EPA/450/2-81/017d
U.S. Environmental Protection Agency
Air Pollution Training Institute
COURSE 81:422
3rd Edition
AIR POLLUTION CONTROL
ORIENTATION COURSE
Unit 4
Sampling and Analysis of Air Pollutants
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United Stater Air Pollution Training Institute EPA 450/2-81-017d
Environmental Protection MD 20 June, 1981
Agency Environmental Research Center
Research Triangle Park, NC 27711
Air
&EPA APTI
Course S 1:422 3rd Edition
Air Pollution Control
Orientation Course
Unit 4
Sampling and Analysis of Air Pollutants
Prepared By:
Northrop Services, Inc.
P.O. Box 12313
Research Triangle Park, NC 27709
Under Contract No.
68-02-2374
EPA Project Officer
R. E. Townsend
United States Environmental Protection Agency
Office of Air, Noise, and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
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Introduction
This unit covers the major elements of sampling and analysis of air pollutants in
both the ambient air and source emissions. It focuses on the standard procedures
specified by the Environmental Protection Agency under the provisions of the
Clean Air Act, as amended. When you complete the unit, you will understand the
fundamental concepts of sampling and analysis and will be prepared for further
study.
The unit, unlike most others in the course, consists of this book only (there is no
accompanying audio tape). You should work through it at your own speed,
stopping to relax or going back for review whenever you feel the need. You will
find reviews and questions in each of the five lessons. These are designed to help
you learn the material efficiently, so even if you're confident that you understand
what you have read, be sure to answer all the review questions. The review test at
the end of the unit will help you determine your mastery of the learning objectives.
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Lesson 1
Overview of Sampling and Analysis
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Objectives
Upon completing this lesson, you should be able to:
1. define ambient air.
2. give an example of a stationary source.
3. give at least three uses of ambient monitoring data.
4. give at least three uses of source emissions data.
5. list the criteria pollutants.
6. name the two kinds of standards which apply to source emissions.
7. define a manual reference method.
8. define an automated reference method.
9. identify the most important elements of quality control and quality assurance.
10. list the major elements of a data handling system.
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This lesson provides an overview of the unit on sampling and analysis, introducing
key terms and outlining the monitoring process from sampling to reporting.
Monitoring is central to any air pollution control program, because it helps to
determine where air pollutants are, what they are, and how concentrated they are.
Let's start with where. We sample air pollutants in two basic areas: the ambient
air and at the source. Ambient air is the outdoor air surrounding a city, com-
munity, or region. Pollutants in the ambient air may come from many sources,
some known and some unknown, and are generally in diluted form. Source emis-
sions are the emissions from a known source, either stationary or mobile. An
industrial stack is a readily identifiable kind of stationary source. Pollutants emit-
ted from a source may be highly concentrated, and as they move away from the
source, they become diluted to their ambient concentrations.
Sampling and analysis (or monitoring) of both the ambient air and source emis-
sions can produce information which is useful in many ways. Monitoring data are
essential to the development and enforcement of regulations and to the evaluation
of the effectiveness of air pollution control programs. The following lists provide
you with the major uses of monitoring data from both the ambient air and source
emissions.
Uses of Ambient Monitoring Data
• determining ambient air quality levels over time
• judging progress made toward attaining or maintaining ambient air quality
standards
• determining baseline air quality data before new sources begin operating
• studying emission patterns from specific sources
• developing and evaluating air pollution dispersion models
• identifying potential episodes (times of unusually high pollutant concentrations)
so that emergency control programs can be activated
• determining correlations between air pollution and effects on human health and
pollutant concentrations
• scientific research
Uses of Source Emissions Data
• evaluating source compliance with emission regulations
• evaluating efficiency and effectiveness of pollution control equipment
• evaluating production efficiency
• scientific research
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Now that you know generally where and why we monitor air pollutants, let's
briefly discuss the specific pollutants. Currently, EPA has identified seven "criteria"
pollutants, for which National Ambient Air Quality Standards have been set. All
the criteria pollutants are monitored in the ambient air and some are monitored as
source emissions as well. These criteria pollutants are:
• sulfur dioxide (SOX)
• suspended paniculate matter
• carbpn monoxide (CO)
• ozone (O3)
• hydrocarbons (HC)
• nitrogen dioxide (NOt)
• lead (Pb)
All of these pollutants have been determined by EPA to be harmful to the public
health and welfare.
In addition to the criteria pollutants, EPA has identified four others—asbestos,
beryllium, mercury, and vinyl chloride (a fifth, benzene, is pending)— which are
also harmful to human health. These hazardous pollutants are monitored at their
source, under the provisions of the National Emission Standards for Hazardous Air
Pollutants (NESHAPS). Other harmful pollutants monitored in source emissions
are specified by EPA in its Standards of Performance for New Stationary Sources,
commonly known as New Source Performance Standards (NSPS). Examples of such
pollutants are acid mist, hydrogen sulfide, total reduced sulfur, hydrogen fluoride,
and volatile organic compounds.
In later lessons of this unit we will discuss more fully the criteria pollutants and
the pollutants covered by NSPS.
Before continuing with this overview of sampling and analysis, let's briefly review
the major points covered so far:
• both ambient air and source emissions are monitored.
• monitoring data are essential to the development and enforcement of regula-
tions and to the evaluation of air pollution control programs.
• there are several major uses of monitoring data for ambient and source emis-
sions (review the lists).
• pollutants which are monitored include the seven criteria pollutants, the four
pollutants identified by NESHAPS, and other pollutants identified by NSPS.
The total monitoring process falls into two major systems, which we can call
sensing and data handling. Sampling and analysis procedures constitute the sensing
system, while data gathering, storage and retrieval, analysis, and reporting con-
stitute the data handling system. In the next few paragraphs we will give you a
general overview of these two systems and will then provide more details on them in
later lessons.
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The actual sampling and analysis procedures specified by EPA for monitoring air
pollutants vary widely. They are based upon a number of considerations, of which
the most important are the chemical characteristics of the pollutant, its physical
state at the time of sampling, and its expected concentration. All sampling and
analysis procedures are designed to determine the actual concentration of the
pollutant in the sample. This concentration is expressed in terms of mass per unit
volume, usually micrograms per cubic meter.
EPA has designated Federal Reference Methods for the sampling and analysis of
criteria pollutants in the ambient air. These methods specify precise procedures for
sampling, analysis, calibration, and calculation which must be followed for any
monitoring activity related to compliance with the provisions of the Clean Air Act.
The ambient Federal Reference Methods may be either manual or automated.
In manual methods, the sampling and analysis occur in two separate steps: first the
sample is collected, and then it is analyzed. Analysis is performed at a later time
and perhaps in a location different from the sampling site. Automated methods are
continuous and are performed by instruments. The sample is collected and
analyzed at the same time by an apparatus which links the sampling equipment to
the analyzer.
EPA has also designated Federal Reference Methods for source emission
measurement. These methods are used for the sampling and analysis of SOj, CO,
paniculate matter, oxides of nitrogen, and a number of other pollutants. The
methods are all manual and are used in conjunction with the New Source Perfor-
mance Standards, which provide specific information about variations in sampling
procedures for each type of source.
The Federal Reference Methods specify detailed sampling and analysis pro-
cedures, and these procedures provide raw data about pollutant concentrations.
But what we do with these data is as important as how we get them.
We must first determine whether the data gathered are valid and useful. We do
this through quality control and quality assurance programs, which cover
everything from sample collection through data validation. The key aspect of
quality control is calibration, which helps to ensure that processes and equipment
accurately sample and analyze pollutants. Calibration is so important that the
Federal Reference Methods give very precise instructions about it.
Quality assurance, which is essentially "quality control on quality control,"
verifies the accuracy of calibration. EPA provides guidance on quality assurance
principles and procedures for both ambient and source monitoring in the three-
volume Quality Assurance Handbook. Just as calibration is the most important part
of quality control, so the audit process is the most important part of quality
assurance. While audits can be performed in several ways, the essential nature of
an audit is to compare data from air samples with data from standard samples or
to compare several different analyses of the same air sample. The audit results will
indicate the accuracy of the monitoring activity.
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Before going on to a discussion of data handling, let's review the key points in
the previous section.
• Federal Reference Methods specify precise procedures for sampling, analysis,
calibration, and calculation.
Manual methods are divided into a sampling step and an analysis step.
Automated methods are continuous and are performed by instruments.
All reference methods for source emissions are manual.
Calibration is the key element of quality control.
Quality assurance is "quality control on quality control;" its key-element is the
audit.
Verified data, which are outputs of the sensing system, become inputs to the
data handling system for air pollution monitoring. The major elements of the data
handling system are preparation, storage and retrieval, analysis, and reporting.
While there are many different kinds of data handling systems in use, we will
concentrate in this unit on EPA's standard computerized system developed for the
National Aerometric Data Bank (NADB). EPA has standard formats for the
reporting of data to NADB called Storage and Retrieval of Aerometric Data
(SAROAD) and National Emissions Data System (NEDS). SAROAD is used by
EPA for storing, analyzing and reporting ambient air quality and NEDS for source
emission data for all the States and territories.
