Unit 1, Lesson 5

IAQ Learning Module

The filters typically used in residential forced-air
heating and cooling systems are low air resistance
fiberglass panel filters that remove larger particles.
They are used primarily to keep the ventilation
system clean and, in part, to protect the equipment.
Some individuals may be sensitive to the oils, resins,
disinfectants, and scents that may be used in the
manufacture of the filters. These low efficiency
filters are also used as prefilters in air cleaners.

Extended surface filters (also called pleated filters)
are basically panel filters chat have been pleated or
folded to provide more filter surface per unit area of
filter face. The filter media may stand alone or be
encased in a frame. These filters are more efficient
and can hold more dust than comparable panel
filters. By extending the surface of the collecting
medium, the flow velocity through the filter is
reduced, and this reduces the pressure drop across
the filter. Therefore, denser and more efficient filter
media can be used while maintaining acceptable
pressure drops.

High efficiency particulate air (HEPA) filters are
extended filters that remove submicron particles
with high efficiency (greater than 99.97% removal
efficiency for particles 0.3 microns and larger). In
some designs, HEPA filters consist of a core filter
that is folded back and forth over corrugated
separators that add strength to the core and form the
air passages between the pleats. The filter is
composed of very fine submicron glass fibers in a
matrix of larger fibers (1 to 4 microns).

In the typical furnace system, the standard low
efficiency filter can be replaced by a medium
efficiency filter but not by a HEPA filter. If it is
not part of the original installation, the HEPA filter
must be installed in a separate housing. Some
manufacturers, however, do make HEPA filter-
containing furnaces.

HEPA filter room and whole house air cleaners
range in cost from about $200 to $2000. Air flow
capacity ranges from about 100 cfm for smaller
units to 2000 cfm for larger units.

Charged-media filters combine aspects of both
mechanical filters and electrostatic filters, and they
can be both ionizing and nonionizing. The electret
filter is a relatively new product chat consists of a
charged-media filter that attracts dust particles onto
permanently charged plastic films or fibers called
electrets. The positive and negative charges can be
produced by the friction of air flowing over the
filters or as a result of high-voltage imprinting
during manufacture. These filters have high
particulate removal efficiencies, and they do not
produce ozone. However, they must be cleaned
regularly, and there is some controversy about their
efficiency after they have been loaded with particles
(Fisk et al., 1987).

Removal of Particles by Electronic
Air Cleaners

Electronic air cleaners use an electrical field to trap
charged particles. Like mechanical filters, they can
be installed in central heating and/or cooling system
ducts, or they may be portable units with fans.
Electronic air cleaners include electrostatic precipi-
tators; ion generators are sometimes classified as
electronic air cleaners.

Electrostatic precipitators apply a charge to
particles which are then removed from the air by
becoming attracted to oppositely charged plates.
Electrostatic precipitators have a high removal
efficiency for small particles.

In residential and commercial applications, ionizing
flat-plate precipitators are widely used. Residen-
tial units cypically consist of two stages. Particles
are ionized in the first stage and collected in the
second stage. In some cases, the electrostatic
precipitators have prefilters to remove large particles
or adsorbents such as charcoal to remove gaseous
contaminants after air leaves the precipitator. The
removal of gaseous contaminants is discussed below.

Because of the high voltages which are used in
electrostatic precipitators, some safety precautions
are needed. Electrostatic precipitators should shut-



Final Examination

IAQ Learning Module

84. What would help in attaining a major
program objective?

85.

a. build in a larger timeframe than necessary
b. develop an accompanying action plan a.
c. have a tough-minded program manager
d. gain the support of people in the news .
media c.
Whar should a program manager do before d.
implementing a new indoor air program?
a. ensure that there is popular support for the
program
b. work out administrative relationships with
other supporting departments
c. attend as many management training
courses as possible
d. avoid becoming involved in internal

politics

86. Which of the following is important when
deciding whether to include enforcement as
part of the indoor air program?

de-emphasize this aspect with the news
media

place equal emphasis on education

ensure that the proper legal and administra-
tive support is in place

all of the above are correct



IAQ Learning Module

Unit 1, Lesson 3

respiratory irritants cause a physical reaction in a
susceptible population. This population is assumed
to have been stressed for a period of time by low-
level chemical exposures, physical conditions,
workplace stresses, or other factors (Colligan and
Murphy, 1979; Colligan, 1981). The individual
perceives the trigger to be threatening, the auto-
nomic system is aroused, and physical complaints
and symptoms result. These complaints and
concerns are thought to spread quickly throughout
the workplace.

The diagnosis of mass psychogenic illness is sug-
gested by symptoms that do not have an organic
basis or are inconsistent with exposure to any
suspected contaminants. Another important
component of the diagnosis is that individuals
usually do not become ill unless they see or hear
that others are becoming ill (Fischbein, 1990).

Mass psychogenic illness has been reported to occur
among workers in low-paying stressful jobs that
often involve boring and repetitive work, an
unrealistic pace, rigid authoritarian organizations,
lack of social supports, and physical stresses from.

noise and poor lighting (Colligan and Smith, 1978).

Multiple Chemical Sensitivity

It is well recognized that individual sensitivities to
chemical and biological agents in air, water, and
food can vary significantly, and that some persons
may be hypersensitive to particular agents at levels
which do not generate an observable response from
the general population. It is also recognized that
certain chemicals may be sensitizers, and once an
individual becomes sensitized to a relatively high
dose of a contaminant, the individual may be
sensitive to much lower subsequent doses.

In addition to these specific sensitivity issues, there
is a body of anecdotal evidence which suggests that
some subset of the population may be especially
sensitive to a broad range of chemicals at levels
common in today’s home and working environ-

ments. This potential condition has come to be
known as multiple chemical sensitivity (MCS)
(Cullen, 1987). Reported symptoms include vague
feelings of not being well, joint and muscle aches
and pains, recurrent respiratory infections, food
intolerances, recent memory loss, and many others.

There is significant professional disagreement
concerning whether MCS actually exists and what
the underlying etiology might be. The concept of
MCS was developed and is supported by physicians
known as clinical ecologists. Although there are
some areas of agreement between clinical ecologists
(some of whom are also board certified allergists)
and traditional allergists, there are disagreements
about the levels of exposure that are necessary to
cause health effects, what symptoms or diseases are
associated with specific chemical exposures, and
what mechanisms come into play (Ashford and
Miller, 1989).

Based on their review of the literature and personal
interviews with medical practitioners, Ashford and
Miller (1989) conclude that there is sufficient
collective evidence (anecdotal and scientific studies)
to present a compelling case for MCS that warrants
further study. Other reviews have not found con-
vincing evidence to support the concepts underlying
clinical ecology or its methods of diagnosis and
treatment (American College of Physicians, 1989;
Kahn and Letz, 1989).

Different hypotheses have been formulated in an
attempt to explain this apparent phenomenon.
These include, for example, a “spreading” phenom-
enon in which sensitization to one chemical spreads
to other, often unrelated chemicals; a process of
adaptation or addiction to chemicals involving
overlapping stimulatory and withdrawal effects; and
a total load concept in which the human body
becomes overloaded with environmental (and
possibly other) stressors (Asford and Miller, 1989).
Psychiatric disorders have also been suggested as an
explanation for reported symptoms (Black, Rathe,
and Goldstein, 1990).



EPA/400/3-91/002

Introduction to
Indoor Air Quality

A Self-Paced Learning Module

United States United States National
Environmental Protection Public Health Environmental
Agency Service Health Association

July 1991


Final Examination

IAQ Learning Module

52.

53.

54.

55.

56.

Which of the following contaminants could
result from the use of a heat exchanger or
evaporative cooler?

a. carbon monoxide
b. carbon dioxide

c. nitrogen dioxide
d.

microorganisms

Which of the following air cleaning devices
can remove respirable particulates with
efficiencies of over 99%?

panel filters

extended surface filters
HEPA filters

heat recovery ventilator

aorP

Which of the following contaminants could
result from the use of electronic air
cleaners?

ozone
microorganisms
carbon monoxide
carbon dioxide

aor

Which of the following is a control device
in which gaseous contaminants are
attracted to and retained on the surface of
materials such as alumina?

ionizing flat-plate filter
adsorption device
electret filter

heat recovery ventilator

ao rP

Which of the following is the most com-
monly used material for adsorption of gases
and odors?

alumina
sodium carbonate
activated charcoal

ange

potassium permanganate

57.

58.

59.

Which of the following standards/guide-
lines identifies acceptable levels of indoor
air contaminants?

a. National Toxic Release Inventory
b. Uniform Building Code

c. ASHRAE standards

d. NIOSH Criteria Documents

Which of the following standards/guide-
lines identifies acceptable ventilation rates
for indoor air environments?

a. World Health Organization Air Quality
Guidelines for Europe

b. CABO One and Two Family Building Code

c. Canadian Exposure Guidelines for Indoor
Air Quality

d. American Conference of Governmental
Industrial Hygienists Guidelines

Which of the following statements about
ASHRAE’s Standard 62-1989 Indoor Air
Quality Procedure is correct?

a. acceptable indoor air quality is defined as
air that does not have known harmful
contaminants and 80% or more of the
people exposed do not express dissatisfac-
tion

b. acceptable indoor air quality must be
achieved by meeting acceptable concentra-
tions of indoor air contaminants

cc. the standard recommends using a safety
factor of 1/100 as a preliminary guideline
for contaminants that are not specifically
listed

d. the standard is designed to provide protec-
tion to the entire population, including
those who are especially sensitive to
chemical exposures



UNIT 2: MEASURING AND EVALUATING PROBLEMS

LESSON 6
INDOOR AIR QUALITY MEASUREMENTS

During the past few years technological advances have resulted in
the ability to detect ever smaller concentrations of contaminants with
equipment that is increasingly user friendly and compact. However,
the measurement of indoor air contaminants remains an undertaking
that requires careful thought and preparation in order to ensure that
data of high quality will be collected. An investigator's develop-
ment of expertise in the measurement of indoor air contaminants
depends on an understanding of the basic principles of the measure-
ment process including options for sampling and analysis, sources of
error, and quality assurance. Detailed information on specific
methods and equipment is provided in Section 6 of the Reference
Manual.

LESSON OBJECTIVES

At the end of this lesson you
will be able to:

© identify different options for
equipment used to monitor indoor
ir contaminants;

© identify sources of error in the
‘measurement process and ways to
minimize errors; and

© describe important components of a
quality assurance program.



74

Unit 2, Lesson 6

IAQ Learning Module

In the case of direct reading instruments, calibration
standard materials (calibration standards) are used to
quantify the relationship between the output of a
sensor and contaminant concentrations. This
relationship allows the user to know that the
instrument is responding accurately (or inaccu-
rately) to contaminants in the air.

Without proper calibration of equipment and
methods, the sampling results cannot be assumed to
be accurate and reliable. Considerable money and
time can be wasted in the long run when investiga-
tors skimp on calibration.

Sampling pumps, flowmeters, analyzers, calibration
gases, and laboratory analytical procedures must all
be calibrated. It is essential for any chemical
reagents or gases that are used in the calibration to
be of the highest reliability. This means they must
be certified in some manner; materials that are
traceable back to NIST will provide the highest
reliability.

The frequency of calibration varies depending on
the requirements of data acceptability, performance
between scheduled calibrations, and manufacturer's
recommendations. The conditions under which the
instruments are used and the number of people
using the instruments and their skill levels should
also be considered. A general rule is to calibrate
before and after each sampling period if equipment
is turned off or transported between measurements.

Methods of calibration for equipment and laboratory
methods are specified in EPA methods and several
references (Taylor, 1987; Katz, 1977; and EPA,
1977; 1989; NIOSH, 1984); these should be used
whenever possible. Section 6 of the Reference Manual
contains more information on the calibration of
equipment.

Proficiency Testing
Proficiency testing is an external quality control

check that involves the analysis of reference samples
once or twice a year. Certified samples are sent to

laboratories for analysis. The laboratory’s perfor-
mance is judged by the accuracy of the analysis.
Proficiency testing is a commonly used technique in
industrial hygiene and environmental analysis. It
provides additional assurance about the quality of
the data produced by laboratories.

Proficiency testing is not routinely available in
indoor air quality work; however, programs do exist
for the measurement of radon and asbestos. These
programs are administered by EPA, and EPA
publishes a list of companies that pass the perfor-
mance tests. Selecting a company that passes the
proficiency test provides additional assurance that
quality data will result. EPA also provides compari-
son standards (audit materials) for the compendium
methods through the Atmospheric Research and
Exposure Assessment Laboratory, Quality Assurance
Division, MD-77B, Research Triangle Park, NC
27711.

Validation of Collected Data

The validation of data is a final critical point in the
measurement process, and the investigator should
have a set of criteria by which to judge the validity
of collected data. These criteria should include the
following:

1) instruments should operate properly during
sampling periods (if an instrument or pump
is not operating at the end of a designated
sampling period, the data collected during
that time period should not be used);

2) analysis of blanks and duplicate samples,
and calibrations must be performed prop-
erly and be within pre-determined limits
during the times the data were collected;

3) extreme values must be checked to deter-
mine causes;

4) calculations and data transfers must be
performed properly; and



IAQ Learning Module

Unit 1, Lesson 2

Concentrations of these contaminants in polluted air
vary, but values that are 5 to 10 times higher than
background levels have been measured in many
locations.

The building’s envelope (roof, walls, and windows)
acts as a barrier to prevent outdoor air from entering
the living space, but it does not provide a perfect
seal and contaminants in the outdoor air enter the
indoor environment through infiltration and natural
ventilation. Whether or not outdoor air becomes a
major contributor to indoor air pollution depends
on outdoor contaminant concentrations, air ex-
change rates, and the extent to which the building
envelope (shell) removes the contaminants.

Generally, as outdoor concentrations of contami-
nants increase, so do indoor air concentrations. This
increase is at a slower rate and with a slight lag in
time, but if the outdoor concentrations stay at a
constant value, the indoor concentration could
eventually be expected to reach that of the outdoors
for most contaminants.

Outdoor air sources close to the building can
dramatically influence indoor air quality. Contami-
nants from street traffic, outdoor pesticide applica-
tions, barbecue grills, trash storage areas, or similar
sources can enter through open doors and windows
or infiltrate through the building envelope.

In commercial buildings with mechanical ventila-
tion systems, a major contributor to indoor air
quality problems has been improperly located
outdoor air intake vents. When intake vents are
improperly located, contaminants from loading
docks, parking areas, roofing tars, and other sources
can enter through the intake vent and contaminate
the indoor environment. Also, contaminants from
building exhausts, including restroom exhausts, can
reenter the building through the outdoor air intake
vents when the exhaust and intake vents are located
close to one another.

Geology and soil structure are important determi-
nants of the potential contamination indoors by

radon and other contaminants. Radon is perhaps
the most widely known example of a gas that can
migrate from the soil into a structure. Other gases
and chemical liquids can also enter the living space
from contaminated soils. For example, methane,
carbon dioxide, and other gases can migrate from
sanitary landfills into basements; contaminants from
leaking storage tanks and hazardous waste sites can
also migrate through the soil and enter interior
spaces. The migration of these contaminants
indoors can occur when building interiors are
depressurized due to wind, by the operation of
exhaust fans, or by an improperly balanced mechani-
cal ventilation system.

In addi
chemicals or radon can release these contaminants to
the inside air during showering, dishwashing, and
similar activities.

ion, water contaminated with organic

Air Exchange Rates (RM 2.1)

The air exchange rate is the rate at which indoor air
is exchanged with outdoor air, and it is expressed as
the number of times the air volume in a structure is
exchanged with the outdoor air each hour. Air
exchange in a structure occurs by infiltration,
exfiltration, natural ventilation, and mechanical
ventilation (Figure 2-1).

The air exchange rate has units of air changes per
hour (ach). The nominal air exchange rate can be
calculated as the rate at which outdoor air enters the
structure (m?/hr or ft3/hr) divided by the volume of
the structure (m? or ft’).

Assuming that a house has a volume of 500 m*, and
250 m* of outdoor air enters the house each hour to
replace the same amount of indoor air, the nominal
air exchange rate is 0.5 ach. In this example, air
equal to one half the volume of the house is replaced
by outdoor air every hour, and an exchange of air
equal to the total volume of the house will occur
every two hours if all conditions remain the same.
This does not mean that every air molecule in the
house will be exchanged every two hours. Air



IAQ Learning Module

Unit 2, Lesson 6

Standards and Technology (NIST), formerly the
National Bureau of Standards (NBS), can be pur-
chased for about $200. (See discussion below under
standard materials)

The sling psychrometer has a thermometer holder
that telescopes into a swivel handle which has a
slide rule that contains scales for relative humidity
and wet- and dry-bulb temperatures. The psy-
cheometer is whirled by hand to produce the air
velocity required to determine the wet-bulb tem-
perature which is needed along with the dry-bulb
temperature to read the relative humidty. Sling
psychrometers can be purchased for about $75. A
powered psychrometer can be purchased for about
$350, but this level of expense is not needed.

Light: The intensity of visible light can be mea-
sured using light meters. These meters measure the
quantity of light per unit area in foot-candles (ft-c).
Light meters can measure light intensities over a
broad range (from 0 to 99,900 ft-c). Analog meters
can be purchased for about $100 and digital meters
can range from about $150 to $300, depending on
the range of light to be measured and whether the
meters are traceable to NIST.

Air Motion: In most situations air movement can
be measured using analog or digital meters and
smoke tubes. When using meters to measure air
motion it is important to use devices that are
nondirectional or to monitor the orientation of the
meter carefully to ensure that the true air speed is
being measured.

Air velocity can be measured in rooms or inside
heating and ventilating ducts, grilles, and diffusers.
The unit of measurement for air velocity is feet per
minute (fpm) or meters per second (mps). Some
meters also contain scales for measuring static
pressures in ducts. A mechanical air velocity meter
kit that can measure velocities, and differencial
pressures at a variety of locations costs about $1000.
Mini-sized air velocity meters, which can measure
the same air velocity range but not static pressures,

can be purchased for about $250 to $500. These
mechanical systems do not require power sources or
batteries.

Direct readings of airflow [in cubic feet per minute
(cfm) or cubic meters per second (cms)} can be
obtained with air volume meters. Standard-sized
units cost about $1700 and mini-sized meters cost
about $1000. Both units have hoods of different
sizes which fit directly over supply and exhaust
openings that channel the air through a manifold to
a specially designed base that senses airflow and
averages the results. A wide range of flows can be
measured (0 to about 2000 cfm).

Smoke tubes or smoke candies release visible smoke
which blends readily with air to aid in observing
airflow. These devices should be used cautiously
because they can trigger fire alarms and the smoke
can be irritating. Smoke tubes or candles can be
purchased in different sizes depending on the
amount of smoke to be generated. Costs are about
$2 to $7 per tube or candle.

Noise: There is a variety of equipment available for
measuring noise. For most evaluations, the sound
level meter (A-weighted scale) will provide suffi-
cient information. In some instances an octave band
analyzer may be needed. Meters with the A-
weighted scale only can be purchased for about
$300; an acoustical calibrator (about $200) must
also be purchased. Meters that have more capability
are slightly more expensive.

Particle and Aerosol Detectors

Particles and aerosols are most commonly collected
onto a filter medium and the analyzed gravimetri-
cally or by other methods, but instruments are
available which can provide a direct reading of
particles without an intermediate step. These
instruments are relatively complex and expensive
(from $500 to over $10,000). They operate by
sensing some property of the particulate such as
size, electrical charge, or mass.



Unit 1, Lesson 3

IAQ Learning Module

Table 3-2. Subpopulations at greatest risk from exposure to indoor air contaminants.’

SUBPOPULATION

Newborns

Young children

Elderly

Heart patients

Persons with bronchitis
Persons with asthma
Persons with hay fever
Persons with emphysema

Smokers?

SOURCE: Adapted from U.S. EPA (1989)

SIZE OF THE PERCENT OF
SUBPOPULATION POPULATION’

3,731,000 15
18,128,000 1S
29,172,000 12.1
18,458,000 77
11,379,000 47
9,690,000 40
21,702,000 9.0
1,998,000 08
46, 772,500 26.5

All subpopulations except smokers are based on 1986 data. Data for live births, children < 5 yrs, and persons > 65 yrs are based on
U.S. Bureau of Census records. Data for persons with heart disease, bronchitis, asthma, hay fever, and emphysema are based on

National Center for Health Statistics records.

21986 national population of 241,078,000 was used for all categories except smokers.

Persons > 17 yts of age who smoked in 1986; Smoking and Health: A National Status Report. 1990. U.S, Department of Health and

Human Services (DHHS). DHHS (CDC) 87-8396.

many conditions. However, it does appear that the
initial step of chemical exposures involves the
recognition of the toxic chemical by a specific
molecule(s) known as the receptor. The chemical
binds itself to the receptor which initiates a chain
reaction that may lead to an adverse health effect.
As long as the receptor and the chemical are bound
together, adverse effects can occur.

Over time, a balance is reached between bound and
unbound receptors, and this balance can change as

exposures increase or decrease. If a stored chemical
is released, the potential for a toxic effect increases

as the substance combines with receptors. For

example, if a person who has been exposed to a
nonpolar chemical such as PCBs loses weight, that
chemical will be released into the bloodstream and
adverse effects could result if the PCBs are not
excreted.

The frequency of exposure also affects whether or
not adverse effects occur. The body may be able to
handle small exposures separated by long time
periods during which the contaminant is metabo-
lized and excreted. However, if the periods of time
between exposures are shortened, adverse health
effects may appear. For this reason, it is important
to characterize exposures accurately.



Unit 2, Lesson 8

IAQ Learning Module

want to conduct medical tests on the client which
may be helpful, or these data may have already been
obtained. This may also be a good opportunity to
share information that will inform the health care
provider about indoor air quality problems with
which he/she is not familiar.

If monitoring is needed, explain to the client what
tests are needed and what the results may or may
not reveal. If preliminary and conclusive results are
available at the site, share them with the client,
explaining how the data relate to standards or
guidelines. Any limitations of the data should be
communicated clearly. Indicate that the informa-
tion is preliminary and that a final report will
follow.

Time spent during the inspection to keep the client
informed will help the client become knowledgeable
and less apprehensive about indoor air quality
problems.

REFERENCES

Herman, R.E. 1983. “How to handle complaints.” J Environ
Health. 45(5): 238-240.

National Insticuce for Occupational Safety and Health
(NIOSH). 1987. “Guidance for indoor air quality investiga-
tions.” 25 pp. NIOSH. 1989. Indoor Air Quality Selected
References, NIOSH, Division of Standards Development and
Technology Transfer: Cincinnati, OH.

Sterling, E.M., E.D. McIntyre, C.W. Collett, J. Meredith and
TSterling. 1987. “Field measurements for air quality in office
buildings: A three-phased approach to diagnosing building
performance problems.” Sampling and Calibration for Atmospheric
Measurements. J.K. Taylor (ed). ASTM STP 957. American
Conference of Governmental Industrial Hygienists:

Cincinnati, OH.

Woods, J.E., Morey, P.R. and D.R. Rask. 1987. “Indoor air
quality diagnostics: Qualitative and quantitative procedures to
improve environmental conditions.” Presented at the ASTM
Symposium on Design and Protocols for Monitoring Indoor Air
Quality. April 26-29. Cincinnati, OH.

PROGRESS CHECK

5. What are the basic elements of effective communication?

1. Whot ore the two basic types of survey forms, and what criteria should ony survey form meet?
2. What bosic elements are involved in conducting a residential investigation?

3. What are the systems that should be evaluated during an inspection?

4. Explain on effective approach to characterizing contaminants.



IAQ Learning Module

Unit 1, Lesson 4

Changes in pulmonary function (lang volume and
lung capacity) can also result from exposure to
indoor contaminants such as environmental tobacco
smoke, nitrogen oxides, and sulfur dioxide. (Section
3, of the Reference Manual defines some of the terms
used in lung function testing). The significance of
these changes, particularly relatively modest
changes, has not been resolved. Changes in pulmo-
nary function may or may not manifest themselves
in symptoms such as breathing difficulties.

Asphyxiants

Asphyxiants are chemicals that interfere with the
availability of oxygen for the tissues. A complete
absence of oxygen in the blood (anoxia) will result
in brain death in 3 to 5 minutes. Partial asphyxia-
tion results in low levels of oxygen in the blood
(hypoxia), and may result in brain damage or death,
depending on the length of exposure. The normal
oxygen level in the air is about 21%. Levels of
oxygen in air below 19.5% are considered unsafe in
the workplace {29 CFR 1910. 94 (d) (9)].

There are two classes of asphyxiants, simple and
chemical, that differ in their mode of action.
Simple asphyxiants are physiologically inert gases
that act by diluting or displacing oxygen in air
below the level required for normal function.
Simple asphyxiants include carbon dioxide, nitric
oxide, nitrous oxide, and nitrogen. Symptoms
associated with exposure to levels of concern
typically include drowsiness, headache, and changes
in the rate and depth of respiration.

Chemical asphyxiants react chemically with the
body to prevent the uptake of oxygen by blood or
interfere with the transport of oxygen from che
Jungs to the tissues. Chemical asphyxiants include
carbon monoxide, hydrogen sulfide, hydrogen
cyanide, and others. Of these, carbon monoxide is
the most likely to be encountered in indoor investi-
gations. Typical sources in residential investiga~
tions include heating and cooking appliances as
noted above, and in some instances, the ambient air
or emissions from automobiles in attached garages.

In nonresidential investigations any combustion
sources in the building or adjacent to air intakes
should be evaluated. Effects from exposure to
chemical asphyxiants can include the above symp-
toms plus depressed respiration, muscle spasms,
visual disturbances, loss of appetite, impaired gait
and balance, insomnia, weakness, and depression.

Narcotics and Anesthetics

Narcotics and anesthetics are chemicals that prevent
the central nervous system from performing nor-
mally. Narcotic substances can result in symptoms
that are similar to those caused by asphyxiants.
Examples of narcotics and anesthetics include
aliphatic ketones (methyl ethyl ketone, methyl!
isobutyl ketone, acetone), aliphatic alcohols (metha-
nol, ethanol, isopropanol), and aromatic and substi-
tuted hydrocarbons (xylene, toluene, styrene,
chlorobenzenes). Many of these chemicals are
contained in paints, varnishes, pesticides, glues, and
organic solvents that are commonly used in and
around homes and in other nonindustrial settings.

Some of the anesthetic solvents can also result in
cardiac sensitization. Inhalation of low levels of
these compounds can make the heart very sensitive
to certain chemicals (catecholamines) in the body,
which in turn, can result in ventricular cardiac
arrhythmias. There have been cases of cardiac
sensitization reactions which resulted in the death of
people who were working with solvents related to
hobbies and crafts in poorly ventilated rooms.
Caffeine and alcohol may enhance the ability of sol-
vents to produce heart arrhythmias (Benowitz, 1990).

Systemic Toxicants

Systemic effects are those that occur after the
distribution and absorption of the chemical at a site
that is distant from the point of entry. The wide
variety of ingredients in consumer products and in
materials encountered in the nonindustrial environ-
ment can result in a range of systemic effects that is
difficult to anticipate. Substances toxic to the liver
(hepatotoxicants), kidney (nephrotoxicants), blood



IAQ Learning Module

Unit 1, Lesson 5

Standards and guidelines that are most important to
indoor air include:

Air quality standards which specify maximum
concentrations of a contaminant beyond which
health risks are deemed to be unacceptable,

Source emission standards which specify maximun
rates at which a contaminant can be emitted from a
source;

Ventilation standards which specify minimum
rates for the introduction of outdoor air into indoor
spaces;

Building codes which are frequently issued as
regulations by state and local governments and
provide design and construction specifications for
buildings and building systems;

Maintenance guidelines which specify procedures
and timetables for operating and maintaining
building equipment; and

Diagnostic and measurement protocols which
establish methodologies for measuring and assessing
indoor air quality problems.

Regulatory Approaches

Regulations impose requirements on individuals or
organizations and carry the force of law. Generally,
they contain provisions for either civil or criminal
penalties for noncompliance. The most common
regulations relevant to indoor air are specific to a
given contaminant or source. Different types of
regulations include:

© aban of restriction on the use of specific
chemicals or products such as asbestos or
chlordane;

* arequirement that products meet certain
standards such as the requirements for
oxygen sensors on unvented gas heaters or

the product standards for formaldehyde in
manufactured housing;

© requirements for testing and certification,
such as for pesticides prior to manufacture;

© — labeling standards for specific products such
as cleaners, pesticides, sealants, paints, and
solvents which require disclosure of infor-
mation about chemical contents, effects,
and instructions for proper use.

ROLES AND RESPONSIBILITIES (RM 5.3)

Many different entities in the public and
private sectors are responsible for the control of
indoor air quality through the implementation of
these strategies. Some of their roles and responsi-
bilities are outlined in Table 5-2. It is clear that
none of these groups or roles can stand alone; each
depends on the expertise and cooperation of the
others for the effective control of indoor air quality
problems.

Private Sector Roles

The private sector has a significant role to play in
both the policy-making process and in the design,
operation, and maintenance of systems and products
to ensure a healthful indoor air environment.

* Manufacturers, engineers, architects and
builders can design, manufacture, and build
products and structures that minimize
indoor air quality problems.

© Occupants can properly use and maintain
products and equipment, and building
owners and managers can properly operate
and maintain buildings to reduce indoor air
quality problems.

* Environmental health and other related
professionals can educate the public about
indoor air quality, conduct research to



UNIT 1: UNDERSTANDING INDOOR AIR QUALITY

LESSON 4
HUMAN RESPONSE TO INDOOR AIR QUALITY:
Classification of Indoor Air Contaminants

The complaints and health effects which might be related to building
environments are sometimes similar to those from colds, flu, stress,
and other causes. When the reported complaints are nonspecific and
diverse, it can be difficult initially to determine if problems are
caused by the sources or conditions in the building, and what can be
done to remedy the complaints. A building investigation is per-
formed in an effort to make these determinations.

In some instances, a specific source of contamination or a specific
building condition causing the complaints is readily obvious. In the
majority of cases, however, the investigator must consider all the
factors that relate to indoor air quality (Lesson 2) to identify
possible contaminants and stressors which could be responsible for the
reported complaints and effects.

Because the process of relating symptoms and health effects to stressors
and sources is complex, a multilevel approach is probably most likely
to narrow the universe of possible causes of the problems. For
example, the investigator may begin by formulating hypotheses about
classes of contaminants or physical stressors based on the reported
symptoms, These general classes of contaminants may then give rise
to hypotheses concerning specific contaminants which are associated
with specific sources in the building. At the same time, the investi-
gator maintains an open mind about sources that may not be readily
apparent and considers other causes, such as inadequate ventilation.
Through a process of identifying and evaluating potential contami-
nants, sources and other factors, the causal factors can frequently be
identified.

This lesson begins with an overview of the health effects and symp-
toms of general classes of toxic substances and physical stressors and
closes with effects of specific contaminants.

LESSON OBJECTIVES

At the end of this lesson, you
will be able to:

© discuss classes of contaminants and
physical stressors and symptoms
elated to these classes; and

© identify health effects related to
specific contaminants.



Unit 1, Lesson 5

IAQ Learning Module

‘American Society of Heating, Refrigerating and Air-Condition-
ing Engineers (ASHRAE). 1985. 1985 ASHRAE Handbook.
Fundamentals, ASHRAE: Atlanta, GA.

American Society of Heating, Reftigerating and Air-Condition-
ing Engineers (ASHRAE). 1984. 1984 ASHRAE Handbook.
Systems, ASHRAE: Atlanta, GA.

‘American Society of Heating, Reftigerating and Air-Condition-
ing Engineers (ASHRAE). 1988. 1988 ASHRAE Handbook.
Equipment. ASHRAE: Atlanta, GA.

Consumers Union. 1985. “Air cleaners.” Conswmers Reports.
50Q): 7-11.

Consumers Union. 1989. “
54(2): 88-93.

i purifiers.” Consumers Reports.

Fisk, W J., RK. Spencer, D-T. Grimstud, F.J. Offerman, B.
Pedersen, R. Sextro. 1987. Indoor Air Quality Techniques.
Radon, Formaldebyde, Combustion Products, Noyes Data
Corportation: Park Ridge, NJ.

Lenchek, T., C. Mattock, and J. Raabe. 1987. Superinsulated
Design and Construction. Van Nosttand Reinhold Co, New
York, NY.

Mann, P.A. 1989 Illustrated Residential and Commercial
Construction. Prentice Hall: Englewood Cliffs, NJ.

Ramanathan, K., VL. Debler, M. Kosusko, and L.E. Sparks.
1988. “Evaluation of control strategies for volatile organic
compounds in indoor air.” Environmental Progress. (4): 230-
235.

Sandia National Laboratories. 1982. Indoor Air Quality
Handbook. Sandia Report Sand82-1773. Sandia Nacional
Laboratories: Albuquerque, NM.

USS. Environmental Protection Agency (EPA). 1988. Directory
of State Indoor Air Contacts. EPA/400/1-88/003. U.S. EPA,
Office of Air and Radiation: Washington, DC.

U.S. Environmental Protection Agency (EPA). 1990. Current
Federal Indoor Air Quality Activities, EPA 400/10-90/006. U.S.
EPA, Office of Air and Radiation: Washington, DC.

U.S. Environmental Protection Agency (EPA). 1990. Residen-
tial Air-Cleaning Devices. A Summary of Available Information.
EPA 400/1-90/002. U.S. EPA, Office of Atmospheric and
Indoor Ait Programs: Washington, DC.

OGRESS CHECK

~

1. What are the three general strategies that can be used to control indoor air contamination?

2. What are the source control options that can he used to reduce contaminant concentrations? Give one example of each.
3. Which removal options are based on increasing the exchange of contaminated air with fresh, dean air?

4. Which options are based on the removal of contaminants from the air stream by physical or chemical means?

5. Compare ways of controlling or providing ventilation using infiltration, natural ventilation, and mechanical ventilation.
6. What is a fresh air connection? Evaporative cooler? Heat recovery ventilator?

|. What indoor oir problems can result from heat recovery ventilator?

8. Whot és the difference between o panel filter ond a HEPA filter?



UNIT 3: DEVELOPING A PROGRAMMATIC RESPONSE

LESSON 9

ESTABLISHING AN INDOOR AIR
QUALITY PROGRAM

The responsibility for developing new environmental health services
often rests with environmental professionals who are not involved in
day-to-day program administration. This unit is provided for the
reader who either may want to propose an indoor air quality
program within an organization or may actually be given the
responsibility for implementing a program without having had
previous administrative experience. In either case, understanding the
basic elements of program management will be critical to one’s success
in nurturing a new program.

LESSON OBJECTIVES

At the end of this lesson you
will be able to:

© identify the basic elements of
program management;

© know how to develop program
objectives;

© identify the principal components of
program budget; and

© understand the concept of program
evaluation.



IAQ Learning Module

Unit 1, Lesson 4

Radioactive Contaminants

Radon is a naturally occurring radioactive gas
which does not result in immediate symptoms. It is
estimated that about 15% of the lung cancer cases
in the United States are due to indoor radon expo-
sures (Pushen and Nelson,1989). Smokers are at a
much higher risk than nonsmokers of developing
either asbestos-induced or radon-induced lung
cancer. Radon is classified as a “Known Human
Carcinogen” by EPA.

Airborne Biological Contaminants

Exposure to airborne pathogens and allergens such
as viruses, bacteria, fungi, dust mites, human or
animal dander, excreta from insects or arachnids, or
pollen can result in conditions such as Legionnaires’
disease, Pontiac fever, allergic rhinitis, bronchial
asthma, and hypersensitivity pneumonitis. Symp-
toms produced by these conditions include eye,
nose, and throat irritation; shortness of breath;
dizziness; lethargy; fever; digestive problems; and
severe allergic reactions.

Mycotoxins, which are produced by some fungi, are
toxins which can result in direct or indirect effects
on the body. Exposure to some mycotoxins can
result in immunosuppression or direct effects such
as gastrointestinal lesions, central nervous system
impairment, and suppression of the blood-forming
and reproductive systems. Nonspecific symptoms
such as those associated with sick building syn-
drome can also occur. Although the effects of these
toxins are primarily associated with ingestion, it is
possible for inhalation to result in toxicity (U.S.
EPA, 1989).

Environmental Tobacco Smoke

Environmental tobacco smoke can contain over
3800 compounds, many of which are carcinogens
and mutagens (NRC, 1986). Exposure to tobacco
smoke has been associated with an increased inci-
dence of lung cancer in healthy nonsmoking adults,
and it may contribute to heart disease. Other health

effects from exposure to environmental tobacco
smoke include eye, nose, and throat irritation;
headaches; bronchitis; and pneumonia. Children
who are exposed to environmental tobacco smoke
have an increased risk of pulmonary and respiratory
infections. There is also some evidence that parental
smoking may affect the rate of lung growth in
children and increase the risk of chronic ear infec-
tions (NRC, 1986).

