, min.
9.2 Sample Volume
9.2.1 Flow Rate Conversion. Convert the initial and final rotameter readings
to true airflow rate, Q, using the calibration curve of subsection 8.1.2.
9.2.2 Volume of Air Sampled. Calculate the volume of air sampled by
V -
where
V » Air volume sampled, m
Q. - Initial airflow rate, m /min
Q- = Final airflow rate, m /min
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V » True air volume at atmospheric pressure, m
Si
P = Barometric pressure, mm Hg _
P = Pressure drop at inlet of primary standard, mm Hg
V__ * Volume measured by primary standard, m .
M
9.1.2 Conversion Factors
Inches Hg x 25.4 * mm Hg. _
Inches water x 73.48 x 10~ = inches of Hg. I
Cubic feet air x 0.0284 - cubic meters air.
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T «" Sampling time, min.
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9.3 Mass Concentration
Calculate mass concentration of total suspended particulates by
(W- - W ) x 106
TSP - r,
where
TSP *
W » Initial weight of filter, g
TSP * Mass concentration of total suspended particulates, yg/m
W. « Final weight of filter, g
3
V * Air volume sampled, m
10 » Conversion of g to yg.
10.1 REFERENCES
1. C. D. Robson and K. E. Foster. "Evaluation of Air Particulate Sampling
Equipment." Am. Ind. Hyg. Assoc. J. 24 (1962): 404.
2. G. P. Tierney and W. D. Conner. "Hygroscopic Effects on Weight Deter-
minations of Particulates Collected on Glass-Fiber Filters." Am. Ind.
Hyg. Assoc. J. 28 (1967): 363.
3. Robert M. Burton et al. "Field Evaluation of the High-volume Particle
Fractionating Cascade Impactor A Technique for Respirable Sampling."
Presented at the 65th Annual Meeting of the Air Pollution Control Asso-
ciation, June 18-22, 1972.
4. Peter K. Mueller et al. '"Selection of Filter Media: An Annotated
Outline." Presented at the 13th Conference on Methods in Air Pollution
and Industrial Hygiene Studies, University of California, Berkeley,
California, October 30-31, 1972.
5. F. Smith and A. C. Nelson, Jr., "Guidelines for Development of Quality
Assurance Programs and Procedures Applicable to Measuring Pollutants for
Which National Ambient Air Quality Standards Have Been Promulgated,"
Final Report, Research Triangle Institute, Contract No. EPA-Durham-
68-02-0598, Environmental Protection Agency, Research Triangle Park,
N.C. 27711, August 1973.
6. J. B. Pate and E. C. Tabor. "Analytical Aspects of the Use of Glass-
Fiber Filters for the Collection and Analysis of Atmospheric Particulate
Matter." Am. Ind. Hyg. Assoc. J. 23 (1962): 144-50.
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A-12
ADDENDA
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A. ALTERNATIVE EQUIPMENT
A modification of the high-volume sampler incorporating a method for
recording the actual airflow over the entire sampling period has been described,
and is acceptable for measuring the concentration of total suspended particu-
lates (J. S. Henderson. Eighth Conference on Methods in Air Pollution and
Industrial Hygiene Studies, Oakland, Calif. 1967). This modification consists
of an exhaust orifice meter assembly connected through a transducer to a f
system for continuously recording airflow on a circular chart. The volume of
air sampled is calculated by the following equation:
V = Q x T
3 I
Q = Average sampling rate, m /min.
T * Sampling time, minutes. _
The average sampling rate, Q, is determined from the recorder chart by estima- |
3 3
tion if the flow rate does not vary more than 0.11 m /min. (4 ft /min) during
33
the sampling period. If the flow rate does vary more than 0.11 m (4 ft /min) p
during the sampling period, read the flow rate from the chart at 2-hour inter-
vals and take the average.
B. PRESSURE AND TEMPERATURE CORRECTIONS
If the pressure or temperature during high-volume sampler calibration is
substantially different from the pressure or temperature during orifice
calibration, a correction of the flow rate, Q, may be required. If the pres-
sures differ by no more than 15 percent and the temperatures differ by no more
than 100 percent (°C), the error in the uncorrected flow rate will be no more
than 15 percent. If necessary, obtain the corrected flow rate as directed
below. This correction applies only to orifice meters having a constant orifice p
coefficient. The coefficient for the calibrating orifice described in 5.1.4
has been shown experimentally to be constant over the normal operating range
33
of the high-volume sampler (0.6 to 2.2 m /min; 20 to 78 ft /min). Calculate
corrected flow rate:
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1/2
where
Corrected flow rate, m /min
Flow rate during high-volume sampler calibration (subsection
8.1.2), m /min
Absolute temperature during orifice unit calibration (subsection
8.1.1), K or °R
Barometric pressure during orifice unit calibration (subsection
8.1.1), mm. Hg.