The point of a data handling system like NADB and its subsystems is to provide
a standardized procedure through which raw data gathered from monitoring sites
can be prepared in a usable form for convenient computer entry and for later ease
of storage, retrieval, and analysis. The computer processes the data mathematically
and facilitates future analysis and reporting of data which has been uniformly
gathered and processed.
Monitoring data are provided to EPA by the States in quarterly and annual
reports, depending on what the data are and what surveillance program they are to
be used for. One example of data reporting is the annual air quality data summary
which must be submitted to EPA by each state. Data reported to EPA may be used
to determine whether the National Ambient Air Quality Standards are being met
or maintained, to determine emissions from stationary and mobile sources, and the
like.
State and local agencies may also use such data to develop and revise the State
Implementation Plans, to demonstrate the effectiveness of control strategies, and
the like. In addition, EPA currently requires that agencies provide a daily air
quality index report in all urban areas with a population exceeding 500,000.
This concludes the overview of sampling and analysis. Review the lesson if you
need to and then go on to the next lesson.
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Lesson 2
National Ambient Air Quality
Standards and Reference Methods
for Sampling and Analysis
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Objectives
Upon completing this lesson, you should be able to:
1. define the primary and secondary National Ambient Air Quality Standards.
2. define an equivalent method.
3. classify the reference methods by type (manual or automated).
4. name the measurement principle for each ambient reference method.
5. name the two major considerations of monitor siting.
6. identify three main types of monitoring stations.
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Part 1. Introduction to Standards and Methods
Criteria Pollutants and Ambient Air Quality Standards
The seven criteria pollutants are especially important in ambient air monitoring.
Remember, these pollutants are sulfur dioxide (SOS), suspended paniculate matter
(TSP), carbon monoxide (CO), ozone (Os), hydrocarbons (HC), nitrogen dioxide
(NOi), and lead (Pb). They have been designated by EPA because of their
widespread effects on the public health and welfare and because of the multiplicity
of their sources. Under the provisions of the Clean Air Act, any such pollutant
designation must be supported by a Criteria Document (hence the name "criteria"),
which represents the best scientific information available on the effects of the pollu-
tant. Such effects include not only those on human health but also effects on the
economy, visibility, esthetics, and the like. The number of criteria pollutants can
be increased at any time through the development of additional Criteria
Documents.
For each criteria pollutant, EPA establishes a National Primary and Secondary
Ambient Air Quality Standard, often referred to as NAAQS (National Ambient
Air Quality Standard). The primary standard specifies maximum acceptable con-
centrations for the protection of the public health. The secondary standards specify
maximum concentrations acceptable for the protection of the public welfare from
known or anticipated adverse effects. "Public welfare" includes such concerns as
crop damage, animal health, and materials deterioration. The primary and secon-
dary standards are expressed as pollutant mass per volume of air—usually
micrograms per cubic meter. The standards apply uniformly throughout the
United States.
We won't go into the National Ambient Air Quality Standards any further than
this. If you are interested in reading the standards, they are published in the Code
of Federal Regulations (CFR), which is updated annually. Title 40 of the Code,
entitled "Protection of the Environment", contains the regulations pertinent to air
pollution. The ambient air quality standards appear in Part 50 of Title 40 (40
CFR, Part 50).
Before continuing, review the list of criteria pollutants and the definitions of the
National Ambient Air Quality Standards.
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Federal Reference Methods
Along with the air quality standards, EPA has specified procedures for the
sampling and analysis of the criteria pollutants. These procedures are the Federal
Reference Methods, and they must be used for any monitoring that is subject to
the provisions of the Clean Air Act.
The Federal Reference Methods for the sampling and analysis of ambient air
pollutants covered by the NAAQS appear in the seven appendices of 40 CFR,
Part 50. Here's a listing of the appendices, with the titles exactly as they are
published:
Appendix A— Reference Method for the Determination of Sulfur Dioxide in the
Atmosphere (Pararosaniline Method)
Appendix B — Reference Method for the Determination of Suspended Par-
ticulates in the Atmosphere (High Volume Method)
Appendix C— Measurement Principle and Calibration Procedure for the Con-
tinuous Measurement of Carbon Monoxide in the Atmosphere
(Nondispersive Infrared Spectrometry)
Appendix D— Measurement Principle and Calibration Procedure for the
Measurement of Ozone in the Atmosphere.
Appendix E— Reference Method for the Determination of Hydrocarbons Cor-
rected for Methane.
Appendix F— Measurement Principle and Calibration Procedure for the Con-
tinuous Measurement of Nitrogen Dioxide in the Atmosphere
(Chemiluminescence)
Appendix G— Reference Method for the Determination of Lead in Suspended
Paniculate Matter Collected from Ambient Air.
Each reference method specifies everything that is pertinent to the sampling and
analysis process, including measurement principles, apparatus, procedures, and
calculations.
At some convenient time, you might want to take a look at the appendices of 40
CFR, Part 50 to see how specific the reference methods are.
In the overview to this unit we said that the Federal Reference Methods are
either manual or automated. A manual method is a procedure specified by EPA
for the collection and analysis of a sample. Currently the reference methods for
SOX, suspended paniculate matter, and lead are manual. Only one manual
reference method is designated for each of these pollutants—there can be no other
manual reference methods for them.
This is not the case with the automated methods, however, because for them
"method" has a slightly different meaning. In practical terms, an automated
reference method is an instrument. EPA specifies a measurement principle and
calibration procedure for the method and then certifies as "reference methods"
instruments which use that principle and procedure and which meet other
technical requirements. EPA's designation of automated reference methods changes
from time to time, and updated lists are published in the Federal Register.
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Table 2-1 provides a summary of the manual and automated reference methods
for the criteria pollutants. Note the variety of automated reference methods
(instruments) for CO, Os, and NO,. You may notice that there is no reference
method listed for hydrocarbons. That's because no instrument using the specified
measurement principle and calibration procedure currently meets EPA's
requirements.
Table 2-1. EPA approved reference methods as of April 17, 1981.
Manual
Automated
Reference
TSP
Pb
High volume method
Hi Vol/AA Spect.
Equivalent
1 Hi Vol/AA Speci
2. Hi Vol/Flameless AA
Spect
3 Hi Vol/lCAP Speci
Reference
Equivalent
SO,
Pararounilinc method
1 Technicon I
2 Technicon 11
1 LearSiegler SM1000 (.5)
2 MeloySA185-2A(.5, 1 0)
3 Thermo Electron 43 (.5. 1.0)
4 Philips PW9755(.5)
5 Philips PW9700 (.5)
6 Monitor Labs 8450 (.5, 1 0)
7 Aurco 500 (.5. 1.0)
8 Beckman 953 ( 5. 1.0)
9 BendiA 8303 (.5. 1 0)
10 Meloy SA285E ( 05. .1. .5. 1 0)
11. Monitor Labs 8850 (.5, 1.0)
12 Meloy SA 700 (.25. .5, 1 0)
13 Lear Sieglrr AM2020 ( 5)
CO
1 Bendix 8501 5CA (50)
2 Beckman 866 (50)
3 MSA 202S (50)
4 Horiba AQM 10. 11. * 12(50)
5 Monitor Labs 8310 (50)
6 Horiba 300E/300SA (20. 50. 100)
7 MASS-CO 1 (50)
8 Dasibi 3003 (50)
O,
1 Meloy OA325-2R ( 5)
2. Meloy OA3502R(.5)
3 Bendix 8002 (.5)
4 McMillan 1100-1 (.5)
5. McMillan 1100-2 ( 5)
6 McMillan 1100-3 ( 5)
7 Monitor Libs 841OE (.5)
8 Beckman 950A (.5)
9. CSI 2000 ( 5)
1 Datibi 1003 AH. PC. RS (.5. 1.0)
2 Philips PW9771 (.5)
3 Thermo Electron 49 (.5. 1 0)
NO,
1 Sodium anenite
2 Sodium anenite
/Technicon
3 TSG ANSA
1 Monitor Labs 8440E(.5)
2 Bendix 8101-C(.5)
3. CSI 1600 (.5)
4. Meloy NA530R ( 1. .25. .5. 1 0)
5. Beckman 952 A (.5)
6 Thermo Electron 14 BE (.5)
7 Thermo Electron 14 D/E ( 5)
8 Bendix 8101-B (.5)
9 Philips PW9762/02 (.5)
10 Monitor Labi 8840 (.5. 1.0)
Look again at Table 2-1. There are also "equivalent" methods listed. EPA can
designate as an equivalent method either a manual procedure or an automated
instrument. An equivalent method differs from a reference method in measurement
principle and calibration procedure, but it must still meet EPA's performance
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specifications. An equivalent method may be either manual or automated,
regardless of whether the reference method is manual or automated. In Table 2-1
you will see that the manual reference method for SO, has both manual and
automated equivalents, and the automated reference method for NO2 has manual
equivalents. The list of equivalent methods, like that for automated methods, may
change intermittently.
What's the significance of equivalent methods? As far as EPA is concerned, there
is no difference between reference and designated equivalent methods for federally-
required ambient monitoring. This applies only to ambient monitoring. There are
currently no provisions for equivalent methods in source emissions monitoring.
Before we go any further with the Federal Reference Methods, answer the ques-
tions which follow.