SYMPTOMS, CONTAMINANTS, AND SOURCES
(RM 4)

As previously discussed, the health effects
of indoor air contaminants can range from irritation
effects to death, and there is overlap among the
types of symptoms that could be caused by indi-
vidual contaminants or physical stressors. Contami-
nants can be classified by their effects as irritants,
contaminants, narcotics and anesthetics, systemic
toxicants, carcinogens, developmental and reproduc-
tive toxicants, and airborne pathogens and allergens.
Physical stressors include temperature, humidity,
air movement, light, and noise.

The complexity of symptom patterns can complicate
the task of relating symptoms to contaminants, but
a knowledge of the sources of contaminants and
general symptoms for different classes of contami-
nants can facilitate the investigation of indoor air
quality problems. Table 4-1 helps identify which
specific symptoms could be caused by various
contaminant classes and physical stressors. This
information can help the investigator narrow the
contaminant classes that are most likely causing the
problem. Table 4-2 identifies specific contaminants
that are associated with each contaminant class
identified above, and Table 4-3 provides informa-
tion on common sources of those contaminants.
This information should help the investigator
identify potential sources in the building that may
be causing particular problems. More complete lists
of sources, contaminants, and health effects are
provided in Sections 2, 3, and 4 of the Reference
Manual.



Unit 2, Lesson 7

IAQ Learning Module

Occupational Standards and Guidelines
ACGIH Guidelines

‘The American Conference of Governmental Indus-
trial Hygienists (ACGIH) is an association of
occupational health professionals that is devoted to
the development of administrative and technical
policies for worker health protection. Through its
technical committees, ACGIH regularly reviews the
best available information from industrial studies,
epidemiological studies, and animal studies to
develop new limits and revise old ones.

ACGIH first published its limits, Threshold Limit
Values (TLVs), in 1968, and they are updated
annually (ACGIH, 1989). The TLVs are concentra-
tion limits and conditions to which it is thought
nearly all workers may be repeatedly exposed day
after day throughout their working lifetime without
adverse effects. However, because of the individual
variation in response to chemical exposure, the
ACGIH recognizes that a small percentage of
workers may experience discomfort at levels below
the TLVs, and an even smaller percentage may
experience more serious effects such as aggravation
of a preexisting condition or the development of an
occupational illness at levels below the TLVs.

Some of the limits protect against impairment of
health while others protect against irritation,
narcosis, nuisance, or other forms of stress. Because
of the increasing evidence that physical irritation
can initiate, promote, or accelerate physical impair-
ment, ACGIH states that limits based on physical
irritation should be no less binding than those based
on physical impairment.

ACGIH disclaims liability for the improper use of
TLVs, and it specifically cautions that the limits are
intended for use in the workplace and not for other
uses such as the control of community air pollution
nuisances, estimating the toxic potential of continu-
ous, uninterrupted exposures, or as proof or disproof
of an existing disease or physical condition. The

ACGIH guidelines are recommendations; they are
not legally binding.

Three categories of TLVs are defined.

© The Time Weighted Average (TLV-TWA) is
the time-weighted average concentration
for a normal 8-hour workday and a 40-hour
workweek to which workers can be exposed
day after day without adverse effect.

© The Short Term Exposure Limit (TLV-STEL)
is the concentration to which workers can
be exposed continuously for a short period
of time without experiencing irritation,
chronic or irreversible tissue damage, or
narcosis to a degree that would increase
accidental injury rates, or reduce work
efficiency significantly. The STEL is
defined as a 15-minute time-weighted
average exposure which should not be
exceeded at any time during a work day or
occur more than 4 times each day. In
addition, there should be at least 60
minutes between successive exposures at the
STEL.

© = The Ceiling Limit (TLV-C) is a concentra-
tion that should not be exceeded during any
part of the working exposure.

OSHA Standards

The Occupational Safety and Health Administration
(OSHA) is responsible for protecting workers from
unsafe or unhealthy work environments. Standards
for the workplace are promulgated by the Secretary
of Labor under the Occupational Safety and Health
Act of 1970 (U.S. DOL, 1989). These are manda-
tory standards.

The exposure standards for air contaminants are set
at levels which will protect a worker from “material
impairment of health or functional capacity” even if
the worker is exposed for 8 hours per day for an
entire working lifetime. The occupational health



Unit 1, Lesson 1

IAQ Learning Module

CONTAMINATION OF INDOOR AIR

Dissatisfaction with the quality of indoor
air is not new. Problems probably date to the time
when early man and woman discovered the use of
fire and were exposed to the products of incomplete
combustion. Mummified lungs from the pre-indus-
trial age show considerable carbonaceous pigmenta-
tion, and these people were probably also exposed to
carbon monoxide.

Early evidence of exposure to indoor air contami-
nants and efforts to control them comes from the
placement of fires in caves and the presence of vent
holes in the roofs of caves. It is also demonstrated
by the way in which ancient native people in the
United States constructed noncave dwellings. This
can clearly be seen in the ruins of early settlements
in such locations as Mesa Verde, Colorado and
Chaco Canyon, New Mexico.

In modern times, the use of synthetic building
materials and fabrics has become commonplace.
After World War I, traditional building materials
such as wood were replaced with cheaper alternative
materials that could be produced and processed on
a large scale. New products such as plastics and
pressed-wood products were introduced as materials
for building construction and furnishings.

An explosion also occurred in the development of
personal care products, pesticides, and household
cleaners. Relatively simple and less toxic household
cleansers such as baking soda, vinegar, soap, and lye
solutions were replaced by more sophisticated
chemical formulations. These consumer products
were increasingly packaged in convenient aerosol
cans which released their contents directly into the
indoor air.

Most recently, the energy crisis of 1974 and the
increase in the cost of oil from $3/barrel to $30/
barrel focused concern on conserving energy in
homes and other buildings. The desire to reduce

heating and cooling costs led to changes in con-
struction techniques in both residential and com-
mercial buildings which reduced building ventila-
tion rates. These changes included tighter building
envelopes; fewer and inoperable windows; decreased
use of operable windows in older construction; use
of sealant foams and vapor barriers; reductions in
the amount of outdoor air used for ventilation;
improperly sized and designed heating, ventilating,
and air-conditioning (HVAC) systems; renovations
of existing buildings without corresponding
changes to the HVAC systems; and inadequate
building maintenance.

These changes have had two basic effects: an
increase in the number and types of contaminants
released into the indoor environment, and a decrease
in the amount of fresh outdoor air that is introduced
into structures to dilute contaminants and satisfy
the health and comfort needs of occupants.

Now, the drafty, uninsulated home or office of the
first part of the century has been replaced by a new
structure that is tightly sealed by comparison. The
introduction of outdoor air available to dilute indoor
levels of contaminants has dropped from an esti-
mated 1.5 air changes per hour (ach) to about 0.5
ach or lower in especially efficient residential
construction.

Increased insulation in buildings and changes in
acceptable operating temperatures increased energy
efficiency, but also resulted in tight buildings which
retained moisture and other contaminants and
provided a more favorable environment for micro-
bial growth. Decreases in the amount of outside
replacement air led to “stuffy” environments that
felt too damp and cold in winter and too warm and
stuffy during the summer. Some people switched to
auxiliary heating appliances such as unvented gas
stoves and kerosene heaters to provide economical
sources of heat. These appliances raised concerns
about respiratory health effects and potential
asphyxiation.



IAQ Learning Module

List of Tables

LIST OF TABLES

lesson 2

Table 2-1. Factors affecting indoor air quality and examples
of the parameters which influence them.

lesson 3

Table 3-1. Key factors affecting the hazard posed by toxic
substances.

Table 3-2. Subpopulations at greatest risk from exposure
to indoor air contaminants.

lesson 4

Table 4-1. Typical symptoms of contaminant classes and
physical stressors.

Table 4-2. Health effects of selected contaminants.

Table 4-3. Potential sources of selected indoor air
contaminants.

Table 5-1. Examples of indoor air contaminant
control strategies.

Table 5-2. Public and private sector roles.
lesson 6

Table 6-1. Factors to consider in the selection of
measurement methods and equipment.

7

22

26

31
40

42

47
61

65



Unit 1, Lesson 4

IAQ Learning Module

temperatures are less than optimum in the winter, it
is important to maintain low air movements to
minimize discomfort from local drafts. In the
summer, increased air movement is desirable to
extend the comfort zone.

Lighting should be free of glare, reflections, flickers,
contrasts, and it should have the proper spectral
distribution. The human eye can adjust to a very
large range of light intensity, but symptoms can
result depending on the light source and if the
levels are too low or too high. When fluorescent
lamps are used as the predominant source of light,
many people describe the light as annoying, vibrat-
ing, or glaring; and they may develop eyestrain,
fatigue, headaches, and other symptoms.

The importance of proper lighting for good health
has been underscored in recent years with the
discovery of cases of winter depression in areas that
have a lack of natural light. This condition, which
is manifested by a broad range of symptoms includ-
ing fatigue, headache, and depression, can be cured
through the use of lamps with the proper spectral
distribution at home and the workplace.

In homes, artificial light levels of 6 footcandles over
the area of a room at a height of 30 inches above the
floor are considered adequate (CABO, 1989). In
commercial buildings, proper lighting requirements
vary with the activity or task to be performed.
Illumination levels of 75 to 100 footcandles have
been recommended for offices (IES, 1981). A major
complaint of VDT operators is glare and/or contrast
ptoblems. These can result in significant com-
plaints even if lighting levels are adequate, and
added measures may be needed to reduce glare and/
or contrast problems (Smith, 1984).

Noise is considered by some medical practitioners to
be one of the most significant stressors of modern
times. Noise can contribute to tension, fatigue,
hearing loss, deficiencies in attention span, ulcers,
high blood pressure, and heart disease. Sound levels
are measured by a relative scale. The preferred unit
for measuring sound in industrial, speech interfer-
ence, and community disturbance conditions is the

A-weighted decibel. The A-weighting delineates a
frequency weighting scale which simulates the way
in which the human ear actually responds to sound.
The decibel scale is logarithmic, and the entire
range of audible sound pressure for individuals with
normal hearing can be expressed on a scale of 0 (the
threshold of hearing) to 140 dBA (deafening and
painful noise).

Levels below 40 dBA are considered to be comfort-
able. The average residence without a stereo
playing will have a noise level of about 30 dBA,
while noise levels in an average office will be about
50 dBA (U.S. HUD, 1985). The hearing of most
people will probably be degraded by continuous
exposure to levels above 85 dBA (U.S. HUD, 1985).
It has been estimated that nearly half of the U.S.
population is regularly exposed to noise levels that
interfere with normal activities and 1 in 10 people
may be exposed to noise levels that are sufficient to
cause a permanent reduction in their ability to hear.

The U.S. Department of Housing and Urban
Development (HUD) has developed exterior noise
standards for new housing construction that is
assisted or supported by the Department (U.S.
HUD, 1985). HUD'’s regulations do not contain
standards for interior noise levels, but the exterior
standard should ensure that noise levels indoors do
not exceed HUD’s goal of 45 dBA for interior

spaces.
EFFECTS OF SELECTED CONTAMINANTS (RM 4)

The ptevious section classified indoor air
contaminants and stressors according to broad
classes and health effects which might typically be
associated with those classes. This section provides
a summary of specific effects associated with
selected contaminants. When the terms high and
low concentrations are used they refer to concentra-
tions that could be found in occupational and
nonoccupational environments, respectively. The
actual concentration ranges which have been
associated with specific effects can be found in
Section 4 of the Reference Manual.



Unit 2, Lesson 6

IAQ Learning Module

Figure 6-2. Examples of passive samplers.

a. HCHO Diffusion Monitor

b, Air Quality Research International. With permission.
¢. Air Technology Labs. With permission.

b, NO, Diffusion Monitor

a. ©3M Occupational Health and Sofety Products Division. With permission.

C. $02Passive Bubbler

Breathing
Tone
Sampling

‘Area Sampling

the small size of sampling tubes and pumps, they
are easy to use in a variety of indoor situations.

Analytical Methods

The number of analytical methods available for
identifying and quantifying contaminants and
physical stressors can be overwhelming. Most
indoor air quality investigations will be handled by
relatively few methods, but it is useful to have an
awareness of other methods that could be used in
special circumstances.

Physical Stressor Detectors

Temperature: Room air temperature can be
measured by liquid-in-glass thermometers (alcohol

or mercury), resistance thermometers (platinum,
thermisters), thermocouples, and bimetallic ther-
mometers. Analog thermometers can be purchased
for less than $10, and the cost of digital thermom-
eters is about $35 to $100.

Humidity: Humidity is commonly measured as the
relative humidity which is the ratio of the amount
of water vapor in the air at a specific temperature to
the maximum amount of water vapor that the air
could hold at that temperature. Relative humidity
can be measured using hygrometers or psychrom-
eters.

Analog hygrometers can be purchased for as little as
$35; digital units that can also measure temperature
and are traceable to the National Institute of



IAQ Learning Module

Unit 2, Lesson 6

REFERENCES

GEOMET Technologies, Inc. 1985. “Quality Assurance Plan
for Indoor Environment Program,” GEOMET Report No. ES-
1528, GEOMET Technologies, Inc.: Germantown, MD.

Katz, M. (ed). 1977. Methods of Air Sampling and Analysis.
2nd edition. American Public Health Association: Washing-
ton, DC.

Lioy, PJ. (ed). 1983. Air Sampling Instruments for Evaluation of
Atmospheric Contaminants, 6th edition. American Conference of
Governmental Industrial Hygienists: Cincinnati, OH.

McConnaughey, P.W., E.S. McKee and J.M. Pritts. 1982.
“Passive colorimetric dosimeter tubes for ammonia, carbon
monoxide, carbon dioxide, hydrogen sulfide, nitrogen dioxide,
and sulfur dioxide”. Toxic Materials in the Atmosphere: Sampling
and Analysis. ASTM Special Technical Publication 786.
American Society for Testing and Materials: Philadelphia, PA.

Nader, J.S., J.P. Lauderdale, and C.S. McCammon. 1983.
“Direct reading instruments for analyzing airborne gases and
vapors.” Chap. V. Air Sampling Instruments. 6th edition.
American Conference of Governmental Industrial Hygienists:
Cincinnati, OH.

Nagda, M.L. and H.E. Rector. 1983. Guidelines for Monitoring
Indoor Air Quality. EPA-600/4-83-046. U.S. Environmental
Protection Agency: Washington, D.C.

Nagda, N.L., H.E. Rector, and M.D. Koontz. 1987. Guidelines
{for Monitoring Indoor Air Quality. Hemisphere Publishing Corp.:
Washington, D.C.

Public Works Canada. 1988. Indoor Air Quality Test Kit User
Manual. AES/SAG 14:88-4. Public Works Canada, Architec-
tural and Engineering Services: Ottawa, Canada.

Olishifski, J.B. 1988. “Methods of Evaluation.” Chap. 17.
IN: Fundamentals of Industrial Hygiene. 31d edition. B. Plod
(ed), National Safety Council: Chicago, IL.

Taylor, J.K. (ed). 1987. Sampling and Calibration for Atmospheric
Measurements, ASTM STP 957. American Society for Testing
and Materials: Baltimore, MD.

U.S. Environmental Protection Agency (EPA). 1975. Quality
Assurance Handbook for Air Pollution Measurement Systems.
Volume I - Principles. U.S. EPA, Quality Assurance and
Environmental Monitoring Laboratory, Office of Research and
Development: Research Triangle Park, NC.

U.S. Environmental Protection Agency (EPA). 1977. Quality
Assurance Handbook for Air Pollution Measurement Systems.

Volume II - Ambient Air Specific Methods. (Revised 7/84 and 9/85)
EPA-600/477-027a. U.S. EPA, Environmental Monitoring
Systems Laboratory, Office of Research and Development:
Research Triangle Park, NC.

US. Environmental Protection Agency (EPA). 1980. Interim
Guidelines and Specifications for Preparing Quality Assurance Project
Plans. EPA QAMS-005/80. U.S. EPA, Office of Monitoring
Systems and Quality Assurance, Office of Research and
Development: Washington, DC.

US. Environmental Protection Agency (EPA). 1989. Compen-
dium of Methods for the Determination of Air Pollutants in Indoor
Air. Draft. U.S. EPA, Atmospheric Research and Exposure
Assessment Laboratory, Office of Research and Development:
Research Triangle Park, NC.

USS. National Institute for Occupational Safety and Health
(NIOSH). 1984. NIOSH Manual of Analytical Methods. 3td
edition. P.M. Eller (ed). NIOSH: Cincinnati, OH.

Wallace, L.A. and W.R. Ott. 1982. “Personal monitors: A
state-of-the-art survey.” J. Air Poll. Cont. Assoc. 32(6):
601-610.

77


United States United States National EPA/400/3-91/002
Environmental Protection Public Health Environmental July 1991

Agency Service Health Association

Office of Air and Radiation (ANR-445W)

Introduction to
Indoor Air Quality

A Self-Paced Learning Module



IAQ Learning Module

Unit 3, Lesson 9

While major program objectives are contingent
upon area needs, as well as organizational priorities
and resources, the following are a few examples of
objectives pursued by existing indoor air programs:

a) conduct a radon exposure study in ran-
domly selected residences to be completed
by (date);

b) correct hazards (specify percent) identified
during building complaint investigations;

c) identify and correct all friable asbestos
conditions within municipally-owned
buildings by (date); or

d) conduct a survey to determine if unvented
space heaters are being used in a manner
which is creating indoor air contamination
problems.

There are other policy and procedural issues that
will need to be addressed, and a few of these may
have a bearing on the general direction of the indoor
air program. One major question is whether the
program will be purely consultative and educa-
tional, or whether enforcement will be a component
of the program. If there is to be enforcement, a
legal structure will have to be in place, including
ordinances or statutes, an administrative appeal
process, a willing prosecutor, and legal staff.

Community awareness of the indoor air issues and
program services is another consideration in plan-
ning health education objectives, and it can also
affect staff workload. Publicity about the program
will generally result in more requests for service,
which affects both field investigation and clerical
staffs. Program management, as much as possible,
should influence the nature and timing of public
information so that it will have maximum educa-
tional benefit, minimize public confusion and
overreaction, and not tax program resources with
the demand for services that will likely result from
the release of information.

Program Evaluation

The process of evaluating a new program starts
during the implementation phase and culminates
with an assessment of what was actually accom-
plished compared to the expectations defined by the
major objectives. The only way to evaluate a
program at any stage is to have an adequate amount
of information that reflects what is happening and
what is being achieved. A thorough record-keeping
system must be developed which indicates how
program personnel spent their time and what they
accomplished. As with all environmental health
programs, inspections and other field activities will
have to be thoroughly documented. The organiza-
tion will also have to document the expenditure of
funds for all of the items specified in the budget.

A primary function of the program manager is to
review summary data derived from records kept by
field and support staff. Time must also be spent
communicating with all staff members, whether in
informal discussions or in a more structured setting
such as a staff conference, in order to understand
staff concerns and to benefit from ideas about
program improvement.

The point of program evaluation is to determine
whether the program is effective and efficient.
Determining program efficiency involves comparing
the level of input to the level of output, or relating
costs to the amount of services produced. Over
time, efficiency information can help determine
what level of services can be provided for a given
amount of money, and it can also help the program
manager diagnose operational problems. However,
drawing meaningful, precise, cost efficiency infor-
mation can be a complex task because the cost of
each activity in the indoor air program will have to
be calculated. The program manager will either
have to become familiar with cost accounting
procedures, or seek the assistance of someone who is
knowledgeable. Most initial program evaluation
efforts, however, will probably focus on determining
program effectiveness rather than efficiency.
Effectiveness in the public sector is a measure of a



List of Figures IAQ Learning Module

LIST OF FIGURES

lesson 2

Figure 2-1. Pathways of air exchange.
Figure 2-2. The stack effect.

lesson 3

Figure 3-1. Multifactorial model for che sick
building syndrome.

Figure 3-2. Dose-effect relationships.
lesson 5

Figure 5-1. Example of a residential heating system
with an outdoor air connection.

Lesson 6

Figure 6-1. Examples of active samplers.
Figure 6-2. Examples of passive samplers.
Figure 6-3. Accuracy and precision.
Lesson 8

Figure 8-1. Flow chart of an investigation strategy for
indoor air quality problems.

18
24

52

66
68
73

92



Unit 3, Lesson 9

IAQ Learning Module

program’s success in fulfilling important public
needs. The major objectives of the indoor air
program should reflect the community's needs and
the program manager must be able to derermine the
program’s level of achievement. If any objectives
‘were not met, the manager must identify the
reasons based on available information. It may be
that the resources were inadequate or personnel did
not perform up to expectations. Similarly, other
obstacles may have arisen which were not identified
at the outset.

The process of program evaluation is a time for
reassessment and a preparation for future objective-
setting. Although objectives should be taken
seriously, they are not carved in stone and should be
modified whenever it is clear that one’s initial
assumptions were not valid. Similarly, if the
objectives were valid but unmet, it is necessary to
find and correct deficiencies in the operation.
Finally, the manager must clearly communicate to
key decision-makers the successes, and thus the
effectiveness, of the indoor air program in order to
ensure future support.

REFERENCES

Epstein, P.D. 1984. Using performance measurement in local
government. A guide to improving decisions, performance, and
accountability. Van Nostrand Reinhold Co.: New York, NY.

McConkey, D.D. 1975. MBO for nonprofit organizations.
AMACOM: New York, NY.

Ruchelman, LJ. 1985. A workbook in program design, State
University of New York Press: Albany, NY.

U.S. Department of Health and Human Services (DHHS).
(undated). Program management. A guide for improving program
decisions. U.S. DHHS, Centers for Disease Control: Atlanta,
GA.

PROGRESS CHECK

information.
‘1. What ere some possible olements of a program objective?

1. What types of information are needed fo justify the need for an indoor air program?
2. Name six major budget items that should be induded in a program proposal and indicate where you would obtain the cost

4. What possible effects should a program manager take into account before deciding to publicize the indoor air program?
5. What are possible reasons for the lack of effectiveness of an indoor air program?



Unit 1, Lesson 3

IAQ Learning Module

the environment. Two basic dose-effect curves are
used to describe the relationship between effects and
the dose.

Curve A in Figure 3-2 shows that no matter how
low the dose, an effect will occur. This curve is
called the linear dose-effect curve, and it is used to
describe the carcinogenic effect of exposure to
carcinogens such as asbestos and radiation.

Curve B describes a contaminant that will not cause
an effect below a certain dose. This curve shows
that there is a threshold for the occurrence of effects.
For example, the lowest-observed-effect level for
decreased hemoglobin production and central
nervous system effects as a result of lead exposure in
children is reported to be 0.1-0.2 micrograms of
lead per milliliter of blood (WHO, 1987). In
adults, the lowest-observed-effect level (for de-
creased hemoglobin production) is in the range of
0.15-0.3 micrograms of lead per milliliter of blood.

In the standard-setting process, the dose-effect curve
is important because it, along with exposure
assessments, determines what levels of contaminants
are assumed to pose potential health risks.

Factors Related to the Environment

Environmental factors such as temperature, humid-
ity, light, and noise levels can have direct and
indirect effects on the host. These factors can affect
the host directly by causing discomfort (for ex-
ample, eye strain or headache) or even dysfunction
(such as hearing loss). These factors may also affect
the susceptibility of the occupant to other environ-
mental contaminants or factors.

Temperature, humidity, and light alter the chemical
nature of some contaminants which can make them
more hazardous. In addition, high temperature and
humidity can increase the rate of volatilization of
organic chemicals such as formaldehyde. High
humidity can foster the growth of microorganisms
or increase the rate of chemical reactions which form
acid aerosols. Reduced barometric pressure inside

Figure 3-2. Dose-effect relationships.

CURVE A
Severity
of
the
Effect
— >
Increasing Dose
CURVE B
Severity
of
the
Effect
——
Increasing Dose

dwellings relative to the outside pressure can
increase the rate of entry of radon (and other soil
gases) into the interior environment.

Factors Related to the Occupant

The development of health effects in an individual
who is exposed to chemical, physical, and biological
stressors also depends on factors including genetics,
sex, personal habits, diet, age, and health status.
Table 3-2 identifies some of the subpopulations
with potentially greater susceptibility to indoor air
contaminants.

Genetic variability can range from individuals who
have no disease resistance from birth to those who
are seemingly never ill. Most people fall in between
these extremes, but even in this middle area there
can be significant variation in response to contami-
nants, particularly at the low level of exposures that
might be encountered in homes and offices.



Unit 2, Lesson 7

TAQ Learning Module

indoor air quality is defined by ASHRAE as “air in
which there are no known contaminants at harmful
concentrations as determined by cognizant authori-
ties and with which a substantial majority (80% or
more) of the people exposed do not express dissatis-
faction.” However, ASHRAE recognizes the stan-
dard does not, and cannot, assure that no adverse
health effects will occur.

Acceptable air quality can be achieved in two ways.
The Ventilation Rate Procedure specifies the rate and
quality of ventilation air which must be supplied to
a given space, and it also specifies methods to
condition the air. The Indoor Air Quality Procedure
provides an alternate performance method in which
acceptable concentrations of some contaminants are
identified, but ventilation rates or air treatment
methods to achieve those concentrations are not
specified.

The Ventilation Rate Procedure

The ventilation rate procedure specifies minimum
ventilation rates for about 85 types of residential,
commercial, institutional, vehicular, and industrial
spaces (Section 7 of the Reference Manual). In order
to achieve these rates, the procedure specifies the
quality of outdoor air used for ventilation. Accept-
able outdoor air quality is basically air that meets
the National Ambient Air Quality Standards;
however, these standards include only six contami-
nants. If outdoor air contaminant levels exceed the
NAAQS, the standard specifies that the air can be
treated by filtering or other appropriate air cleaning
devices.

The outdoor air requirement as defined by
ASHRAE is 15 cfm or more per occupant for
different spaces. For example, the office space
requirement is 20 cfm per occupant. The outdoor
air requirement for residential living areas is 0.35
ach but not less than 15 cfm per occupant. This is a
level which should be met during all occupied
periods and during all seasons. In kitchens, a rate of
100 cfm is required if intermittent exhaust ventila-
tion is used and 25 cfm for continuous ventilation.

The outdoor air requirement for baths and toilets is
50 cfm for intermittent ventilation or 25 cfm for
continuous ventilation. Ventilation requirements in
kitchens, baths, and toilets can be met with oper-
able windows. The ASHRAE standard also specifies
that the combustion system, kitchen, bathroom, and
clothes dryer vents should not be exhausted into
attics, crawlspaces, or basements.

The outdoor air requirement for residential garages
is 100 cfm per car which is normally satisfied by
infiltration or natural ventilation.

The Indoor Air Quality Procedure

This alternate procedure specifies minimum levels
of indoor air contaminants as defined by generally
accepted air quality standards and guidelines, but it
does not specify ventilation rates or air treatment
methods to achieve those levels. The contaminants
which are specified within the standard include
those identified in the EPA ambient air quality
standards plus carbon dioxide, chlordane, ozone, and
radon gas. ASHRAE also recommends that relative
humidity in habitable spaces should be maintained
between 30% and 60% to minimize the growth of
allergenic or pathogenic organisms. In addition,
Standard 62-1989 refers the reader to Appendix C
which contains tables of standards and guidelines of
contaminants which are used in the United States,
Canada, and by the World Health Organization.
Appendix C is not part of Standard 62-1989, but it
is intended to provide guidance on acceptable
contaminant levels for the indoor environment.

Other Ventilation Requirements
HUD Ventilation Requirements

HUD ventilation requirements are incorporated
into its minimum property standards for residences
(U.S. HUD, 1990b) which are part of its mortgage
insurance and low rent public housing program and
in construction requirements for manufactured
housing (U.S. HUD, 1990c).



UNIT 2: MEASURING AND EVALUATING PROBLEMS

LESSON 7
STANDARDS AND GUIDELINES FOR INDOOR AIR
CONTAMINANTS AND VENTILATION

Standards and guidelines were discussed in Lesson 5 as one of the
policy tools available to both government and private sector organi-
zations to control indoor air quality. This lesson summarizes
standards and guidelines, and discusses their applicability to indoor
air quality.

LESSON OBJECTIVES

At the end of this lesson, you
will be able to:

© identify and discuss the primary
public health and occupational air
quality standards and guidelines;

© identify and discuss the primary
ventilation stondards/ guidelines,

© identity the primary building code
provisions that affect indoor air
quality; and

© understand the strengths and
weaknesses of existing standards
and guidelines.



Unit 1, Lesson 2

IAQ Learning Module

ACTORS AFFECTING INDOOR AIR QUALITY
(RM 2)

In general, the quality of the indoor air is a
combination of physical stressors and the concentra-
tion of contaminants. Physical factors which
include temperature, humidity, noise, and light are
discussed in Lesson 4. The level of contaminants is
determined by the net influence of those factors
which emit, mix, and remove contaminants. These
factors ate introduced in this lesson, and may be
classified into five broad categories: sources of
contaminants, air exchange rates, contaminant
removal mechanisms including chemical reactions,
volume of the structure, and mixing efficiency of
the indoor environment.

Table 2-1 summarizes some of the variables that
influence these factors. The listed factors are used
mainly in a qualitative way to evaluate contaminant
problems. These factors can also be quantified to
varying degrees and are used in predictive math-
ematical models to evaluate indoor air quality.
Section 2 of the Reference Manual provides an
overview of a basic model that quantifies the
relationships among these factors.

Sources of Contaminants (RM 2.2)

Sources of contaminants that influence indoor air
may be located in the interior or the exterior of the
structure. Descriptions of example sources and
source categories follow. Section 2 of the Reference
Manual contains a more detailed list of sources and
the individual contaminants which can be released
by them.

The rate of contaminant release from a source is
called the emission rate. Emission rates can vary
considerably even for a single source and can be
affected by changes in the operation of equipment
and appliances (for example, combustion contami-
nants) or by changes in environmental conditions
such as temperature and humidity (for example,
formaldehyde emissions from building materials).
Emission rates are used in mathematical models to

calculate contaminant concentrations under a
variety of conditions. Section 2 of the Reference
Manual summarizes data on emission rates which
have been determined for some contaminants.

Indoor Sources

Indoor sources of contaminants are important
contributors to indoor air pollution. Major source
categories include consumer and commercial
products, building sources, and personal sources.

Consumer and commercial products: There are
numerous consumer and commercial products
which can result in the release of indoor air con-
taminants. These include cleaners and waxes, paints
and associated supplies, pesticides, adhesives,
cosmetics and personal care products, automotive
products, hobby supplies, paper products and
printed material, moth repellents and air fresheners,
dry cleaned fabrics, and furnishings. Hundreds of
inorganic and organic compounds can be released as
a result of using these products. Examples include
caustic aerosols and other particulates, volatile
organic compounds (VOCs) and semi-volatile
organic compounds (SVOCs) such as alcohols,
ketones, ethers, esters, aliphatic and aromatic
hydrocarbons, and other substituted hydrocarbons.

In addition to the active or primary ingredients,
containerized products may contain other ingredi-
ents which can also be hazardous. Carriers or
solvents, propellants, dyes, curing agents, flame
retardants, mineral spirits, plasticizers, odor-
forming ingredients, hardeners, resins, binders,
stabilizers, and preservatives are some of the other
ingredients which may be hazardous and are
contained in these products.

Aerosol products are of concern because the aerosol
droplets which are produced are in the inhalable size
range. These droplets can remain in the air for
extended time periods providing a mechanism for
inhalation exposure to occur to less volatile compo-
nents of the product.



IAQ Learning Module

Unit 1, Lesson 5

Table 5-1. Examples of indoor air contaminant control strategies (continued).

CONTROL METHOD

Ventilation (continued)
Local (Exhaust) Ventilation

CONTAMINANT

use in kitchens, bathrooms
ventilate crawl spaces

ventilate areas where solvents
and other organics are used

apply ventilation techniques
such as sub-slab ventilation

Air Cleaning

Filtration, Electrostatic Precipitation

cooking contaminants, moisture, microorganisms
radon and decay products; termiticides

organics

radon and other soil gases

use HEPA filtration and electro-
static precipitation

use flat or pleated filters for
HVAC equipment

dust, allergens, inhalable
particles

dust, some allergens

If outdoor air is of acceptable quality, ventilation
can effectively reduce contaminant concentrations
by diluting contaminated air with cleaner outdoor
air and exhausting contaminants to the outdoors. If
the outdoor air is contaminanted, it may have to be
treated to prevent the transfer of contaminants
indoors. The exchange of outdoor air with stale
contaminated air occurs through the mechanisms of
infiltration and exfiltration, natural ventilation, or
mechanical ventilation.

Infiltration

Minimizing infiltration is an energy conserving
strategy that can reduce heat loss, maximize thermal
comfort, and allow for greater control of ventilation
rates. These advantages, however, can be offset by
the potential of increasing the damage caused by
condensation on cold surfaces. Both of these factors
must be considered during construction, renovation,
and problem-solving.

Infiltration can be controlled by either reducing the
surface pressures driving the flow of air around a

structure or reducing the air leakage into a struc-
ture. Landscaping can be used to reduce surface
pressures on the building. Air leakage can be
reduced by first identifying the leakage points and
then sealing them. Leakage sites can be identified
using the fan pressurization method (independent of
weather), smoke sources, or by noting the leakage
points when the building is depressurized in cold
weather (ASHRAE, 1989). Caulking, weather-
stripping, and storm windows or doors can be used
to seal leakage points.

One of the most effective ways of reducing air
leakage through the building envelope is construc-
tion of a continuous air or air/vapor retarder. The
air/vapor retarder stops or slows the movement of air
and water vapor; an air retarder only controls air
movement, not water vapor. The air or ait/vapor
retarder must be carefully installed and sealed at all
window and door openings; ceiling, wall, and floor
junctions; electrical, plumbing, or other service
outlets. Details of construction techniques can be
found in Mann (1989), Lenchek et a/. (1987), or
other housing construction books.



IAQ Learning Module

Unit 2, Lesson 8

structure. An example questionnaire is provided in
Section 8 of the Reference Manual.

When new forms are developed, extreme care must
be taken to ensure that unbiased information will be
collected. The survey form should meet two
criteria: 1) the information to be collected must
meet the objectives for doing the survey, and 2) the
wording of questions, directions, and other commu-
nications must ensure that the information obtained
will be accurate, complete, and consistent.

The design of questions is a separate field of study.
Because there are many ways in which bias can enter
a study or investigation, it is wise to consult with
someone who has expertise in questionnaire design
to make sure that a new questionnaire will result in
the collection of accurate and unbiased data.

STAGES IN AN INVESTIGATION (RM 8)

Most investigations will probably be in
response to residential complaints or requests before
a house is occupied, during the time a house is
occupied, or when a real estate transaction is
contemplated. In the future, indoor air quality
investigations may become an important component
of residential real estate environmental audits.

An indoor air quality investigation is an iterative
ptocess involving discussions with the clienc, direct
observations of the building, and, in some cases,
measurements of environmental conditions.
Throughout this process, the investigator develops
and tests hypotheses and, through a process of
elimination and narrowing, attempts to seek a
solution.

Often, the client may be helped to a solution simply
by following a number of suggestions made by the
investigator based on knowledge of “good practice,”
without ever identifying a specific contaminant,
source, or cause of the problem. Proper care and
operation of appliances, provisions for adequate
ventilation, and controlling microbiological con-

tamination are examples of good practice that may
solve some indoor air quality complaints.

Investigations ate most efficiently conducted using a
phased approach that opens with an initial contact,
progresses to an investigation which may or may not
include a characterization of contaminants, follows
with an evaluation of results, and finishes with a
report of results which may include recommenda-
tions for referrals. If recommendations or referrals
are followed, the investigator evaluates the effective-
ness of each and closes the case by reporting on the
results (Figure 8-1).

At each of these stages the investigator plays an
important role in educating the client about indoor
air quality and general environmental health
problems that come to the investigator’s attention
during the course of the investigation.

The Initial Contact

Investigations are usually initiated by a telephone
call from an individual who has a concern or a
problem. The initial contact is a time for informa-
tion gathering, and the investigator begins to
develop preliminary ideas about the problem. The
initial interview should begin to answer the follow-
ing questions:

© What is the problem?

«© Where is the problem?

* Who is affected?

* When does the problem occur?
Much can be accomplished during the initial
contact, and its importance should not be underesti-
mated. At this stage, it is possible to:

* solve the problem;

© — provide information or literature that may
be useful to help the client understand



70

Unit 2, Lesson 6

IAQ Learning Module

Instruments for measuring particulates can be
grouped into four categories: optical detectors,
piezoelectric detectors, beta attenuation detectors,
and electrical detectors. Optical detectors can be
useful in routine indoor air quality investigations.
The other techniques are probably more appropriate
in outside air quality, occupational, or research
investigations.