Absolute temperature during high-volume sampler calibration
(subsection 8.1.2), K or °R.
Barometric pressure during high-volume sampler calibration (subsec-
tion 8.1.2), mm. Hg.
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B-l
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. . APPENDIX B
EXAMPLE CALCULATIONS
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B-2
1
Example Data Sheet
1
TABLE 1 1
SIMULATED TSP DATA FOR CANDIDATE AND
REFERENCE HI -VOL METHODS |
X
= TSP
ug/m3
Measured by Reference
Hi-Vol Method
459
419
375
334
310
305
309
319
304
273
204
245
209
189
137
114
Y
=TSP
Response
Measured by Candidate
Method
357
392
311
281
240
287
259
233
231
237
209
161
199
152
115
112
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Example:
B-3
Basic Worksheet Showing the Calculation Steps
V denotes Candidate Method Response, X denotes Reference Hi-Vol Responses
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(yg/m3)
a) IX =
=
b) X" =
=
c) n =
Step (1)
Step (2)
Step (3)
Step (4)
Step (5)
Step (6)
Step (7)
Step (8)
Step (9)
Sum of X d) ZY = Sum of Y
4505 = 3776
Zx/n= Average of X e) 7 = Zy/n = Average of Y
282 = 236
Number of Test Pairs
16
Z XY = Sum of X times Y
= 1,170,731
(ZX) (ZY)/n
= 1,063,180
Sv.. = Z (X - X) (Y - Y), ZXY - (SX)(ZY)
*y M
Step (1) - Step (2)
= 107,551
ZX2 = Sum of Each X Squared
= 1,404,543
(ZX)2/n = a2/c
= 1,268,439
S = Z (X - I)2 = Step (4) - Step (5)
XX
= 136,104
0
ZY = Sum of Each Y Squared
= 985,740
"> 9
(EY)Vn = dVc
= 891,136
o
$vv= Z (Y- Y> = St£P (7> ' SteP (8)
JJ
= 94,604
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Step (10) Z = xy = Slope of the Regression Curve
sxx
= Step (3) * Step (6) I
= 107,551/136,104 = .79
Step (11) I = 7 - Z X" = Y intercept
= e - Step (10)b
= 236 - .79 (282) = 13.2 1
Step (12) r = Correlation Coefficient
2 2
Sxx - Z(X - X)c; Syv = Z(Y - Y)'; Syv = Z(X - X)(Y - Y);
r =
rt/V ' JJ
= Step (3)/[Step (6)]1/2 [Step (9)]1/2
= 107,551/[136104.J1/2 [94604]1/2 |
= _.95 I
Step (13) Method for Displaying Relationship
(a) Equation of Regression Line
Y » I + ZX
Y = 13.2.+ .79 X
(b) To predict the reference Hi-vol Method Value from
the actual value obtained by the candidate method, use
X - (Y - I)/Z _
For example let y - 240 (units) |
(c) X = (240 - 13.2)7.79
X = 237 ug/m3 |
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing}
1. REPORT NO.
OAQPS 1.2-114
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
Guidance for Selecting TSP Episode Monitoring
Methods
Feb. 12, 1979
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
George Manire
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U.S. Environmental Protection Agency
Monitoring & Reports Branch
Monitoring Section, Monitoring & Data Analysis Di\
10. PROGRAM ELEMENT NO.
2AD889
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Office of Air, Noise, & Radiation
Office of Air Quality Planning & Standards
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This guideline explains the principles of operation of the two episode
particulate monitoring methods which are modification of the reference
method and the procedures for establishing a site and season-specific
relationship between the high volume method and particulate methods
other than the modified reference methods.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COS AT I Field/Group
Episode monitoring
site-season relationship
18. DISTRIBUTION STATEMENT
release to RO, state and local
agencies
19. SECURITY CLASS (ThisReport)
unclassified
21. NO. OF PAGES
20. SECURITY CLASS (Thispage)
unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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