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Questions
1. In order to determine the acceptable ambient concentration of sulfur dioxide
in terms of protection of vegetation, you would consult which of the following:
a. the reference method for SOi
b. the primary standard for SOS
c. the secondary standard for SOX
2. Which of the following pollutants are covered by the NAAQS and ambient
Federal Reference Methods?
NO, H,S04
sulfuric acid asbestos
NOX suspended paniculate matter
hydrocarbons CO2
3. To find the value of the Federal NOt primary air quality standard you would
consult that section of the CFR devoted to your state. (True or false)
4. Where would you find the NAAQS and Federal Reference Methods?
a. 40 CFR, Pan 60
b. SO CFR, Pan 50
c. 40 CFR, Pan 50
d. 40 CFR, Part 40
5. How are pollutant concentrations usually expressed in the standards?
6. True or false?
a. the measurement principle of an equivalent method is the same as that for
a reference method.
b. Federal Reference Methods for ambient monitoring may be specified pro-
cedures or designated instruments.
c. the reference methods for CO, NOt, and Os are manual methods.
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Answers
1. (a) the secondary standard for SOj
Vegetation damage is part of the "public welfare" covered by secondary stan-
dards; primary standards cover only/ human health.
While you would need to use the reference method to find out what the SO,
concentration in your area actually is, you consult the standard to find the
concentration that is considered acceptable.
2. NO,, hydrocarbons, suspended paniculate matter
The other pollutants may be important, but only the seven we've discussed
are covered by the NAAQS. Remember, they are: SO,, suspended paniculate
matter, CO, ozone, hydrocarbons, NO,, and lead.
3. False. Yes, you would consult the primary standard, but there are not
individual state standards. The concentration specified by the primary stan-
dard applies throughout the country.
4. (c) 40 CFR, Part 50
5. Mass per volume (micrograms per cubic meter)
6. a. false
b. true
c. false
If you're satisfied that you've learned the material thus far, go on to the next
part. If not, reread any sections that still give you trouble.
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Part 2. Reference Methods for Criteria
Pollutants in the Ambient Air
In this part of the unit you will learn more about the seven reference methods for
the criteria pollutants, through a summary of the basic concepts for each method.
The information presented will give you a good idea of what each method involves,
without confusing you with detail. The most important concepts you should learn
are the type (manual or automated), the measurement principle, and the general
procedure for each method. We will not discuss the calibration procedures.
The sampling and analysis methods will determine the amount of pollutant col-
lected. Determining the pollutant concentration (pollutant mass per sample
volume) requires additional calculations specified by the reference methods. You
will not learn about the calculations in this unit, nor about sampling frequency,
sampling duration, and other aspects of the reference methods; simply be aware
that they appear in the CFR as part of the reference methods.
A simplified diagram of the procedure or equipment appears with the discussion
of each method. It will provide you with a valuable reference in following the
written description.
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Reference Method for Sulfur Dioxide (Pararosaniline Method)
Type: Manual
Measurement Principle: Colorimetric
The light absorbance of the final colored solution is proportional to the concen-
tration of SO* and is measured with a spectrophotometer.
Procedure: (Figure 2-1):
Air is collected at a specified flow rate and time in a collection device containing
a solution of potassium tetrachloromercurate (TCM). Any SOZ in the sample is
absorbed by the TCM. A dye called pararosaniline and other chemicals are then
added to the solution containing SOZ; the result is a compound which has a pink to
purple color.
The SOj concentration is determined with a spectrophotometer—a device that
measures light absorbance. The sample solution is read and then compared with
the reading for a solution known to contain no SO,. The difference in readings
indicates the concentration of SO» in the sample.
This method is sometimes called the West-Gaeke method, after its developers,
and sometimes the pararosaniline method, after the key chemical in the process.
Sample
Pararosaniline,
other chemical*
Colored solution
Figure 2-1. Reference method for sulfur dioxide.
The manual reference method for SO, is not commonly used. There are a
number of equivalent automated methods which employ a variety of measurement
principles (see Table 2-1). These equivalent instruments are more convenient to use
than the manual method.
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Reference Method for Suspended Particulate Matter
(High Volume Method)
Type: Manual
Measurement Principle: Gravimetric
The mass of suspended paniculate matter is determined by weighing the par-
ticles collected.
Procedure: (Figure 2-2):
Air is drawn by a high-flow-rate blower into a covered housing through a filter
of known weight made of glass fiber, contained in a covered housing. The
apparatus used is called a "high volume sampler."
Both before and after sampling, the filter is conditioned to less than 50%
relative humidity to eliminate any interference caused by the water-attracting
tendencies of either the filter or the collected particles. The filter is then weighed.
The weight gain of the filter is due to the suspended paniculate matter collected.
[(Filter weight + paniculate weight) - clean filter weight = paniculate weight.]
I I 1
Air out
Figure 2-2. The high volume sampler.
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Reference Method for Lead
Type: Manual
Measurement Principle: Atomic Absorption Spectrometry
Procedure: (Figure 2-3)
The reference method for lead consists of measuring the lead content of par-
ticulate matter collected by the suspended paniculate matter reference method's
high volume sampling procedure. After sample collection, lead is acid-extracted
from the paniculate matter of the high volume filter, and the lead content of the
resulting solution is determined by atomic absorption spectrometry.
IT1
Air out
High volume sampler
Atomic absorption spectrophotometer
Figure 2-3. Lead reference method.
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Measurement Principle for Carbon Monoxide
(Nondispersive Infrared Spectrometry)
Type: Automated
Measurement Principle: Spectrometric
Carbon monoxide absorbs infrared radiation at characteristic wavelengths. The
absorption can be measured with an instrument.
Procedure: (Figure 2-4)
The apparatus contains two matched cells (one for reference and one for
sampling) and a detector. The sealed reference cell contains a nonabsorbing gas.
Infrared energy continually passes through both cells, while air flow is continuous
only through the sample cell.
When no carbon monoxide is present in the sample cell, the signals from each
cell are balanced and the instrument reads zero. When carbon monoxide enters the
sample cell and absorbs infrared radiation, the resulting change is detected
electronically.
Water vapor can be an interferent for some analyzers. It may be minimized by
condensing it out of the sample air.
Reference cell
Infrared •
light
source
£Tn 0_00000
• Detector
Sample in
CO molecules
(absorb infrared)
Other molecules
Figure 2-4. Infrared spectrometer.
Are you becoming bewildered by the reference methods? Let's review the first
four. If you're still not confident that you understand the methods after this review,
you should reread the previous discussions.
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Sulfur Dioxide (SO,)
Type: Manual
Measurement principle: Colorimetric
Procedure:
Pararosaniline dye and chemicals are added to a solution containing SO,. The
light absorbance of the resulting colored solution, measured by a spectro-
photometer, indicates the amount of SOj.
Sample
Pararotaniline,
other chemicals
Colored solution
Suspended Paniculate Matter
Type: Manual
Measurement Principle: Gravimetric
Procedure:
Particles are collected in the filter of a high volume sampler. The filter is
weighed before and after sampling. The difference in weight is due to the par-
ticulate matter.
' Air nut •
Air out
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Lead
Type: Manual
Measurement Principle: Atomic Absorption Spectrometry
Procedure:
First, particulate matter is collected with a high volume sampler. Then, lead is
extracted from the collected matter by using acid. The lead content of the
resulting solution is determined by atomic absorption spectrometry.
Carbon Monoxide (CO)
Type: Automated
Measurement Principle: Nondispersive Infrared Spectrometry
Procedure:
Air is drawn through a sample cell. Infrared radiation passes through both the
sample cell and a sealed reference cell. Absorption of infrared radiation by CO is
detected by the instrument.
Reference cell
Infrared
light
•ource
OO
Ltr
Sample in
Sample cell
j
Detector
Sample out
A CO molecules
^ (absorb infrared)
O Other molecules
If you feel that you understand the basis of these reference methods, continue to
the next method. If not, study the first four methods some more.
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Measurement Principle for Ozone
Type: Automated
Measurement Principle: GOJ Phase Chemiluminescence
Ozone reacts chemical!) with ethylene to emit light which is detected by a
photomultiplier tube.
Procedure: (Figure 2-5)
Sample air is drawn in continuously and mixed with a high concentration of
ethylene. If ozone is present in the sample, it reacts chemically with the ethylene
and light is emitted. The amount of light is proportional to the amount of ozone.
A photomultiplier tube detects the light and sends signals to a recorder.
Sample air in
Exhaust
Li
w i
gh
t
Ethylene in
"N
Photomultiplier
tube
Figure 2*5. Chemiluminescence method for ozone.
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Reference Method for Hydrocarbons Corrected for Methane
Type: Automated
Measurement Principle: Gas Chromatography with Flame lonization Detection
Methane, which is not the pollutant of interest, can be separated from other
hydrocarbons by gas chromatography. The presence of hydrocarbons in a hydrogen
flame increases the number of ions emitted; the increase can be measured by an
ion detector.
Procedure: (Figures 2-6, 2-7)
The accurate detection of hydrocarbons is extremely difficult. Hydrocarbons of
different types don't all react in the same way, and erroneous readings may result
when you try to measure all the hydrocarbons together.
Because of these problems, there is as yet no instrument that meets EPA
specifications for the reference method.