Optical detectors are based on the interaction of
particles with light. These instruments can deter-
mine particle size and number. Particles in the size
range from 0.5 to 10 microns can be detected with
single particle detectors. Instruments which can
analyze fibrous aerosols, including asbestos, are also
available.

Gas and Vapor Detectors

There are many instruments that can detect con-
taminants in the gaseous phase at the same time
they are being sampled. Although they are more
expensive than indirect reading methods (typically,
several thousand dollars to over $10,000) and
require skilled operators, they may be cost effective
for contaminants which are routinely measured.

Some situations such as the investigation of faulcy
furnaces or gas leaks require direct reading instru-
ments. In other situations, the convenience of a
direct reading is attractive because it eliminates
potentially lengthy turnaround times in a labora-
tory.

In general, there are seven analytical methods that
can be applied to the analysis of gases and vapors
(Nader, Lauderdale, and McCammon, 1983). These
methods are electrical, electromagnetic, chemi-
electromagnetic, thermal, gas chromatography,
magnetic, and radioactive. They can be incorpo-
rated into direct reading field instruments or
laboratory-based instruments and techniques. They
are described in Section 6 of the Reference Manual.

Direct Reading Colorimetric Indicator
Devices

One of the most commonly used techniques for
gases (and some particulates such as lead) is the
colorimetric indicator device. These devices, which
can be active or passive, are widely used in indus-
trial hygiene and emergency response applications
to sample contaminants at relatively high concentra-
tions (in the range of the OSHA standards). This
technique is generally inadequate for indoor air
monitoring because of the lack of specificity of some
tubes and accuracy. Nevertheless, there may be
some instances when these devices can be usefully
employed.

These devices rely on the chemical reaction between
a contaminant and a reagent to produce a color
which can be interpreted visually or optically. They
may consist of liquid reagents, chemically treated
papers, and glass indicating tubes containing solid
chemicals. The color changes can be observed as a
length of stain on a calibrated tube or a color change
in a tube or badge which is compared to a standard
color chart.

If these methods are used, cautions should be
observed. Devices should be refrigerated, stain
fronts or color changes should be read immediately
after sampling, and pumps should be checked for
leaks and calibrated regularly. And, most impor-
tant, the accuracy and lower detectable limits
should always be foremost in the mind of the
investigator when selecting these devices and
interpreting results.

MINIMIZING ERRORS (RM 6.2. 6.3, 6.4)

Sampling Protocol

One important way of minimizing errors is to
develop a sampling protocol or written plan before



Unit 1, Lesson 4

IAQ Learning Module

SYMPTOMS AND CLASSES OF TOXIC
SUBSTANCES (RM 3, 4)

Symptoms do not always fit “textbook”
patterns, and similar symptoms may be caused by
different contaminants. In many instances reports
of symptoms will include “low-level” complaints
that are vague in nature and which could be attrib-
uted to any number of diseases or conditions. Very
frequently, symptoms are characteristic of colds or
the flu, or they are similar to symptoms accompany-
ing stress and tension. Some examples of com-
plaints include: “I feel tired and rundown.” “I’m
usually never sick, but now I have a lot of head-
aches.” “I've been nauseated and have had a slight
stomachache the last few months.” “My nose always
seems to be dry and my throat is scratchy.”

Symptoms of different contaminants may also
overlap. For example, formaldehyde can result in
irritation of the upper respiratory tract and the eyes,
but so can cleaning chemicals, airborne pathogens,
airborne allergens, and some solvents. In order to
sort through potential sources and interpret data,
one may need to obtain a careful symptom history
along with information about when and where
symptoms occur. In doing this, the investigator
should also be aware of contaminants that may not
result in overt symptoms.

Indoor air contaminants can be classified by their
mechanisms of action in the body and resulting
symptoms. These categories are typically used for
toxic substances and include irritants; asphyxiants;
narcotics and anesthetics; systemic toxicants;
reproductive and developmental toxicants; and
airborne pathogens and allergens. Physical stressors
such as temperature, humidity, light, and noise can
also affect health. Symptoms which are commonly
associated with these categories are summarized in
Table 4-1.

Irritants

Irritants (including pulmonary toxicants) are highly
reactive substances which result in nonspecific tissue

damage when in contact with the body, particularly
the skin and mucous membranes. Irritants such as
formaldehyde, sulfur dioxide, nitrogen dioxide,
ozone, petroleum-based chemicals, soaps, deter-
gents, bleach, and other cleaning agents have been
associated with a wide range of health effects. In
addition, irritation effects can result from fibers
such as fiberglass and other insulating materials;
volatile organics from fabric cleaners, paints, and
pesticides; disinfectants; oven cleaners; glues and
epoxy resins.

The most common reactions include irritation of the
eyes (redness and tearing), nose, throat, and upper
respiratory tract. Upper respiratory tract symptoms
typical of irricant contaminants are also very similar
to irritation effects resulting from low humidity
during the winter season and immunologic re-
sponses to airborne allergens.

Irritant chemicals can also result in acute and
chronic skin irritation including dry, scaling skin;
acne-like skin disease; pigment changes; and
ulceration. Some are carcinogens. Dermatosis is a
term that describes a skin disease from any cause.
Noninflammatory dermatoses can be caused by
excessive heat, low humidity, or sunlight interact-
ing with some prescription drugs.

Dermatitis (acute or chronic; irritant or allergic) is a
skin condition that has an inflammatory compo-
nent. Examples include staph or strep infections
caused by bacteria and exposure to biological
allergens and chemicals. Epoxy resins, formalde-
hyde, metals, pharmaceutical drugs, plants, caustics,
detergents, oils and greases, animal danders, saliva,
and urine are some of the agents which can result in
dermatitis. Usually, dermatitis is the result of
direct contact with the agent; however, once an
individual is sensitized by contact, the response can

occasionally result from oral ingestion or even
inhalation of the offending agent (Nethercott,
1990).



42

Unit 1, Lesson 4

IAQ Learning Module

Table 4-3. Potential sources of selected indoor air contam

CONTAMINANT SOURCES

VOCs Perfumes, hairsprays Paints, stains, varnishes, strippers
Furniture polish Wood preservatives
Cleaning solvents Dry cleaned clothes, moth repellents
Hobby and craft supplies Air fresheners
Pesticides Stored fuels and automotive products
Carpet dyes and fibers Contaminated water
Glues, adhesives, sealants Plastics

Formaldehyde Particleboard, interior grade plywood Urea formaldehyde foam insulation
Cabinetry, furniture Carpet, fabrics

Pesticides Insecticides (including termiticides) Fungicides, disinfectants
Rodenticides Herbicides (from outdoor use)

Lead Lead-based paint Exterior dust and soil

Carbon monoxide
Carbon dioxide
Nitrogen dioxide

Improperly operating gas or
oil furnace/hot water heater, fireplace,
wood stove

Unvented gas heater/kerosene heater
Tobacco products, gas cookstove
Vehicle Exhaust

Sulfur dioxide Combustion of sulfur-containing fuels
(primarily, kerosene heaters)
RSP (Respirable particulates) Fireplace, woodstove Tobacco products

Unvented gas heater

Unvented kerosene heater

PAHs (Polycyclic aromatic
hydrocarbons)

Fireplace, woodstove
Unvented kerosene heater

Tobacco products

ETS (Environmental
tobacco smoke)

Tobacco products

Biological contaminants

Plants, animals, birds, humans
Pillows, bedding, house dust
Wet or damp materials

Standing water
Humidifiers, evaporative coolers
Hot water tank

Asbestos Pipe and furnace insulation Decorative sprays
Ceiling and floor tiles Shingles and siding
Radon Soil and rock Water

Some building materials



Final Examination

IAQ Learning Module

34. Which of the following statements about
direct reading measurement methods is
correct?

a.

d.

they provide concentration readings at the
time a sample is collected without further
analysis

they require low capital expenditures
they require laboratory analysis after
collection

they do not require calibration

35. Which of the following statements about
errors in the measurement process is
correct?

a.

systematic errors vary both in direction and
magnitude and can never be completely
eliminated

interferences will introduce random error
into the measurement

routine calibration will reduce systematic
error

nonfrepresentative samples are not impor-
tant sources of error

36. Which of the following statements about
interferences in measurement methods is
correct?

a.

b.

interferences are not important sources of
error

interferences are chemicals or factors other
than the contaminant of interest that result
in higher or lower concentrations than the
true value

correcting results for interferences is a good
practice and should be done routinely
interferences can be ignored in routine
sampling

37. Which of the following statements about
accuracy and precision is correct?

38.

39.

40.

a.

b.

accuracy describes the variation or scatter
among the data

precision describes how close a measure-
ment is to che true result

a sampling method can be accurate, but
imprecise

all of the above are correct

Which of the following describes the
activities needed to ensure that accurate,
precise, complete, representative, and
comparable data are being collected?

aoe

standard methods
duplicate sampling
proficiency testing
quality assurance

Which of the following defines a check on a
sampling method in which known concen-
trations are introduced and measured on a
routine basis?

aa re

standard method
calibration
standard material
blank

Which of the following statements about
quality control activities is correct?

a.

standard methods are those that have been
tested to determine their accuracy and

EPA has established proficiency testing
programs for radon and asbestos

the sample blank refers to the concentration
of contaminant that is present in a clean,
unexposed sampler

all of the above are correct



Unit 1, Lesson 5 IAQ Learning Module

Table 5-1. Examples of indoor air contaminant control strategies (continued).

CONTROL METHOD CONTAMINANT
Source Control (continued)

Prevention

do not build in areas of high radon radon

potential such as areas where uranium or
phosphate tailings have been used as fill materials

Encapsulation

cover materials that contain urea
formaldehyde with shellac, varnish,
or other barriers*

seal asbestos-containing building
materials

seal cracks in basements walls and
concrete slabs with polymeric caulks*

cover basement walls and concrete
slabs with epoxy paint, polymeric
sealant, or vinyl sheeting*

Spatial Confinement

formaldehyde, organics

asbestos
radon

radon

place combustion appliances
in isolated, ventilated rooms

limit smoking to specific areas

use solvents and other hazardous
chemicals outdoors or in
confined, ventilated areas

Temporal Use

combustion contaminants

environmental tobacco smoke

organics

use solvents only when natural
ventilation is adequate or

when the number of people
exposed is minimized

use pesticides only when children,
pets, and other adults are

not exposed

Ventilation

Natural and Mechanical Ventilation

organics

organics

use according to appropriate standards

4 Noe that the use of sealants can result in the release of contaminants such as VOCs for varying periods of time.

all contaminants



IAQ Learning Module

Unit 1, Lesson 4

REFERENCES

Benowitz, NL. 1990. “Cardiovascular toxicology.” Chap. 19.
Occupational Medicine. J. LaDou (ed). Appleton & Lange:
Norwalk, CT.

Council of American Building Officials (CABO). 1989. CABO
One and Two Family Dwelling Code. CABO: Falls Church, VA.

Illuminating Engineering Society (IES) of North America.
1981. 1981 IES Lighting Handbook: Application Volume.
Waverly Press: Baltimore, MD.

Kung, J.R.M. 1982. The American Medical Association Family
Guide, Random House, Inc: New York, NY.

National Research Council (NRC). 1986. Environmental Tobacco
Smoke. Measuring Exposures and Assessing Health Effects. National
‘Academy Press: Washington, DC.

Nethercott, J.R. 1990. “Occupational skin disorders.” Chap.
17. Occupational Medicine, J. LaDou (ed). Appleton & Lange:
Norwalk, CT.

Pushen, J.S. and C.B. Nelson. 1989. “EPA's perspective on
risks from residential radon exposure.” J. Air Poll. Control Assoc.
39(7): 915-920.

Rudolph, L. and CS. Forest. 1990. “Female reproductive
toxicology.” Chap. 23. Occupational Medicine. J. LaDou (ed),
Appleton & Lange: Norwalk, CT.

Smith, M.J. 1984. “Ergonomic aspects of health problems in
VDT operators.” Elsevier Series in Office Automation, 1. Human
Aspects in Office Automation, B.G.F. Cohen (ed). Elsevier Science
Publishers B.V.: Amsterdam, The Netherlands.

USS. Environmental Protection Agency (EPA). 1989. Report to
Congress on Indoor Air Quality. Vol. I. Assessment and Control of
Indoor Air Pollution. EPA 400/1-89/001C. U.S. EPA, Office of
Air and Radiation: Washington, DC.

U.S. Department of Housing and Urban Development (HUD).
1985. The Noise Guidebook, U.S. HUD, Office of Community
Planning and Development: Washington, DC. HUD-953-
CPD.

PROGRESS CHECK

2. Identify four physical stressors which may affect health.

you suspect?

1. Identify the mojor classes of toxic substances and give an example of an indoor contaminant and its source for each class.

3. Ahomeowner calls complaining of eye, nose, and throat irritation, fatigue, and wheezing. Which classes of contaminants would

4, Upon further investigation, you discover that the home is older and has not been remodeled recently. There was a broken
water pipe, however, about 4 months ago which damaged a ceiling and carpeting. That is about the time when symptoms
began. On which class(es) of contaminant(s) would you now focus your investigation?

5. What range of indoor temperature and humidity is comfortable for most people?



IAQ Learning Module

Unit 2, Lesson 6

Figure 6-3. Accuracy and precision.

x
x x
x
x x

Imprecise and Precise but
Inaccurate Inaccurate
Accurate but Precise and

Imprecise Accurate

SOURCE: Adapted from The Industrial Environment - lts Evaluation and
Control. C.H. Powell and A.D. Hosey. (eds). 1965, Health Services
Publication No. 614. U.S. Dept. Health, Educ., and Welfare:

Cinncinati, OH.

Blanks, Duplicates, and Standard
Materials

Blanks: The term “sample blank” refers to the
concentration of a contaminant that is present in the
medium (chemical, filter) that is used to collect the
sample. For example, if radon is sampled using
track-etch detectors and all samplers are deployed, it
will not be possible to know if there is any contami-
nation of the sampler. However, if a number of
samplers are held back and remain sealed and
unexposed, then they can be sent back to the
laboratory and analyzed, allowing any contamina-
tion to be detected. The value of the sample blank
should always be subtracted from the measured
concentration. If the blank concentration is greater
than the measured concentration, the collected data
should be regarded as invalid.

About 10% of the total number of samples collected
should be blanks, and at least one blank should be
included in each measurement batch.

Duplicates: Duplicate samples are those which are
collected and handled in exactly the same way as the
regular samples. Duplicate samples should be
collected for indirect reading methods and some
direct reading methods. The use of duplicate
instruments for direct reading methods is usually
reserved only for research applications when the
method is being investigated.

Duplicate samples provide an additional check on

the quality of the data, and they should agree very
closely with one another. A useful guideline is to

have duplicates for about 10% of the total number
of samples collected.

Standard Materials: Standard materials are those
for which purity and concentration have been
verified by an outside agency. NIST, EPA, and
NIOSH all provide standard materials that can be
used in the calibration of equipment and laboratory
analytical methods. Section 6 of the Reference
Manual contains a list of materials which can be
obtained from NIST; a list of the EPA’s regional
Quality Assurance Offices which can be contacted to
obtain more information about standard materials is
also included. EPA does provide, at no charge,
cylinders of standard gases, including hazardous
organic compounds, that may be used to audit the
performance of indoor air measurement systems.

Calibration

Calibration is the establishment of a relationship
between various standard materials and the mea-
surements of them obtained by all or part of a
measurement system. The levels of standard
materials which are used should bracket the range
of levels for which measurements will be made.

rR)


IAQ Learning Module

Unit 2, Lesson 7

standards are based on a healthy adult worker; they
do not take into account the variability of the
general population.

The OSHA standards which encompass 600 chemi-
cals were revised in 1989 (U.S. DOL, 1989). The
first OSHA standards included Permissable Exposure
Limits (PELs) which were the 8-hour time-weighted
average limits developed by ACGIH in 1968. The
revised standard essentially adopts the ACGIH
guidelines for most contaminants, and it includes
the TWA, STEL, and ceiling limits. Some of the
new standards are more stringent than before and
some have been relaxed.

The National Institute of Occupational Safety and
Health (NIOSH) is part of the U.S. Department of
Health and Human Services and it acts as the
research institution for the Occupational Safety and
Health Administration. NIOSH uses the most
complete and current scientific information to
develop and periodically revise recommended
exposure limits to potentially hazardous substances
or conditions in the workplace. The recommended
exposure limits and supporting information are then
submitted to the Department of Labor for consider-
ation in developing PELs. NIOSH recommenda-
tions ate published in criteria documents which can
be obtained by contacting NIOSH.

SOURCE EMISSION STANDARDS

Source emission standards specify maxi-
mum rates at which contaminants can be released
from a source. Source emission standards may be
developed by governmental agencies such as the
Consumer Product Safety Commission (CPSC), the
Department of Housing and Urban Development
(HUD), or by professional associations.

HUD has issued a product standard which limits
the level of formaldehyde emitted from pressed
wood products installed in mobile and manufac-
tured homes. The HUD rule requires formaldehyde
emissions not to exceed 0.2 ppm from plywood and
0.3 ppm from particleboard as measured by speci-

fied air chamber tests. (U.S. HUD, 1990a). The rule
was established to provide indoor formaldehyde
concentrations less than 0.4 ppm when the indoor
temperature does not exceed 77°F, the relative
humidity is less than 50%, the ventilation rate is at
least 0.5 ach, and there are no other major emitters
of formaldehyde in the home (U.S. HUD, 1984).
The rule does not consider the carcinogenic poten-
tial of formaldehyde and other limits are more
stringent.

Underwriters’ Laboratories, CPSC, and the National
Kerosene Heater Association are working together
to develop limits for oxide of nitrogen emissions
from unvented kerosene heaters; this standard
however is not currently available.

VENTILATION STANDARDS (kM 7)

Ventilation standards specify minimum
rates for the introduction of outdoor air into indoor
spaces. The most widely used ventilation require-
ments are specified by the American Society of
Heating, Refrigerating, and Air-Conditioning
Engineers, Inc. (ASHRAE), a private standard-
setting trade association, in ASHRAE Standard 62-
1989. Other ventilation standards include model
building codes, standards of HUD and the Ameri-
can Public Health Association (APHA) model
housing code.

ASHRAE Standard 62-1989

ASHRAE Standard 62-1989, Ventilation for Accept-
able Indoor Air Quality, specifies minimum ventila-
tion rates which are expected to be acceptable to
occupants and avoid adverse health effects
(ASHRAE, 1989). This standard was developed by
an interdisciplinary committee, and it reflects a
consensus opinion that attempts to balance the
requirements of acceptable indoor air quality and
efficiency in energy consumption. The standard
applies to all indoor or enclosed spaces which people
may occupy including residential and commercial
spaces, classrooms, bathrooms, kitchens, locker
rooms, swimming pools, and saunas. Acceptable



IAQ Learning Module

Unit 1, Lesson 4

Volatile Organic Compounds (VOCs)
including Formaldehyde

VOCs are compounds which volatilize readily;
VOCs include aromatic hydrocarbons, halogenated
hydrocarbons, alcohols, ketones, aldehydes, ethers,
esters, and others; several hundred VOCs have been
identified in indoor air (U.S. EPA, 1989).

VOCs can result in eye, nose, and throat irritation;
headaches; loss of coordination; loss of memory;
nausea; and damage to the liver, kidney, and
nervous system. Some organic gases cause cardiac
sensitization reactions, and some are also known or
suspected of causing cancer in humans. Exposure to
mixtures of VOCs commonly found in building
materials may be an important source of sick
building complaints. In general, however, the
health effects of exposure to VOCs through indoor
air are not well understood.

Formaldehyde, which is probably the best known
VOC, is often implicated as a cause of many indoor
air quality complaints. It is an irritant. Eye, nose,
and throat irritation, as well as symptoms including
headache, wheezing, coughing, fatigue, and skin
irritation may be experienced at the concentrations
encountered in nonoccupational environments.
Formaldehyde is also a known skin sensitizer. It has
been shown to cause cancer and mutations in
laboratory animal studies, and EPA has classified it
as a “Probable Human Carcinogen.”

Pesticides

Pesticides include both organic and inorganic
chemically-based products which are used to kill
household and garden pests including weeds,
insects, termites, and rodents. Although there are
data gaps for many pesticides, the EPA is in the
process of accelerated re-registration of currently
registered pesticides.

Severe acute exposures are generally easy to deter-
mine because a history of exposure is usually
available and the symptoms are marked. Exposure to

high enough levels can result in damage to the
central nervous system, eyes, skin, heart, respiratory
tract, kidneys, and liver. Symptoms could include
headache, dizziness, blurred vision, skin rashes and
sores, apprehension, confusion, bizarre behavior,
convulsions, depression, loss of consciousness,
pulmonary edema, heart arrhythmias, muscle
weakness, paralysis, and others.

Chronic exposures can result in a variety of effects
including central nervous system dysfunction
(problems with memory, mood, fatigue), liver
damage (abdominal pain, weight loss, vomiting,
jaundice), tingling and numbness in the
extremeties, kidney damage (difficulty urinating,
incontinence), weakness, and other problems. The
cancer-causing potential of some pesticide chemicals
is also of concern.

Mild acute intoxication or subacute poisoning is
more difficult to identify because a history of
exposure may not be apparent, and symptoms may
be nonspecific and similar to the flu.

Particulates

Particulates which can be released into the indoor
environment include inorganic fibers, metals, and a
variety of organic materials. Particulates in the
inhalable range (10 microns aerodynamic diameter
or less) are potentially hazardous to health.

Lead exposure can affect both adults and children,
but children (and fetuses) are at greater risk because
of their smaller body size, breathing patterns, and
the way lead is metabolized in their bodies. Health
effects include damage to the kidneys, nervous
system, red blood cells, and potential increases in
high blood pressure. Lead exposure may also result
in decreased coordination and mental abilities. The
effects of lead exposure can be reversed if treatment
begins in a timely fashion and continues for the
prescribed course of therapy; however, if treatment
is delayed or stopped prematurely, then permanent
brain damage can result.

37


Final Examination

IAQ Learning Module

Which of the following are reasons for
concern about indoor air today?

a. people spend most of their time indoors
the use of natural ventilation has decreased

c. many buildings and furnishings are pro-
duced from synthetic chemicals

d. all of the above are reasons for concern

Which of the following statements is
correct?

a. the relationship between indoor air pollu-
tion and health has been intensively studied
for about 30 years

b. staying indoors always protects inhabitants
from outdoor air pollution

c. the reduced air changes in new construction
is one reason for the deterioration of indoor
air quality

d. people are probably exposed to fewer indoor
air contaminants today than 50 years ago

Which of the following can affect the

quality of indoor air?

a. vegetation surrounding the house

b. quality of water supply

c. geology

d. all of the above can affect indoor air quality

Which is most likely to be a potential
source of formaldehyde?

a. particleboard subflooring
b. roofing felt

c. paint

d. solid hardwood floors

Volatile organic compounds are most likely
to be released from which of the following
sources?

asbestos insulation

freshly painted interior room

recently poured concrete basement floor
old, moldy carpet

ao>rPr

Which contaminant is more likely to result
from an outdoor source than an indoor
source?

a. asbestos

b. radon

c. volatile organic compounds
d. pollen

Which statement about air exchange rate is
correct?

a. air exchange rates of older houses that have
not been weatherproofed are typically in the
range of 0.10 ach to 0.5 ach

b. air exchange generally increases with strong
winds

c. air exchange can be increased through the
use of vapor barriers

d. indoor air contaminant concentrations will
always be inversely proportional to the air
exchange rate

Assuming all other factors are constant,
which conditions will result in the highest
infiltration rate?

a. outside temperature of 32°F, inside tem-
perature of 68°F

b. outside temperature of 70°F, inside tem-
perature of 75°F

c. outside wind calm

d. cloud cover and rain

If a house has a volume of 15,000 ft? and air
is replaced at a rate of 500 ft per minute,
how many air changes are occurring each
hour?

a. .5 ach
b. 1 ach
c. 2 ach
d. .25 ach



IAQ Learning Module

Final Examination

74. Which of the following describes a contro-
versial condition in which some subset of
the population is said to be especially
sensitive to a broad range of chemicals at
low levels of exposure?

mass psychogenic illness
multiple chemical sensitivity
sick building syndrome
none of the above

aoge

75. Which of the following statements about
communication of results is correct?

a. preliminary results should not be given
because of liability problems

b. a written report should always be prepared
even if a verbal report is given

c. if remedial services are needed, the investi-
gator should recommend a contractor

d. if no cause of the problem is apparent, the
investigator should suggest a referral of the
client to a mental health agency

76. Which of the following is a basic element of
effective communication?

a. listening

b. caring

c. documenting
d. all are correct

77. How will the investigator ensure that
correct information is obtained?

repeat information back to the client
use standard forms

use a systematic approach

all are correct

aore

78. What is the first step in establishing an
indoor air program?

set the program objectives
obtain the necessary funds
define the need for the program
hire the staff

aoe

79. Which is not an element of a major program
objective?

a. specify the intended result

b. provide a target date for completion

c. stick to the original plan, regardless of
circumstances

d. anticipate obstacles

80. Which is a source of information for esti-
mating program costs?

a. personnel specialists

b. equipment vendors | 1 7
c. indoor air staff in other agencies

d. all of the above

81. What actions should the program manager
take when providing information on the
indoor air program to the news media?

decline to comment on controversial issues
strive for the maximum publicity
anticipate the impact of the program

refer all questions to superiors

aorPp

82. What will assist the program manager in
proper evaluation of the program?

a. program manager should closely supervise
all the employees

b. program manager should be technically
expert in all aspects of indoor air quality

c. program manager should have adequate
information about whether the objectives
were attained

d. program manager should not share sensitive
program information with the public

83. What actions should be taken if major
program objectives are not being achieved?

a. those responsible should be dismissed

b. the program manager must diagnose the

problem and take corrective action

it would be unfair to charge fees for services

d. it should not be of concern because indoor
air quality is still a new issue

2

Examination continues on next page



IAQ Learning Module

Table of Contents

TABLE OF CONTENTS

INDOOR AIR QUALITY LEARNING MODULE

Acknowledgements

Introduction

Unit 1

Lesson 1.

Lesson 2.

Lesson 3.

Lesson 4.

Lesson 5.

Lesson 6.

Lesson 7.

Lesson 8.

Unit 3

Lesson 9.

UNDERSTANDING INDOOR AIR QUALITY
Historical Perspective
Factors Affecting Indoor Air Quality

Human Response to Indoor Air Quality:
Principles of Toxicology

Human Response to Indoor Air Quality:
Classification of Indoor Air Contaminants

Controlling Indoor Air Quality

MEASURING AND EVALUATING PROBLEMS
Indoor Air Quality Measurements

Standards and Guidelines for Indoor Air
Contaminants and Ventilation

Investigation Techniques

DEVELOPING A PROGRAMMATIC RESPONSE

Establishing an Indoor Air Quality Program

vii

ix

29
45

63

79
89

99



IAQ Learning Module

Unit 3, Lesson 9

8) coordinating activities with other agencies
at the local, state, and federal levels; and

9) developing an appropriate legal framework
and enforcement capability.

Program Resources

During the initial planning stages one seldom
knows exactly how much money is likely to be
committed to a new program. Preparing several
options with cost estimates may be desirable for at
least two reasons.

¢ First, it starts to bring the major program
priorities into focus and provides the
program manager with an outline of an
action plan once the funding level is
determined.

© Second, the people who decide upon the
funding level can more easily reach a
decision if they can review a limited
number of options spelled out in reasonable
detail.

Asa practical matter, everyone in the decision-
making process will feel more confident about the
proposal if they believe the person who initiated it
has both a command of the details and an open-
minded view of the alternatives. Each program
alternative should include cost estimates. Potential
costs include:

© Personnel Costs--wages, salaries, and
benefits for full-time and part-time person-
nel; benefits include social security, retire-
ment, medical insurance, life insurance, and
other programs offered to employees by the
organization;
© —Equipment--items for conducting indoor
air investigations, office equipment,
computer hardware, and furniture;

*  Supplies--items such as paper, pens,
pencils, postage, batteries, and computer
supplies;

¢ Building rental or purchase costs;
¢ Utility payments;

¢ =©Training programs;

© Consultant fees;

© Maintenance Costs--includes field testing
equipment and major office equipment;

* Vehicle costs or mileage payments for field
personnel;

° Computer software;
© Computer access time; and
* Laboratory fees.

The preceding list is not intended to be comprehen-
sive, but it should provide a general guide to overall
program costs. Specific cost information for items
not unique to an indoor air program usually can be
obtained from purchasing or accounting specialists
within the organization. Information about wage
and salary classifications as well as benefits, should
be available from line managers within the chain-of-
command or from personnel specialists.

For information about special equipment needs and
costs, other public agencies involved in indoor air
investigations can be helpful. Equipment vendors
are very accommodating about providing specifica-
tions and pricing information. Professional environ-
mental health associations and academicians are
other valuable resources within the information
network.

The costs of the indoor air program should be
projected beyond the “start-up” period. Additional
overhead costs will be incurred by the organization



Table 5-2. Public and private sector ro

PUBLIC AND PRIVATE SECTOR ROLES

Consumer

and Health Building Owners | Builders and State and Local Federal
Individuals Professionals Manufacturers and Managers Architects Governments Government
Find low Be knowledgeable | Adopt test proce- ‘Adopt ventilation | Adopt indoor Conduct studies Conduct research
emission products _| of symptoms, effects, | dures and standards | maintenance air quality asa of specific problems _| and technology
in purchasing and mitigation and | to minimize product | procedures to design objective. in state of local transfer programs.
decisions. advise clients. and material eliminate and prevent area and adope

emissions. contamination and mitigation strategies.

ensure an adequate
supply of clean air

to building occupants.

Maintain and use
products to minimize
emissions.

Develop informa-
tion and education
programs to
constituent publics.

Adequately label
products as to
emission level,
proper use, and
maintenance of
products.

‘Use zone ventila-
tion or local
exhaust for indoor
sources.

Ensure compli-
ance with indoor
air quality
ventilation
standards.

Establish build-

ing codes for
design, construction,
and ventilation
requirements to
ensure adequate
indoor air quality.

Coordinate the actions.
of other sectors.

Exercise discre-
tionary control
over ventilation
to ensure clean
air supply.

Substitute mater-
ials to minimize
emissions from prod-
ucts manufactured.

Develop specific
procedures for use
of cleaning solvents
paints, herbicides,
insecticides, and
other contaminants
to protect occupants.

‘Adopt low emis-
sion requirements
in procurement
specifications for
building materials
from manufacturers.

Enforce and
monitor
compliance.

Conduct specific
programs to inform
encourage, or
require specific
sectors to take
actions toward
mitigation.

Be knowledgeable
of indoor air
quality problems
and take actions
to avoid personal
exposure,

Develop training
programs for
commercial users to

ensure low emissions.

Conduct research co
advance mitigation
technology.

Adopt investiga-
tory protocols to
respond to occupant
complaints

Contain or ventilate
known sources.

Educate and inform
building community,
health community,
and public about
problems and
solutions.

SOURCE: EPA (1989)

ajnpow Surusvr] OVI

§ Mossay ‘T UN)


IAQ Learning Module

Unit 1, Lesson 5

Table 5-1. Examples of indoor air contaminant control strategies.

CONTROL METHOD

Source Control

Removal

CONTAMINANT

stop smoking
eliminate kerosene heaters from living space

separate garage from house

environmental tobacco smoke
kerosene heater emissions

auto emissions

remove pets from living space allergens

construct physical barriers organics

for termite control

Substitution ‘

use wood or metal building materials formaldehyde, other
and furnishings instead of interior organics

grade particleboard and plywood

use fiberglass or other type of formaldehyde

insulation instead of
urea-formaldehyde foam

replace combustion appliances
with electric appliances

replace a portable vacuum system
with a central system

replace materials that collect dust, have
water damage, or provide food sources
for insects with other materials

substitute materials which cause
allergies with those that don’t

replace pesticides with physical
or biological controls

Changes in Design or Operation

combustion contaminants:
oxides of nitrogen, carbon monoxide, sulfur
dioxide, particles, carbon dioxide

particulates

allergens

a variety of chemical and biological
allergenic agents

organics

pilotless combustion appliances and
more efficient burner design for gas
stoves, gas and kerosene heaters

adjust and maintain combustion
appliances to provide an efficient burn

HVAC system components that increase
outdoor air ventilation rates

heat exchangers with condensate drains

combustion contaminants

combustion contaminants

allergens

allergens
(continued on next page)

47


Unit 2, Lesson 8

IAQ Learning Module

When monitoring is conducted, these data must be
integrated into the results of the health screening
and inspection to identify sources of problems and
recommend solutions. In some instances the
investigator may have to consult the scientific
literature to evaluate reported symptoms and
measurements.

If in the investigator’s judgment, monitoring is not
needed, but an indoor air quality problem exists,
remedial actions may be recommended either for the
original complaint or for subsequent problems
which are revealed during the inspection.

Finally, after all of the information has been col-
lected, digested, and evaluated, the client should be
informed of the results of the investigation. Results
may be given initially by telephone, but a written
report or letter which summarizes the investigation
and its results should always be sent. A written
report that is complete and understandable (without
bureaucratic and technical jargon) will save the
investigator's time, and it provides the client with a
permanent record that should not be subject to
conjecture. Copies may also be sent to interested
parties such as physicians (upon the request or
approval of the client).

Referrals to Other Service Providers

There will be instances when, in spite of the
investigator's efforts, no apparent cause of reported
symptoms can be found. This situation can be
frustrating to both the investigator and the client,
but it should be handled in a direct manner with
the client. If there are other potential avenues of
exploration that the investigator was unable to
follow, these should be communicated to the client.
The investigator may also recommend that the
client contact other agencies or medical personnel to
pursue health and environmental complaints which
are beyond the jurisdiction of the investigator.
Clients should always be advised to consult with
their health care provider.

If referrals to private laboratories, consultants, and
remediation services are needed, the investigator
should furnish the client with a list of potential
vendors. The investigator should not be placed in
the position of recommending a single individual or
company.

COMMUNICATIONS (RM 8)

One of the most important, but often
overlooked, components of a successful indoor air
quality program is the way in which complaints,
inspections, and requests for information are
handled. Communication with the client is an
integral part of all aspects of the investigation of an
indoor air quality problem beginning with the
initial contact and ending with the communication
of results. Effective communication is the key to
success, and it requires skill and practice to achieve.

The investigator should share information with the
client as the investigation progresses; this will make
the process less mysterious, alleviate anxiety, and
ensure that effective communication takes place.
During all phases of the investigation, the attitude
of che investigator and the ability of the investigator
to communicate with the client will influence the
overall success of the investigation. Guidelines that
have been developed for successful complaint
investigation also apply to indoor air quality
investigations. These include: listening, caring,
informing, taking action, documenting, and
following-through (Herman, 1983).

Communications During the Initial Contact

Initial contacts are usually made by telephone, and
this opportunity should be used to explain capabili-
ties and gather as much information as possible to
assist with developing an overall strategy for
problem-solving.

Keeping an open mind is a cardinal rule. Situations
should not be prejudged based on reactions to a



Unit 1, Lesson 3

IAQ Learning Module

SCIENTIFIC BASIS FOR IDENTIFYING ADVERSE
HEALTH EFFECTS (RM 3.3)

Taformation about the health effects of
exposure to contaminants and physical stressors may
come from several sources. These include animal
data from controlled exposure studies and human
data from accidental exposures, occupational
studies, controlled human exposure studies, and
epidemiological studies. Ideally, health effects
guidelines or standards should be derived from
studies that represent contaminant concentrations
and exposure conditions that approximate the actual
exposures experienced by the general population.
However, the data base for the health effects of
contaminants and physical stressors is generally
limited, in part, because of the expense and inherent
problems associated with studies of health effects.

Animal Exposure Studies

Animal exposure studies are generally based on
large doses of contaminants administered over the
relatively short lifetime of the animal (typically, a
rat, mouse, or rabbit, but also other mammals,
including dogs and monkeys). Standardized
protocols which ensure highly controlled conditions
are used. These studies usually involve 50 animals
of each sex (for two species) treated at 2 to 3 differ-
ent doses over the life expectancy of the animal
(about 2 to 3 years for rats and mice). A control
group is also required. Chemicals are administered
by inhalation, ingestion, injection, or dermal
applications. Relatively high doses are used to
increase the sensitivity of the study. At the end of
the exposure period, the animals are evaluated for
effects, and the data are analyzed using statistical
techniques.

The evaluation of animal data is difficult because
the test animals may not reflect the human experi-
ence accurately. For example, target organs may be
different, and humans and animals may not be
equally sensitive to chemical exposures.