The procedure is accomplished in two parts. In the first step (Figure 2-6), a por-
tion of the air sample is delivered directly to a hydrogen flame ionization detector.
When carbon-containing compounds are burned, the amount of ion formation is
proportional to the amount of hydrocarbons in the sample. However, only the
carbon-containing compounds ionize —other components of the sample do not
ionize. In short, the first part of the procedure detects all the hydrocarbons (THC),
including methane.
Valve
Flame
Flame ionization detector
Recorder
Figure 2-6. Hydrocarbon measurement method, part 1.
2-17
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In the next step, (Figure 2-7) everything in the sample except methane (CKU)
and carbon monoxide (CO) is removed. The CH« and CO are separated, and the
CH» is measured. The amount of CH* is then subtracted from the total hydrocar-
bon concentration, because most methane present in the atmosphere represents a
background, or natural, concentration and does not contribute to ozone formation.
CO is converted to CH4 in a catalytic reduction tube so that it can also be
measured by the flame ionization detector.
Valve
Vent
'CO,, H.67
THC
Chromatographic
i Stripper column
t t
THC
CH4
co|
Chromatographic
analytical
column
• THC analysis pathway
CH4, CO analysis pathway
Catalytic
reduction
tube
Figure 2-7. Hydrocarbon measurement method, part 2.
2-18
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Measurement Principle for Nitrogen Dioxide
Type: Automated
Measurement Principle: Gas Phase Chemilumtnescence with Ozone
Nitrogen dioxide (NOj) is reduced to nitric oxide (NO) which, in turn, reacts
chemically with ozone to emit light that can be detected by a photomultiplier tube.
The principle is identical to that for the measurement of ozone, but different gases
are used*
Procedure: (Figures 2-8, 2-9)
Nitrogen dioxide (NOt) and nitric oxide (NO) are both commonly present in the
air sample, but only NO reacts with ozone to produce light. Therefore NOZ is
measured indirectly in a two-step (or two-cycle) process. In the first cycle, the air
sampled, which contains both NOj and NO, is reacted with ozone. The
luminescence (light), resulting only from the NO reacting with ozone, is detected
and recorded.
Exhaust
Photomultiplier
tube
Figure 2-8. Chemiluminescence method for NO, cycle 1.
2-19
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In the second cycle (Figure 2-9), the sample air, containing NOt and NO is
pulled through a converter which changes the NO2 in the sample to NO while the
original NO is unc inged. The resulting gas represents the total nitrogen oxides
(NOX, equal to NO - NO2). This gas, which is now all NO, is reacted with ozone
and the resulting light is detected and recorded. Subtraction of the first cycle
reading from the second cycle reading results in the difference due to NOt in the
sampled air.
Ozone in
Photomultiplier
tube
Figure 2-9. Chemiluminexence method for NO,, cycle 2.
Sample contains Instrument measures
Cycle 1 NO + NO, NO
Cycle 2 NO + NO (convened from NO,) NO + NO (converted from NO2)
Amount of NO = cycle 1 reading
Amount of NO, = cycle 2 reading — cycle 1 reading
Cycle 2 NO + NO (converted from NO,)
Cycle 1 -NO
NO, = NO (converted from NO,)
2-20
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That completes the discussion of the Federal Reference Methods for ambient air
sampling and analysis. Remember, however, that you've seen a simplified overview
of each method. Further explanation is beyond the objectives of this introductory
course, but you should now be at least familiar with the major concepts.
Look at the summary of the last three methods and reread the entire section on
reference methods if you think it's necessary. Then go on to the review questions.
Ozone
Type: Automated
Measurement Principle: Gas Phase Chemiluminescence
Procedure:
Ozone reacts chemically with ethylene gas to emit light, which is detected by a
photomultiplier tube.
Sample air in
\
Exhaust
r
"N
Ethylene in
X
\ /
Light
f
Photomultiplier
tube
2-21
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Hydrocarbons Corrected for Methane
Type: Automated
Measurement Principle: Gas Chromatography with Flame lonization Detection
Procedure:
Step 1—Total hydrocarbons in the sample are measured by a hydrogen flame
ionization detector. Step 2 —Everything in the sample except methane and carbon
monoxide is removed. The methane and CO are separated, and then the methane
is measured by the detector. The amount of nonmethane hydrocarbons is deter-
mined by subtracting the amount of methane from the total amount of hydro-
carbons present.
Flame
Flame ionization detector
Recorder
Vent
Valve
Chromatographic
Stripper column
Chromatographic
analytical
column
T T
THC analysis pathway
CH«, CO analysis pathway
Catalytic
reduction
tube
CH./CO
2-22
-------
Nitrogen Dioxide (NOS)
Type: Automated
Measurement Principle: Gas Phase Chemiluminescence
Procedure:
NO, is measured indirectly. Cycle 1 —Air containing nitric oxide (NO) and
nitrogen dioxide (NO,) is reacted with ozone to produce light, which is detected by
a photomultiplier tube. Only the NO reacts with ozone. Cycle 2 —The NO, in the
sample is converted to NO. The sample now contains not only the original NO,
but also NO, that has been converted to NO. This gas is reacted with ozone and
the emitted light is measured. The Cycle 2 reading minus the Cycle 1 reading
equals the amount of NO,.
Exhaust
Photomultiplier
tube
Cycle 1
Otone in
Photomultiplier
1 tube '
Cycle 2
2-23
-------
Questions
1. Match each item in column 1 with an item in column 2 and column 3.
1
CO
suspended paniculate matter
S02
NO,
nonmethane hydrocarbons
ozone
lead
2 3
manual pararosaniline/colorimetric
manual atomic absorption spectrometry
automated chemiluminescence/ozone
automated nondispersive infrared
spectrometry
automated gravimetric/high volume sampler
manual chemiluminescence/ethylene
manual gas chromatography/flame
ionization
automated chemiluminescence/methane
CO
suspended paniculate matter
SO,
NO,
nonmethane hydrocarbons
ozone
lead
2. True or false:
a. Chemiluminescence is the emission of ions from a hydrogen flame.
b. Determination of the amount (mass) of a pollutant in a sample gives you
the concentration of pollutant in the air sample.
c. Pararosaniline reacts with NO to emit light.
d. Light absorbance is measured by a spectrophotometer.
e. Gravimetric methods measure infrared absorption.
f. Component gases in a sample can be separated by gas chromatography.
2-25
-------
Answers
CO automated nondispersive infrared spectrometry
suspended paniculate matter manual gravimetric/high volume sampler
SO, manual pararosaniline/ colorimetric
NO, automated chemiluminescence/ozone
nonmethane hydrocarbons automated gas chromatography/flamc
ionization
ozone automated chemiluminescence/ethylene
lead manual atomic absorption spectrometry
If you missed a significant number of these, go back and review the methods.
(a) false. Chemiluminescence is the emission of light from a chemical reaction.
(b) false. While you must determine the amount of the pollutant, you must also
know the volume of air sample to calculate concentration.
(c) false. Pararosaniline is a dye which reacts with a pollutant and changes
color. Remember, ozone reacts with NO to emit light.
(d) true.
(e) false. Gravimetric methods measure mass.
(f) true.
If you're not satisfied with your performance on these review questions, you
should review the things you didn't understand one more time. Don't be dis-
couraged, though —this is difficult material even in simplified form. There's a lot
more information to come in the unit, much of it a little simpler, so make sure you
master each step before going on to the next.
When you are ready, proceed to the next part of the lesson.
2-26
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Part 3. Monitor Siting
Where sampling of ambient occurs is very important to the validity and usefulness
of the data obtained. While monitor siting criteria are not specified by the Federal
Reference Methods, they must be used along with the reference methods in any
effective monitoring program.
Determination of the sampling site is based in part on the reason for the
monitoring and in part on site characteristics. Here's a simple example of siting
based on a monitoring objective. If the objective is to determine the air quality
impact of an isolated source, measurements from at least two sites are needed. A
monitoring site placed upwind from the source would measure the pollutants from
other sources transported into the area. A site downwind from the source would
measure both transported pollutants and those emitted from the source in question.
The difference between the two measurements reveals the impact on air quality of
the source alone.
Site characteristics are also important, because local conditions may affect the
accuracy of the sampling and its ability to achieve the monitoring objective.
Proximity to trees, buildings, roadways, and the like will influence sampling.
Suppose, for example, that the objective is to measure public exposure to carbon
monoxide on urban streets. The monitor must be close to street level (public
exposure generally doesn't occur on rooftops), not subject to accidental destruction
or to vandalism, and far enough from walls and vegetation that it will take a
representative air sample at that location.
As you can see, determining where to take air samples can be a fairly complex
process. EPA has published a considerable amount of information on monitor
siting in four siting guideline documents, which contain siting information for all
the criteria pollutants.
The number of monitoring sites and the pollutants to be monitored at each are,
in part, determined by the requirements of air quality surveillance networks. In
general, the States establish these networks to monitor the criteria pollutants
according to EPA requirements for various monitoring programs.
Some of the main types of monitoring stations currently defined by EPA are:
State and Local Air Monitoring Stations (SLAMS), stations related to Prevention of
Significant Deterioration (PSD), and National Air Monitoring Stations (NAMS).
SLAMS data are used primarily by the States for monitoring their air quality,
while NAMS data are used by EPA in determining national air quality. PSD sta-
tions help to determine the effect of sources in areas with ambient air quality
better than that required by the air quality standards for suspended paniculate
matter and sulfur dioxide.
The air quality surveillance networks are discussed more fully in Unit 9, "Air
Quality Management." At this point you need only to be aware that such networks
exist.
2-27
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This concludes the less, . on ambient sampling and analysis. The following
review questions will help you determine how well you have mastered the informa-
tion. When you have completed the questions and checked your answers, go on to
Lesson 3, which covers source emissions monitoring.
2-28
-------
Questions
1. Examine the diagrams which follow. For each, (a) identify the pollutant for
which the procedure is used, (b) identify the procedure as manual or
automated, and (c) give the measurement principle.
Vllve
Flame
\iSti\ Flame ionization detector
Recorder
Figure A a.
b.
Infrared
light
lource
Reference cell
o o oo On o o
Sample in
Detector
Figure B a.
b.
2-29
-------
Exhaust
Photomultiplicr
tube
Figure C a.
b.
c.
Sample air in
I
Exhaust
Ethylene in
Light
Photomultiplier
tube
Figure D a.
b.
c.
2-30
-------
Sample
Pararosaniline,
other chemicals
Colored solution
Figure E a.
b.
1 t I
Air out
Figure F a.
b.
2. What information do you find in 40 CFR, Part 50, Appendices A-G?
S. Which of the following items are related to primary standards and which to
secondary standards?
a. deterioration of exposed rubber
b. SO2 effects on chickens
c. ozone levels as they affect emphysema victims
d. methane effects on humans
4. Why can there be numerous automated Federal Reference Methods for a
criteria pollutant?
2-31
-------
5. Which of the following pollutants are covered by the National Ambient Air
Quality Standards?
NO, suspended paniculate matter
CO, SO,
methane H,SO4
SOj nonmethane hydrocarbons
CO water vapor
lead ozone
O,
6. True or false?
a. National Ambient Air Quality Standards separately specify allowable con-
centrations of pollutants for each state.
b. An equivalent method uses a measurement principle different from that of
a reference method.
c. There can be more than one manual reference method for a pollutant.
7. You must monitor for SO, in the ambient air, and you want to substitute
another reference method for the pararosaniline method. Can you do this?
8. You have an instrument for NO, sampling and analysis which employs
chemiluminescence with ozone and which has been approved by EPA. Is it a
reference method or an equivalent method?
9. True or false: An automated reference method cannot have a manual
equivalent.
10. List the two major considerations of monitor siting.
11. List three major types of monitoring stations.
2-32
-------
Answers
1. Figure A
a. hydrocarbons corrected for methane
b. automated
c. gas chromatography with flame ionization detection
Figure B
a. carbon monoxide
b. automated
c. nondispersive infrared spectrometry
Figure C
a. nitrogen dioxide
b. automated
c. gas phase chemiluminescence
Figure D
a. ozone
b. automated
c. gas phase chemiluminescence
Figure E
a. sulfur dioxide
b. manual
c. colorimetric (pararosaniline)
Figure F
a. suspended paniculate matter, lead
b. manual
c. gravimetric
2. Federal Reference Methods for ambient sampling and analysis
3. a. secondary
b. secondary
c. primary
d. neither.
Remember, primary standards are based on considerations of public
health; secondary standards on considerations of public welfare (animal
health, property damage, etc.). If you missed (d), you forgot that methane
is not a pollutant covered by the NAAQS.
4. Because automated Federal Reference Methods are instruments which use the
appropriate measurement principle and calibration procedure, meet all EPA
specifications, and have been designated as reference methods by EPA. Any
instrument thus qualified is a reference method.
2-33
-------
5. NO2, CO, suspended particulate matter, SO», nonmethane hydrocarbons,
ozone, lead
6. a. False. NAAOJS concentrations apply uniformly throughout the country.
b. True.
c. False. There can be only one manual reference method; there may be,
however, several manual (or automated) equivalent methods.
7. No. There is only one manual reference method for SOj —the pararosaniline
method. Therefore, you cannot substitute another reference method. You may,
however, substitute an equivalent method, if one has been designated by EPA.
8. Reference method. The instrument uses the measurement principle designated
for NOj and has been approved by EPA. If you gave the wrong answer,
remember: an equivalent method uses a different measurement principle.
9. False. It may be possible for an automated method to have manual and
automated equivalents.
10. Monitoring objective; site characteristics.
11. SLAMS, NAMS, PSD.
2-34
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Lesson 3
Standards of Performance for New
Stationary Sources and Reference
Methods for Source Sampling
and Analysis
-------
Objectives
Upon completing this lesson, you should be able to:
1. distinguish between "new" and "existing" stationary sources.
2. distinguish between the provisions of ambient air and source emissions
standards.
3. state the relationship between source emissions standards and source
sampling reference methods.
4. describe the reference methods for paniculate, SO2, NO,, and CO emissions.
3-2
-------
New Source Performance Standards
Pollutant levels in the ambient air result from emissions from a variety of sources.
The concentration of pollutants emitted from the source may be very high, but it
lessens as the pollutants are diluted in the ambient air. Obviously, then, the rela-
tionship between ambient and source pollution is important, however difficult it is
to determine an exact definition of that relationship. Reduction of source emissions
will usually result in the reduction of ambient pollutant levels.
EPA has established emissions standards and sampling methods for a variety of
identified emissions sources. The standards, entitled Standards of Performance for
New Stationary Sources, are commonly known as NSPS (New Source Performance
Standards) and are published in 40 CFR, Part 60. A new source is defined as one
whose construction begins after EPA proposes standards for that source category in
the Federal Register. Sources constructed before the standards are proposed are
normally subject to State, rather than EPA, regulations, unless they are modified
so as to increase their emission levels.
The New Source Performance Standards apply to a variety of sources, including:
• fossil-fuel-fired steam generators
• incinerators
• nitric acid plants
• sewage treatment plants
• lead smelters
• petroleum refineries
• asphalt concrete plants, and several others.
The list continues to grow as EPA identifies sources and designates standards.
Each standard has five parts, which specify
• applicability
• definitions
• standards for pollutants
• emission monitoring
• test methods and procedures.
If it occurs to you that these standards seem more complex than the ambient air
standards, you're on the right track.
Recall that the National Ambient Air Quality Standards state only the maximum
concentration of criteria pollutants allowable for the protection of the public health
and welfare. The standard is uniform throughout the country; for example, the
given concentration for SO2 —1500 micrograms per cubic meter —applies to
ambient air in Maine or in Texas.
The New Source Performance Standards are quite different. Each standard tells
you to what kind of source it applies, what pollutants should be monitored, what
the allowable concentration for each pollutant is, what kinds of monitoring are
required, and what reference method for source testing must be used. The NSPS
for a given source also describes the modifications to the reference methods that
apply when testing for source compliance. These modifications are contained in the
subparts of 40 CFR, Part 60.
3-3
-------
The main reason for the difference in complexity between ambient and source
standards is that the emphasis in the NSPS is on the emissions of a source. The
standards for different sources may specify different pollutants, as you can see from
the following:
Source
fossil -fuel fired steam
generators
sulfuric acid plants
petroleum refineries
zinc smelters
storage vessels for petroleum
liquids
Pollutants
paniculate matter
SO,
NO,
SO,
acid mist
paniculate matter
CO
SO,
paniculate matter
SO,
visible emissions
hydrocarbons
Even if the same pollutant is designated in different sources, as SO, and par-
ticulate matter are in the examples, the concentration of the same pollutant for
different sources may not be the same. For example, the standard for paniculate
emission in asphalt concrete plants is 90 milligrams per dry standard cubic meter
(dscm), while in zinc smelters it is 50 milligrams per dscm. In shon, the allowable
concentration of a pollutant may vary with the source.
Take another look at the source-pollutant examples. You should notice that,
along with criteria pollutants (paniculate matter, SO,, CO, hydrocarbons, etc.),
there are some pollutants we've not talked about. The Clean Air Act allows stan-
dards to be set for pollutants other than criteria pollutants which are (or may be)
harmful to the public health or welfare. The source emissions standards cover a
wider range of pollutants than do the ambient standards.
There's one other important point about the New Source Performance Stan-
dards. The test methods and procedures section for each standard tells which
reference methods must be used in sampling the designated pollutants; it also gives
sampling times and rates, when pertinent, for the reference methods. The source
sampling reference methods cannot be used, therefore, except in conjunction with
the standards.
3-4
-------
Before we move on to the source emission reference methods, we'd better review
the source standards.
Standards of Performance for New Stationary Sources
• are published in 40 CFR, Part 60
• cover a wide variety of source types
• specify pollutant concentrations
(possibly more than one pollutant per source)
(possibly different concentrations of the same pollutant in different sources)
• specify sampling procedures and reference methods for each pollutant
Review the entire first part of the lesson if you're not certain of the material.
Then answer the questions.
Questions
True or false:
1. A "new" source is one whose construction begins after the publication of a pro-
posed standard for the source category, or one scheduled for modification that
would result in types and/or quantities of emissions that would violate the
standards.