Nonthreshold effects (typically, carcinogens) must
be extrapolated down to the lower concentrations
that are usually experienced in occupational and
nonoccupational exposures. The mathematical
models used for these extrapolations can provide
results that may vary over several orders of magni-
tude for a single toxic substance. In spite of these
uncertainties, animal studies do provide good
evidence of the carcinogenic potential of toxic
substances in humans.

Results for observed threshold effects in animals are
not extrapolated to low doses in humans. These
results may be extrapolated across species by dose,
followed by the application of an uncertainty factor
to obtain a level at which effects are not observed
{no-observed-adverse-effect level (NOAEL)}. There
is also concern in these evaluations about the
adequacy of the animal model.

Accidental Human Exposures

Accidental exposures such as those experienced in
disasters at Chernobyl, Russia (radiation), Seveso,
Italy (dioxin), and others have provided additional
information about the acute and chronic effects of
contaminants at relatively high exposures. Because
these exposures are uncontrolled and it can be
difficult, if not impossible, to reconstruct doses,
these data usually provide only anecdotal support
and are usually not used to develop guidelines,
standards, or risk assessments.

Controlled Human Exposure Studies

Controlled human exposure studies are conducted
under strictly controlled conditions in a laboratory.
Subjects are exposed for generally short time periods
to low levels of various contaminants. These studies
are useful because dose-effect relationships at low
concentrations can be evaluated. Limitations of
these studies include the narrow populations studied
(small number of healthy adults or those with mild
disease are usually studied); the most hazardous



Unit 1, Lesson 3

IAQ Learning Module

TYPES OF ADVERSE RESPONSES TO INDOOR
AIR QUALITY PROBLEMS (RM 3)

‘There is a continuum of human response
from exposure to contaminants and environmental
stressors that ranges from burdens which do not
manifest physiologic changes, at one end of the
spectrum, to mortality, at che other end. A wide
variety of health effects between these two extremes
has been associated with poor indoor air quality.

Classes of Effects

Human responses to contaminants and stressors can
be categorized according to the type and degree of
responses and the time frame in which they occur.
‘These general classes of effects can apply to expo-
sures in the occupational, outdoor air, and indoor air
environments, and a single exposure can result in
more than one effect.

Acute effects are those that occur immediately
(usually within 24 hours) after exposure. For
example, chemicals released from building materials
may cause headaches or pollen may cause itchy eyes
and runny noses in sensitive individuals shortly after
exposure. Generally, acute effects are not long-
lasting and usually disappear shortly after the
exposure ends. However, some exposures (usually
occupational or accidental exposures to high
concentrations) can result in irreversible acute
effects or even death.

Chronic effects are long-lasting responses to
contaminants which are generally the result of
frequently repeated exposures to concentrations
(often low) over an extended period of time. The
manifestation of effects is generally delayed rather
than immediate. Emphysema which may be caused
by smoking cigarettes is an example of a chronic
effect which develops over time and fully manifests
itself years after smoking begins. Cancer has been
associated with exposure to contaminants such as
asbestos, radon, environmental tobacco smoke, and
organic chemicals such as benzene.

Subtle effects are those which are too small to be
readily noticeable by the individual. For example,
small changes in visual discrimination or pulmonary
function can be measured in response to chemical
exposures, but the person affected may not be able
to discern these changes. The significance of some
of these changes is not known.

Discomfort effects such as being too warm or too
cold, typically result from climatic stressors such as
temperature and the rate and direction of air flow.
Mild irritation of the mucous membranes and
respiratory tract has been associated with low
humidities. Eye strain and headache have been
related to light levels that are too low or bright.

Although the base of knowledge is expanding for
identifying adverse health effects of indoor air
contaminants, these effects are not fully known for
all contaminants or mixtures of contaminants. This
lack of dose-effect and exposure data can complicate
the interpretation of data and the evaluation of
individual indoor air quality problems.

Emerging Concerns
Contaminant Mixtures

Exposure to low-level contaminant mixtures is an
issue of increasing interest. Contaminants do not
exist in isolation, but as part of a complex and
dynamic mixture which changes depending on
time, human activities, and location. Contaminants
in mixtures can have effects which are antagonistic,
additive, or synergistic. Of particular interest are
synergistic effects in which the combined effect is
greater than the sum of the effects of the individual
components. For example, the risk of getting lung
cancer from exposure to asbestos and cigarette
smoke is greater than it is from each risk added
together. Antagonistic effects are those in which
the combined effect is less than the sum of the
effects from individual contaminants, and additive
effects are those in which the combined effect is



Unit 3, Lesson 9

IAQ Learning Module

Defining Program Need

The need for any new service must be carefully
justified, especially one that is still relatively
unfamiliar to most people. In the case of indoor air
pollution, one must be prepared to educate decision-
makers and others likely to influence the allocation
of resources about the types of indoor air hazards
and associated health risks. As much as possible,
these risks should be discussed within the context of
the population served by the organization.

It will be necessary to make a persuasive case that
there are potential indoor air problems, and the
needs of the community are not being met. Docu-
menting actual indoor air problems within the
geographical area of concern without having an
active indoor air program may be difficult. How-
ever, there are now numerous research studies and
articles in the popular press and trade journals
which provide a basis for assessing the potential
magnitude of indoor air contaminants on the
population within a given area. Some types of
information which can be used to support the need
for indoor air quality services include:

¢ Records of requests for service from citizens
who believe they are being exposed to
indoor air hazards.

* Anaging housing stock can be a source of
carbon monoxide caused by faulty furnaces,
or these structures can contain friable
asbestos.

© The indoor air problems encountered in
both new and old commercial office
buildings are well-documented and are
common to most geographical areas.

* The U.S. EPA and the Surgeon General
have recommended testing all residences for
radon.

¢ A large number of manufactured housing
units in the community could be an
important source of formaldehyde exposure.

Program proposals seldom succeed on their merits
alone. It is important to adhere to the organiza-
tion's chain-of-command when proposing a new
program, and one must be alert to the politics of the
organization. As the proposal progresses one should
be prepared to provide clarifying information to key
decision-makers, such as board members, elected
officials, and interest groups whose support will be
important both before and after the program is
implemented.

One should be prepared to respond to questions
about the most common indoor air quality prob-
lems, resource needs, federal and state activities,
what the program will do, and how it will be done.

Elements of a Program

Basic elements of a program which could be consid-
ered include:

1) mechanisms to respond to complaints;
2) providing public information and guidance;

3) analytic studies to define the nature and
magnitude of the problem in the jurisdic-
tion;

4) conducting residential and commercial
building investigations;

5) special programs to deal with individual
hazards such as radon, asbestos, and pesti-
cides;

6) distribution of federal and state guidance to
the building community and the public;

7) publishing directories of contacts within
the jurisdiction for individual subject areas
relevant to indoor air;



Unit 1, Lesson 3 IAQ Learning Module

PROGRESS CHECK

1. Discuss some of the problems that con be encountered in trying to fit symptoms and health effects to indoor oir contaminants.

2. What ore the types of studies which provide information on health effects of indoor oir contaminants?

3. What is the difference between chronic effects and acute effects?

4. What are the different factors that can affect potential health risks of contaminants?

5. What ore importont properties of gases ond porfices that determine their potential for health effects?

6. Discuss the concept of dose-effect relationships.

7. Which host factors con affect the risk posed by indoor air contaminants?

8. Briefly explain the differences between building related illness and sick building syndrome.

% Bie expla ule sry and ms ychogeic Hes. Wt some cancers cht hes wo emerging
issues!



Final Examination

IAQ Learning Module

16.

17.

18.

19.

Which of the following statements about
the dose-effect curve is correct?

a. the linear dose-effect curve indicates that
there is a dose below which effects do not
occur

b. the threshold dose-effect curve indicates
that effects occur at all doses, no matter
how low the dose

¢. carcinogens are generally considered to
follow the threshold dose-effect curve

d. none of the above are correct

Which of the following is an example of a
subgroup of the population which is prob-
ably more susceptible to health effects from
chemical exposure than the general popula-
tion?

a. infants and children

b. pregnant women

c. the elderly

d. all are examples of subgroups that are
probably at greater risk to health effects
from chemical exposures

Which of the following is an example of an
irritant?

formaldehyde
carbon dioxide
carbon monoxide
radon

aor Pp

Which of the following is an example of a
contaminant that could act as an irritant
and also affect the central nervous system?

lead
chlordane
sulfur dioxide
nitric oxide

aooP

20.

21.

23.

24,

Which of the following is a condition in
which the air sacs lose elasticity and
breathing becomes more difficult?
a. bronchitis
b. pneumonitis
c. emphysema
d. edema
Hepatotoxicants affect which of the
following body systems?
a. kidney
b. blood
c. reproductive organs
d. liver
22. Which of the following has been associated
with a lack of natural light during the
winter?
a. winter depression
b. irritation of the eyes, nose, and throat
¢. cancer
d. poor vision
Which of the following is most likely to be
associated with dry air?
a. fatigue
b. chest pain
c. irritation of the eyes, nose, and throat
d. sweating
Which of the following is a condition that

has been associated with airborne
pathogens or allergens?

a. migraine headache
b. emphysema

c. bronchitis

d.

humidifier fever



IAQ Learning Module

Unit 1, Lesson 5

that they balance supply and exhaust air streams.
Disadvantages include cost ($150 to $1500) and
potential problems associated with condensation in
older units. These units require regular cleaning to
reduce the risk of microbial contamination. Calcu-
lations of overall energy efficiency should include
the energy required for the fans. Units tend to be
more cost effective in colder climates.

Air Cleaning Devices

Air cleaning devices can also be used to reduce the
levels of some contaminants, but they are not a
substitute for source control or adequate ventilation.
Contaminants can be removed either from the
outdoor air before it enters the home or from the
recirculating air inside the home. Air cleaners for
residential use can be effective in removing some
particles, but may be of limited value in removing
gases and vapors. If air cleaning devices are used,
they must be properly sized and maintained.

Commercially available air cleaning devices are
based on the principles of filtration, electrostatic
attraction, or adsorption. Filtration and electro-
static attraction reduce particulate contaminants
and adsorption reduces gaseous contaminants. Air
cleaners come in many different sizes and configura-
tions, and their performance varies considerably.

Portable units include small table top units and
larger console units which are intended for localized
situations. Some air cleaners can be located cen-
trally, or in the HVAC ducts, to clean air from the
entire house.

It should be noted chat expected removal efficiencies
for air cleaning devices are not the same as the
effectiveness of the unit in actual use. Efficiency
only measures the percent removal of contaminants
in che air that flows through the air cleaning device.
Effectiveness in use depends on how much of the
interior air actually goes through the unit in a given
time period. These differences are discussed in more
detail later in this lesson. A summary of available

information on air cleaning devices is available from
EPA (U.S. EPA, 1990).

Removal of Particles by Filtration

Filtration removes particles by a mechanical barrier
which allows only particles of a certain size to pass
through. Filters can be made of fiberglass, metal, or
natural fibers. Some filters are disposable, and
others must be cleaned for reuse. As the air stream
passes through the filter, particles are removed by
the fibers through direct interception, inertial
deposition, diffusion, and electrostatic effects. The
relative importance of each of these collection
mechanisms varies with particle size. Diffusion
dominates for particles less than 0.01 microns in
diameter while interception and inertial impaction
dominate the removal of particles greater than 1.0
micron in diameter. For all filters, there is a particle
size for which the removal efficiency is at a mini-
mum. Some of the factors that affect filter efficiency
include fiber size, fiber density, air flow rate, and
particle diameter.

Mechanical filters can be grouped into panel filters
and extended surface filters, (including high
efficiency particulate air (HEPA) filters). Section 5
of the Reference Manual compares the performance of
these types of filters based on standard ASHRAE
performance tests (tests are explained in the Reference
Manual).

Panel filters consist of a filtering medium (coarse
glass, animal hair, synthetic fibers, animal fibers,
metals, foils) held in place by a rigid or flexible
frame. The filter fibers have a low packing density
and are usually coated with a viscous substance (oil,
for example) which traps particles. Panel filters are
inexpensive (approximately $1-$2 for furnace
fileers). They are characterized by a low pressure
drop across the filter and a high removal efficiency
for very large particles such as lint, but a very low
removal efficiency for respirable particles. Perma-
nent panel filrers must be cleaned regularly, usually
with steam or water and detergent.



FINAL EXAMINATION INSTRUCTIONS

The final examination consists of 86 multiple choice questions on the
content of the entire module. It is a learning tool as well as a
measure of your understanding of the material.

Use Answer Sheet

Mark your answers on the answer sheet provided, being sure to
follow the directions given. Make certain that you complete all the
information requested on the answer sheet.

Read Carefully

Read each question carefully. There is only one correct answer to
each question. NEHA will score your exam and return your
corrected answer sheet.

Minimum Score

Since this is an “open-book” exam, a minimum score of 75 percent
correct must be achieved. You will receive a certificate of comple-
tion if you score this minimum or higher.

Time for Completion of the Module and Final
Examination

Please indicate in the space provided the amount of time you spent
in studying the material and completing the final examination.
This information will assist NEHA in determining the number of
continuing education credits that will be granted for this course.

MAIL YOUR ANSWER
SHEET TO:

National Environmental Health
Association

720 South Colorado Blvd.
#970 S. Tower

Denver, CO 80222



TAQ Learning Module

Unit 2, Lesson 6

sampling begins. The protocol is a valuable tool
which can ensure that the measurement problem has
been thought-out, and that time, money, and
resources will be optimized to provide quality data.
The protocol should include basic information such
as what will be sampled and how, where, when, and
by whom the sampling will be accomplished. A key
component of the protocol is the evaluation of data
reliability through the use of a quality assurance
plan.

The selection of appropriate equipment, and the
proper operation, routine maintenance, and calibra-
tion of equipment are critical to the success of any
sampling program. Calibration is a check on the
sample collection system and the analytical method
to verify that accurate measurements are made. It is
the cornerstone of any sampling protocol and can
make or break the validity and usefulness of the
collected data.

It is the investigator's responsibility to know each
piece of equipment or method that will be used and
to identify maintenance and calibration require-
ments before sampling begins. Maintenance and
calibration schedules should be delineated in the
protocol and followed strictly.

Instructions should also be included on sample
handling, storage, and transport. Directions for
calculations and criteria for accepting data should
also be included in the protocol along with other
quality assurance procedures. In developing the
protocol, it is a good idea to seek advice from both a
chemist, industrial hygienist, or other person who
has expertise with the proposed analytical methods
and a statistician, if the project involves multiple
locations or measurements. If the sample is to be
collected and then analyzed at a later time in the
laboratory, the investigator must also be sure that
the laboratory personnel follow a quality assurance
program.

A major objective in designing a sampling program
is to collect a representative sample--one that
reflects the exposure that is being experienced. This

requires careful attention to sample size and selec-
tion of methods (Section 6 of the Reference Manual).
Failure to collect a representative sample can be an
important source of error in any investigation.

Quality Assurance

Quality assurance (QA) describes the activities
needed to provide assurance that high quality data
are being collected. The objectives of a quality
assurance program are to ensure that the data are
accurate, precise, complete, representative, and
comparable. Factors in a quality assurance program
include:

1) adequately trained and experienced person-
nel;

2) proper equipment and facilities in good
working order;

3) written sampling, calibration, and mainte-
nance procedures and schedules;

4) data validation programs;
5) chain-of-custody procedures; and
6) a supportive management team.

Quality control refers to that part of the quality
assurance plan that directly raeasures data reliability
through calibrations and other checks such as blanks
and duplicates.

Ideally, a good indoor air quality sampling program
will have a written plan that incorporates as many of
the components of an ideal quality assurance
program as possible. Although such a plan may not
be required, it is sound practice to develop and use
as many of the components as feasible. Additional
information on the elements of quality assurance
programs for quality measurements are discussed in
EPA ambient air quality assurance documents (U.S.
EPA 1975, 1977, and 1980) and in the compen-
dium of methods for indoor air (U.S. EPA, 1989).



Unit 1, Lesson 3

IAQ Learning Module

substance, the dose, the environment, and the
occupant (Table 3-1).

Factors Related to the Toxic Substance

Toxicity is the innate ability of a contaminant to
cause injury to biological tissue. The toxicity posed
by natural and synthetic chemicals varies depending
on the contaminant’s chemical and physical proper-
ties and how those properties interact with the
human body.

Two additional terms, hazard and risk, are some-
times confused with toxicity. Hazard describes a
situation which may result in a health effect. Risk
is the likelihood or probability that the health effect
will occur in a specific exposure situation.

Solubility is simply the ability of one substance to
dissolve in another substance. Chemicals can be
classified as those that are soluble in polar solvents
and those that are soluble in nonpolar solvents.
From a health standpoint this difference is impor-
tant. Chemicals which are polar in nature (such as
table salt) will be more easily excreted from the
body; chemicals which are nonpolar (such as PCBs
and DDT) will not readily be excreted and will

remain in the body for long periods of time.

Vapor pressure is a term that describes how readily
liquids and solids vaporize or evaporate into the air.
Vapor pressure is important because those chemicals
having a high vapor pressure (for example, methyl-
ene chloride in paint strippers and toluene in paints)
will be more likely to be inhaled than those with a
low vapor pressure (for example, hydrocarbons in
solid floor waxes).

Chemical structure is one of the most important
characteristics of natural and synthetic chemicals
which determines toxicity. The body has receptor
molecules that recognize and react to chemicals as
helpful to the body or as harmful intruders. For
example, when a banana is eaten, the carbohydrates
are recognized as helpful, and they are broken down
and used for fuel in the body. On the other hand,
the presence of harmful bacteria in the body ini-
tiates a different set of reactions aimed at destroying
the intruders and ridding the body of them.

The body has the ability to discriminate among very
subtle differences in chemical structure. For
example, two chemicals that have exactly the same
type and number of elements may have very differ-

Table 3-1. Key factors affecting ti

Factors Related to the Toxic Substance:
Chemical Properties

Physical Properties

Toxicity

Factors Related to the Dose:

Concentration
Duration of exposure
Route of entry

hazard posed by toxic substances.

Factors Related to the Environment:

Temperature

Humidity

Light and noise levels

Pressure differences

Presence of other contaminants

Factors Related to the Occupant:

Genetics

Sex

Personal habits
Diet

Age

Health status



UNIT 2: MEASURING AND EVALUATING PROBLEMS

LESSON 8
INVESTIGATION TECHNIQUES

The investigator may be called upon to evaluate a variety of situa-
tions including complaints at residential, public, and commercial
buildings. In other situations, the investigator may want to conduct
a survey or study for research purposes. The specific investigation
techniques may vary with each of these cases, but the underlying
principles will be the same.

The complexity of indoor air quality investigations can range from
those in which the sources, health effects, and solutions can be
identified easily to complicated investigations which ave difficult to
resolve.

Before embarking on any investigation, the investigator should have
a basic understanding of the types of factors that can influence
indoor air quality (Lesson 2); health effects related to indoor air
contaminants (Lessons 3 and 4); measurement methods (Lesson 6);

and standards and guidelines for indoor air quality and ventilation

(Lesson 7). The investigator will have to integrate this knowledge
during the course of the investigation to solve a specific problem or to
research a specific issue.

The focus of this lesson is the investigation of residential indoor air
quality problems. Section 8 of the Reference Manual provides a
detailed discussion of techniques for individual contaminants.
Information on the investigation of nonresidential buildings can be
obtained by contacting the Indoor Air Division of EPA (see
Resources).

LESSON OBJECTIVES

At the end of this lesson you
will be able to:

© discus the methods of gathering
data;

© understand the general process for
investigating indoor air quality
problems;

© identify the systems to be evaluated
in residential indoor air quality
investigations; and

© discuss the principles for achieving
effective communication with clients.



IAQ Learning Module

Unit 1, Lesson 1

The use of biomass fuels (wood, crop residues, and
dung) is an important source of contaminants
worldwide. In developing countries about 30% of
urban households and 90% of rural households use
these fuels (Smith, 1987). It is estimated that
about half of the world’s households use biomass
fuels as their principal source of energy for cooking.
Most of the cooking is done indoors using unvented
stoves. Indoor levels of contaminants (such as
carbon monoxide, formaldehyde, respirable particu-
lates--especially benzo(a)pyrene) have been shown to
be considerably higher than outdoor levels in these
countries (Smith, 1987).

HEALTH CONCERNS

Persons in the United States and Europe
generally spend over 90% of their time indoors
(U.S. EPA, 1989). This means that the quality of
the air they breathe indoors is a dominant consider-
ation in determining their overall exposure to air
contaminants.

Overall, changes in construction techniques,
ventilation rates, and the increased use of synthetic
products have resulted in an increasing number of
complaints about the quality of indoor air, both at
home and in the workplace.

Knowledge about the relationship between exposure
to indoor air contaminants and health has evolved
more slowly than knowledge about outdoor air
contaminants. Contact, including direct droplet
spread, was accepted for many years as the only way
in which contagious diseases were spread. This
theory was challenged beginning around 1935, but
even as late as 1946, a Committee to Evaluate the
Effectiveness of Methods to Control Airborne
Infection reported at the annual meeting of the
American Public Health Association: “Conclusive
evidence is not available at present that the airborne
mode of transmission of infection is predominant for
any particular disease” (Langmuir, 1980).

During the 1950s and 1960s it did become clear
that diseases could be spread by the airborne
transmission of microorganisms. This was demon-
strated in a pivotal study by Riley ef a/. in 1959 in
which it was shown that vented air from a tubercu-
losis ward contained droplet nuclei capable of
infecting guinea pigs.

The ability co detect health effects and routes of
transmission has become more sophisticated. Now,
it is known that organisms causing diseases such as
Legionnaires’ disease can be incubated and distrib-
uted indoors under the right conditions. Also, it is
known that a wide range of contaminants can be
released into living spaces from building materials,
furnishings, combustion appliances, and as a by-
product of using various consumer and commercial
products.

Beginning with the late 1940s, regulatory efforts
focused on controlling outdoor air pollution because
it was assumed to be the main source of exposure to
ait contaminants outside of the workplace. This was
largely a consequence of serious air pollution
problems that occurred in large urban areas
throughout the world. In the United States,
photochemical smog was recorded in Los Angeles in
the 1940s, and the first “smokestack” episode
occurred in Donora, Pennsylvania in 1948. This
episode occurred when dust and fumes from steel
mills and zinc smelters became trapped in a stag-
nant air mass over the community. Over 6000
people became ill and twenty died as a result of
breathing the polluted air.

During the 1950s, 1960s, and early 1970s it was
assumed that being indoors would provide protec-
tion from outdoor air pollution. Plans for emer-
gency action during episodes of high air pollution
were written to encourage susceptible individuals to
remain indoors during days of high outdoor air
pollution. It is now known chat the quality of air
indoors can be worse than outdoor air in some cases.



72

Unit 2, Lesson 6

IAQ Learning Module

An example quality assurance plan for indoor
environments is given in GEOMET Technologies,
Inc. (1985).

Accuracy and Precision

All measurement methods are subject to error.
Accuracy and precision are two measures of data
quality that help evaluate errors in the measurement
process (Section 6 of the Reference Manual discusses
each in greater detail). Accuracy is a measure of
how close data points are to the true result, and
precision describes the variation or scatter among
the results (Figure 6-3). Precision is a measure of
the uncertainty of the average concentration--it is
not related to the true concentration.

Accuracy is affected by sources of error that can be
identified and controlled. These errors are known as
systematic errors because they result in measured
values that are consistently above or below the true
value. Systematic errors can arise from many sources
including errors in calculation, incorrect calibra-
tions, contaminated reagents, interferences, im-
proper operation of equipment, and improper
handling and storage of samples. Systematic errors
cannot be treated by statistical methods.

Precision is affected by sources of error that are
random and cannot be controlled. Sources of
random error include variations in equipment such
as airflow fluctuations, variations in the contami-
nants being tested, and variation in the analytical
methods, including instrument responses. Random
errors can vary in magnitude and direction, and they
are never completely eliminated. Random errors
can be accounted for and minimized by statistical
techniques. For example, random errors can be
minimized by increasing the size of the sample.

Ideally, the sampling or analytical method that is
employed will be both accurate and precise. How-
ever, it is possible for a method to have high
precision, but low accuracy because of improperly

calibrated equipment or inaccurate measurement
techniques. Alternatively, a method can be accu-
rate, but imprecise, because of low instrument
sensitivity or factors beyond the investigator's
control.

Interferences

Interferences are chemicals or factors other than the
contaminant of interest which react during sam-
pling or analysis to give concentrations that are
higher or lower than the true value. Interferences
can result in significant sampling errors and must
be considered before a sampling method is selected.
Most standard methods and equipment specifica-
tions identify major interferences.

‘When standard methods are not used, it is impor-
tant to review the literature to obtain information
on potential interferences. The potential impact of
interferences on the data can be estimated, and then
a decision can be made to try another method,
ignore the interference, or correct for the interfer-
ence. Ignoring interferences and correcting results
are common practices, but they should be ap-
proached cautiously.

Reporting only corrected results obscures informa-
tion that affects the validity of the data. For
example, data that have a 5% correction factor for
interferences will likely be viewed differently than
those that have a 25% or 50% correction factor. If
correction factors are applied, they should always be
reported along with the data.

Limit of Detection and Limit of
Quantification

The limit of detection (LOD) is the smallest
quantity or concentration of a contaminant for
which an analytical method will show a response.
The limit of quantification (LOQ) is the smallest
quantity or concentration that can be quantified in
an environmental sample.



Unit 2, Lesson 6 IAQ Learning Module

PROGRESS CHECK

1. Briefly explain the dassification of measurement methods according to sampling times, portability, and oir mover systems.
What i the mest common method of culecting partides?

3. Exploin two general methods of collecting gases.

4. What ore some drawbacks to using colorimetric detector tubes?

5. Identify different detection methods and/or instruments for sampling portides, gases, and physical stressors.

6. Briefly explain what is meant by sampling protocol, quality assurance program, and standard methods. Why are these
important?

7. Briefly exploin the terms precision, accuracy, interference, LOD and 100, blanks, duplicates, stondard materials, and
calibration.

8. What are some general guidelines for evaluating the quality of dato?



IAQ Learning Module

Introduction

INTRODUCTION

OVERVIEW OF THE MODULE

Tndoor air quality is a topic of increasing concern to
environmental health professionals. Most people spend over 90%
of their time indoors, and for some contaminants, exposure to
indoor air poses a potentially greater health threat than outdoor air
exposures.

The last 15 years have been punctuated by concern over several
specific indoor air contaminants including formaldehyde, radon,
asbestos, and environmental tobacco smoke. Emerging concerns
include exposure to combustion contaminants, microorganisms,
pesticides, volatile organic compounds, and mixtures of contami-
nants. In addition, it is becoming more evident that many indoor
air quality problems are inextricably linked to indoor climatic
conditions including temperature, humidity, and rates of ventila-
tion.

The purpose of this module is to introduce environmental health
professionals to the information needed to recognize, evaluate, and
control indoor air quality problems. A Reference Manual, which
can be used as a reference guide and a vehicle for continuing
education, has been developed as a companion document to this
module. The Reference Manual contains more detailed information
about topics related to the Learning Module. Mastery of the
information in the Reference Manual will provide the practitioner
with a strong foundation for understanding specific contaminants,
sources, measurement and interpretation of data, control methods,
and investigation techniques.

The Learning Module approaches the broad topic of indoor air
quality by developing an understanding of the general principles
needed to recognize, diagnose, mitigate, and prevent indoor air
quality problems. Unit 1 provides an historical perspective on
indoor air quality, presents background information on the factors
which influence indoor air quality, lays the foundation for evaluat-
ing health effects from indoor air contaminants, and discusses
general principles for controlling the indoor air environment.
Unit 2 discusses general principles of measuring indoor air
contaminants, identifies standards and guidelines for ventilation
and air contaminants, and describes techniques which can be used
to investigate indoor air quality problems. Finally, Unit 3
provides the basic background needed to establish an indoor air
quality program.

MODULE OBJECTIVES

After you complete this
module, you will be able to:

© understand and identify the sources
and factors that affect indoor air
quality,

© discuss health effects and symptoms
in terms of dasses of contaminants
cand recognize the limitations of
solving problems based on health
effects alone;

© discuss principles of measuring
indoor ir contaminants;

© identify general and specific methods
of controlling indoor air quality,

© identify the types of standards and
guidelines which are available to
assist in the interpretation of indoor
cir quality data and recognize the
limitations of each;

© understand the basic principles for
conducting an indoor air quality
investigation and interacting with
dients; and

© understand the basic administrative
requirements for establishing an
indoor air quality program.



Resources

IAQ Learning Module

American Industrial Hygiene Association
P.O. Box 8390

345 White Pond Drive

Akron, OH 44320

American Society of Testing Materials
Subcommittee D22.05 Indoor Air Quality
1916 Race Street

Philadelphia, PA 19103

Canada Mortgage and Housing Corporation
National Office

682 Montreal Road

Ottowa, Ontario Canada KIAOP7

National Air Duct Cleaners Association
1518 K Street NW
Washington, D.C. 20005

National Association of Home Builders
15th and M Street, NW
Washington, D.C. 20005

National Center for Appropriate Technology
P.O. Box 3838
Butte, MT 59702

National Environmental Health Association
720 South Colorado Blvd.

South Tower Suite 970

Denver, CO 80222

National Pest Control Association
8100 Oak Street
Dunn Loring, VA 20027

Home Ventilating Insticute
39 West University Drive
Arlington Heights, IL 60004

EPA REGIONAL OFFICES

(Write to the Indoor Air Contact at the appropriate
office below)

EPA Region 1

JEK Federal Buildig

Boston, MA 02203

(CT, MA, ME, NH, RI, VT)

EPA Region 2

26 Federal Plaza

New York, NY 10278
(NJ, NY, PR, VD

EPA Region 3

841 Chestnut Street
Philadelphia, PA 19107
(DE, MD, PA, VA, DC)

EPA Region 4

345 Courtland Street, NE

Atlanta, GA 30365

(AL, FL, GA, KY, MS, NC, SC, TN)

EPA Region 5

230 South Dearborn Street
Chicago, IL 60604

(IL, IN, MN, OH, WI)

EPA Region 6

1445 Ross Avenue
Dallas, TX 75202-2733
(AR, LA, NM, OK, TX)

EPA Region 7

726 Minnesota Avenue
Kansas City, KS 66101
(IA, KS, MO, NE)

EPA Region 8

One Denver Place

999 18th Street, Suite 1300
Denver, CO 80202-2413
(CO, MT, ND, SD, UT, WY)

EPA Region 9

215 Fremont Street

San Francisco, CA 94105

(AZ, CA, HI, NV, AS, GU, TT)

Region 10

1200 Sixth Avenue
Seattle, WA 98101
(AK, ID, OR, WA)



76

Unit 2, Lesson 6

IAQ Learning Module

cartridge with subsequent analysis by gas
chromatography with flame ionization and
mass spectrometry detection or high
performance liquid chromatography;

7) selective pesticides using low volume
polyurethane foam sampling with gas
chromatography/electron capture detector;

8) acid, bases, aerosols, and particulate matter
using an annular denuder coupled with
filter pack assembly or transition flow
reactor;

9) particulate matter using an impactor with
filter pack assembly or a continuous
y
particulate monitor; and

10) air exchange rate using perfluorocarbon
tracer or tracer gas.

Whether or not a specific method will be appropri-
ate for a given application will depend on economic
resources, available expertise, and the application
itself. Not all methods will be appropriate or
possible for routine sampling applications.

Information on the EPA methods can be obtained
from the EPA Atmospheric Research and Exposure
Assessment Laboratory, Research Triangle Park,
NC 27711.

Canadian Indoor Air Test Kit

The Building Performance Division of Technology,
Architectural and Engineering Services within

Public Works Canada has developed an indoor air
quality cest kic (Public Works Canada, 1988) which
is intended to be simple, easy to use, and require
little technical training. This kit includes an
investigation strategy that begins with a prelimi-
nary assessment followed by measurements with
simple instruments and complex instruments, if

needed.

Step-by-step instructions are contained in the test
kit which includes equipment for measuring carbon
dioxide, carbon monoxide, formaldehyde, radon,
volatile organic compounds, relative humidity,
temperature, and air movement.

More information about this kit can be obtained by
contacting the Architectural and Engineering
Services Division, Public Works Canada, Sir Charles
Tupper Building, Riverside Drive, Ottawa, Ontario,
K1A OM2.

NIOSH Analytical Methods

The National Institute for Occupational Safety and
Health (NIOSH) publishes a manual of analytical
methods that includes 350 methods for over 600
substances (NIOSH, 1984). However, these
methods were developed for the industrial environ-
ment, and many of the substances are not relevant
for other indoor air quality problems. Nevertheless,
some of the methods, particularly those for formal-
dehyde and volatile organic compounds are used
successfully by NIOSH in investigating nonindus-
trial workplaces. The manual is available from the
U.S. Government Printing Office.



Unit 3, Lesson 9

IAQ Learning Module

if a new program and additional staff are added;
support functions such as personnel, payroll, and
accounting will have to absorb an additional

workload.

The indoor air program may be able to generate
revenue to offset costs. Charging fees for services
has become increasingly popular in the public sector
as traditional revenue sources have been stretched to
the limic. This is an issue worth exploring, but be
aware that the politics can be more complex than
the economics, and acquiring an understanding of
the prevailing policies toward service fees within the
political subdivision is important.

Personnel

Initial staffing requirements will depend upon both
the nature of the program’s objectives and the
funding commitment. Most state and local indoor
air programs have modest beginnings, with one or
two full or part-time environmental health special-
ists. Job descriptions, candidate qualifications, and
position salary classifications should be determined
in conjunction with personnel specialists; however,
the program manager will be relied upon to help
define the educational and experience background
needed by the indoor air specialist.

An entry-level indoor air specialist usually has an
academic background in environmental health,
industrial hygiene, or other closely related area.
Candidates should also have a working knowledge
of environmental chemistry, toxicology, air sam-
pling techniques and instrumentation, and a
knowledge of ventilation systems. It may be
possible to correct deficiencies in these and other
areas through formal training programs, self-
instruction courses, or on-the-job experience.

Training programs in indoor air quality and various
sub-specialties are available from many sources.
Agencies of the Federal government provide
periodic training programs on a variety of topics at
regional centers. Many universities now offer short-

term educational programs, and faculty members
may individually assist state and local government
personne! with technical issues. Professional
associations such as NEHA, ASHRAE, ACGIH, Air
and Waste Management Association, American
Society for Testing and Materials, Health Physics
Society, and others conduct educational conferences
and meetings, often specifically related to indoor air
quality topics. These opportunities for “network-
ing” with other indoor air professionals can be
extremely valuable.

Program Implementation

Once the resources are secured, a program manager
will be designated to implement the indoor air
program. It is the program manager's responsibility
to make the most effective and efficient use of
available resources. Very simply, the manager must
have a plan, and planning involves specifying
program objectives.

An objective is basically a statement of a result
which one intends to achieve. Ideally, the statement
should say what the result will be and when it will
be accomplished. It should also be clear who is
expected to achieve the objective. Of course, all
objectives which are set should relate to the overall
goal(s) established for the indoor air program. A
broad goal might be to reduce risks to human
health related to indoor air hazards. This serves to
remind everyone why they are there, and that
everything they do should help move the program
toward that goal.

More specific objectives should focus on major
priorities. Initially, the objective might be to
establish a fully operational indoor air program by a
particular date. Objectives must be realistic,
measurable, and attainable. The success of an
objective can be increased by devising action plans,
which are simply stepping stones toward the desired
result. All of these plans need the full involvement
and commitment of those who will have responsi-
bility for implementing them.



IAQ Learning Module

Unit 2, Lesson 7

provide adequate ventilation for indoor air
quality purposes.

© There is no guarantee chat builders follow
current code requirements or that they did
so in the past.

© Most jurisdictions do not have adequate
inspection and enforcement capability to
ensure that code requirements are followed.

¢ If energy efficiency measures have been
employed that generally tighten buildings
or exceed the designed capacity, inadequate
ventilation may result.

¢ Even if newer buildings are designed to
meet the most current ventilation stan-
dards, improperly operated and poorly
maintained systems will defeat the design
loads and reduce ventilation efficiency.

* Another problem in new construction is
that ventilation requirements can be met
using either operable windows or mechani-
cal ventilation. New residential construc-
tion techniques that result in tight build-
ing envelopes without outdoor air intakes
(in addition to combustion air) will be
more likely to have indoor air quality
problems because windows may not be used
to provide outdoor air.

In spite of the inadequacies in both air quality
contaminant and ventilation standards, these two
approaches can be used to control indoor air con-
taminants in both old and new construction. New
approaches, such as using performance standards for
operating HVAC equipment in commercial struc-
tures, may provide additional measures to ensure
adequate indoor air quality in both residential and
commercial buildings.