2. The allowable concentration for a pollutant in source emissions is uniform,
regardless of source.
3. No more than one pollutant is designated for each source.
4. New source standards may cover pollutants other than criteria pollutants.
5. Source sampling reference methods specify complete procedures for sampling
and analysis.
3-5
-------
Answers
1. True. An unmodified source already in operation is an existing source.
2. False. Specified concentrations are not necessarily uniform ai;:ong sources. You
must consult the standards.
3. False. The number of pollutants to be monitored varies with the source.
4. True.
5. False. Unlike ambient reference methods, source reference methods are not
complete in themselves. The standards indicate not only which reference
methods must be used but also the required flow rates and sampling times for
the reference methods. Standards and methods must be used in conjunction.
3-6
-------
Reference Methods for Source Emissions
The Federal Reference Methods for sampling and analysis of source emissions are
published in 40 CFR, Part 60, Appendix A. To date, more than twenty methods of
three distinct types have been designated:
Location of sampling points Method 1
Determination of volumetric flow Methods 2-4
rate of stack gas and other data
essential for the calculation of emissions
Determination of pollutant mass Methods 5-20
To acquaint you with the methods, we will summarize representative ones.
The first four methods specify procedures which are basic to the ultimate deter-
mination of any pollutant concentration. They are usually used in combination
with the methods for determining pollutant mass, but only when specified by the
appropriate New Source Performance Standard.
Method 1: Sample and Velocity Traverses for Stationary Sources
Describes the procedures for selecting sampling location in a stack and determining
both the number and location of traverse points (exact sampling points) in the
stack.
Method 2: Determination of Stack Gas Velocity and Volumetric
Flow Rate
Describes the procedure for determining the average gas velocity with an S-type
pitot tube and provides the equation for determining the stack volumetric flow
rate.
Method 3: Gas Analysis for Carbon Dioxide, Excess Air,
and Dry Molecular Weight
Describes the procedure for determining the gases in the stack and the dry
molecular weight of COt, CO, Ot, and Nf. This data is necessary for the calcula-
tion of the volumetric flow rate.
Method 4: Determination of Moisture in Stack Gases
Describes the procedure for determining the percentage of water vapor in the stack
gas. This data is necessary to figure the dry molecular weight of stack gas.
As you can see, these four methods are basic to collection and calculation,
regardless of the pollutant which is to be sampled.
S-7
-------
The next four reference methods for source sampling that we'll examine are
similar in many respects to the methods for ambient air. As you read, you'll find
yourself recognizing measurement principles and collection techniques. But you'll
also see many differences, because the requirements of source sampling are more
complex.
One of these requirements is sampling technique, which is based on stack gas
characteristics. There are a number of sampling techniques used in source
sampling:
Isokinetic: The velocity of the gas in the sampling probe at the nozzle is equal to
that of the gas stream at the sample point. Used only for paniculate matter,
isokinetic sampling insures that a representative sample of pollutant is taken.
Grab: The sample is taken through a probe into a collection vessel whose volume
can be measured. While a grab sample is usually taken over a short period
(seconds), it may be taken over a longer period if pollutant concentrations are low.
The grab sample is taken at only one location.
Integrated: The sample is usually taken over an extended period of time (e.g. 20
minutes) which is not necessarily continuous. The integrated sample may be taken
at several locations as well.
Continuous: The sample is measured continuously by a source emission monitor.
While isokinetic sampling is distinct, grab and integrated sampling may be very
similar. The key differences are in time, continuity, and potential number of loca-
tions per sample. The reference methods for determination of pollutants specify
sampling technique. But remember that the parameters of sampling appear in the
standards, so you must consult both the standard and the reference method.
Before you continue, go over the following review.
Source Reference Methods
Publication: 40 CFR, Part 60, Appendix A
Types:
a. location of sampling points and traverse locations (Method 1)
b. determination of volumetric flow rate and other data essential to calculations
(Methods 2-4)
c. determination of pollutant mass (Methods 5-20)
Methods 1-4: basic to collection and calculation, regardless of pollutant; used only
when specified by a New Source Performance Standard
Sampling Techniques:
a. Isokinetic: sampling velocity equal to stack velocity
b. Grab: usually short in duration; taken at only one location and through one
continuous period
c. Integrated: usually longer in duration; may be taken at different locations
through a discontinuous period
3-8
-------
Now let's examine some representative reference methods for pollutants in source
emissions. In most methods you will see that water vapor is removed from the sam-
ple gas. Water vapor is generally present in stack gas, and its removal is necessary
for valid data collection. We'll focus on the determination of pollutant mass; as
with ambient analysis, concentration is determined by given equations of mass and
volume of the sample and is expressed as mass per volume (specifically milligrams
per dry standard cubic meter). You will find the accompanying schematics for each
method useful.
Method 5: Determination of Particulate Emissions
from Stationary Sources
Type: Manual
Sampling Technique: Isokinetic
Measurement Principle: Gravimetric
Procedure:
The gas stream is sampled isokinetically to insure that representative particles are
collected. Sampling below the isokinetic rate will bias the sample toward the larger
particles. Sampling above the ioskinetic rate will bias the sample toward the
smaller particles. The particles are collected by a heated filter of known weight
(Figure 3-1) which is removed after sampling. The amount of particulate matter is
determined by weighing the filter after collection and subtracting the weight of the
clean filter.
Temperature sensor
Filter for particulate collection
Probe
Pitot tube
Manometer
Figure 3-1. Sampling for particulate matter from stationary sources.
3-9
-------
As you can see (Figure 3-2), the filter is very close to the beginning of the
sampling train. What's the function of the rest of the train, then? Part of it,
including the pump and the manometers (pressure gages), helps to maintain the
isokinetic sampling rate. The impingers in the ice bath condense out any moisture
in the sample gas, and the dry gas meter measures the flow rate during the
sampling.
Heated area
Filter holder
Temperature
sensor
Sampling nozzle
Probe
Reverse-type
pitot tube
Stack wall
Vacuum line
^•>
Silica gel
Pitot manometer
Orifice
Orifice
manometer
Thermometers
By-pass valve
Air-tight pump
Figure 3-2. EPA method 5 sampling train for paniculate matter.
Method 6: Determination of Sulfur Dioxide Emissions
from Stationary Sources
Type: Manual
Sampling Technique: Integrated
Measurement Principle: Colorimetric
Procedure:
The sampling train for this method (Figure 3-3) is similar to the one for par-
ticulate sampling. The sampling train is comprised of four midget impingers or
bubblers. An integrated sample is extracted from the stack at a rate of one liter
per minute for twenty minutes.
3-10
-------
Suck wall
/
Probe _ if
V I
v I Midget bubbler
Midget impingers si,ica ^j drying tube
80% isopropyl alcohol
3% hydrogen
peroxide
Needle valve
Dry gas meter
Pump
Figure 3-3. EPA method 6 sampling train for SO,.
The SO2 in the stack gas is separated from the major interferents, SO3 and acid
mist in a midget bubbler. Here SOS and acid mist are absorbed by isopropyl
alcohol. The SO2 is collected in the two impingers by absorption in a solution of
hydrogen peroxide. The third impinger is dry.
As in the paniculate sampling train, the ice bath surrounding the impingers
helps to condense water vapor. But in this train it also prevents the hot stack gas
from vaporizing the collection solutions. The silica gel drying tube further
eliminates water vapor.
Upon collection of sampling, the sample containing SO2 is removed from the
impingers and titrated until it turns from orange to pink and the SO2 mass is then
calculated. The sampled gas is measured by the dry gas meter.
3-11
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Method 7: Determination of Nitrogen Oxide Emissions
from Stationary Sources
Type: Manual
Sampling Technique: Grab
Measurement Principle: Colorimetric
Procedure-
The sampling train for the NO, method and the sampling procedure are rela-
tively simple (Figure 3-4). The three-way valve is central to the train. In the first
step of sampling, the valve is turned so that the pressure of the collection flask,
which is of known volume and contains an absorbing solution, can be lowered by
the vacuum pump. Later in the procedure, this lower pressure will cause the sam-
ple to be drawn into the flask.
Foam
Manometer
Purge
Sample
Figure 3-4. Source sampling method for NO. emissions.
In the second step, the valve is turned to the purge position. The squeeze bulb is
used to remove any ambient air from the probe after it is placed in the stack.
In the final step, the valve is turned to the sampling position, and the lower
pressure in the flask pulls in the sample of stack gas. The flask is encased in foam
to prevent injury from possible breakage during evacuation and to provide thermal
insulation.
3-12
-------
For analysis of the sample, the flask contents are allowed to equilibrate for 16
hours, during which the NO, (NO + NOz) in the sample is all convened to NO,.
The sample is then dried and mixed with an acid; the resulting solution turns
yellow if NO2 is present. The amount of NO, in the sample is determined with an
instrument that measures color intensity (a spectrophotometer).
One grab sample may not give an accurate indication of NO, concentrations,
however, so usually several samples are taken and the data averaged to produce
more representative collection data.
Method 10: Determination of Carbon Monoxide Emissions
from Stationary Sources
Type: Manual
Sampling Technique: Integrated or Continuous
Measurement Principle: Nondispersive Infrared Spectometry
Procedure:
The principle in this method is the same as in the reference method for sampling
of CO in the ambient air; however, interferences due to water vapor and carbon
dioxide are removed a little differently.
The sample is taken through a probe and is immediately passed around a cooled
condenser to begin removing water vapor (Figure 3-5). It is collected in a flexible
bag of measurable volume (Figure 5-6).
Rotameter
Air cooled
condenser
Probe
Quick disconnect
Filter
(glass wool)
Rigid container
Figure 3-5. Method 10 determination of carbon monoxide in source emissions (sampling).
3-13
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Needle
valve
Zero Span
gas gas
Rotameter
Figure 3-6. Method 10 determination of carbon monoxide in source emissions (analysis).
For analysis, the bag is connected to the analysis train. The two gas sources and
rotameters are used for calibration. As the sample is pulled through the two
impingers, water vapor and COj are removed. The now-dry gas containing CO is
then passed through the nondispersive infrared spectrometer, which operates
exactly as it does in the analysis of ambient CO. That is, it measures CO through
the infrared-absorbing qualities of the pollutant.
If a continuous sampling method is employed, the sample is pulled (after water
vapor is removed) into the analyzer rather than into the bag.
We have shown you only four representative methods, chosen to illustrate the
differences and similarities in ambient and source reference methods. Most of the
differences are due to two major factors—sampling environments and sample gas
characteristics. Sample gas characteristics especially affect analysis, primarily
because of the differences in pollutant concentrations likely to be encountered. If
you're interested in further information on the methods we've discussed, or on the
other source sampling methods, look for them in 40 CFR, Part 60, Appendix A.
Examine the review of the last four reference methods. Then, since the questions
which follow the review cover the entire lesson, go back and look again at any
material you're not sure about.
S-14
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Particulate Matter
Type: Manual
Sampling Technique: Isokinetic
Measurement Principle: Gravimetric
Procedure:
Stack gas is sampled isokinetically, and panicles are captured by a filter. The
filter is weighed before and after sampling. The gas sampled is dried and sample
volume determined with a dry gas meter.
Heated area
Filter holder
Temperature
tensor ~~
Sampling nozzle
Probe
Reverse-type
pilot tube
Suck wall
Pitot manometer
Orifice
Vacuum line
Silica gel
Vacuum
Main valve
By-pass valve
Orifice Therm«»nete« Dry gas meter Air-tight pump
manometer
3-15
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Sulfur Dioxide (SO,)
Type: Manual
Sampling Technique: Integrated
Measurement Principle: Colorimetric
Procedure:
Sampling rate is extracted at a rate of one liter per minute for twenty minutes.
Interferems are removed in an impinger containing isopropyl alcohol, and SOt is
collected in impingers containing hydrogen peroxide. The SOZ sample is removed
and titrated to a specified color change, and SOj mass is then calculated. During
the collection process, the sampled gas is dried and measured with a dry gas meter.
Probe
Suck wall
80% isopropyl alcohol
Ice bath
Midget
bubbler
Midget impingers
Silica gel drying tube
3% hydrogen peroxide
Dry gas meter
3-16
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Nitrogen Oxide (NOJ
Type: Manual
Sampling Technique: Grab
Measurement Principle: Colorimetric
Procedure:
Sample gas is collected by the grab technique in an evacuated flask containing
an absorbing solution which collects the NO,. The sample is dried, then mixed
with an acid to form a yellow solution. The amount of NO, is determined by a
spectrophotometer—an instrument that measures color intensity. Volume of the gas
sampled is calculated through flask volume.
Squeeze bulb
Flask valve Valve
Foam
Manometer
3-17
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Carbon Monoxide (CO)
Type: Manual
Sampling Technique: Integrated
Measurement Principle: Nondispersive Infrared Spectrometry
Procedure:
Sample gas is collected in a bag. The bag is attached to the analysis train which
removes water vapor and COt. CO in the sample is measured by a nondispersive
infrared spectrometer. Volume of the gas sampled is calculated by measurement of
the sampling bag volume.
Air cooled
condenser
Probe
Filter
(glass wool)
Rigid container
Sample in
Pump
Needle valve
Rotameter
gw
When you feel you've reviewed enough, answer the questions for Lesson 3.
5-18
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Questions
1. Identify the measurement principle for each source reference method:
CO
SO,
Paniculate matter
NO,
2. Define a "New Stationary Source."
3. Identify each item as true of ambient air standards or source emissions
standards:
a. only criteria pollutants are designated
b. more than one pollutant may be specified by each standard
c. the standard contains information which must be applied to reference
methods
d. the standard specifies a uniform pollutant concentration
e. published in 40 CFR, Part 60
f. published in 40 CFR, Part 50
4. In sampling, the sample is taken at one location during a short
time period.
5. In sampling, the velocity of gas in the sample probe at the
nozzle is equal to the velocity of the stack gas.
6. You must use the reference method when sampling for SOt emissions. Is all the
information you need found in the reference method? (yes/no). Explain your
answer.
7. Source reference methods 1-4 are pertinent to which of the following?
a. NO, emissions
b. location of sampling points
c. determination of dry molecular weight
d. weighing of collected paniculate matter
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Answers
1. (CO) nondispersive infrared spectrometry
(SOi) colorimetric
(Paniculate matter) gravimetric
(NOX) colorimetric
2. Any existing source whose modification results in emissions of different types
and/or quantities, or any new source whose construction begins after the
publication of a proposed standard for the source category in the Federal
Register.
3. a. ambient
b. source
c. source
d. ambient
e. source
f. ambient
4. Grab
5. Isokinetic
6. No. You must also use specific information given in the test methods and pro-
cedures section of the appropriate source standard.
7. (b) location of sampling points; (c) determination of dry molecular weight.
If there is information in the lesson on source emissions monitoring that still con-
fuses you, be sure to review it further before proceeding to the next lesson.
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Lesson 4
Quality Control and Quality Assurance
-------
Objectives
Upon completing this lesson, you should be able to:
1. identify and define the primary quality control measure.
2. define quality assurance.
3. define the two major types of audits.
4. identify a major reference source for quality assurance.
4-2
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Sampling and analysis of either ambient air or source emissions produces data. But
are the data valid? If they aren't, then, sampling and analysis efforts are virtually
useless. Quality control and quality assurance measures help insure needed validity.
Quality control is a system of activities and measures employed to provide quality
of output. For sampling and analysis, the primary quality control measure is
calibration. Calibration is the process of establishing the relationship between the
output of a measurement process, or a portion of a measurement process, and a
known input. In practical terms, calibration checks the accuracy of measurement.
We didn't go into calibration when we discussed the Federal Reference Methods,
but you should be aware that each method gives very precise information about
calibration. So calibration is important —perhaps the most important part of any
sampling and analysis procedure.
Even calibration, however, doesn't always insure validity of data. To increase
data validity, quality assurance programs have been developed. In essence, quality
assurance is "quality control on quality control." It's important in sampling and
analysis because it is cost effective, adds credibility to data, and supports legal
actions.
Just as calibration is the most important part of quality control, so the audit pro-
cess is the most important part of quality assurance. In essence, an audit verifies
whether the calibration is correct by comparing monitoring output from air
samples against monitoring output from known standard samples, or by comparing
several different analyses of the same sample. Audits can be performed within a
single lab (intralaboratory) or among labs (interlaboratory).
4-3
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Intralaboratory Audits
Typically, intralaboratory audits are performed in either of two ways. In one
(Figure 4-1), identical parts of the same overall air sample are analyzed. In the
other (Figure 4-2), standard samples are analyzed using the same procedures that
are used for analyzing actual air samples.
Sample
Methods/instruments
Analyses
Figure 4-1. Intralaboratory audit (same sample).
Standard samples
Analyses
Figure 4-2. Intralaboratory audit (standard sample).
4-4
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Intel-laboratory Audits
Interlaboratory audits are typically either collaborative studies or performance
audit surveys. In collaborative studies, (Figure 4-5) which test both sampling and
analysis processes, participants gather at a common location and all sample an
identical test atmosphere with their own equipment. For performance audit
surveys, (Figure 4-4) samples are sent from a single source to participants with
instructions on how to analyze the samples. Participants then send the data back to
the originator for evaluation.
Sample
Figure 4-3. Colloborative study.
C I I D I L_E
Figure 4-4. Performance audit survey.
4-5
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EPA also conducts a performance audit program, which is free of charge. It
includes both ambient and source testing, and both manual and automated
methods.
For more information about this program, contact the quality assurance
coordinator in your EPA Regional Office or write:
Director, Environmental Monitoring Systems Laboratory
USEPA, MD-77
Research Triangle Park, NC 27711
EPA's quality assurance program is published in the three-volume Quality
Assurance Handbook for Air Pollution Measurement Systems. Volume 1 covers
quality assurance principles, Volume 2 quality assurance procedures for specific
ambient methods, and Volume 3 quality assurance procedures for specific source
methods. You can obtain the Handbook by writing to the address above, with
attention to Distribution Record System.
The EPA quality assurance program encompasses 23 elements, of which auditing
is the most important. Some other major aspects of the program are data valida-
tion and document control. In data validation, blocks of data are reviewed to
identify questionable data —that is, whether the data seem reasonable for the par-
ticular monitoring activity—and to determine whether they are truly valid. Docu-
ment control is a system of written procedures for all monitoring activities, along
with a system for updating the procedures. This is important in assuring that all
monitoring activities are uniform, so that the data produced are comparable.