REFERENCES

American Society of Heating, Refrigerating, and Air-Condi-
tioning Engineers, Inc. (ASHRAE). 1981. Thermal Environmen-
tal Conditions for Human Occupancy. ASHRAE Standard 55-1981.
ASHRAE: Atlanta, GA.

American Society of Heating, Refrigerating, and Air-Condi-
tioning Engineers, Inc. (ASHRAE). 1989. Ventilation for
Acceptable Indoor Air Quality, ASHRAE Standard 62-1989.
ASHRAE: Adanta, GA.

Building Officials & Code Administrators (BOCA) Interna-
tional, Inc. 1989. BOCA Basic/National Building Code. BOCA
International, Inc: Country Club Hills, IL.

Council of American Building Officials (CABO). 1989. CABO
One and Two Family Dwelling Code. CABO: Falls Church, VA.

Environmental Health Directorate. 1987. Exposure Guidelines
{for Residential Indoor Air Quality, Environmental Health
Directorate, Health Protection Branch: Ottawa, Canada

International Conference of Building Officials (ICBA). 1988.
Uniform Building Code, \CBA: Whictier, CA.

Mood, E. (editor) 1986. APHA-CDC Recommended Minimum
Housing Standards, American Public Health Association,
Committee on Housing and Health: Washington, D.C.

Southern Building Code Congress (SBC) Internacional, Inc.
1986. Standard Building Code. SBCC: Birmingham, AL.

U.S. Department of Housing and Urban Development (HUD).
1984. “Manufactured home construction and safety standards;
final rule.” Federal Register. 4955): 31996-32013.

U.S. Department of Housing and Urban Development (HUD).
1990a, “Manufactured home construction and safety standards.”
Code of Federal Regulations, Title 24, Part 3280, Sections
3280.308 and 3280.406.

U.S. Department of Housing and Urban Development (HUD).
1990b. “Minimum property standards.” Code of Federal
Regulations, Title 24, Part 200, Subpart S, Sections 200.925
and 200.926.

U.S. Department of Housing and Urban Development (HUD).
1990c. “Manufactured home construction and safety standards.”
Code of Federal Regulations, Ticle 24, Part 3280, Sections
3280.103 and 3280.710.

US. Environmental Protection Agency (EPA). 1989. “National
Primary and Secondary Air Quality Standards.” Code of Federal
Regulations, Title 40, Part 50, Sections 50.1-50.12.

87


IAQ Learning Module

Unit 1, Lesson 5

off automatically when doors to the high voltage
parts are opened.

The collection surfaces of electronic electrostatic
precipitators must be cleaned regularly
(manufacturer's recommendations may be once per
month to once every few months with soap and
water in residential units) to remove the accumu-
lated dust particles. In some air cleaners the cells
must be removed for cleaning, but in other designs
the cells are cleaned in place.

The generation of ozone may be a problem if there is
continuous arcing and brush discharge or if the
units are not properly ventilated or maintained.
Some individuals may be sensitive to ozone concen-
trations of 0.1 ppm or less (WHO, 1987).

Average removal efficiencies of up to 98% at low air
flow velocities (150 to 350 fpm) can be achieved
with individual units (ASHRAE, 1989). Efficiency
decreases as the collecting plates become loaded or if
the collection velocity is variable or too high.

Whole house units have expected removal efficien-
cies of 50% to over 95% depending on the unit and
the particulate to be removed (ASHRAE, 1989).

Ion generators are portable devices that use static
charges to remove particles from the air. These
devices charge particles so they are attracted to
surfaces such as walls, floors, draperies, occupants,
and furniture. These units may have a collector to
attract the charged particles back into the unit or
may be equipped with other removal devices such as
mechanical filters. If ion generators do not have
collection units, soiling of walls and other surfaces
may occur. Advertising claims may include state-
ments about the harmful effects of positive ions on
health and the beneficial health effects of negative
ions, but these claims are controversial.

Removal of Gases

The technology for removing gases from residential
and commercial buildings is not as established as

particulate control technology, and it is not possible
with current data to evaluate the overall effective-
ness of air cleaning devices in removing gaseous
contaminants.

Adsorption is a technique that is used to remove
gaseous contaminants from indoor air environments.
Gaseous contaminants are attracted to and retained
on the surface of materials such as activated char-
coal, alumina, and silica gel. The gas is the adsor-
bate and the solid material is the adsorbent. The
degree of adsorption depends on the surface area of
the adsorbent, the volume and size of pores in the
adsorbent, the concentration of the contaminant,
and the chemical properties of the contaminant.
The efficiency of adsorption devices is inversely
proportional to the amount of contaminant which
has been captured. As the adsorbent is used over a
period of time, efficiency decreases.

Physical adsorption is a process in which the
contaminant is retained on the surface of the
adsorbent by the forces of attraction between the
contaminant and the adsorbent. Eventually the
adsorbent becomes saturated and unable to remove
any more of the contaminant. Chemisorption is a
process in which molecules of the contaminant
become chemically bonded to the surface of the
adsorbent. It is a more selective process than
physical adsorption, and it is often irreversible.

Adsorbents need a large surface acea per unit mass
in order to efficently remove contaminants. For air
cleaning applications, air can be passed through a
bed of adsorbent that is up to a few centimeters
thick.

Activated charcoal is the most commonly used
adsorption medium. When activated charcoal
becomes saturated, it must be replaced or regener-
ated. Because it is nonpolar, it can remove some
organic compounds, particularly high molecular
weight compounds, such as those contained in
cooking odors or in solvents which are used in
paints, polishes, waxes.



IAQ Learning Module

Unit 1, Lesson 5

is ducted to the outside. An aluminum mesh screen
filter, which can easily be removed and cleaned,
traps grease; and a fan or blower exhausts smoke and
moisture to the outside. Ductless hoods filter the
air through aluminum and activated carbon filters
and return the air back into the kitchen through
louvers in the front of the hood. These hoods have
been used more often in recent years as an economi-
cal alternative to ducting to the outside. The filters
must be cleaned regularly. Ductless hoods are far
less effective than ducted hoods in removing
contaminants and are not recommended.

Fans which exhaust the entire kitchen can also be
used, but they are not as effective as ducted range
hoods. If kitchen exhaust fans are used they must
be ducted to the outside and should be located as
close to the range as possible.

Whole house ventilation can be very effective in
cooling an entire house without air-conditioning.
Whole house exhaust fans (sometimes called attic
fans) can be installed in a variety of locations
including in the attic, on the roof, in a wall, or ina
window. Regardless of location, it is important for
air to circulate freely to the fan. Openings may be
sealed during the winter to reduce heat loss. If the
exhaust fan is not balanced by infiltration, air intake
vents, or windows, a backdraft from chimneys or
flues can result, or soil gases such as radon may be
drawn in through the basement foundation. If
radon is a problem, a whole house fan may not be
advisable.

Supply ventilation uses supply fans to draw air
indoors, causing a slight positive indoor air pressure
which tends to force air outside through available
cracks or openings. Supply fans can be used to
ventilate entire homes or only one level of a home.
Advantages of using supply fans include reductions
in contaminant levels, reductions in cold drafts from
cracks, and the abilicy co control the source of
supply air.

Central forced-air systems are heating, ventilating
and conditioning systems that rely on fans to

circulate room air through ducts, pass the air
through a filtering system to clean it, and redistrib-
ute the air throughout the home after the air has
been heated, cooled, or otherwise conditioned.
Residential central forced-air heating and cooling
systems can be modified to reduce contaminant
levels by installing air cleaning devices and/or an
outdoor air connection (Figure 5-1).

The outdoor air connection is a three-to six-inch
duct that brings outside air into the return side of
the furnace (where the room air enters the furnace).
The amount of outdoor air that is introduced is
controlled by a damper. Care should be taken to
ensure that the outdoor intake vent is located away
from outdoor sources of contamination.

Some jurisdictions now require an outdoor air
connection in new houses. The cost of an outdoor
air connection in most new construction is minimal
(about $100), but there is an energy penalty regard-
less of whether the house is new or older.

The outdoor air connection is different from the
combustion air supply for the furnace. Many
exiscing furnaces can be retrofitted with an outdoor
air supply, but care should be taken to make sure
that the furnace can accommodate this kind of
connection. If an outdoor air supply can be in-
stalled, it can provide a reasonably cost effective
method for providing sufficient dilution ventilation.
During cold weather, condensation can occur.

Evaporative coolers (also known as swamp coolers)
can result in effective air exchange (10 to 20 ach),
and they can simultaneously cool and humidify the
air. They are most effective in dry climates. As
outside air is forced through a water saturated filter
to the inside of a structure, the air is cooled as water
absorbs heat from the air and evaporates. One
disadvantage of evaporative coolers is that the filters
can foster microbial growth, and they should be
cleaned and serviced regularly.

Ventilation with heat recovery can be an effective
method for providing outdoor air ventilation while



Unit 1, Lesson 2

IAQ Learning Module

Figure 2-2. The stack effect.

4

\ f

Higher Pressure

Neutral
Pressure

ZA AN

YY

exhaust contaminants from localized areas (kitchen
and bath) or to ventilate whole houses or structures.

SOURCE: Adapted from ASHRAE (1989); Mann (1989)

The type and location of mechanical ventilation will
affect contaminant concentrations. Local exhaust
fans that are located in close proximity to a source
(for example, range hood fans and bathroom fans)
and exhausted outside can effectively remove
contaminants. Exhaust fans must be properly sized
to be effective, and they must be balanced by an air
supply to prevent chimney backdrafting and to
prevent unwanted infiltration.

In homes, mechanical (forced-air) systems are
generally used to circulate conditioned air through-
out the structure. In larger buildings, central
ventilation systems are used not only to circulate air,
but also to dilute contaminants by introducing
outdoor air into the occupied spaces. As efforts have
increased to make homes and offices more energy
efficient, builders are reducing infiltration, and
increasingly relying on mechanical ventilation
systems to provide sufficient outdoor ait to the

interior of buildings. In order to operate efficiently
and effectively, these systems must be properly
designed, installed, operated, and maintained. In
some instances, the mechanical system can become a
source of contaminants such as microorganisms
(from contaminated ducts and equipment), and
VOCs (from adhesives and ducting material).

Contaminant Removal (RM 2.1)

Some contaminants can be removed by air cleaning
devices, and some removal may also occur through
chemical reactions and mechanical interactions
between contaminants and surfaces inside the
structure.

Filters and other air cleaning devices can remove
gaseous and particulate contaminants; these meth-
ods and their effectiveness are discussed in greater
detail in Lesson 5. Removal of particulates in
residential and commercial environments by air
cleaning devices is more feasible and has been more
widely practiced than removal of gases. Proper
installation, operation, and maintenance are critical
to maximize the success of these devices.

Not all contaminants are removed in the same way.
For example, carbon monoxide and carbon dioxide
are unreactive with indoor surfaces and are removed
ptimarily by air exchange. Some removal of nitro-
gen dioxide, sulfur dioxide, and formaldehyde, on
the other hand, occurs through chemical reactions
with surfaces. And, particles often settle out, attach
to surfaces, or are removed by air cleaning devices.

The rates of chemical reactions with surfaces (for
example, furnishings, wall and floor coverings) have
not been thoroughly characterized for all contami-
nants, but the type of surface and the surface-to-
volume ratio are important in determining removal
rates. Removal rates have been calculated for some
contaminants (see Section 2 of the Reference Manual),
but they are subject to the same limitations as
calculations of source emission rates. Rough
textured walls and furnishings (carpet, upholstered



IAQ Learning Module Unit 1, Lesson 4

Table 4-2. Health effects of selected contaminants’ (continued).

CONTAMINANT CONTAMINANT CLASSIFICATION?

I A AIN ST P/A C Comments
biological contaminants x x infectious diseases; allergic reactions;
(bacteria, viruses, molds, toxic effects

fungi, pollen, animal and
‘uman dander, insects and

arachnid excreta)

environmental x x irritation of mucous membranes,

tobacco smoke cardiovascular stress, chronic and acute
pulmonary effects in children

polycyclic aromatic x x some are irritants and can result in

hydrocarbons cardiovascular effects

asbestos x x asbestosis at occupational exposures,
mesothelioma

radon x

SOURCE: Adapted from U.S. EPA (1989).

"These are effects which have been associated or are thought to be associated with the individual contaminants based on toxicology or
epidemiology studies. The concentration required for manifestation of the effect depends on a variety of factors. For some contami-
nants, there is scientific disagreement about various effect levels, and for other contaminants, there is insufficient data to determine
effect levels.

*Classification Codes
I-ieritant A -asphyxiant A/N - anesthetic/narcotic ST - systemic toxicant P/A - pathogen/allergen C - carcinogen



Unit 1, Lesson 5

1AQ Learning Module

ENGINEERING STRATEGIES (RM 5.1, 5.2)

‘Three basic engineering strategies can be
used to control indoor air quality. First, source
control methods reduce or eliminate contaminant
emissions from the source into the indoor environ-
ment. Once contaminants are in the air, ventilation
can reduce concentrations by diluting indoor air
with outdoor air or by exhausting contaminants out
of the building. Finally, contaminants can be
removed from the indoor air by air cleaning devices.

Each of these strategies is discussed below. Table
5-1 summarizes the application of these methods to
some specfic contaminants.

Source Control

Sources can be controlled by removal, substitution,
changes in their design or operation, encapsulation,
spatial confinement, or temporal use.

Removal of a source of indoor contamination is
appropriate in situations where the source is known
(for example, microbial contamination, cigarette
smoking, asbestos) and is not required. In many
cases less polluting alternatives can be substituted
for sources. It should be noted that the removal of
some contaminants such as asbestos and lead in
lead-based painted surfaces can result in airborne
emissions if removal is not conducted properly. In
fact, in many situations in-place management of
asbestos is more appropriate than removal.

Emissions from some sources can be reduced by
changing the design of a source. This is usually
done by a manufacturer. Pilotless combustion
appliances are a good example. However, the way
in which individuals operate or use sources also
affects emissions. For example, the flame adjust-
ment on combustion sources or the application
method for pesticides or cleaners can greatly
influence emissions.

‘A source can also be encapsulated, as with the use
of sealants on building materials, so that the release
of a contaminant into the indoor air is restricted.
The use of some encapsulants, however, can release
contaminants such as VOCs into the indoor air for
varying periods of time.

Building occupants can control the release of
contaminants through the placement and use of
sources. One technique, spatial confinement, is to
place a source in a confined area that has limited air
exchange with the remainder of the living space.
An example of spatial confinement is to place a hot
water heater in a garage.

The temporal use of sources can also reduce
exposure, even though emissions are not changed.
Using solvents or pesticides when no one else is
present, for example, will minimize exposure.

Source control can significantly improve indoor air
quality, and in some cases, it is the only solution.
Most source control methods require little or no
upkeep and result in minimal energy penalties.
Disadvantages in some cases, however, include high
initial costs for using more expensive materials,
appliances, construction practices, or manufacturing
processes.

Ventilation

Ventilation is needed in structures for three basic
reasons: 1) to replace air used by combustion
sources; 2) to remove excess humidity; and 3) to
remove contaminants released by indoor sources.

Because ventilation systems are so closely tied to
heating and cooling systems, all of these systems
must be considered when evaluating indoor air
quality. The ventilation system is especially critical
in energy efficient construction. Section 5 of the
Reference Manual provides a review of different
heating and air supply systems that might be
encountered in residential investigations.



IAQ Learning Module

Unit 2, Lesson 6

5) results should be evaluated to determine if
they are consistent with other measure-
ments.

In general, it is best to flag data which are outside
the designated data validation criteria. Data which
do not meet the designated acceptable criteria, with
few exceptions, should not be included in statistical
summaries. There is a real temptation to rationalize
the inclusion of data that are outside the designated
data validation bounds because of the effort that
goes into data collection, but this should be resisted.
Report only those data in which there is confidence.

There are instances when data will be useful in a
qualitative evaluation even though they may not
pass all of the validation criteria. If data that have
not met the inclusion criteria are included in a
report, be sure to flag them for the reader, clearly
pointing out che problems and deficiencies.

Always keep in mind how data will be used. Willa
decision about a health risk be made? Will a policy
decision be made? If the data are to be used for
critical decisions, it is far better to repeat measure-
ments and incur the extra expense, rather than
including lesser quality data that may have far-
reaching consequences. The investigator must
exercise careful judgment in deciding the validity of
data.

Data that are within pre-designated acceptable
criteria but are either much higher or lower than
other measurements should be included in the data
summary. Statistical tests can be applied to deter-
mine if a value is an “outlier,” but even when
outliers are verified statistically, they should be
included in the report of the data. Under no
circumstances should data arbitrarily be excluded
from a report simply because they do not fit the
mold. If, after careful evaluation of the entire
sampling process, no reason can be found to exclude
the data, they should be reported as valid. How-
ever, outliers may be treated differently in the
analysis and interpretation of data.

STANDARD METHODS (RM 6)

Standard methods or procedures do not
currently exist for the measurement of all indoor air
pollutants, but EPA has developed 21 methods for 9
categories of contaminants plus two methods for
determining air exchange rates (U.S. EPA, 1989).

In addition, there are some ambient air quality and
industrial hygiene procedures which are suitable for
indoor air quality investigations.

EPA’s Compendium of Methods for
Indoor Air

In response to the need for specific guidance on the
determination of indoor air contaminants, EPA has
developed methods for the determination of selected
contaminants in indoor air. However, EPA cautions
that these methods at this time are not certified and
are not officially recommended or endorsed by EPA.
The following methods have been developed:

1) volatile organic compounds using summa®
stainless steel canister sampling or solid
adsorbents;

2) nicotine using XAD-4 solid adsorbent,
active filter cassettes, or passive filter
cassettes;

3) carbon monoxide and carbon dioxide using
nondispersive infrared spectroscopy or gas
filter correlation;

4) nitrogen dioxide using continuous luminox
LMA-3, Palmes diffusion tube, passive
sampler badge, or a transducer technology
electrochemical technique;

5) formaldehyde using solid adsorbent Sep-
PAK 2,4-DNPH cartridge, passive sampler
badge, or a continuous CEA monitor;

6) benzo(a)pyrene and other polynuclear
aromatic hydrocarbons in air using a
combination quartz filter/adsorbent

75


IAQ Learning Module

Unit 1, Lesson 2

Table 2-1. Factors affecting indoor air quality and examples of the parameters which

influence them.
EXAMPLE PARAMETERS
Outside Inside Related
Factors Structure Structure To Occupants
SOURCES outdoor air building materials occupant density
geology appliances smoking
water supply furnishings use of combustion
appliances and consumer
products
AIR meteorology heating, operation, maintenance,
EXCHANGE ventilating, and use patterns for natural
topography air-conditioning and mechanical vent-
(HVAC) systems ilation
surrounding obstacles
temperature
structure orientation
windows/doors
season
insulation and
time of day weather-proofing
CONTAMINANT building envelope surface area and operation and mainte-
REMOVAL materials nance of air cleaning
devices
local exhausts
air filters/cleaners
VOLUME building design
MIXING EFFICIENCY local exhaust opened/closed doors
fans furniture placement
location of vents
building design



Unit 1, Lesson 5

IAQ Learning Module

Examples of air/vapor retarders include polyethylene
sheeting, aluminum foil-faced foam insulation
boards, gypsum board primed with vapor-retarder
paint as a sealant, and paper-faced insulation batts.
Tyvek housewrap (spunbonded polyolefin) is an air
retarder (not a vapor retarder) that can reduce
infileration by 30-40% (Mann, 1989). Vapor
retarders must be installed on the warm side of
insulation to prevent condensation from occurring
on the insulation. Air retarders can be installed on
the warm or cold side of the framing wall, depend-
ing on the material.

Houses with low infiltration should have mechani-
cal ventilation systems or air intake openings to
ensure good indoor air quality and proper humidity
levels; combustion appliances should be equipped
with a separate outdoor combustion air supply to
prevent backdrafting of flue gases.

Natural Ventilation

Natural ventilation can be provided through
windows, skylights, roof ventilators, doors, louvers,
jalousies, specially designed inlet or outlet openings,
stacks connected to registers, or other openings. Air
intakes should be located so that fresh air is drawn
into the building, but contaminated air from nearby
sources is not. Exhausts should be located so that
they do not exhaust into air intakes of the same or
other buildings.

Opening windows, doors, and skylights can produce
effective ventilation, but this method is limited by
weather conditions. Special openings such as wall
vents can also be installed to provide fresh air
ventilation. All windows should be accessible and
operable.

For maximum effectiveness, windows should be
located in opposing pressure zones. Two openings
on opposite sides of a space increase the ventilation
flow. Ventilation to a greater area can be provided
by locating openings on adjacent sides. Ifa room
has only one external wall, widely spaced windows
can maximize airflow.

Windows at the same level and near the ceiling will
be less effective. To take advantage of the stack
effect, the vertical distance between openings should
be maximized. Thermally induced ventilation is
least effective for openings close to the NPL. The
greatest air flow per unit area of total opening will
result from inlet and outlet openings that are nearly
equal in size.

Roof ventilators are weather-proof air outlets that
use the wind to help draw air out of the interior
space. It is important to position the roof ventilator
so it receives the full, unrestricted wind. Roof
ventilators, which can be powered or unpowered,
come in a variety of configurations that can be
installed on the roof or in gables. These devices
prevent moisture from trapping in the attic and
reduce cooling costs in the summer. Stack or
vertical flues should also be located so that wind can
act on them from any direction.

Mechanical Ventilation

Mechanical ventilation results in air exchange by
using fans to force the air to move between the
inside and outside of a building. Mechanical
ventilation can remove contaminants from entire
buildings or from localized areas within a building.
In each case, fans, which can range in size from
small fans to large whole house fans, are used to
force air out of or into a house, to recirculate air, to
cool or heat air, or to clean air by passing it through
a filter.

Exhaust ventilation uses exhaust fans to draw air
out of a building, creating a slight negative indoor
pressure which draws fresh air in through available
cracks and openings. Exhaust fans that are properly
rated and ducted to the outside can effectively
remove contaminants and moisture from entire
houses or from localized areas such as kitchens,
bathrooms, and clothes dryers.

The best method of removing contaminants from
the kitchen (combustion gases, smoke, grease,
moisture, and odors) is a range hood exhaust which



IAQ Learning Module

Foreword

The Indoor Air Quality Learning Module and its companion docu-
ment, the Indoor Air Quality Reference Manual were produced under
a cooperative arrangement between the National Environmental
Health Association, the U.S. Public Health Service, and the U.S.
Environmental Protection Agency. The documents are designed
to provide an introduction to indoor air quality for environmental
health professionals. The documents cover those aspects of indoor
air quality important for establishing and implementing an indoor
air quality program by a state or local governmental agency.

Because there is substantial guidance already available from EPA
on radon and asbestos, the Learning Module and the Reference
Manual contain little information on these subjects. In addition,
while most of the information presented is useful for all types of
indoor environments, the primary focus for both documents is on
residential indoor air quality.



IAQ Learning Module

Unit 2, Lesson 6

Passive Samplers

Passive samplers (Figure 6-2) do not have pumps to
move the air through the sampling device; rather,
contaminants diffuse or permeate through the
collecting medium, Contaminant concentrations
can be read directly or further analysis may be
required. These samplers have the advantages of
being lightweight, compact, and inexpensive for
single samples. They are easy to use and require
liccle or no training. They are good for initial
screenings, and are commonly worn by an indi-
vidual to estimate personal exposures. Disadvan-
tages include decreased sensitivity and limited
accuracy (usually + 25% or more). Passive samplers
provide integrated data rather than real time data.
If the sampler is not direct reading, the additional
time required for analysis may be a drawback to its
use. Section 6 of the Reference Manual provides a
summary of some passive sampling methods.

Collection Methods
Particles and Aerosols

Particles and aerosols can be sampled using filtra-
tion, inertial, gravity, electrostatic, or thermal
collectors. Section 6 of the Reference Manual
summarizes some commonly used collection
methods for asbestos, other fibers, inhalable particu-
lates, and metals. Filtration and inertial collectors
have been the most widely used methods because of
ease of use, low cost, and broad applications.

Filtration is a cechnique in which filters are used to
collect particles which are subsequently analyzed for
metals, organic compounds, fibers, microorganisms,
and radon progeny. The choice of filter type ina
given situation depends on the general characteris-
tics of the filter, background filter impurities, flow
resistance over time, collection efficiency, ease of
analysis, cost, and availability. A wide variety of
filters is available including cellulose, glass fiber,
membrane, and nucleopore. Interest in collecting
respirable particles (those that are 10 microns or less
in diameter) has resulted in the increased use of

inertial collectors. These collectors can separate
particles in the gas stream according to particle size
using impaction, impingement, or centrifugal force.

Gases and Vapors

Gases and vapors can be collected using both active
and passive systems with ewo basic collection
techniques: 1) collection into a suitable container
such as a bag, bottle, or canister; and 2) removal
from the air and concentration by adsorbing or
absorbing the gas onto a solid or into a liquid
solution.

Plastic sampling bags can be used for collecting
integrated samples for periods ranging from instan-
taneous samples to 8-hour samples. Samples can
remain stable for hours to several days. Some
common bag materials include Mylar®, Teflon®, and
polyethylene.

Absorption is a process in which gases are trans-
ferred into a liquid or solid medium in which they
dissolve. The concentration of the gas that is
dissolved in the liquid or solid increases uncil an
equilibrium is established with the concentration of
the gas in the air. Continued sampling past this
poine will not increase the concentration of the gas
in the solution.

Adsorption is a method of collecting gases in which
the gas is attracted to, concentrated in and retained
ona substrate. After the gas has been collected, it
can be removed from the adsorbent for analysis by
treatment with chemicals, heat, or inert gases. Solid
sorbents have been used to determine volatile
organic compounds in indoor air; activated charcoal
has been a commonly used sorbent in passive and
active samplers. Other adsorbing agents include
activated alumina, silica gel, and porous polymers
(Tenax-GC, Chromosorb, Porapak Series, Amerlite
XAD-2).

Solid sorbents can provide an integrated sample of
varying time (typically 8-12 hours), and because of

67


IAQ Learning Module

Unit 1, Lesson 3

chemicals cannot be studied for ethical reasons; and
studies are generally limited to short exposure
times.

Epidemiologic Studies

Epidemiology is the study of the distributions and
determinants of health- and disease-related condi-
tions in human populations. In an epidemiologic
study, the investigator observes the occurrence of
disease in people who are segregated into groups on
the basis of a common experience or exposure.
Epidemiologic studies can be used to associate
health effects with the personal characteristics of
those who are affected, the places where they live,
work, or travel, and the time when effects occur.
Analytic techniques can be used to determine the
tisk factors associated with a health effect.

Epidemiologic studies of indoor air quality may

involve asking participants a variety of questions
about products used, health status, and personal

habits, and may attempt to evaluate exposures

through the use of personal or fixed-site monitoring.

Limitations of epidemiologic studies include the
expense of conducting studies which require large
study populations in order to observe effects;
difficulty in determining exposure rates; and the
difficulty of identifying and quantifying factors (for
example, occupation and smoking) which may also
account for observed effects.

While laboratory studies can establish the causal
association of a factor with a health effect more
conclusively than epidemiologic studies, epidemi-
ologic studies have provided and continue to
provide a major contribution to our understanding
of many diseases.

One source of controversy that has emerged from
exposure studies is the interpretation of statistically
significant results. A study of a large population
can yield statistically significant results which
cannot easily be interpreted biologically, and effects
that are biologically important may not be statisti-

cally significant if the sample size is too small. As
Samet (1985) comments, epidemiologic studies (and
animal studies) describe the risks of groups, but not
of specific persons, and other types of data may be
needed to characterize susceptible persons and their
responses to contaminants.

Risk Assessment Studies

Epidemiologic, animal, and human exposure studies
provide the basis of risk assessments which may be
used to determine policy. Risk assessments are
estimates of the health impacts on the general
population or specific subpopulations as a result of
exposure to contaminants. Risk assessments can be
conducted for both carcinogenic and noncarcino-
genic effects, but most of the emphasis has been on
carcinogenic effects.

EPA has published guidelines for exposure assess-
ments and for evaluating risks from carcinogens,
mutagens, teratogens, and chemical mixtures (U.S.
EPA, 1986a-e). A four-step process begins with
hazard identification, which is a review of the scien-
tific literature to determine whether or not a
contaminant may pose a human hazard. The second
step, dose-response assessment, is the process of charac-
terizing the relationship between health effects and
specific doses of the contaminant. Exposure assess-
ment, the third step, is the process of measuring or
modeling the intensity, frequency, and duration of
human exposure to the contaminant. The last step,
risk characterization, is the process of combining the
previous three steps to quantitatively estimate the
risk and identify the uncertainties involved in the
assessment. Section 3 of the Reference Manual
discusses the process of risk assessment in greater
detail.

FACTORS AFFECTING POTENTIAL HEALTH
RISKS FROM CONTAMINANTS (RM 3.1, 3.2)

The potential health effects that will
result from exposure to indoor air contaminants
depend on a variety of factors interacting with one
another. These include factors related to the toxic



IAQ Learning Module

Unit 2, Lesson 6

Table 6-1. Factors fo conside:

Measurement Objectives:

Operating Specifications:

in the selection of measurement methods and equipment.
screening or in-depth

size; weight; power source requirements; range; flow

rates; heat output; temperature requirements;
exhaust requirements; noise

Performance Specifications:

accuracy; precision; range; minimum detectable

limits; zero and span drift; interferences; linearity;
recording capability; lag, rise and fall times

Labor Requirements: operation; calibration; maintenance; analysis;
personnel (number and expertise)
Costs: purchase of equipment and supplies; operation;

calibration; maintenance; training

References that provide useful descriptions of equipment include Lioy (1983); Nagda and Rector (1983); Nagda, Rector and Koontz (1987); and

‘Wallace and Ore (1982).

expensive, time intensive, and requires extensive
training to use.

Integrated samplers provide an average concentra-
tion over a period of time ranging from minutes to
weeks to months. Some samplers can provide data
sequentially in an automatic mode without needing
a technician to change parameters. One disadvan-
tage of integrated methods is that concentration
highs and lows are lost. Equipment for integrated
methods is low to moderate in cost and some
training is required for use, but the required
training is not as extensive as for continuous
methods.

Grab samplers provide a concentration measure-
ment at a single point in time. The equipment is
inexpensive to moderately expensive, depending on
the number of samples to be taken. Minimal
training is required, but the data are not very
reliable.

Portability

After the required time frame for sampling has been
identified, sampling equipment can be selected
based on the need for mobility or spatial variation.
Based on this criterion, equipment can be classified
as stationary, portable, or personal.

Stationary samplers operate from a fixed location.
The equipment is generally bulky, heavy and
requires a power source. Continuous samplers are
usually stationary.

Portable samplers are small enough to be conve-
niently carried from place to place. Most equip-
ment uses batteries for power, but some also has the
option of using direct current. Integrated and grab
samplers are typically portable, but some continuous
equipment can also be portable. (Note: Batteries
should be removed from battery-operated samplers
when not in use to ensure proper charge, especially
when a battery level indicator is not present.)



58

Unit 1, Lesson 5

IAQ Learning Module

© — incorporation of additional control mea-
sures into the design, if necessary, to
maintain a healthful indoor air environ-
ment.

Responsiblity for good air quality does not end with
the design and construction of buildings. Building
managers and individuals can promote good air
quality in both new and older construction by:

© operating equipment properly;

© implementing maintenance activities such
as regular cleaning of heating, ventilating,
and cooling components which minimize
indoor air quality problems;

© developing indoor air quality protocols for
the use of cleaning products, paints and
related supplies; pest management; roof
repairs or replacement; and odor control;

¢ following energy management techniques
consistent with good indoor air quality
management practices.

Since the energy crisis of the 1970s, the concept of
energy management in buildings has become an
important objective of designers and managers of
residential and commercial buildings. There has
been a push to tighten building envelopes and
reduce outdoor ventilation air in order to save
energy costs. However, building managers and
homeowners should understand that energy conser-
vation strategies must incorporate the need for outdoor
ventilation air. The proper operation of HVAC
systems can be a very effective strategy to control
indoor air contaminants at the same time that
energy is conserved.

ADMINISTRATIVE CONTROLS

Administrative controls include actions
which inform the public about indoor air quality
issues or actions which encourage or require that
certain steps be taken to protect building occupants.

The administrative control of indoor air pollution
problems includes both regulatory and
nonregulatory options.

Nonregulatory Approaches

Government, consumer protection professionals,
health professionals, and industry all play important
roles in furthering nonregulatory approaches to
indoor air quality problems. Research, training and
technical assistance, public information, and
voluntary standards and guidelines may be used to
identify indoor air quality problems and solutions.

Research is used to determine the nature of the
problem, its magnitude, and methods of control.
The Federal government is a leader in conducting
and sponsoring research, and both the public and
private sectors benefit from Federal government
research activities through technology transfer
programs. Academic institutions, industry, state
and local governments, and professional associations
also contribute to the scientific data base.

Training and technical assistance programs
develop expertise which can be used to implement
policy objectives, solve problems, or establish indoor
air quality programs.

Information dissemination to inform the public
about indoor air quality problems and solutions is
particularly important because a well-informed
individual can significantly reduce exposures
through the wise selection and use of products and
services.

Standards and Guidelines

Standards and guidelines are frequently issued by
private sector organizations and governments.
While the majority of private sector standards are
voluntary (nonregulatory), they can become the
basis for acceptable professional practice, and are
often incorporated into government regulations by
reference. Governments can issue standards and
guidelines as either regulatory or voluntary policies.



Unit 1, Lesson 2 IAQ Learning Module

PROGRESS CHECK

1. What are the factors that affect the concentration of contaminants indoors?

2. Nome five sources ond one contaminant for each source that can be found indoors.
3. What isthe air exchonge rote ond what voriables affect if?

4, What is meant by infitration ond excfiltration?

5, What are some sources of ir leakage into structures?

6. How does the stock effect affect air exchange?

7. How does the volume of the structure or mixing efficiency affect concentrations?



Table 4-1. Typical symptoms of contaminant classes and physical stressors.

CONTAMINANT CLASSIFICATION PHYSICAL STRESSORS
Irritant
(includes Airborne
pulmonary Anesthetic! Systemic __Pathogen/ Temper- Light/
SYMPTOMS toxicants) Asphyxiant Narcotic Toxicant — Allergen Carcinogen* —_ ature Humidty Noise

v

v
v

Eye Irritation, burning

Dry of sore throat

Skin irtitation, dryness ot scaling
Skin rash

Tightness in the chest

Runny nose

Asthma (exacerbation of)

Cough

Wheezing or other breathing problems
Chest pain

Changes in rate and depth of breathing
Changes in pulse rate

Visual disturbances

Dizziness

Fatigue

Depression

Clumsiness

Drowsiness

Headache

Fever

Repeated chroat infections

Sinus irritation ot infection
Muscular pains

Change in heart rhythm
Tingling or numbness in extremities
Muscle twitching/convulsions
Nausea or vomiting

Abdominal pain

Diarrhea

Loss of appetite

Cold/flu symptoms

Cold extremities

Difficulty in sleeping

Irritability

Backache/neckache

<
iS

NN
iS

NISISISISIS ISISI
RINISILISIS

SISISIIS

o (noise)

SINE IRIS

NINN

INISISISINISINIS,

SIS, ISISISISIS
SSL ISIS

SIS

SISISIGISIS

Y (noise)

USS

INIS

SISIN

SIS

Eye strain
‘Ie is not possible to determine whether or not exposure fo a carcinogen will result in a cancerous tumor based on symptoms because of the lag time between exposure and
tumor development, However, carcinogens may also be classified as irritants, systemic toxicants, or anesthetic/narcotic, and may result in symptoms typical of these
contaminant classes.

71 OVI

juULUAD.

anpow 8

p uossry ‘| 14U()


Unit 1, Lesson 5

IAQ Learning Module

Figure 5-1. Example of a resid

ial heating system with an outdoor air connection.

Weatherstrip
Door

Circulation

Air

SOURCE: Adapted from Energy Design Update. Cutter Information Corp: 37 Broadway, Arlington, MA 02174. Used with permission.

maximizing energy efficiency. Heat recovery
ventilators (air-to-air, ground-to-air, or water-to-air
heat exchangers) provide controlled ventilation at
high air exchange rates while conserving the energy
needed for heating and cooling. A heat recovery
ventilator usually consists of two small fans and a
heat transfer unit which are mounted in a box that
is connected to the interior and exterior of the house
by metal ducts. There are many different types of
heat transfer units which consist of a matrix of
alternate layers of metal, plastic, or treated paper
plates. (Paper plates may pose problems because
they tend to collect moisture and dirt and can
become perforated).

During the heating season the supply fan draws cold
outside air through specific passages in the matrix
before it is distributed throughout the house. At
the same time, the exhaust fan draws warm room air

from the house through alternate passages in the
matrix. The heat from the exhaust air is absorbed
by the matrix and transferred to the supply air. The
two airstreams never meet.

As the warm air comes into contact with the cool
plates of the matrix, condensation can form. The
condensed moisture is a problem for two reasons. It
can freeze and block the movement of air, and it can
become a reservoir for bacteria and fungi which can
be carried into the room air. Improved units have
an automatic defroster and drain to prevent mois-
ture accumulation.

Heat recovery ventilators can effectively ventilate
tightly sealed areas and they are energy efficient.
The units typically are mounted in the basement,
crawl space, utility room, or attic; they can also be
mounted in walls or ceilings. Another advantage is



IAQ Learning Module

Unit 1, Lesson 3

equal to the sum of the effects from individual
contaminants.

Although the extent of chemical interactions in
mixtures is not known, they may play an important
role in causing the acute symptoms of various
building associated health effects.

Building Associated Health Effects

Exposure to air inside buildings can result in
specific diseases and a variety of health complaints
that are primarily acute effects. These conditions
are generally closely related in time to the
individual’s presence in the building. There is also
concern that exposure to contaminants in building
environments could result in possible chronic effects
such as cancer and noncancerous respiratory diseases.
Generally, distinctions are made between those
building associated health effects which are clini-
cally defined and for which a cause can be identified
(building related illness) and those for which the
cause is unclear (sick building syndrome).

Building related illness (BRI) refers to an illness
brought on by exposure to building air when
symptoms of illness, and clinical signs of pathology
are identified, and an airborne agent and pathway
for the agent are recognized. The causative agent
can be chemical; frequently, however, the agent is a
pathogen or a biological allergen. Typical sources of
biological agents include contaminated humidifiers,
cooling towers, cooling coils, drain pans or filters,
and water-damaged building materials or furnish-
ings.

Symptoms may be specific or mimic more general
symptoms typical of che flu, including fever, chills,
and cough; and serious lung and respiratory diseases
may occur. Legionnaires’ disease, hypersensitivity
pneumonitis, and humidifier fever are examples of
building related illness.

Sick building syndrome (SBS) refers to a series of
acute, nonspecific complaints which occur in high
prevalence among building occupants. SBS may

also be referred to as tight or closed building
syndrome. Typically, these symptoms are associated
with being in che building and are relieved when
the individual leaves; but for some individuals,
symptoms may not subside on leaving the offending
environment. Symptoms typically include irritation
of the eyes, nose and throat; sensation of dryness in
the mucosa and skin; erythema (reddening of the
skin), mental fatigue; headache; runny nose; asthma-
like symptoms; and odor complaints. Sensory
irritation normally dominates the symptoms.

SBS probably does not cause death or life-shortening
disease, but it does contribute to increased absentee-
ism, reduced work efficiency, discomfort, and
irritation (WHO, 1986).

Unlike building related illness, a specific etiology
for SBS is not known, and it is characterized by
minimal physical signs and an absence of clinical
abnormalities (laboratory studies, including spirom-
etry and x-rays, are normal). Investigators are
seldom able to identify any single exposure factor
which exceeds a generally acceptable health thresh-
old; as a consequence, specific causative agents are
seldom identified. The causality, therefore, is often
assumed to be multifactorial involving the com-
bined effects of environmental and other stressors
(Molhave, 1985; Berglund and Lindvall, 1986). A
general model reflecting this hypothesis is presented
in Figure 3-1.

In chis model, building and climatic factors can
operate additively, synergistically, or antagonisti-
cally to affect the exposed individual. Buildings at
highest risk appear to be new or recently remodeled
buildings with tight envelopes, especially those
with large ventilation systems that depend on
limited fresh air sources (WHO, 1986). Improper
ventilation, thermal conditions, and occupant lack
of control over climatic and working conditions are
other factors that may increase the likelihood of a
building being linked to sick building syndrome.

Atopic individuals with a history or findings
consistent with allergic rhinitis or asthma seem to



TAQ Learning Module

Unit 2, Lesson 7

Ventilation for the construction of manufactured
housing can be met in two ways. The rule specifies
that an area equivalent to not less than 8% of the
floor area must be available for natural ventilation
(windows or doors), or alternatively, a mechanical
system must be capable of changing the room air
every 30 minutes (that is, 2 ach). Bathrooms and
toilet compartments require either 1.5 ft? of
openable glazed area or a mechanical system capable
of producing 5 ach. The mechanical system must
exhaust directly outside the house.

The rule for manufactured housing construction
specifies the venting of combustion appliances and
requires purchasers to be presented with options to
improve overall ventilation. HUD is now consider-
ing ways to improve this standard.

Ventilation Requirements in
Model Codes

Building codes identify design and construction
specifications for buildings. The primary building
codes that are in use in the United States include
those written by che Building Officials and Code
Administrators International (BOCA), the Southern
Building Code Congress International (SBCCD, the
Council of American Building Officials (CABO),
and the American Public Health Association
(APHA) model code.

These codes are updated periodically to reflect new
knowledge and incorporate standards developed by
other organizations. State and local governments
can either adopt these codes in their entirety or
revise them as needed. Sufficient time has not
elapsed for these organizations to consider incorpo-
rating provisions of the new ASHRAE Standard 62-
1989.

The ventilation requirements of the CABO and
APHA codes are summarized as follows; relevant
portions of the Uniform Building Code and addi-
tional CABO requirements are summarized in
Section 7 of the Reference Manual.

The CABO One and Two Family Dwelling Code
(1989 edition): The CABO code specifies ventila-
tion requirements in habitable rooms as follows.

¢ All habitable rooms must have window
space of not less than 8% of the floor area of
such rooms and at least one half of the
required area must be openable.

* Windows do not have to be operable if a
mechanical ventilation system can provide
1 air change every 30 minutes (2 ach).

¢ Bathrooms, toilet compartments, and
similar rooms must have window space of
not less than 3 ft”, one-half of which must
be operable. The window space is not
required if a mechanical ventilation system
can provide a change of air every 12
minutes (5 ach). Bathroom exhaust must be
vented directly to the outside.

* Crawl spaces must have enough ventilation
openings to ensure ample ventilation; these
openings should not be less than 1 ft? for
each 150 ft? of crawl space area, and one
opening should be within 3 ft of each
corner of the building. The required space
can be reduced to 1/1500 of the underfloor
area where the ground surface is treated
with an approved vapor barrier and one
opening is within 3 ft of each corner of the
building. The vents may have operable
louvers.

¢ When a building official determines that
attic ventilation is necessary, attics must
have cross ventilation for each separate
space. The net free ventilating area should
not be less than a ratio of 1 to 150 of the
area of the space ventilated. This can be
increased to 1 to 300, provided that certain
requirements are met.



38

Unit 1, Lesson 4

IAQ Learning Module

Exposure to lead can occur via air, water, and food.
Food is the largest contributor to the daily intake of
lead for most people, but water and air can be
important routes of exposure.

Asbestos is a naturally occurring mineral that can
separate into long flexible fibers which are micro-
scopic in size. Exposure to asbestos fibers does not
result in immediate symptoms, but cancer and other
effects can develop years after the exposure occurs.
Mesothelioma, which is a cancer of the lining of the
lung or abdomen, is considered to be a marker
disease (specific to a contaminant) for asbestos
exposure. Exposure to asbestos fibers can also result
in other lung cancers and asbestosis. High levels of
exposure are required to produce asbestosis, but
much lower exposures can result in asbestos-related
cancers. Smoking signficantly increases the risk of
developing cancer. EPA has classified asbestos as a
“Known Human Carcinogen.”

Combustion Contaminants

Potential contaminants from combustion sources
include carbon monoxide, carbon dioxide, oxides of
nitrogen, sulfur dioxide, formaldehyde and other
aldehydes, particulates, and water vapor.

Carbon monoxide at low concentrations can result
in fatigue and drowsiness in healthy people, and it
can cause shortness of breath and chest pain in
people with heart disease. At higher concentrations,
symptoms in healthy people can include irritability,
headaches, increased respiration, impaired vision,
lack of coordination, nausea, dizziness, confusion,
and impaired judgment. Symptoms can be reversed
if prompt medical treatment is received. At very
high concentrations, coma and death result.

Carbon dioxide, which is also released from normal
metabolic processes, can act as both a respiratory
depressant and stimulant. Exposure to carbon
dioxide has been shown to change the blood pH and
carbon dioxide levels. It can also increase the
respiration rate and decrease the ability to perform
strenuous exercise. The long-term significance of

chronic exposure to carbon dioxide is not known,
but increases in respiratory and gastrointestinal
disorders have been postulated. Exposure to low
levels would not be likely to result in symptoms; at
higher concentrations rapid pulse and breathing
rates may be accompanied by a sensation of heavi-
ness in the chest, particularly if the person is
performing moderate activity.

Nitric oxide can interfere with the transport of
oxygen to the tissues and may increase cardiovascu-
lar stress. Symptoms of exposure to nitric oxide at
higher concentrations would be similar to those for
carbon monoxide.

Nitrogen dioxide is a deep lung irritant which can
also result in irritation of the eyes, nose, and throat.
Some epidemiological studies suggest that children
who are exposed to gas stove emissions experience
increased rates of respiratory illness, but the evi-
dence is mixed, and not conclusive. Changes in lung
function have also been observed in laboratory
studies of adults exposed to nitrogen dioxide, but
this evidence is also mixed. Asthmatics may be
particularly sensitive to nitrogen dioxide.

Sulfur dioxide, acting alone or in combination with
particulates, can result in decreases in pulmonary
function at low levels, but the significance of these
decreases is not known. Irritation of the eyes, nose,
and throat can also result. Because of the variability
in response to sulfur dioxide in normal subjects and
asthmatic subjects, there may not be a no-observed-
adverse-effect level of exposure.

Respirable particulates from combustion sources
have been associated with eye, nose, and throat
irritation; respiratory infections; and bronchitis.
Symptoms of irritation may result at low exposure
levels. Some respirable polycyclic aromatic
hydrocarbons (PAHs) such as benzo(a)prene,
benz(a)anthracene, and others have been associated
with an increased risk of lung cancer and they are
classified as “Probable Human Carcinogens” by
EPA.



Unit 2, Lesson7

IAQ Learning Module

AIR QUALITY STANDARDS AND GUIDELINES
(RM 7)

Air quality standards and guidelines
specify maximum concentrations and exposure
times for specific contaminants for indoor and
outdoor environments. They are designed to protect
specified classes of individuals from adverse health
impacts. Different standards are designed to protect
different classes of individuals, and to different
degrees, depending on the nature and purpose of the
standards.

There are two broad types of standards and guide-
lines: public health standards and occupational
standards. Public health standards are designed to
protect the general public, and are therefore most
applicable to residential, educational, commercial,
and public building environments. Occupational
standards, on the other hand, are designed to protect
workers, and are generally applied to industrial
work environments.

Public health standards are generally one to two
orders of magnitude lower (more protective) than
occupational standards for several reasons.

* Occupational standards protect healthy
adult workers while public health standards
are designed to protect all segments of the
population, including potentially sensitive
subgroups--the elderly, infants and chil-
dren, pregnant women, and those with
preexisting heart and lung diseases.

© Occupational standards protece workers for
limited periods of time (usually che 8-hour
work day) while public health standards
generally protect the public for continuous
lifetime exposures (24 hours/day).

¢ Occupational standards factor cost and
technical feasibility into the recommended
limits while public health standards are
often established without regard to cost or
feasibility.

In the United States there are no Federal standards
that have been developed specifically for indoor air
contaminants in nonoccupational environments.
There are related existing standards and guidelines
that can be used for some comparisons, but most of
these are not directly applicable to indoor air quality
problems.

The limited inventory of public health standards
and guidelines for most of the contaminants com-
monly found in indoor environments complicates
the interpretation of data. Occupational standards
are sometimes divided by an arbitrarily selected
protection factor (somtimes 10 to 1000), and the
resulting number is used as a benchmark for
evaluating indoor environments. This practice is not
recommended because these standards were not
derived to protect the general population, and the
application of protection factors can result in
significant inconsistencies among contaminants.
The resulting numbers may not provide sufficient
protection, or they may be unduly restrictive.

In the absence of standards for specific contami-
nants, or in the face of several standards or guide-
lines for a single contaminant, good public health
ptactice requires a conservative approach to the
interpretation of measured data. If there are several
published standards or guidelines for a particular
contaminant, it is appropriate to use the lower end
of the range for the interpretation of data. If there
are no indoor air quality standards or guidelines, for
a particular contaminant, a review of the literature
can be useful along with obtaining advice from
experts.

Setting standards for indoor air quality contaminants
is in its infancy. Section 7 of the Reference Manual
identifies contaminant levels and exposure times
specified by organizations and government agencies
which have published standards and guidelines.
This lesson reviews these standards and guidelines
in terms of their general concepts, terminology, and
guiding principles.



TAQ Learning Module

Unit 1, Lesson 5

achieved by adding 100 ft? of “clean” air each
minute. The effectiveness of room air cleaners is
rated for test dusts of tobacco smoke, pollen, and
dust. The ANSI/AHAM program is relatively new
and only a limited number of air cleaners have been
tested. Section 5 of the Reference Manual provides
more information on these standards.

Evaluations conducted by Consumers Union (CU,
1985; 1989) and others have shown that portable air
cleaners vary considerably in their ability to remove
particulates from indoor air. In the 1989 evalua-
tion, units with electrostatic precipitators and
HEPA filters (CADRs in the range of 120-290 cfm)
more effectively removed particulates and smoke
than units with flat filters (CADRs in the range of
100-130 cfm). CADRs for 21 console units were
higher (30-290 cfm) than for 6 table-top units (10-
130 cfm). Overall, there was considerable variabil-
ity among the units.

Gases: There are limited data on the effectiveness
of air cleaners in removing gases. The performance
of solid sorbents depends on the flow rate of air
through the sorbent; the concentration of the
contaminant; the presence of other gases, vapors and
humidity; the amount of sorbent; and the physical
and chemical characteristics of both the contami-
nants and the sorbent. In general, as contaminants
accumulate on the sorbent the efficiency of the
sorbent decreases.

Cleaners for gaseous contaminants are usually rated
in terms of the sorption capacity and penetration
time, which is the amount of time before the
capacity of the sorbent is reached. One problem in
evaluating these cleaners is that the testing methods
are not standardized, but the National Institute of
Standards and Technology is in the process of
developing a standard method to be used in evaluat-
ing the effectiveness of media used for gaseous
contaminant removal (U.S. EPA, 1990). Evalua-
tions are also limited because the effect of additional
contaminants on the removal process has not been

evaluated, and the tests do not replicate the actual
indoor environment. Preliminary information
indicates that air cleaning devices may be able to
reduce some specific contaminants at least on a
temporary basis, but they probably cannot remove
all of the various contaminants which are typically
present in an indoor environment (U.S. EPA, 1990).

DESIGN, OPERATION, AND MAINTENANCE
STRATEGIES (RM 5.1, 5.2)

Adequate design, proper operation and
maintenance, and appropriate energy management
of commercial and residential buildings are critical
for maintaining good air quality. Architects and
builders can play a significant role in minimizing
indoor air quality problems by ensuring the:

* consideration of proposed uses of space and
potential sources of contaminants;

* — design of interior spaces to provide good air
flow, adequate light levels, and low noise;

© consideration of potential heat loads due to
penetration of sunlight;

© use of low contaminant-emitting building
materials;

° — design of heating, ventilating, and cooling
systems to exhaust contaminants from
known sources and to ensure an adequate
supply and distribution of outdoor ventila-
tion air throughout the building;

¢ — design of the heating, ventilating, and
cooling system to prevent outside contami-
nants from entering the outside air intake,
and to provide adequate access to filters,
condensate pans, ductwork, and other
system components;

© adherence to minium code requirements;
and

57


IAQ Learning Module

Unit 2, Lesson 7

Public Health Standards and Guidelines
Ambient Air Quality Standards

The EPA National Ambient Air Quality Standards
(NAAQS) (U.S. EPA, 1989] apply to the outdoor
air, and they are developed under the authority of
the Clean Air Act. These standards are enforced by
the states which may either adopt the Federal
standards or promulgate more stringent standards.
Standards have been developed for six contaminants
(sulfur dioxide, nitrogen dioxide, ozone, lead,
particulates, and carbon monoxide).

Primary standards are designed to protect human
health and secondary standards are designed to
protect the public welfare (buildings, crops and
other vegetation, animals). The standards protect
against short-term and long-term effects that might
result from exposure to contaminants in the outdoor
air.

Under the Clean Air Act, primary standards are to
be developed with an adequate margin of safety to
protect the public health without consideration of
cost. Primary standards should also protect che
most sensitive subgroups of the population (for
example, asthmatics or those with chronic respira-
tory problems).

The required margin of safety is established by the
Administrator of the EPA, and it can vary from
contaminant to contaminant. When it establishes
standards, EPA considers the uncertainty in the
scientific information, the activity level of the
exposed population, and to some extent the possibil-
ity of other exposure routes. These standards may
not be directly applicable to indoor air environ-
ments because of differences in averaging times.

Air Quality Guidelines for Europe

The World Health Organization (WHO) Air
Quality Guidelines for Europe is a compilation of air
quality guidelines and summaries of the scientific
evidence for 28 organic and inorganic substances

(WHO, 1987). The major consideration in estab-
lishing the guidelines was health effects, but
ecological guidelines are recommended for some
contaminants. The guidelines include both short-
term and long-term exposure limits designed to
protect sensitive subgroups in the populacion.

For some contaminants, the guidelines provide an
estimate of lifetime cancer risk arising from expo-
sure to substances that are proven human carcino-
gens or substances for which there is at least limited
evidence of human catcinogenicity. For other
contaminants the guidelines identify concentrations
combined with exposure times, at which no adverse
noncarcinogenic effect is expected.

Canadian Exposure Guidelines

The Canadian Exposure Guidelines for Residential
Indoor Air Quality were developed under the author-
ity of che Minister of Health and Welfare by the
Federal-Provincial Working Group on Indoor Air
(Environmental Health Directorate, 1987). The
guidelines contain specific quantitative limits for
ten contaminants or contaminant categories (total
aldehydes, carbon dioxide, carbon monoxide,
formaldehyde, nitrogen dioxide, ozone, particulate
matter, sulfur dioxide, water vapor, and radon).
Recommendations are also included to eliminate or
control exposure for other contaminants for which
specific exposure limits were not practical. The
guidelines were developed by evaluating human and
animal studies. They include an Acceptable Long-
Term Exposure Range (ALTER) which is based on a
lifetime of exposure without undue risk to health
and an Acceptable Short-Term Exposure Range
(ASTER) which is based on exposures of varying
time periods (5 minutes to 1 hour).

The guidelines are intended to ensure that there is
“negligible” risk co the health and safety of occu-
pants in residences; however, the Working Group
notes that complete protection for the hypersensi-
tive portion of the population may not be provided
by the guidelines.



Final Examination

IAQ Learning Module

66.

67.

68.

69.

Which of the following statements about
survey forms is not correct?

a. survey forms must ensure the collection of
consistent data

b. form design is not difficult

the confidentiality of collected information

must be preserved

d. survey forms can include questionnaires
with yes/no questions or open-ended

9

questions

Which of the following should be included
in a residential inspection?

a. educating the client about indoor air
problems

b. administration of a health/symptom
instrument

c. _asystems evaluation of the residence

d. all of the above are correct

Which of the following statements about
record-keeping is false?

a. inspection data should be written in a
notebook and then transferred to data
sheets in the office

b. information should be recorded at the time
it is taken

c. bias can be reduced by using standard
forms

a. record-keeping should be limited to
collecting information during sampling
and analysis

Which of the following is not important
when obtaining data on health effects?

smoking history
occupational history
caffeine intake

all are important

ao TP

70.

71.

72.

73.

Which of the following is a parameter that
should be part of the site evaluation?

a. amount of sunlight reaching the house
b. annual rainfall

c. geology and soil

d. annual ambient temperature

Which of the following should be thor-
oughly evaluated in a walk-through?

a. electrical wiring

b. plumbing system

c. HVAC system

d. amount of storage space

Which of the following statements about
measuring contaminants during an inspec-
tion is correct?

a. carbon dioxide and carbon monoxide should
always be measured

b. average and worst case exposures are needed
to fully evaluate potential health effects

c. samplers should be located away from the
center of a room to avoid problems with
infiltration and exfiltration

d. ifa contaminant is suspected based on the
health survey, its presence should be
measured before doing anything else

Which of the following does not explain
why it is difficult to evaluate measurement
results?

a. there are many different types of houses

b. the variability in human response to
contaminants

c. the lack of consensus on standards and
guidelines

d. the similarity of symptoms resulting from
exposure to indoor air contaminants and
stress



—— ge —— — — EE

IAQ Learning Module Answer Sheet
ANSWER SHEET
HOW TO USE THE
In order for us to accurately score and return your examination, you ANSWER SHEET
must complete all information requested. Print your name as you
want it to appear on your certificate of completion. 1. Place on X through the letter that
corresponds with the correct answer
for each question.
Name
Example:
Address AKCD
City State Zip 2. If you change an answer, be certain
that the change is clearly indicated.
Phone Home ( )
3. Do not make o copy of this answer
Work ( ) sheet. Remove this page and answer
sheet and send, along with a check for
Title of Module $7.50 made payable to NEHA, to:
Time Spent Studying Material Notional Environmental
Health Association
Time to Complete Final Exam 720 Colorado Blvd.
#9705. Tower

Denver, Colorado 80222



IAQ Learning Module

Unit 1, Lesson 3

Men and women may also be affected differently by
exposures to contaminants and other stressors
because of their different chemical makeup. For
example, men and women differ in the amount and
distribution of body fat; this, in turn, may lead to a
different distribution and accumulation of chemicals
and subsequent toxic effects.

Personal habits such as smoking, alcohol intake, and
other drug use can alter the body's ability to handle
exposures to contaminants. Diet and psychological
factors may also play an important role in determin-
ing the body's response to exposures. For example,
individuals experiencing high stress levels may be
more susceptible to the adverse effects of chemical
exposure (Calabrese, 1978). In addition, stress may
result in symptoms such as skin rash and anxiety
which can appear to be chemically related.

Age is an important factor that affects sensitivity to
contaminants. Infants and children are more
sensitive to chemical exposures than adults. Their
brains are not fully developed until they are about 6
to 7 years of age, and they may experience irrevers-
ible changes in learning ability or behavior if
exposed to lead and mercury compounds. They are
also more sensitive because they have smaller body
size, faster breathing rates, immature immune and
lung systems, and they are generally oral (mouth)
breathers. Oral breathing circumvents some of the
respiratory tract’s defense mechanisms, resulting in
larger doses to the remaining respiratory tract.

Older people may also be more sensitive to the
effects of contaminant exposures because of the
effects of aging on the immune system. The effects
of aging and health status in response to chemicals
were clearly illustrated during the serious air
pollution episodes of the 1940s and 1950s. The
people who were most affected and experienced the
highest mortality were older people with preexist-
ing heart and lung conditions.

In general, immunosuppressed individuals or those
with chronic respiratory or cardiovascular diseases

are more susceptible to the effects of indoor air
contaminants, regardless of sex or age.

FATE OF CONTAMINANTS IN THE BODY
(RM 3.2)

A\fter a contaminant enters the body it
may be absorbed into the bloodstream, excreted
unchanged, or transported throughout the body.
Once it reaches the body’s tissues it can be stored or
interact with che body to produce toxic effects.

Metabolism is the process by which a chemical is
changed in the body through the action of enzymes
to form a new chemical called a metabolite. Me-
tabolism, which occurs primarily in the liver and
kidneys, generally is not 100% efficient, so some of
the original chemical will remain. One of the main
purposes of metabolism is to detoxify harmful
chemicals by converting them into less harmful
chemicals which can easily be excreted. Sometimes
metabolites are formed which are more harmful
than the original chemical.

After a chemical has been metabolized it may have
the same fate in the body as the original chemical.
Ic may be excreted or stored in the blood or other
parts of the body. Nonpolar compounds (PCBs,
chlordane, DDT) are stored primarily in the fat;
metals such as lead and cadmium may be stored in
bone, and others can be stored in the blood.

The kidney is the most important excretory organ in
the body and it is able to excrete polar molecules
such as alcohols, but it is less efficient with nonpolar
molecules such as xylene. If a nonpolar metabolite
is formed by the metabolism of a polar compound,
the metabolite will be hard to excrete and may exert
a toxic effect on the kidney. The original chemical
or its metabolites can also be excreted through the
feces, Jungs, sweat, saliva, or breast milk.

The mechanisms by which toxic effects occur in the
body have not been determined for all contami-
nants, and the process is not well understood for



SECTION 1.
OVERVIEW OF THE
REFERENCE MANUAL

The Indoor Air Quality Reference Manual is
the companion document to the Indoor Air Quality
Learning Module. The purpose of the Reference
Manual is to provide an opportunity for continuing
education plus useful reference material on selected
indoor air quality topics.

The Reference Manual is divided into 8 sections
corresponding to the first eight lessons of the
Learning Module, Section 1 provides an overview of
the Reference Manual and suggests ways that the
Reference Manual can best be used as an adjunct to
the Learning Module. Sections 2-8 contain informa-
tion that supplements the corresponding lessons in
the Learning Module. For example, Lesson 2 of the
Learning Module describes the factors that affect
indoor air quality, while Section 2 of the Reference
Manual shows how those factors are combined in
indoor air quality modeling to simulate indoor

environments; Section 2 also provides specific
information and data on individual factors.

Sections 3 and 4 of the Reference Manual correspond
to Lessons 3 and 4 of the Learning Module and
contain information on the nature of human re-
sponses as well as health effects from specific
contaminants. Section 5 contains information about
air cleaning devices and residential heating and air
mover systems.

The Reference Manual also contains information and
exhibits which can be directly used in field investi-
gations. For example, Section 4 contains tables
which relate symptoms, contaminants, and sources
in a way that could assist in diagnosing indoor air
quality problems; Section 6 provides information on
specific measurement techniques and equipment,
including availability of equipment from various
manufacturers; Section 7 provides a listing of public
health and occupational standards which can be
useful in interpreting measured data; and Section 8
includes specific forms and questionnaires which can
be used to collect data during field investigations.



Unit 1, Lesson 4 IAQ Learning Module

Table 4-2. Health effects of selected contaminants.’

CONTAMINANT CONTAMINANT CLASSIFICATION?
I A AN ST. P/A-— C_ Comments
VOCs x x x x x many of these contaminants are neuro/

behavioral toxicants, hepatotoxicants, and
cardiac sensitizers

formaldehyde x x may induce allergic responses

pesticides x x x many of these contaminants are
neurotoxicants, hepatotoxicants,
reproductive toxicants, and sensitizers

lead x neurotoxic and behavioral effects which
may not be reversible

carbon monoxide x increased frequency and severity of angina
in patients; decreased work capacity in
healthy adult males; headaches, decreased
alertness, flulike symptoms in healthy
adults; exacerbation of cardiopulmonary
dysfunction in compromised patient

carbon dioxide x can also act as respiratory stimulant;
increased respiration and decreased ability
to perform strenuous tasks in humans;
changes in blood pH and pCO, calcifica-
tion of kidneys and structural changes in
lungs of guinea pigs

nitrogen dioxide x decreased pulmonary function in asthmat-
ics; effects on pulmonary function in
children, perhaps adults; synergistic
effects with other contaminants in animals
and children; increased susceptibility to
infection in animals; animal studies
indicate decreased immune capability,
changes in anatomy and function of the
lungs

sulfur dioxide x decreased lung function in asthmatics and
normal exercising males; animal studies
show decreased lung function



Introduction

IAQ Learning Module

The Reference Manual is divided into eight sections,
corresponding to the first eight lessons of the
Learning Module. If more detailed information is
needed on a particular subject, the reader can easily
find the relevant portion of the Reference Manual that
pertains to that subject. Frequent references to the
Reference Manual are also included within the text of
the Learning Module. In addition, to further assist in
locating information, parenthetical notations in
smaller typeface, which refer the reader to the
relevant sections in the Reference Manual, are occa-
sionally included next to section headings in the
Learning Module.

The material in the Learning Module (and the
Reference Manual) is directed primarily to residential
structures, but nonresidential buildings, including
schools, office buildings, and public buildings are
also addressed. EPA is developing guidance
documents for the investigation and control of
indoor air quality in nonresidential buildings.

HOW TO USE THIS MODULE

Each lesson in the module begins with
learning objectives that are the focus of the lesson,
and closes with a progress check that contains
questions about the material in the lesson. The
progress checks give you a measure of your under-
standing of the material contained in the lesson.
You should complete each progress check before
starting the next lesson. Answers to the progress
checks can be found within the text.

Be sure to review the lesson before going to the
next one if you answer any of the questions
incorrectly.

A final examination covering the material contained
in the lessons can be found at the end of the module.
If you wish to receive a certificate that acknowledges
your mastery of the material in the module, com-
plete the examination as instructed. The National
Environmental Health Association (NEHA) will
score the examination and issue a certificate to you
if you complete the examination with an acceptable
score.



34

Unit 1, Lesson 4

IAQ Learning Module

(hematopoietic toxicants), the nervous system
(neurotoxicants), and the reproductive system can
impair the functioning of these vital body systems.

Exposure of the kidney to chemicals can result in
scarring of the filtering tissues which may ulti-
mately lead to kidney failure. The liver has a crucial
role in regulating the composition of the blood and
also plays a role in other body processes. The
central and peripheral nervous systems are also
susceptible to damage from a wide range of toxic
substances including metals (lead, arsenic, mercury),
chlorinated hydrocarbons, volatile organic hydrocar-
bons, and various organic pesticides. Changes in
fertility as a result of exposure to systemic toxicants
have been documented for both men and women.

Acute or chronic exposures to chemicals which
affect the body’s systems can result in a wide range
of symptoms that include fatigue, weakness,
changes in blood pressure, changes in pulse rate,
skin rash, sweating, depression, muscle twitching
and convulsions, headache, tingling and numbness
of the extremities, double vision, difficulty breath-
ing, chest pain, wheezing, changes in respiration,
coughing, vomiting, diarrhea, decrease in urinary
output (oliguria), menstrual irregularities, muscle
weakness, and others. Exposure to low concentra-
tions may not result in immediate symptoms, but
biochemical or structural effects can occur in the
absence of symptoms.

Mutagens, Carcinogens, Developmental,
and Reproductive Toxicants

Only a small fraction of the chemicals in commer-
cial and consumer products have been tested for
their potential as mutagens, carcinogens, and
developmental or reproductive toxicants, and even
less is known about mixtures of contaminants.

A mutagen is an agent that alters the genes or
chromosomes of a living cell to cause mutations.
Mutations can also occur spontaneously in the cell,
and some are inherited. Cancer is thought to

develop from a single cell that develops abnormally
because of an alteration or mutation in the genetic
material (DNA) which can occur spontaneously or
after exposure to carcinogenic agents. Cancer
usually develops years after exposure (7 to 40 years)
to the agent.

Radon, asbestos, cigarette smoke, and formaldehyde
are some of the agents in the indoor environment
which have received attention for thei carcinogenic
potential. Symptoms of cancer typically do not
occur until the tumor is already advanced.

Developmental toxicants are agents that cause some
defect or malformation in the fetus; some defects
may be so serious during the embryonic stage that a
spontaneous abortion occurs. The fetus is most
susceptible to the effects of developmental toxicants
during the first three months of growth because this
is a time of rapid cell growth and when organ
systems begin to differentiate. Adverse effects,
however, can occur throughout gestation.

Known human fetal toxicants include lead, alcohol,
ionizing radiation, organic mercury, and some
cancer-fighting drugs. Many more chemicals such
as benzene; 2,4-D; nitrogen dioxide; PCBs;
tetrachloroethylene; xylene; benzo(a)pyrene; phtha-
lates; and others have been shown to be develop-
mental toxicants in animal studies, but their effects
‘on humans is not known (Rudolph and Forest,
1990).

Reproductive toxicants are agents that can result in
menstrual disorders in women and decreased
fertility in men and women. These agents typically
are encountered through occupational exposures.

Pathogens and Allergens

Exposure to pathogens and allergens can result in a
broad range of effects from mild irritation to life-
threatening fevers and debilitating illness. These
agents of illness can be particularly difficult to
identify and relate to symptoms.



IAQ Learning Module

Final Examination

60.

61.

62.

Which of the following statements about
ASHRAE'’s Standard 62-1989 Ventilation
Rate Procedure is correct?

a. residences are the only buildings to which
the standard applies

b. ventilation rates can be achieved only
through the use of acceptable outdoor air
quality

c. the ventilation requirements are designed
to protect healthy adults

d. recirculated air can be used to meet ventila-
tion requirements if the air is treated by
contaminant removal equipment

Which of the following correctly identifies
ASHRAE’s 62-1989 outdoor air require-
ments for living areas in residential
housing?

a. 0.35 ach but not less than 15 cfm per
person

b. window space of not less than 8% of the

habitable floor area, half of which must be

openable

1 air change every 30 minutes

d. 0.5 ach of fresh air, if window space is equal
to at least 4% of the habitable area

°

Why may ventilation standards/guidelines
be inadequate to protect indoor air quality
in the U.S.?

a. the housing stock was constructed at
different times under different code/
standard requirements

b. some HVAC systems may be poorly
maintained and operated incorrectly

c. although adequate openable window space
may be available, it may not be used

d. all of the above reasons are correct

63. Why are standards/guidelines for the

workplace inappropriate for residential
applications?

a. occupational standards are intended to
protect healthy adult workers, but not all
segments of the population including the
old, the young, and the ill

b. occupational standards are based on 8-hr
exposures for a working lifetime, not
continuous exposures

¢. occupational standards generally consider
cost and technical feasiblity

d. all of the above are correct

. Which of the following statements is

correct about the Canadian exposure
guidelines?

a. the guidelines protect all members of the
public, including those who are especially
sensitive to chemical exposures

b. the guidelines are written for outdoor air
pollution

c. the guidelines protect the public against
short-term and long-term effects

d. the guidelines have been developed for over
200 contaminants

. Which of the following identifies an exist-

ing source emission standard?

a. formaldehyde from particleboard and
plywood in manufactured housing

b. asbestos from vinyl asbestos floor tile

c. xylene from latex paints

d. radon from gypsum board

Examination continues on next page



IAQ Learning Module

Unit 1, Lesson 2

furniture, curtains) are more effective in retaining
particles than are smooth-textured surfaces. A large
surface-to-volume ratio also favors removal of
contaminants. These surfaces can also become
sources if the contaminants are released back into
the air at a later time.

Volume of the Structure (RM 2.1)

In general, as the available volume for contaminant
dispersal increases, contaminant concentrations
resulting from a given source decrease. For ex-
ample, a kerosene heater operated for 2 hours in a
1000 ft’ space with 0.5 ach would likely result in
higher carbon monoxide concentrations than if the
same heater were operated under identical condi-
tions in a 2000 ft? space.

The entire volume of the house is not always
available for contaminant dispersal. The extent to
which the entire volume is used depends upon
multiple factors including the configuration of the
space, location of walls and other impediments to
airflow, closed or partially closed doors that separate
rooms, number of floors and circulation of air
between floors, location of sources, thermal gradi-
ents, use of circulation fans and mixing of contami-
nants.

If a house has more than one floor, contaminant
concentrations will likely be greatest on the floor
that contains the source and the floors above that
one due to thermal buoyancy, providing there is no
mechanical mixing of the air. In a house with three
levels, for example, radon concentrations generally
will be greatest in the basement and lowest in the
upper floor. If a fan is used to mix the air, the
concentrations on the lowest level will likely
decrease while the concentrations on the upper floor

will likely increase. Concentrations on all floors
will become more uniform as long as the fan is

operating.

Mixing efficiency refers to the speed with which
contaminants become dispersed throughout the
interior space. Mixing efficiency depends on the
volume of the interior space, the rate of air move-
ment, and whether or not local exhausts are used.
Mixing generally occurs at a faster rate in smaller
spaces than in larger spaces. For smaller residences,
complete mixing between rooms generally occurs
within an hour or less, while complete mixing in
larger homes may require more time.

REFERENCES

American Society of Heating, Refrigerating, and Air-Condi-
tioning Engineers (ASHRAE). 1985. “Natural ventilation and
infiltration.” Chap. 23. 1984 ASHRAE Handbook. Systems.
ASHRAE: New York, NY.

American Society of Heating, Reftigerating, and Air-Condi-
tioning Engineers (ASHRAE). 1989. “Infiltration and
ventilation.” Chap. 23. 1989 ASHRAE Handbook. Fundamen-
tals, ASHRAE: Adanta, GA.