The Quality Assurance Handbook covers much more information than you've
read about here, but we have given you the fundamental concepts of quality con-
trol and quality assurance. If you're satisfied that you understand the basic prin-
ciples in this lesson, go on to the next one. If not, review any parts you need to
before proceeding.
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Lesson 5
Data Handling and Reporting
-------
Objectives
Upon completing this lesson, you should be able to:
1. list the basic elements usually included in raw monitoring data.
2. identify the two major formats of the AEROS system and the kinds of data for
which they are designed.
3. identify the computer programs which States may use in preparing monitoring
data reports for EPA.
4. describe the daily air quality report to the public that some agencies are
required to make.
5-2
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The data produced by ambient and source emissions monitoring may be in a
variety of forms, ranging from data sheets prepared from manual methods to con-
tinuous strip charts recorded by automated methods. At a minimum, "raw" data
provides information on pollutant concentration, monitoring location, date, and
time of day. Depending on monitoring objectives, there may also be such
meteorological data as wind speed and direction, barometric pressure, relative
humidity, and temperature.
Raw data, to be useful, must be assembled in standard formats for ease of
storage and interpretation. At this point the monitoring data, which are outputs of
the sensing system, become inputs to the data handling system. As we mentioned in
the overview, the major elements of a data handling system are preparation,
storage and retrieval, analysis, and reporting.
EPA has developed a standard computerized data handling system, with several
subsystems, for the National Aerometric Data Bank (NADB). This overall system is
called the National Aerometric and Emissions Reporting System (AEROS). The
two major formats for AEROS are the Storage and Retrieval of Aerometric Data
(SAROAD) for ambient air data and the National Emissions Data System (NEDS)
for source emissions data. Remember that these are basic elements of EPA's data
handling system, whose primary inputs are data produced by State and local
agency monitoring activity.
At the State and local level, the data handling system which is both comparable
to and compatible with AEROS is the Comprehensive Data Handling System
(CDHS). CDHS has two computer programs which put monitoring data into
SAROAD and NEDS formats for reporting to EPA. These programs are called Air
Quality Data Handling Subsystem —II (AQDHS—II) for ambient data and Emis-
sions Inventory System/Permit and Registration (EIS/P&R) for source emissions
data.
Are all the systems and acronyms confusing you? If so, reread the section and
then look at the following summary.
NADB
I I
SAROAD NEDS
(ambient) (source)
t t
AQDHS-II EIS/PfcR
(ambient) (source)
State and local agencies
5-S
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This has been a highly simplified discussion of the data handling systems
generally in use. The most important points for you to remember are that the
systems are computerized and are designed to provide standardized procedures for
preparation, storage, retrieval, and analysis of air pollution data which have been
uniformly gathered and processed.
Monitoring agencies prepare and code their data in the standard formats. The
data are then entered into the computer system. Once there, they can be easily
arranged for comparison, analysis, and reporting to EPA.
EPA requires that an annual summary of data from the State and Local Air
Monitoring Stations (SLAMS) be reported to the NADB; it also requires quarterly
reports from the National Air Monitoring Stations (NAMS). Here's an example of
SLAMS reporting for suspended paniculate matter. To comply with EPA
requirements, a State must report for each monitoring site:
• the annual geometric mean concentration
• the highest and second highest daily concentrations and dates of occurence
• the number of exceedences of both the 24-hour primary NAAQS and the
secondary NAAQS
• the number of 24-hour concentrations within each of eight specified ranges.
This kind of summary can be prepared for EPA by the AQDHS —II computer
program.
In addition to reporting to EPA, agencies must also report to the public on air
quality through the Uniform Air Quality Index. This index must currently be
reported daily for at least 5 days per week in all urban areas with populations
exceeding 500,000; after January 1, 1983, the requirement will be extended to all
urban areas with populations exceeding 200,000. In essence, the Uniform Air
Quality Index converts pollutant concentrations to a scale of 0-500, which is
divided into segments related to the NAAQS and criteria for air pollution episodes.
The pollutant with the highest index value is designated as the critical daily pollu-
tant and is accompanied by a descriptor of its place on the scale.
This lesson, which concludes the unit on sampling and analysis, has covered the
highlights of the most important data handling systems and reporting procedures
and is intended only to make you aware that data handling and reporting are
integral parts of the entire monitoring process. Look over any parts you're not sure
you have mastered and then answer the review questions for this lesson.
You may then want to review the previous lessons in the unit before going on to
the review test, which will help you determine any gaps in your knowledge.
5-4
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Questions
1. List the elements of AEROS and CDHS designed for handling ambient air
monitoring data.
2. List the elements of AEROS and CDHS designed for handling source emissions
monitoring data.
3. List the major elements of a data handling system.
4. For what is the Uniform Air Quality Index used?
5-5
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Answers
1. SAROAD (AEROS), AQDHS-II (CDHS)
2. NEDS (AEROS), EIS/P&R (CDHS)
3. preparation, storage and retrieval, analysis, reporting
4. daily air quality reports to the public in major urban areas
5-6
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Review Test
1. Do the National Ambient Air Quality Standards cover any pollutants other
than criteria pollutants?
2. Define quality assurance.
3. Define New Stationary Source.
4. Where would you find the published reference methods for ambient air?
5. What is the AEROS format for source emissions monitoring data?
6. An instrument for ozone monitoring employs chemiluminescence with ethylene.
Is it a reference method or is it an equivalent method? Why?
7. True or false:
a. There can be no equivalent method for an ambient manual reference
method.
b. Equivalent methods can be designated for source sampling reference
methods.
c. There are qualified instruments for each automated ambient reference
method.
8. Examine the diagrams which follow. For each, (1) identify the pollutant for
which the procedure is used, (2) identify the measurement principle, and
(S) identify the procedure as either a source or ambient reference method.
Rotameter
Air cooled
condenser
Valve
Filter
(glass wool)
Rigid container
6-1
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Sample in
Pump
Needle valve
Rotameter
Figure A 1.
2.
3.
Sample
air
Con verier
Exhaust
\
Ozone in
T
-\
Light
Photomultiplier
tube
Figure B 1.
2.
S.
6-2
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Flask valve
Foam
Manometer
Figure C 1.
2.
3.
Air out
Figure D 1.
2.
3.
6-3
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9. True or false:
a. A new source is one whose construction is begun before the publication of a
proposed standard for that source category.
b. New source standards may designate allowable concentrations for more than
one pollutant.
c. New source standards cover only criteria pollutants.
d. In isokinetic sampling, the sampling rate is proportional to the stack gas
rate.
10. You must monitor SO2 emissions from a new fossil-fuel-fired steam generator.
a. In which document will you find which pollutants you must sample and
analyze? (Give a name, not the CFR number).
b. Where will you find the essential information on sampling and analysis
procedures?
11. Name a useful resource for quality assurance information.
12. Identify the information published in each of the following:
a. 40 CFR, Part 50
b. 40 CFR, Part 60
c. 40 CFR, Part 60, Appendix A
13. You are concerned about the effects of NOt on vegetation. To find the
allowable concentration of NO2 pertaining to vegetation in your neighborhood,
you would consult which of the following:
a. the source emission standard for NOZ
b. the ambient reference method for NOZ
c. the primary ambient standard for NO2
d. the secondary ambient standard for NOZ
14. Which of the following would be a use of ambient monitoring data?
a. evaluating the efficiency of an emission control device
b. studying emission patterns from specific sources
c. judging compliance with emission regulations
15. Name the two major kinds of performance audits.
16. Why are the standard air pollution data handling systems important?
17. What are the major considerations of monitor siting?
6-4
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Review Test Answers
1. No.
2. "Quality control on quality control"
3. A source whose construction begins after the publication of a proposed stan-
dard for that source category, or an existing source scheduled for modification
that would result in increased emissions.
4. 40 CFR, Part 50, Appendices A-G
5. National Emissions Data System (NEDS)
6. Neither. It employs the correct measurement principle but has not been
designated by EPA. If it were, it would be a reference method.
7. a. false
b. false
c. false
8. Figure A 1. CO
2. nondispersive infrared spectrometry
3. source
Figure B 1. NOZ
2. chemiluminescence with ozone
3. ambient
Figure C 1. NO,
2. colorimetric
3. source
Figure D 1. suspended particulates, lead
2. gravimetric
3. ambient
6-5
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9. a. true
b. true
c. false
d. false
10. a. The New Source Performance Standard for the source
b. The New Source Performance Standard and the source reference methods
for the pollutants designated by the standard
11. The Quality Assurance Handbook, published by EPA.
12. a. National Ambient Air Quality Standards (NAAQS) —both primary and
secondary; ambient reference methods (in Appendices A-G)
b. Performance Standards for New Stationary Sources (NSPS)
c. reference methods for source sampling and analysis
13. d. the secondary ambient standard for NO*
14. b. studying emission patterns from specific sources
15. interlaboratory, intralaboratory
16. They provide standardized procedures for preparation, storage, retrieval, and
analysis of data and help insure uniformity.
17. monitoring objectives; site characteristics
6-6
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