Lenchek, T., C. Matlock, and J. Raabe. 1987. Superinsidated
Design and Construction. Van Nostrand Reinhold Co.: New
York, NY.

Mann, P.A. 1989. Illustrated Residential and Commercial
Construction. Prentice Hall: Englewood Cliffs, NJ.

Persily, A. 1989. “Ventilation rates in office buildings.”
Presented at the ASHRAE IAQ 89 Conference. The Human
Equation: Health and Comfort. ASHRAE: San Diego, CA.

Sandia National Laboratories. 1982. Indoor Air Quality
Handbook for Designers, Builders and Users of Energy Efficient
Residences. SAND 82-1773. Sandia National Laboratories:
Albuquerque, NM.



Unit 1, Lesson 2

TAQ Learning Module

Consumer use patterns and activities are also
important in determining whether or not contami-
nants will be released by products or activities. Dry
sanding or open-flame burning of lead-based paint
can release lead; soldering can release lead and other
metals. The use of solvents and pesticides in
enclosed or poorly ventilated spaces can pose special
hazards. The use of unvented heating appliances or
improperly installed, operated, or maintained
heating appliances can result in elevated levels of
combustion contaminants indoors. Airborne
pathogens and allergens can result from poor
hygienic conditions, excess moisture, or water
damaged materials. They can also become airborne
when using vacuum cleaners.

Perhaps the most important source of indoor air
contaminants is tobacco smoke which contains both
organic and inorganic particles and gases; many of
these contaminants are carcinogens or can promote
the carcinogenic potential of other contaminants.

Building sources: Many different types of VOCs,
including formaldehyde, can be released by building
materials such as pressed wood products; glues and
adhesives; sealants; insulating materials such as
styrofoam, urethane, and urea formaldehyde foam
insulation (UFFI); floor and wall coverings; plastics;
and electrical equipment.

Airborne pathogens and allergens can thrive in a
variety of building sources including wet or moist
insulation, wood, walls, or ceilings. In addition,
poorly maintained humidifiers, dehumidifiers, air
conditioners, and heat recovery ventilators can also
hecomie sources of airboinc pathogens and allergens.

If openings exist from the soil to the interior of the
building, radon and other soil gases can migrate
indoors. Occasionally, earth-derived building
materials such as gypsum, brick, concrete, soil, or
rock from some areas can serve as a source of radon.

Combustion contaminants such as carbon monoxide
and the oxides of nitrogen can be released from
leaking furnaces, chimneys, and flues; downdrafting

from wood stoves and fireplaces; improper stoking
of fires; gas cooking stoves; unvented kerosene and
gas heaters; and automobile exhaust from attached
garages. Polynuclear aromatic hydrocarbons (PAHs)
can be released from the combustion of wood and
coal.

The building can also be a source of particulates
such as asbestos from poorly maintained or damaged
insulating materials, lead from sanding lead-based
painc, and other fibers and dusts.

Humans, plants, and pets: Humans, plants, and
pets can be sources of allergens (such as dander),
pathogenic viruses, and bacteria. Plants also can
release allergenic spores into the air. Pets can be an
additional source of pesticides (for example, con-
tamination from flea powder and other pesticides).
Also, small amounts of carbon monoxide, carbon
dioxide, and a variety of VOCs such as acetone,
acetic acid, alcohols, ketones, and aldehydes are
released when human and pets respire.

Outdoor Sources

Contaminants in the air, soil, and water from
outdoors can migrate indoors. Outdoor air,
contaminated by emissions from industrial plants,
motor vehicle exhaust, and residential heating units
can result in both trace and elevated levels of a
broad range of inorganic and organic particles and
gases indoors. Emissions from soil and/or drinking
water can result in elevated levels of radon gas, other
radioactive contaminants, and VOCs indoors.

The composition of outdoor air varies from one
location to another. The major constituents of
outdoor air include nitrogen (78.1%) and oxygen
(20.9%), minor constituents include the noble
gases, methane, carbon dioxide, water vapor, and a
variety of contaminants from both nacural and man-
made sources. Background concentrations of some
of these contaminants are in the range of 300 parts
per million (ppm) carbon dioxide, 0.02 ppm ozone,
0.1 ppm carbon monoxide, 0.003 ppm nitric oxide,
and 0.001 ppm nitrogen dioxide (ASHRAE, 1985).



IAQ Learning Module

Acknowledgements

ACKNOWLEDGEMENTS

The Indoor Air Quality Learning Module and
the Indoor Air Quality Reference Mannal were devel-
oped under a cooperative arrangement between the
National Environmental Health Association, the
Bureau of Health Professions of the U.S. Public
Health Service, and the Indoor Air Division of the
Environmental Protection Agency.

The documents were written by:

Ingrid Ritchie, Ph.D., Associate Professor
School of Public and Environmental Affairs
Indiana University

The following persons are gratefully acknowledged
for their contributions:

Barry Stern had the foresight to recognize the
importance of indoor air quality issues and the need
to strengthen the competency of practicing environ-
mental health professionals in this area, His
initiative in developing this project, his support,
and his patience have been fundamental to the
success of this work.

David Mudarri was the principal technical advisor
for this project. He provided expert technical
guidance and made extensive and invaluable
editorial contributions. His insight and thoughtful
assistance provided the framework for both docu-
ments, and his tireless effort and encouragement
helped steer the project through many difficult
times.

Edward Culver (Bureau Administrator, Bureau of
Environmental Health, Health and Hospital
Corporation of Marion County, Indianapolis,
Indiana) contributed Lesson 9 of the Learning
Module, “Establishing an Indoor Air Quality
Program.”

Geraldine Struensee spent many hours typing
complex tables and initially formatting the docu-
ments. Her forbearance through innumerable
revisions is sincerely appreciated.

Reviewing Organizations

Individuals from the following organizations
reviewed and commented on al] or part of the two
documents.

Federal Agencies

Bonneville Power Administration,
Department of Energy
Consumer Product Safety Commission
Department of Health and Human Services
National Insticute of Environmental Health
Sciences
National Institute for Occupational Safety
and Health
Department of Housing and Urban Development
Office of Policy Development and Research
Environmental Protection Agency
Office of Air and Radiation
Office of Pesticides and Toxic Substances
Office of Research and Development
Office of Water
General Services Administration
Public Buildings Services

State and Local Government Agencies

Association of Local Air Pollution Control Officials,
Washington, DC

Central District Health Department, Boise, ID

Clark County Health Department, Las Vegas, NV

Connecticut Department of Health Services,
Hartford, CT

Division of Environmental Services, Toledo, OH

Forsyth County Environment Affairs Department,
Winston-Salem, NC

Health and Hospital Corporation of Marion County,
Indianapolis, IN

Illinois Deparement of Public Healch,
Springfield, IL

Lincoln-Lancaster County Air Pollution Control
Agency, Lincoln, NE

Mansfield Health Department, Mansfield, MA

Maryland Department of Education, Baltimore, MD

(continued next page)



IAQ Learning Module

Resources

RESOURCES

National Hotlines and Information Services

Public Information Center (PM 211 B)
Environmental Protection Agency

401 M Street, SW

Washington, D.C. 20460

202-382-2080

(Distributes [AQ Publications)

National Pesticides
Telecommunications Network
1-800-858-PEST

In Texas: 806-743-3091

(Provides information on pesticides)

TSCA Hotline Service

202-554-1404

(Provides information on asbestos and other toxic
substances)

Safe Drinking Water Hotline
202-382-5533

CPSC Product Safety Hotline
1-800-638-CPSC

Teletypewriter for the hearing impaired
Outside Maryland 1-800-638-8270
Maryland only 1-800-492-8104

Federal Agencies

Indoor Air Division (ANR-445W)
Environmental Protection Agency
401 M Street, SW

Washington, D.C. 20460

Office of Conservation and Renewable Energy
U.S. Department of Energy

1000 Independence Avenue, SW

Washingon, D.C. 20585

Office of Smoking and Health
U.S. Public Health Service
5600 Fishers Lane Room 1-10
Rockville, MD 20857

Consumer Product Safety Commission
Chemical Hazards Program

5401 Westbard Avenue, Rm. 419
Bethesda, MD 20207

National Institute for Occupational Safety and
Health

Hazards Evaluations and Technical Assistance
Branch (R-9)

4676 Columbia Parkway

Cincinnati, OH 45226

Occupational Health and Health
Administration

U.S. Department of Labor

200 Constitution Avenue, N.W.
Washington, D.C. 20210

Bonneville Power Administration
Residential Programs Branch
P.O. Box 3621-RMR

Protland, OR 97208

‘Tennessee Valley Authority
Industrial Hygiene Branch
328 Multipurpose Building
Muscle Shoals, AL 35660

Health/Consumer Organizations

Your Local Lung Association, or the
American Lung Association

1740 Broadway

New York, NY 10009

Consumer Federation of America
1424 16th Street NW, Suite 604
Washington, D.C. 20036

Professional/Industrial Associations

American Society of Heating, Refrigerating, and
Air-Conditioning Engineers

1791 Tullie Circle NE

Atlanta, GA 30329

American Conference of Governmental
Industrial Hygienists

6500 Glenway Avenue

Building D-7

Cinncinati, OH 45211



Unit 2, Lesson 6

IAQ Learning Module

TYPES OF MEASUREMENT METHODS (RM 6)

"The term “measurement” is a broad term
that encompasses the measurement of air contami-
nants; physical parameters such as temperature,
humidity, atmospheric pressure, ventilation rates,
and air exchange rates; characteristics of the build-
ings being investigated; and the health and activity
patterns of occupants. This lesson focuses on the
measurement of air contaminants.

Before indoor air contaminants can be characterized
they must be collected and analyzed. Measure-
ment method describes the overall procedure that
is used (sampling plus analytical method). Sam-
pling method is a term that describes the collection
of the air contaminant; these methods and the
equipment used for collection (samplers) do not
analyze the data. Sampling methods can be active
(pumps move air) or passive (air movement by
diffusion). Analytical method refers to the chemi-
cal method that is used to identify and quantify the
contaminant. Monitoring method refers to
measurement methods in which electronically-based
equipment is used to both collect and analyze the
air contaminant. Active or passive methods can be
used to deliver air to the detector, but a power
source is typically required for analysis. In this
lesson, the terms sampling equipment and samplers
will also be used to refer to monitoring equipment
and monitors.

Measurement methods can be direct or indirect
reading. Direct reading methods are those in which
sample collection and analysis are accomplished in
one step; the results are determined as the sample is
collected. Many of these methods are electronically
based in which a sensor detects an input signal that
is converted by mechanical and electrical compo-
nents into a concentration or other measurement
that can easily be interpreted. Other direct reading
methods rely on colorimetric indicators to react
chemically with a contaminant to produce a color
change which can be interpreted according toa
calibrated scale. Although most direct reading
methods require moderate to large capital expendi-

tures, they can be economical if many analyses are
required (for example, in routine sampling for
carbon monoxide, carbon dioxide, radon, particu-
lates, and other contaminants).

Indirect reading methods are those in which
sampling and analysis are accomplished in two
steps. The sample is collected onto or into a
substrate which undergoes a separate analysis,
typically in a laboratory. Particulates can be
collected onto a filter and gases can be collected into
a liquid or onto solid chemicals or chemically
treated papers. Some indirect reading analytical
methods such as the gravimetric analysis of particu-
lates are relatively moderate in cost (about $25 for
each gravimetric analysis), but other methods such
as gas chromatography and/or mass spectroscopy for
gases can be very expensive ($200-$300 per sample
analyzed). If the costs for sampling and analysis are
combined, these methods can be characterized as
moderate to expensive.

Measurement methods can also be grouped accord-
ing to required sampling times, portability, pres-
ence of an air mover system, and collection and
analytical methods. Section 6 of the Reference
Manual contains a summary of indoor air sampling
equipment with information on these and other
parameters including lower detectable limits,
sampling rates, estimated prices, weight, and
dimensions. The final selection of equipment will
depend on operating and performance specifications,
labor requirements and costs which are outlined in
Table 6-1.

Based on the length of time a contaminant is
measured, sampling equipment (and monitoring
equipment) can be classified as continuous, inte-
grated, or grab.

Continuous samplers provide a real-time record of
contaminant concentrations. The equipment can
provide very reliable data, but it is generally



Unit 1, Lesson 3

IAQ Learning Module

Figure 3-1. Multifactorial model for sick building syndrome.

BUILDING AND ATMOSPHERIC FACTORS

Air Contaminants
Temperature
Humidity

Airtlow
(other factors)

i]

ADDITIVE, SYNERGISTIC AND/OR
ANTAGONISTIC EFFECTS

i

INDIVIDUAL SUSCEPTIBILITY
FOR EFFECTS

i

THE SICK BUILDING SYNDROME

Irritation of Eyes, Nose and Throat,
Runny Nose, Asthma-like Symptoms,
Mental Fatigue, Headache
(other symptoms)

4 Psychosocial
[~~ Factors
1
!
p--___--—--—l

SOURCE: Adapted from Indoor Air and Human Health, by R.B. Gammage and $.W. Kaye. Copyright 1985, Lewis Publishers, Inc.,

Chelsea, MI. Used with permission.

be at higher risk. An affected individual may
respond with a number of symptoms that vary in
intensity depending on the effect of other factors
such as age, personal habits, and health status. In
addition, psychosocial factors can contribute to SBS,
and they can enhance or minimize the attention
given to certain symptoms. However, the presence
of a psychosocial feedback loop in Figure 3-1 should
not be interpreted to mean that SBS is solely a
psychological problem.

Mass Psychogenic IlIness

A controversial syndrome that has been reported in
some nonresidential investigations is mass psycho-
genic illness (less satisfactorily known as mass
hysteria, mass conversion reaction, hysterical
contagion, or epidemic psychogenic illness). This
syndrome has been defined as a group of symptoms
that develop in a group of individuals in the same

indoor environment who are under some type of
physical or emotional stress. It should be noted that
the term mass psychogenic illness does not mean
that individuals have a psychiatric disorder or that
they are imagining symptoms.

There are concerns about labeling indoor air investi-
gations as psychogenic illness when no cause can be
found for reported problems. This diagnosis should
be made carefully after thorough investigation and
testing for suspected contaminants and stressors,
and preferably, in consultation with an expert in
psychogenic illnesses and a medical epidemiologist
(Kreiss and Hodgson, 1984). It is important to
note that the diagnosis should not be made solely on
the basis of excluding physical, chemical, and
biological agents (Kreiss and Hodgson, 1984).

It is hypothesized that a trigger such as unexplained
or unpleasant odor, stuffy air, or low levels of



Unit 1, Lesson 1

IAQ Learning Module

Beginning with the late 1960s and early 1970s, a
series of issues drew public attention to the poten-
tial health effects associated with exposure to indoor
air contaminants and focused scientific and govern-
ment attention on the need for more research and
programs in this area.

In the United States, the release of formaldehyde
from urea-formaldehyde foam insulation (UFFI) and
construction materials used in conventional and
mobile homes was widely perceived as a major
health threat reportedly related to effects ranging
from odor complaints to respiratory tract irritation
to cancer. Subsequently, asbestos and radon were
recognized as major indoor air contaminants, and
Federal programs were developed to deal specifically
with these issues.

After the energy crisis, reports of discomfort effects
and illness among people living and working in
“tight,” energy efficient buildings became wide-
spread. The mysterious Legionnaires’ disease
outbreak in 1976 heightened concern about the
incubation and transmission of microorganisms via
HVAC systems.

Many of the advances in knowledge about health
effects were the direct result of technical advances in
the measurement of contaminants and exposures.
The development of personal exposure monitors
(PEMs) and measurement concepts involving a
Total Exposure Assessment Methodology (TEAM)

have contributed to the ability of scientists to
evaluate indoor exposures as part of total environ-
mental exposures. The TEAM studies and others
have shown that indoor concentrations of some
contaminants are often 2 to 5 times higher than
outdoor concentrations, and the primary route of
exposure for these contaminants is through the
indoor air (Wallace, 1987).

REFERENCES

Langmuir, A.D. 1980. “Changing concepts of airborne
infection of acute contagious diseases: A reconsideration of
classic epidemiologic theories.” Airborne Contagion. R.B.
Kundsin (ed.) Annals of the New York Academy of Sciences. 353:
35-44.

Riley, R.L. , C.C. Mills, W. Nyka, N. Weinstock, P.B. Storey,
LU. Sultan, M.C. Riley, and W.F. Wells. 1959. “Aerial
dissemination of pulmonary tuberculosis: A two-year study of
contagion in a tuberculosis ward.” Am. J. Hyg, 70: 185-196.

Smith, K.R. 1987. Biofuels, Air Pollution, and Health. A Global
Review. Plenum Press: New York, NY.

U.S. Environmental Protection Agency (EPA). 1989. Report to
Congress on Indoor Air Quality. Vol. Il, Assessment and Control of

Indoor Air Pollution. EPA 400/1-89/001C. U.S. EPA, Office of
Ait and Radiation: Washington, DC.

Wallace, L.A. 1987. The total exposure assessment methodology
(TEAM) study: Summary and analysis. Volume 1. EPA 600/6-
87/002a. U.S. Environmental Protection Agency, Office of
Research and Development: Washington, DC.

om

aloes cir quality?

1. Give three reasons why indoor air quality hes become a serious problem in modern times. What are some of the differences in
‘Ceuairection practices, ventilation rates, building materials and furnishings, ond consumer products that affect indoor ait

2, What air quality issees wore of concern before 1970? Alter 1970, what wore some of the issues that focused attention on



IAQ Learning Module

Unit 1, Lesson 3

ent effects on the body simply because of the
location of the elements in relation to the overall
structure of the chemical.

Size and shape are important physical properties of
particles. Submicron-sized particles are more likely
to be inhaled deep into the respiratory tract. The
toxicity of asbestos is thought to be due to both its
size and needlelike shape.

Factors Related to the Dose

The body’s response to toxic substances (contami-
nants) depends in large part on the dose. The dose
is the total amount of contaminant that is received
by the target tissues. It depends on the concentra-
tion, the duration of the exposure, and on the route
of entry.

Concentration, Exposure, and Dose

Dose should not be confused with the terms expo-
sure or concentration. Concentration is the amount
of contaminant that is present in the air at a given
time and place. Exposure characterizes the contact
between the contaminant and the person (skin, eyes,
respiratory tract). The exposure will depend on
both the concentration of the contaminant in a space
and the length of time the person is in contact with
the contaminant in that space. Dose is the amount
of contaminant that is actually absorbed by the
body. In many studies and assessments of risk,
concentration is used as a surrogate for exposure or
dose because the actual exposure or dose is difficult,
and sometimes impossible, to measure.

In general, as the concentration of contaminants in
the air increases, the exposure, dose, and effects also
increase. People who are exposed to identical
concentrations of contaminants, however, can
receive different doses. For example, the dose of
ozone received by a person who is sitting in a park
on a hot day in Los Angeles will be different from
the dose received by a person who is jogging in the
park. The jogger receives a greater dose of ozone
than the person who is sitting because the jogger is

breathing faster and more deeply, causing more
ozone to be in contact with the cells of the respira-
tory tract.

Route of Exposure

Contaminants can enter the body through ingestion,
skin puncture, absorption through the skin, and
inhalation. Except for inhalation, these routes of
exposure are generally unimportant in residential or
office indoor air quality problems. Inhalation is the
most important route of exposure for airborne
contaminants because chemicals are quickly and
rapidly absorbed from the lungs into the blood-
stream, where they can be carried to other parts of
the body.

Absorption through the skin can be an important
route of entry for certain organic substances. Some
substances can be absorbed through hair follicles,
and others dissolve in the fats and oils of the skin
(for example, organic pesticides and solvent com-
pounds). Ingestion could become an important
route of entry if improper fumigation with pesti-
cides resulted in contaminated food or dishes.

Dose-Effect Relationship

The relationship between the dose and its effect on
the body is known as the dose-effect relationship,
and it can be represented graphically (Figure 3-2).
Small doses (characterized by low concentrations,
short exposure times, and low respiration rates)
usually cause minimal or no observable effects. As
the dose increases (higher concentrations, longer
exposure times, higher respiration rates) progres-
sively more severe effects occur, which may include
death at the highest doses. It should be noted,
however, that a group of individuals who receive an
identical dose of contaminant, might not respond
uniformly because of human variability.

Attempts to relate health effects to exposure to air
contaminants are rooted in dose-effect curves, and
these curves are important tools in developing
public policy for chemicals and other toxic agents in

23


IAQ Learning Module

Unit 2, Lesson 8

clients will not be able to relate complaints to
specific events.

Because there are many factors which can influence
the response to contaminants, it is important to
remember that there can be a wide range of re-
sponses from individual to individual and within a
single individual. This means that it is possible
during an indoor air quality investigation to
encounter only one person in a household or a few
people in an office setting who complain of health
symptoms. Their symptoms may be real and
legitimate even though no one else is experiencing
them, and the investigator has the responsibility of
maintaining an open mind and following all leads
that may be able to explain the complaints.

The time when the symptoms began is important.
If the symptoms started three months ago, try to
ascertain what major actions took place just prior to
the onset--new home, new furniture, new furnace,
change of season, new pet, and other changes.
Questions can also help the client associate the
symptoms with given activities or events. Ques-
tions of this nature may give clues about the
potential cause, around which preliminary hypoth-
eses can be formulated and verified by the client.
The client may then be able to solve the problem, or
at least call back at a later date with more informa-
tion after taking some actions to test preliminary
hypotheses.

For example, if the symptoms occur only after the
client has gone to bed, the client might try sleeping
in another room. If the symptoms go away, the
source of the problem is probably in the bedroom.
Or, the client might try removing potential sources
or increase ventilation (for example, sleeping with
the window cracked open) to see if the problems
persist. If it is not clear that the cause of the
symptoms is the air in the home, it may be possible
for the client to spend several days away from home
(for example, staying with a neighbor or relative) to
see if the problems persist. If they do, the cause of
the symptoms may be unrelated to the air in the
home.

The Inspection

The best approach for conducting an inspection is to
use standard forms (questionnaires, checklists,
diaries) in all phases of the inspection. This reduces
problems with information recall, lost notes,
deciphering cryptic messages, and bias. Another
reason for using standard forms is that the
investigator's records may become part of a legal
action.

Health Effects Evaluation

The inspection should begin with the administra-
tion of a health effects questionnaire which can be
completed either by the client or administered to
the client by the investigator. A health effects
questionnaire should be broad enough so that other
confounding health problems will be elucidated.

‘When an occupant perceives an indoor air quality
problem, it is usually in response to a health or
discomfort symptom or an odor. Because of the
overlap of symptoms and the sometimes general
nature of symptoms (“I just don’t feel right.”),
health and comfort complaints must be interpreted
carefully. The health effects questionnaire will be a
useful tool in guiding the investigation, but it
should never be the sole focus. If the investigator
becomes fixed on symptoms, it is possible that other
important indoor air-related factors may be ob-
scured or overlooked.

Health effects forms can range from a simple
checklist to more sophisticated questionnaires that
employ a combination of checklists, open-ended
questions, and yes or no questions.

A useful approach in obtaining information about
health symptoms is to utilize a checklist of symp-
toms that begins to identify both the severity and
frequency of symptoms (Section 8 of the Reference
Manual). It is also important to obtain histories of
smoking, caffeine intake, medical problems and use
of medicines, occupation, hobbies, and craft activi-
ties. Health care providers such as family physicians,



Unit 2, Lesson 7

IAQ Learning Module

PHA Model Housing Code: The APHA model
code (Mood, 1986) also specifies ventilation air
requirements. In the model code, ventilation
requirements can be met in three ways: 1) each
habitable room must have at least one window or
skylight facing directly outdoors that can be opened
easily, 2) the habitable room must be connected to
a room or area used seasonally that provides ad-
equate ventilation, or 3) some other devices can be
used to ventilate the room adequately. The total
operable window or skylight area in every habitable
room shall be equal to at least 45% of the minimum
window or skylight area which is 8% of the floor
area of the room. The code also requires HVAC
units which are integral to the structure to be
operated continuously; if the unit becomes inoper-
able alternate provisions for ventilation are to be
provided.

The code also contains a provision which requires
ventilation, either natural or mechanical, to provide
acceptable indoor air quality in every habitable
room at all times when occupied. In addition,
bathroom and kitchen exhaust air cannot be
recirculated.

The model code does not specify numerical limits
for indoor air contaminants. Instead, it defines
acceptable indoor air quality as indoor air in which
there are no known concentrations which are in
excess of those which have been established by the
Director of Health. This provision provides local
jurisdictions with additional flexibility and control
because the local health officer has the authority to
declare a particular situation a health hazard and
require remediation.

THERMAL COMFORT STANDARDS (RM 7)

‘Thermal Environmental Conditions:
ANSI/ASHRAE Standard 55-81 specifies thermal
conditions which will be acceptable to 80% or more
of occupants in a building. Establishing appropriate
thermal environmental conditions is important to
minimize energy costs, maximize worker productiv-
ity, and minimize discomfort effects.

There are many factors which influence the percep-
tion of comfort, temperature, and thermal accept-
ability. Important environmental factors include
temperature, radiation, humidity, and air move-
ment; personal factors include clothing and activity
level. Section 7 of the Reference Manual provides a
summary of the acceptable ranges of temperature
and humidity for winter and summer conditions.
ASHRAE 55-81 also provides acceptable thermal
conditions for different types of clothing, air
raovement, nonsteady state conditions (temperature
cycling, temperature drifts), and nonuniform
conditions (vertical temperature differences, radiant
assymetry, floor temperatures). Some of these are
summarized in Lesson 4.

SUMMARY AND CONCLUSIONS

Tandoor air quality can be controlled
through the development and implementation of air
quality standards and guidelines, source emission
standards, ventilation standards, and thermal
comfort standards.

The development of standards and guidelines for
contaminant levels indoors and sources of contami-
nants is still in its formative stages. More research
is needed before comprehensive standards can be
developed that specifically address indoor air quality
concerns.

Inadequate ventilation is one of the major causes of
indoor air quality problems, and ventilation stan-
dards are an important method of control. Prob-
lems, however, do exist in relying on ventilation
standards in building codes as the sole protector of
the public health. Some underlying problems are
enumerated below.

© The current building stock has been
constructed under different building codes
with different requirements.

© The current codes may be dominated by
energy efficiency considerations, and code
requirements may not be sufficient to



UNIT 1: UNDERSTANDING INDOOR AIR QUALITY

LESSON 2
FACTORS AFFECTING INDOOR AIR QUALITY

The quality of air indoors depends on many factors related to the
structure, the outdoor environment, and the occupants. An under-
standing of how these factors affect indoor air quality is important
to the successful prevention, diagnosis, and mitigation of problems.

LESSON OBJECTIVES

At the end of this lesson you
will be able to:

© identify and understand different
factors that affect indoor air quality;

© list important sources of indoor air
contaminants and identify some of
the major contaminants of interest;

© understand the concept of air
exchange rate and the factors that
affect it; and

© understand the concept of infiltration
and identify mojor sources of air
leakage in residential structures,



92

Unit 2, Lesson 8

IAQ Learning Module

Figure 8-1. Flowchart of an investigation st

gy for indoor air quality problems.

Who?
What?
Where?
When?

Intitial -> Referrals to Other Standards,
Contact Service Providers Guidelines,
or
Scientific Literature
Health
| and
a Symptom
p History
e Characterization .
c > of Evaluation
t Contaminants
i
° Building Report
f inspection Findings Po,
T '
' '
‘
Referrals to H Y
Other Service <“--~ Remedial
Providers Action

Report
Effectiveness

Evaluate
Remedial
Actions

<- - —

indoor air quality, take actions to improve
indoor air quality, or find a solution to
identified problems;

© — suggest initial actions that will test pre-
liminary hypotheses to help narrow the
possible causes;

© schedule an appointment for a site visit; or

¢ refer the client to other service providers.

Although standardized forms do not need to be used
at this point, it is important to use a Systematic
approach when obtaining preliminary information.
Try to get information that is specific. For example,
if there is a health complaint, a general statement,
“I haven't felt well in weeks,” does not give much
insight. However, complaints of headache which
are limited to times when unvented combustion
sources are present, or upper respiratory tract
irritation which started when a room was remod-
elled, give more clues about possible causes. Some-
times, however, complaints will not be specific and



IAQ Learning Module

Unit 2, Lesson 8

client. When a homeowner or other person com-
plains about an indoor air quality problem, he may
share his own frustration about dealing with the
bureaucracy, physicians, or private industry. The
individual may be anxious or angry. Typical
questions include: “Have you ever heard of this
before?” “Why is this chemical/product allowed to
be used?” “Can you make someone do something
about this?” “Should anyone have to live/work like
this?”

It is important to demonstrate a healthy concern
about the problem that is being presented. Listen
carefully, take notes, ask questions or get clarifica-
tions, and be professional and polite during all
contacts. Keep the discussion focused on the issue
in an organized manner to yield information for
diagnosing and solving the problem. Occasionally,
individuals who are very anxious or seem unduly
panicked will call. These calls should receive the
same consideration as any other call to determine if
the symptoms reported are associated with the
quality of the indoor air. Under no circumstances
should a caller ever be handled in a cavalier or
demeaning manner.

In extreme cases, referral to appropriate legal or
social service agencies may be needed. Permission
of the client may be required in some jurisdictions
for referral to a physician or other health care
provider.

When asking questions, use a systematic approach,
and repeat information back to the client so poten-
tial errors will be minimized. It is important to
allow the individual to explain the problem and
symptoms, and to refrain from leading; the investi-
gator should always be aware of the potential to
lead.

After collecting preliminary information, some ideas
about possible avenues for further investigation may
emerge. This is the time to explain your capabili-
ties to the caller. Does the department handle these
types of complaints? If so, when can an investiga-
tion be scheduled? Will there be a fee for any of the

services that could be provided? Explain the
procedure for investigating a complaint; explain
your goals in investigating the complaint. If the
person wishes you to follow up, schedule an ap-
pointment.

In order to maintain a good working relationship,
be on time for scheduled inspections. It is always a
good idea to confirm an appointment by telephone.

If the investigator has any important observations
after obtaining the health and symptom history,
these should be shared with the client before
proceeding with the investigation. For example, if
the individual is concerned about radon, but is
complaining about watery eyes, it is appropriate to
let him know that watery eyes are not related to
radon exposure, but there may be other possible
explanations.

Communications During the Investigation

During the investigation, potential sources that will
be of particular interest can be identified to the
client; if nothing appears to stand out, that can also
be shared. Remember, it is anxiety-producing not
to have information. Sharing information is also
likely to result in more information and cooperation
from the client.

In some instances, the investigator may need to
speak to a client’s physician to get a more detailed
history for a specific complaint. Although it is
possible for a client to call health care providers and
give them permission to talk to the investigator,
this is not a good practice. The client should be
asked to send the physician or other provider a
release request that specifies the information that
can be released.

If contact with a physician or other health care
provider is necessary, be sure to explain your role,
obtain the needed information, identify any hypoth-
eses that you have, and get feedback from the health
care provider on your hypotheses and the reported
health complaints. The health care provider may

97


IAQ Learning Module

Final Examination

41, Which method has been most widely used to

42.

43.

44,

45.

46.

sample particles and aerosols?

a. adsorption

b. filtration

c. absorption

d. electrostatic precipitation

What is a source of systematic errors in
sampling?

lack of proper calibration
incorrect design of the sampling program
interferences

aooe

all of the above are examples of systemic
errors

Which of the following is an example of a
nonregulatory administrative approach to
the control of indoor air contaminants?

building codes

housing codes

training of investigators
ventilation standard

ao op

Which of the following is an example of a
design and maintenance strategy to control
indoor air contaminants?

use of safe building materials
indoor air contaminant standards
public information

research and development

ao rp

Which is an example of source control?

enclosing asbestos pipes

reducing humidity with evaporative coolers
opening windows while spraying pesticides
using a panel filer to control house dust

ao TP

Which of the following would be least
effective in ventilating a new energy effi-
cient home?

cross ventilation
whole house fan
infiltration and exfiltration

aoge

local exhaust ventilation

47.

48.

49.

50.

51.

The roof ventilator is an example of which
type of ventilation?

simple ventilation
cross ventilation
supply fan
exhaust fan

ooo8

Which of the following statements is
correct about air infiltration or leakage?

a. air infiltration can be effectively reduced
through the use of a continuous air or air/
vapor barrier

b. a fan pressurization test is one way of
identifying air leakage points

c. condensation in cold cavities is a concern if
air/vapor barriers are installed improperly

d. all of the above statements are correct

Through which of the following does the
exchange of outdoor air with indoor air
occur?

infiltration and exfiltration
natural ventilation
mechanical ventilation

all of the above

ao TP

Which of the following must be balanced
by an air supply in order to prevent
backdrafts if a fireplace is used?

supply fan

exhaust fan

infiltration and exfiltration
cross ventilation

aorPp

Which of the following could be added to a
central forced-air heating and cooling
system to reduce both particulate and
gaseous contaminant concentrations?

panel filcer

fresh air connection
chemical adsorbent
electrostatic precipitator

nore

Examination continues on next page



Unit 1, Lesson 5

IAQ Learning Module

identify problems and recommend solu-
tions, and participate in the policy-making
process.

* Consumers are responsible for properly
maintaining their homes and making
intelligent choices about consumer goods
and services.

Governmental Roles

Federal, scate, and local governments have signifi-
cant responsibilities in the effort to control indoor
air contamination. For other environmental health
problems, the Federal government has developed
mandatory standards directed toward limiting the
levels of contaminants in che environment, but in
the area of indoor air quality, it has taken the lead in
research and in making new information available.
This shift in ics role is due in part to the widespread
nature of indoor air quality problems and the
inherent difficulties in regulating che sources of
indoor air contaminants, especially in residences.

At the federal level, there are many agencies such as
the EPA, Department of Energy, Consumer Product
Safety Commission, Department of Transportation,
Department of Health and Human Services, and
others which are involved in indoor air quality
activities. Al! of these agencies are important
resources for consumers, the private sector, and state

and local agencies. Current information about
federal agencies, their activities, status of programs,
and contact persons can be obtained from a publica-
tion which EPA updates on an annual basis (U.S.
EPA, 1990). This publication, Current Federal
Indoor Air Quality Activities, can be obtained from
the Public Information Center, U.S. EPA, Washing-
ton, D.C. 20460.

The establishment of state and local indoor air
quality programs is an important strategy for
ensuring programs and activities that are responsive
to state and local needs. State and local govern-
ments must take the lead in identifying and study-
ing local problems and adopting appropriate control
strategies. Sometimes these activities have been
conducted with the assistance of the Federal govern-
ment (for example, the radon testing program).
EPA in conjunction with the Public Health Foun-
dation has published a document, Directory of State
Indoor Air Contacts which identifies state agencies
and agency contacts by indoor air quality contami-
nants/problems (U.S. EPA, 1988). This directory is
also available from the EPA Public Information
Center.

One of the primary ways that state and local
governments can control indoor air pollution is
through the adoption and enforcement of building
codes for the design, construction, and ventilation of
residencial and commercial buildings.



Unit 2, Lesson 6

IAQ Learning Module

Personal samplers are lightweight, quiet, and can
easily be carried or worn by a person. Although
personal samplers may be preferred for many
sampling problems, they are not available for all
contaminants. If personal samplers are not avail-
able, portable methods are usually favored over
stationary methods because they are generally less
expensive and easier to use.

Air Mover Systems

Air mover systems, which are classified as either
active or passive, transport contaminated air into the
air sampling measurement device. Particles and
gases can be sampled using either system.

Active Samplers

Active samplers (Figure 6-1) use an air mover
system powered by a pump to draw the contami-
nated air through a collector or sensor. Continuous,
integrated, or grab samples of gases or particles can
be collected; these samples can be analyzed on-site

Figure 6-1. Examples of active samplers.

or taken to a laboratory for further processing. The
volume of air moving through an active sampler and
the resulting concentrations can be determined
more accurately than with passive samplers. On the
other hand, these samplers require more training
than passive samplers, and they are also noisier and
bulkier.

Active samplers range in complexity from simple
bellows and piston pumps which are used with
colorimetric tubes or dosimeter badges to mass flow
controlled direct reading instruments.

The personal sampling pump is an active air mover
system that is widely used in indoor air measure-
ments. These compact battery-operated units can
handle flow rates from 1 ml/min to 4500 ml/min.
They are easy to operate, require minimal training,
and can sample a broad range of contaminants using
adsorption tubes, filters, bubblers, colorimetric
tubes, and air bags to collect the contaminant for
further analysis.

115V Adapter
Charge Plug

Personal Sampling Pump

A. Portable Sampler for Gases Particulate
Air In Filter
—
LJ }
Impinger a f Flowmeter
Absorbing Vacuum
Solution Pump
Trap Airflow
(also bag or
adsorption tube)
B. Personal Sampler ;
iP “toy
Sample Cartridge

Air In

(also filter, adsorption tube,
or colormetric tube)



Unit 1, Lesson 2

IAQ Learning Module

Figure 2-1. Pathways of air exchange.

Mechanical
Ventilation

Extittration

Natural
Ventilation

SOURCE: Adapted from Sandia National Laboratories (1982)

exchange is a complex process that depends on air
movement patterns and other factors (Table 2-1).
The specific molecules that are exchanged will
depend on the combined effect of all of these factors.

Generally, the outdoor air serves to dilute indoor air
contaminant levels. That is, for nonreactive con-
taminants, the difference between indoor and
outdoor levels will generally be inversely propor-
tional to the air exchange rate.

A wide range of air exchange rates (as low as 0.1 ach
to over 3.5 ach) have been measured in residential
structures (ASHRAE, 1985). Air exchange rates for
newer construction are generally in the range of 0.5
ach, but they may be as low as 0.1 ach in
superinsulated houses (Lenchek et a/., 1987).
Median air exchange rates for older low income
houses of about 0.9 ach have been reported
(ASHRAE, 1985).

Air exchange rates in mechanically ventilated office
buildings can vary significantly from their design
values, and depend, in parc, on the ventilation

system design; its installation, maintenance, and
operation; and the tightness of the building enve-
lope. In a comprehensive study of 14 buildings
covering a total of approximately 3000 measure-
ments, Persily (1989) reports that the mean value in
each building ranged from 0.29 ach to 1.73 ach
while the median value ranged from 0.41 ach to
1.65 ach. The mean value for all buildings was 0.94
ach and the median was 0.89 ach.

Infiltration and Exfiltration

Infiltration and exfiltration refer to the uncontrolled
leakage of air into or out of a structure, respectively,
through cracks and other uncontrolled openings in
the envelope of the building. The term infiltration
is sometimes used to refer co both infiltration and
exfiltration. Cracks formed as the structure settles;
leaks around windows and doors; openings for pipes,
wires, and ducts; electrical outlets and recessed light
fixtures; baseboard moldings; and connections
between structural components can all serve as
avenues for air movement.

Infiltration and exfiltration result from pressure
differences between indoor and outdoor environ-
ments. These pressure differences can be caused by
wind, temperature differences including stack
effects, or by the operation of flues, chimneys, or
exhaust fans. Air infileration and exfiltration can
vary substantially as these factors change.

Wind effect: As the wind flows over a building, an
area of positive pressure is created on the windward
(facing inte the wind) side and an area of lower
pressure results on the leeward (facing away from
the wind) side. Air is forced into the building on
the windward side, which increases the internal
pressure of the building and forces air out of the
leeward side. The pressures on the other sides of the
building can be negative or positive, depending on
the shape of the building, obstructions to airflow,
and the angle of the wind. Generally, infiltration
will increase with wind speed, and it also depends
on topography and obstacles surrounding the
building. Structures that are protected from the



Unit 2, Lesson 8

IAQ Learning Module

nurses, allergists, and pulmonary specialists should
be consulted as needed (always with permission
from the client). All of this information may be
useful in narrowing the scope of the investigation
and identifying potential indoor air quality causes of
symptoms.

Building Evaluation: Walk-Through

After the health history is obtained, the investigator
may then proceed to evaluate the structure and its
environs (Section 8 of the Reference Manual). The
client should be invited to accompany the investiga-
tor on the walk-through. A standard form should
be employed to evaluate the different systems of the
house or building both for sources of contaminants
and condition. Rooms should be evaluated to
determine if they are being used as intended. The
walk-through should also include an evaluation of
the exterior of the structure and the site. Finally,
the evaluation should identify the use of chemicals
in the building and any new events or activities
which might affect indoor air quality or health.

When conducting the walk-through, the investiga-
tor should keep an open mind. If the investigator
focuses on finding sources of a particular contami-
nant, other problems can be overlooked. The walk-
through of the home should systematically evaluate
the following areas.

© The Site
air pollution, geology and soil, water
supply (especially private sources), sur-
rounding obstacles, noise, electromagnetic
fields, accumulated bird droppings, other
potential sources of contamination

© Building Materials
roofing materials, exterior finishes, interior
surface materials, interior surface finishes,
insulating materials, signs of moisture
accumulation or damage, presence of
asbestos-containing building materials

© Heating, Ventilating, and Air-Condi-
tioning Systems
combustion and noncombustion sources,
venting of combustion sources,
backdrafting of flue gases, venting of
kitchen and bathroom, ducting materials,
humidifiers, energy conservation measures,
temperature, humidity, airflow and bal-
ance, microbial contamination, presence of
asbestos insulation

© The Foundation
drainage and condition, recent treatment or
pesticide applications

¢ The Basement
dampness and condition, recent termiticide
treatment or other pesticide applications,
radon, other soil gases

© The Crawl Space
drainage, ventilation, condition, and recent
termiticide treatments or other pesticide
applications

© Client Activities
use of chemicals and consumer products
which may produce air contaminants

© Building Interiors
changes in building or room use; changes in
interior design; recent decorating changes
or renovation; evidence of mold; condition
of appliances; presence of unvented com-
bustion appliances

° Attached Garage
potential flow of contaminants into the
living space

During the walk-through, the investigator should
mentally review the reported health effects, poten-
tial sources of contaminants, and the condition of
different systems in the building. This helps the



UNIT 1: UNDERSTANDING INDOOR AIR QUALITY

LESSON 3
HUMAN RESPONSE TO INDOOR AIR QUALITY:
Principles of Toxicology

Many sources of indoor contaminants release hundreds, perhaps
thousands, of chemical and biological agents into the air. These
contaminants do not exist in isolation; they are present in complex
mixtures which have been referred to as “chemical soups.”

We are used to thinking in terms of people reacting adversely to
individual contaminants, and much of our knowledge about toxicol-
ogy follows from that framework. However, individuals can react
adversely to cumulative or interactive indoor stresses which include
mixtures of contaminants and the stresses from temperature, humid-
ity, light, or noise conditions. Human reactions to these stressors can
also be affected by psychological or social factors in the individual’s
environment. In addition, there are significant differences in
individual sensitivities to various environmental parameters.

The purpose of this lesson is to help develop a broad framework for
understanding and interpreting human response to indoor air
quality contaminants and stressors.

LESSON OBJECTIVES

At the end of this lesson, you
will be able to:

© identify the general types of health
and discomfort effects which can
result from inadequate indoor air
quality,

© identify methods used to study
health effects;

© identify factors which affect potential
health risks of contaminants;

© discuss the concepts of concentration,
exposure, and dose; and

© identify susceptible subgroups of the
population.



UNIT 1: UNDERSTANDING INDOOR AIR QUALITY

LESSON 5
CONTROLLING INDOOR AIR QUALITY

There are three basic strategies for controlling the indoor air envi-
ronment. First, engineering strategies (source control, ventilation,
air cleaning) can be used to reduce levels of contaminants. Second,
good building design and proper operation and maintenance of
equipment ensure the success of engineering controls. Third, admin-
istrative controls, including both regulatory and nonregulatory
government policies, encourage or require the use of controls by
various parties such as manufacturers, building professionals, and
other individuals.

This lesson provides a summary of engineering control strategies;
discusses the importance of building design, operation procedures, and
maintenance procedures; and summarizes the potential use of admin-
istrative controls through public and private sector programs.

LESSON OBJECTIVES

At the end of this lesson, you
will be able to:

© identify source control options for
products and equipment that can be
used to reduce contominant
concentrations;

© discuss the dilution and exhaust of
contaminants by ventilation;

© discuss the removal of contaminants
by air deaning devices;

© identify and discuss design,
operation, and maintenance
strategies that can be used to control
indoor air quality; and

© identify and discuss administrative
control strategies and the roles of
public and private sectors in
controlling indoor air quality.



Unit 2, Lesson 8

IAQ Learning Module

INVESTIGATION PROTOCOLS (RM 8)

As yet, there are no widely accepted
standard methods or protocols for indoor air quality
investigations, particularly residential investiga-
tions. This should not be interpreted to mean that
none should be used. In fact, it must be emphasized
that a systematic approach is needed in both
residential and nonresidential investigations. Several
approaches have been developed for nonresidential
investigations, (Woods et al., 1989; Sterling et al.,
1987; NIOSH, 1987). and these can either be used
directly or adapted for a particular purpose. Several
professional associations are also developing or
considering the development of protocols for indoor
air quality investigations. For example, the Ameri-
can Society for Testing and Materials (ASTM) has
established Subcommittee D22.05 on Indoor Air to
develop standard methods and practices applicable
to indoor air quality surveys and investigations.
The Indoor Air Division of EPA can also be con-
tacted for the latest EPA information and guide-
lines.

While standard protocols are limited, there are basic
principles which are emerging as statements of good
practice in investigating complaints, regardless of
the type of building. The investigation of indoor air
quality problems is similar to detective work; the
investigator must search through the potential clues
carefully to solve the case. Because of the inherent
potential complexity of many indoor air quality
problems, it has been recommended that a multi-
disciplinary team of individuals with expertise in
the measurement of contaminants, building sys-
tems, and health effects should be employed to
evaluate complex indoor air quality problems. This
approach may be required, for example, in the
investigation of high rise office buildings. How-
ever, the majority of indoor air quality complaints,
especially in residences and smaller buildings, can
often be handled by a knowledgeable person who
understands the technical framework for solving
indoor air quality problems. This lesson develops an
investigation strategy for residences and smaller
buildings. Some aspects of large office building

investigations will differ from the approach outlined
in this lesson and additional guidance can be
obtained from the previously mentioned sources.

STANDARDIZED SURVEY FORMS (RM 8)

Several stages are involved in gathering
information in an indoor air quality investigation
(see below). In each of these stages, survey forms
(questionnaires, activity logs, checklists) may be an
important way of gathering information in a
standard form. These forms (sometimes called
instruments) can be developed for individual
projects or “off-the-shelf” forms can be used.

Two basic types of forms are used for investigations:

© Questionnaires consist of a series of
questions posed either by the investigator
in person, over the telephone, or by mail to
the subject about him/herself, other
occupants, or the structure. The investiga-
tor can also complete a questionnaire about
the structure without the input of the
occupant during a walk-through of the
structure (discussed below). Questionnaires
can include open-ended questions or simple
yes/no questions. Forms with yes/no type of
responses are sometimes called checklists.

© Activity logs are diaries that are kept by the
occupant on his/her activities during the
course of a day, week, month, or longer.
The activity log may require the occupant
to note either in longhand or on a checklist
when certain activities occur (for example,
turning on a kerosene heater) and when
symptoms occur.

In any investigation, procedures should be devel-
oped to ensure that the confidentiality of informa-
tion contributed by clients is protected.

For most routine investigations of residential
properties, a single instrument can be used to
evaluate health complaints and the systems of the



IAQ Learning Module

Unit 1, Lesson 3

REFERENCES

‘American College of Physicians. 1989. “Clinical ecology.”
‘Ann. Intern, Med. 111; 168-78.

Ashford, N.A. and C.S. Miller. 1989. Chemical Sensitivity: A
Report to the New Jersey State Department of Health. December.

Berglund, B. and T. Lindvall. 1986. “Sensory reactions to ‘sick
buildings.” Environ. Intl, 12: 147-159.

Black, Donald W, .A. Rathe, and R.B. Goldstein. 1990.
“Environmental Hlness: A Controlled Study of 26 Subjects with
“20th Century Disease’.” J. Am. Med. Assoc. 264 (24); 3166-
3170,

Calabrese, EJ. 1978. Pollutants and High-Risk Groups. The
Biological Basis of Increased Human Susceptibility to Environmental
and Occupational Pollutants, John Wiley & Sons: New York,
NY.

Colligan, MJ. and L.R. Murphy. 1979, “Mass psychogenic
illness in organizations: An overview.” J. Occup. Psychol. 52:
77-90.

Colligan, MJ. 1981. “The psychological effects of indoor air
pollution.” Bull, N.Y. Acad. Med. 57(10): 1014-1026.

Colligan, MJ. and M.J. Smith. 1978. “A methodological
approach for evaluating outbreaks of mass psychogenic illness in
industry.” J. Occup. Med. 20: 401-402.

Cullen, M.R. 1987. “The worker with multiple chemical
sensitivities: An overview of workers with multiple chemical
sensitivities.” Occupational Medicine, State of the Art Reviews.
Vol. 2, No. 4. Hanley and Belfus, Inc.: Philadelphia, PA.

Faust, HS. and L.B. Brilliant. 1981. “Is the diagnosis of ‘mass
hysteria’ an excuse for incomplete investigation of low-level
environmental contamination?” J. Occup. Med. 23: 22-26

Fischman, M.L. 1990. “Building associated illness.” Chap. 33.
Occupational Medicine. J. LaDou (ed). Appleton & Lange: East
Norwalk, CT.

Kahn, E. and G. Letz. 1989. “Clinical ecology: Environmental
medicine or unsubstantiated theory?” Arn. Intern. Med. 111:
104-105.

Kreiss, K. and M.J. Hodgson. 1984. “Building associated
epidemics.” Chap. 6. Indoor Air Quality. P.J. Walsh, CS.
Dudney, and E.D. Copenhaver (eds). CRC Press: Boca Raton,
FL.

Molhave, L. 1985. “Volatile organic compounds as indoor air
pollutants.” Chap. 31. Indoor Air and Human Health, R.B.
Gammage and S.V. Kaye (eds). Lewis Publishers: Chelsea, MI.

Samet, J.M. 1985. “Defining an adverse respiratory health
effect.” Am. Rev. Resp. Dis, 131 (4): 487.

US. Environmental Protection Agency (EPA). 1986a.
“Guidelines for carcinogen risk assessment.” Federal Register.
51 (185): 33991-34003. Seprember 24.

USS. Environmental Protection Agency (EPA). 1986b.
“Guidelines for mutagenicity risk assessment.” Federal Register.
51 (185); 34005-34025. September 24.

USS. Environmental Protection Agency (EPA). 1986c.
“Guidelines for the health risk assessment of chemical mix-
cures.” Federal Register. 51 (185): 34013-34025.
September 24.

USS. Environmental Protection Agency (EPA). 1986d.
“Guidelines for the health assessment of suspect developmental
toxicants.” Federal Register. 51 (185): 34028-34040.
September 24.

USS. Environmental Protection Agency (EPA). 1986e.
“Guidelines for exposure assessment.” Federal Register.
51 (185): 34041-34054. September 24.

US. Environmental Protection Agency (EPA), 1989. Report t0
Congress on indoor air quality. Vol. I: Assessment and control of
indoor air pollution, EPA 400-1-89-001C. U.S. EPA, Office of
Air and Radiation: Washington, DC.

World Health Organization (WHO). 1986. Indoor Air Quality
Research. EURO Reports and Studies 103. WHO:
Copenhagen, Denmark.

World Health Organization (WHO). 1987. Air Quality
Guidelines for Europe. WHO: Copenhagen, Denmark.



IAQ Learning Module

Unit 1, Lesson 2

wind will have reduced infiltration compared to
those without protection, assuming all else is equal.

Stack effect: The stack effect results from the
tendency of hot air to rise in a column within a
room, up a stairwell in a multi-story building, or
through a solar air shaft, stack, or vertical flue.
During the winter, the differences between indoor
and outdoor temperatures cause warm air to rise,
creating a positive pressure which forces air through
available openings in the top of the structure. At
the same time, reduced air pressure at lower levels
draws in colder air to replace the escaped air

(Fig 2-2). The stack effect is greater in tall struc-
tures or when the difference between the inside and
outside temperature is large.

During the summer, the flows may be reversed and
are generally less dramatic because the temperature
difference between the inside and outside of the
structure is smaller.

Combustion effect: Air leakage can also be affected
by wood stoves, fireplaces, and any other combus-
tion heating systems. If indoor air is used for
combustion, a negative pressure results inside, and
room air that is exhausted through a flue or chim-
ney is replaced by outdoor air. An operating
fireplace, using indoor air for combustion, can
nearly double the infiltration rate; using outside air
for combustion does not have as significant an
effect. A continuous stack effect can occur in
chimneys or flues if the damper is open, or missing,
even if the appliance is not operating.

When the stack or chimney effect is strong, infiltra-
tion increases. However, when the chimney or stack
draft is weak, infilcration decreases and “backdrafts”
can occur, pulling combustion products back into
the living space.

Neutral pressure level: Because of the positive and
negative pressure effects, some infiltration and
exfiltration will occur in all structures. However, at
some locations in the structure, the internal pressure
will equal the external pressure. These points are

called the neutral pressure level (NPL), neutral
plane, or zero pressure point. The NPL depends on
how easily air infiltrates or exfiltrates; it does not
depend on how much air moves into or out of the
structure (ASHRAE, 1989).

Above the NPL, the interior pressure is greater than
the exterior pressure and air flows out of the struc-
ture. This is the normal case during the heating
season. Below the NPL, the exterior pressure is
greater than the interior pressure and air infiltrates
more easily. The position of the NPL can be
changed through the use of vents, dampers, and
fans.

The location of the NPL has practical implications.
For example, a high NPL ensures that airflow
through the structure is in the form of infiltration,
which, in turn, minimizes the likelihood of conden-
sation in cold isolated cavities. However, if the
NPL is located too high, backdrafting can occur.

Natural Ventilation

Natural ventilation is air that is supplied to the
interior of a structure by windows, doors, or other
openings that can be controlled. Natural ventila-
tion occurs because of temperature and wind
differences that cause air to flow through the

openings.

Simple ventilation is a weak force that is driven by
internal heating. It can be used to ventilate a single
floor by allowing warmer air to exit through high
openings and allowing fresh air to replace escaped
air through lower openings. Cross ventilation is a
strong force, driven by wind pressure, that moves air
horizontally across one floor of a house. When a
breeze blows, air flows into available openings on
the upwind side and out of openings on the down-
wind side.

Mechanical or Forced Ventilation

Mechanical ventilation refers to supplying air by
means of fans and ducts. These can be installed to



Unit 1, Lesson 5

IAQ Learning Module

Until recently, tests evaluating the removal of
gaseous contaminants by activated carbon have been
conducted using high concentrations of contami-
nants. Recent work by EPA suggests that the useful
lifetime of activated carbon filters at the low
concentrations (ppb range) typically found in indoor
air may be short because contaminants quickly
penetrate the 6-inch deep carbon filters which are
currently marketed for odor control in in-duct
systems (Ramanathan ef a/., 1988). Another
concern is the ability of activated carbon to reemit
trapped contaminants (U.S. EPA, 1990).

Adsorbents can be impregnated with other chemi-
cals (potassium permanganate, phosphoric acid,
sodium sulfite, sodium carbonate, and metal oxides)
to improve their performance. Activated charcoal
alone, for example, is not effective for compounds
with low molecular weights such as formaldehyde.
Formaldehyde can be adsorbed by sorbents such as
activated alumina impregnated with potassium
permanganate and by activated carbon impregnated
with sodium sulfide. However, effectiveness of
formaldehyde removal during residential applica-
tions has not been verified, and some data suggest
that large quantities of sorbent and high air flow
rates may be needed for effective removal.

Effectiveness of Air Cleaners

Efficiency vs effectiveness: Efficiency is a term that
refers to the ability of the collecting medium to
capture contaminants from the airstream that passes
through it. Efficiency is usually expressed as a
percent. The effectiveness of an air cleaner refers to
its ability to reduce particulate concentrations in the
room air. The effectiveness of an air cleaner is
determined by its efficiency, the amount of air
handled, position in the room, and other factors.

Ic is important to distinguish between efficiency
and effectiveness. A filter may be rated 99%
efficient which means that it will remove 99% of
the particles that move through it, but if the filter
has a low flow rate (if it only handles 10 cfm) it will
take a relatively long time to treat the air ina

typical room of 1000 ft®. This filter can be de-
scribed as efficient, but it is not effective.

Particulates; There is controversy about the ability
of air cleaners to reduce the health effects produced
from larger particles such as pollen, house dust,
molds, animal dander, and some other allergens. It
is thought that these larger particles setcle on
surfaces before they can be captured by the air
cleaning device.

Pollen and some molds, however, can be effectively
controlled by an air conditioner. Also, it appears
that some household dust allergens can be as
effectively controlled by impermeable coverings on
mattresses as by air cleaners (U.S. EPA, 1990).

There are several factors which can affect the
performance of particle air cleaners. For example, if
filters do not fit snugly into holders, effectiveness
decreases because air bypasses the filter. Some
portable units, in particular, may not have effective
seals. Also, air cleaners should be properly sized for
the space to be cleaned. Undersized units will not
be effective.

The placement of portable devices is important.
When sources are known, units should be placed so
that the intake is near the source. The outlet of air
cleaners should not be blocked by walls, furniture,
or other obstructions.

The efficiency of air cleaning filters is rated by
ASHRAE Standard 52-76. This standard allows the
efficiency of different units to be compared with one
another, but it does not rate the effectiveness during
use. A more recent standard developed by the
American National Standards Institute and the
Association of Home Appliance Manufacturers
(ANSI/AHAM AC-1-1988 standard) rates the clean
air delivery rate (CADR) for portable air cleaners
while in use (AHAM, 1988). The CADR is a
measure of the volume of air that a device cleans of a
specific test contaminant. A CADR rating of 100
for dust means that the air cleaner may reduce dust
particles to the same concentration as would be



IAQ Learning Module

Final Examination

10.

i.

12.

Which of the following statements is
correct about providing natural ventilation
through windows?

a. windows should be placed at the same level
and near the ceiling for the most effective
ventilation

b. inlet and outlet openings of unequal size
provide the greatest flow per unit area of
total opening

c. windows should be located opposite one
another to increase ventilation flow

d._abank of windows should be oriented on
the leeward side of a building to provide
the greatest inflow of air

Which of the following statements about
health studies is correct?

a. animal studies can be conducted using
invasive techniques that would not be
allowed in human studies, and they provide
daa at exposures that are typical of indoor
aif concentrations

b. epidemiologic studies can evaluate the
effects of contaminants as people conduct
their day-to-day activities, but it can be
difficult to separate the effects of some
factors

c. human exposure studies can be conducted
on healthy and ill subjects, and experimen-
tal conditions can be strictly controlled

d. risk assessments are based solely on
epidemiologic studies because of the
limitations associated with animal and
human exposure studies

Which term correctly identifies the occur-
rence of eye, nose, and throat irritation in a
person who walks into a new home?

acute effect
chronic effect
subtle effect
delayed effect

ao>ge

13.

14,

15.

Which of the following is not a factor that
determines whether or not health effects
will result from exposure to indoor con-
taminants?

physical properties of the contaminant
age and body size

humidity level

education level

aorPp

Which of the following are important

properties of gases or particulates that
determine whether they will affect the
pulmonary region of the lung?

particle size and shape
solubility

chemical characteristics
all of the above are correct

aore

Which of the following statements about
dose is correct?

a. as the dose increases, effects usually reach a
plateau and then decrease

b. a person at rest receives a greater dose than
one who is active because the air is in
contact with che lungs for a greater length
of cime

c. the dose received through skin absorption is
greater than through inhalation because
chemicals are directly absorbed into the
body

d. two people who are exposed to the same
concentration of chemicals may or may not
receive the same dose

Examination continues on next page



IAQ Learning Module

Final Examination

25. Which of the following is an asphyxiant
that is released by combustion sources?

26.

27.

28.

29.

aoe

nitrogen dioxide
carbon monoxide
sulfur dioxide
respirable particles

Which of the following is a potential
carcinogen which can be emitted from
water, some building materials, and the

soil?

a. lead

b. trichloromethane
c. PCBs

d. radon gas

Which of the following could be present in
painted surfaces in older structures and
could result in mental retardation?

a.
b.
c
d

benzene
cadmium
lead
styrene

Which of the following provides a real-
time record of contaminant concentrations?

Bore

grab sampler
integrated sampler
continuous sampler
passive sampler

Which of the following statements about
passive samplers is correct?

aooe

passive samplers utilize pumps to move air
passive samplers are difficult to use

passive samplers have limited accuracy
passive samplers can only be used to sample
particles

30.

31.

32.

33.

Which of the following statements about
active samplers is correct?

a. active samplers are limited to a narrow
range of flow requirements

b. am active sampler that is widely used in
indoor investigations is the personal
sampling pump

¢. active samplers are less accurate than
passive samplers

d. active samplers require less training than
passive samplers

Which of the following describes the
collection of gases using a process in which
the gas is attracted to, concentrated in, and
retained on a substrate?

a. electrostatic collection
b. adsorption

¢. impaction collection
d. absorption

Which of the following describes a method
of collecting gases in which they are trans-
ferred to and dissolved in a liquid or solid?

a. absorption

b. inertial collection

c. adsorption

d. centrifugal collection

Which of the following statements about
colorimetric indicator tubes is true?

a. they accurately measure contaminants

b. they do not require special handling

c. they can be used to sample both gases and
particles

d. they are generally not recommended for
indoor air quality investigations

Examination continues on next page



Acknowledgements

IAQ Learning Module

Minneapolis Department of Environmental Health,
Minneapolis, MN

Montgomery County Public Schools, Rockville, MD

Plano Health Department, Plano, TX

Southeastern Health District, Pocatello, ID

State College Health Department, State College, PA

Other Organizations

Department of Environmental Health, East Carolina
University, Greenville, NC

Indoor Air Quality and Safety Research,
Gas Research Institute, Chicago, IL

Sponsoring Organizations

National Environmental Health Association

Executive Director: Nelson Fabian
Project Coordinators: Terry Johnson
Larry Marcum

Grants Assistant: Geraldine Struenesee

U.S. Department of Health and Human Services

Project Officer: Barry Stern, M.P.H., R.S.
Bureau of Health Professions
Health Resources and Services

Administration
U.S. Public Health Service

U.S. Environmental Protection Agency

Project Officer: David H. Mudarri, Ph.D.
Indoor Air Division
Office of Air and Radiation
US. Environmental Protection Agency



Unit 2, Lesson 7 IAQ Learning Module

U.S. Department of Labor (DOL). 1989. “Occupational Safety World Health Organization (WHO). 1987. Air Quality
and Health Standards.” Code of Federal Regulations, Title 29, Part Guidelines For Europe. WHO: Copenhagen, Denmark.
1910.

1. What ore the differences between pubic heath and occupational heath standards and guidelines?
2. What ore the primary public health stondords or guidelines that are applied to indoor cir qual problems? Briefly describe
each,

3. What is a source emission standard? Give an example.

4. What ore the some of the ventilation stondards guidelines that ore applied to indoor air quality problems? Briefly describe each
and identify the main provision of each.

5. Discuss the advantages and disadvantoges of existing standards /quidelines for indoor air quality contaminant levels and
ventilation.



Unit 1, Lesson 4

TAQ Learning Module

Pulmonary Toxicants

Acute and chronic exposure of the respiratory tract
to irritants over a long period of time may be
associated with increased susceptibility to bacterial
infection, decreases in pulmonary function, changes
in airway reactivity, and the development of lung
diseases, including cancer.

Depending on particle size and the solubility of
particles and gases, irritant contaminants can affect
the upper or lower respiratory tract. Large particles
and very soluble chemicals such as sulfur dioxide
primarily affect the upper respiratory tract, while
smaller particles and less soluble chemicals such as
nitrogen dioxide and ozone affect primarily the
middle and lower respiratory tract. Pulmonary
toxicants also include airborne pathogens and
allergens. Over time, pulmonary toxicants can
contribute to the development of emphysema,
bronchitis, pneumonitis, and changes in pulmonary
function.

Emphysema (derived from the Greek, meaning
bodily inflation) is a condition in which the air sacs
in the lung become overinflated because the bron-
chioles that feed air into the air sacs become hyper-
trophied and lose their elasticity. This means that
air can flow easily into the air sacs, but it cannot
flow out because the bronchioles are too narrow.
Because the person cannot exhale efficiently, the air
remains in the air sacs. As air pressure builds up in
the cells of the air sacs, the cells rupcure and over
time the air sac comes to resemble a balloon rather
than a cluster of grapes. There is less surface area for
gas exchange to take place and the individual
becomes oxygen deficient. Emphysema is com-
monly associated with smoking and some occupa-
tional exposures to contaminants, and the main
symptom is shortness of breath which is likely to
become worse over a period of years.

Bronchitis is a condition in which the lining of the
bronchi or bronchial tubes becomes inflamed.
Acute bronchitis is usually caused when the same

viruses that cause colds spread into the bronchi, but
sudden increases in air pollution have also been
implicated. Chronic bronchitis has been defined as
a recurrent cough with phlegm production that
occurs on most days during at least three months a
year, usually in winter, for at least two consecutive
years (Kung, 1982).

Bronchitis and other lower lung infections, particu-
larly in children, have been associated with exposure
to indoor air contaminants including environmental
tobacco smoke, respirable particulates, nitrogen
oxides, and sulfur dioxide. Chronic bronchitis
(“smoker's cough”) is typically caused by cigarette
smoke.

Both acute and chronic bronchitis result in cough-
ing and the production of phlegm. Other symp-
toms may include breathlessness, wheezing, fever,
and pain in the upper chest which gets worse when
the individual coughs. If chronic bronchitis is not
treated, it can progress into either pneumonia, or
over a longer period of time, emphysema.

Pneumonitis, alveolitis, and pneumonia are terms
thar refer to an inflammation of the lungs. These
conditions are usually caused by exposure to physi-
cal agents (pneumonitis), microorganisms (pneumo-
nia), and allergic reactions (alveolitis). The terms
alveolitis and pneumonitis are sometimes used
interchangably. Examples of causative agents
include irritant gases and dusts, airborne bacteria
and viruses, and airborne allergens such as mold,
mites, and feathers. Symptoms of all three types
include coughing, difficulty breathing (dyspnea),
fever, chills, and muscle pains.

Chronic pneumonitis and alveolitis can result from
repeated exposures to low levels of the agent or from
recurrent acute episodes. Chronic symptoms
include difficulty breathing, cough, fatigue, and
weight loss; fever is uncommon. Repeated expo-
sures to the agent can result in progressive lung
scarring.



Answer Sheet IAQ Learning Module

ANSWER SHEET

1. AB C D 23. A B C D 45. A B C D 67. A B C D
2 A B C D 24. A B C D 46. A B C D 68. A B C D
3. A B C D | 2. A B C D | 47. A B C D {| 6. AB C D
4. A B C D 2. A B C D 42. A B C D 70. A B C D
5. A B C D | 27. AB C D/] 4. AB C D|v7lsAB C D
6 A B C D | 2.A B C D 50. A B C Dj 72.A B C D
7. A B C D 22. A B C D sl. A B C Di 73. AB C D
8 A B C D 30. A B C D 52. A B C D 74. A B C D
9 A B C D 31. A B C D 533. A B C D 7. A B C D
10 A B C D 32. A B C D 54. A B C D 7. A B C D
11, A B C D 33. A B C D 55. A B C D 77. A B C D
12 AB C D | 34. 4 B C D 56. A B C D 73. A B C D
13. A B C D 35. A B C D 57. A B C D 79. A B C D
14. A B C D 36. A B C D 58. A B C D 80. A B C D
15. A B C D 37. A B C D 59. A B C D | 8l.AB CD
16. A B C D 38. A B C D 6. A B C D 82, A B C D
17, A B C D 39. A B C D 61. A B C D 33. A B C D
18. A B C D | 4. A B C D | 62 A B C D 84. A B C D
19 A B C D/ 41. A B C D } 6. A B C D 8. A B C D
20. A B C D | 42. A B C D | 64 A B C D 86. A B C D
2. AB C D |} 4. A B C D |} 6. A B C D

22 A B C D | 4 AB C D | 6. AB C D



IAQ Learning Module

Unit 2, Lesson 8

investigator to develop a picture of the total envi-
ronment and how that environment could contrib-
ute to indoor air quality problems.

Special attention should be given to indicators of
inadequate ventilation in residential and non-
residential investigations. The investigator should
always consider evaluating humidity, temperature,
and airflow in the home to complete the basic
profile. In addition, the adequacy of outdoor air (and
perhaps carbon dioxide as an indicator of the
adequacy of ventilation) should be considered in the
evaluation of nonresidential buildings. After this
preliminary information has been obtained, the
investigator can decide whether or not to sample for
the presence of indoor air contaminants. In many
investigations, the walk-through and health
effects screening are enough to identify the
problem, and the measurement of contaminants
is not needed.

Characterizing Contaminants

If the investigator decides that a characterization of
contaminants is needed, sampling can be conducted
on-site if the equipment is available. If not, a
follow-up appointment is required. It is best to
evaluate carefully the results of the health screening
and the inspection before making a decision to
monitor in order to maximize resources and mini-
mize disruption by repeat visits. Testing should be
selective and include only those contaminants or
agents suspected of causing problems. An exception
to this selective approach is sampling for radon
(recommended by EPA for all residences) and
identifying potential asbestos-containing materials.

Monitoring for contaminants and physical param-
eters should be conducted in a systematic fashion to
characterize both worst-case and average exposures.
Knowledge of both of these exposures is needed to
evaluate the potential risk to those who are exposed.
Average exposures refer to conditions that usually
exist in the household. In order to obtain worst-case
exposures, conditions may require modification.
Short-term sampling (for example, for radon,

formaldehyde) requires that the house be closed as
much as possible for 12 hours before sampling and
during sampling.

Contaminants should be sampled where and when
symptoms are experienced, where the individual
spends the most time, and where suspect sources are
located. The investigator must sample for a suffi-
cient time to collect samples that will yield mean-
ingful data.

Proper placement of samplers is critical. Samplers
should be located at breathing height. They must
be located away from dead air spaces; locations next
to windows and doors may bias results due to high
infiltration/exfiltration. Samplers should be located
sufficiently away from objects such as curtains and
partitions that affect air flow.

In some situations, it may be appropriate to test
materials (for example, potable water from private
wells for radon or VOCs, and insulation for asbestos).

Evaluation and Reporting of Results

The evaluation of the health, inspection, and
monitoring data is perhaps the most difficult aspect
of the investigation for several reasons.

© There is considerable variability in human
response to contaminants, and many of the
symptoms resulting from exposure to
indoor air contaminants are similar to those
of other health problems and stress.

© There is a lack of standards and guidelines,
and even when standards or guidelines
exist, they cannot be used in a cut-and-
dried manner because of the variability in
response.

* The symptoms experienced may be from
exposure to multiple contaminants at
relatively low levels of exposure. Analysis
of individual contaminants in these circum-
stances will not yield meaningful results.



IAQ Learning Module

Unit 1, Lesson 4

Airborne pathogens are infectious disease-producing
agents such as viruses, fungi, and bacteria that are
disseminated through the air. Common diseases
that are spread by aeropathogens include influenza
(virus), adenovirus and coxsackie respiratory diseases
(virus), and coccidioidomycosis (fungus); other
important diseases include Legionnaires’ disease
(bacterium), Pontiac fever (bacterium), and hyper-
sensitivity pneumonitis (a variety of agents).

Allergens are substances that cause an allergic
reaction in susceptible individuals. The allergic
individual produces large amounts of an antibody
when exposed to an allergen to which the individual
is sensitive. When an antigen-antibody reaction
takes place, histamine and other substances are
released. Effects include dilation of blood vessels,
mucus secretion, contraction of the bronchioles, and
cellular inflammation.

Physical Stressors

Physical stressors such as temperature, humidity,
light levels, and noise can result in a variety of
symptoms which usually produce discomfort. More
severe symptoms and dysfunction, however, can
result if physical stressors are not corrected within
reasonable periods of time.

Thermal Environment

A comfortable thermal environment is a function of
many variables including temperature, humidity,
ait movement, activity level, clothing, and culcural
practices and habits. It should be noted that
guidelines can provide ranges of temperature,
humidity, and air movement that will be perceived
to be comfortable by most, but not all, people.
Further, comfort ranges developed for the United
States may not be valid for other countries where
practices are different.

Temperature conditions affect the human organism
in several ways. The temperature of the body is
normally in the range of about 97.7°F to 99.5°F.
When room temperatures are too cool, the body

reacts by shivering and vasoconstriction (narrowing
of the blood vessels). Vasodilation (widening of the
blood vessels) and sweating occur in warm environ-
ments. Both of these reactions to warm or cool
temperatures are perceived as uncomfortable, and
individuals may react with complaints. Complaints
about stuffiness are more likely to occur in rooms
that are too warm, and complaints about drafts are
more likely co occur in rooms that are too cool.

In the United States, most sedentary or slightly
active people who are in a room with slow air
movement will probably be comfortable at tempera-
tures in the range of 68°F to 75°F during the winter
and in the range of 73°F co 79°F during che summer
(ASHRAE, 1981). It should be noted that infants,
some elderly people, and those whose movements
are confined may require temperatures at the upper
end of the range or higher for comfort. The
ASHRAE guidelines for thermal comfort also
recommend vertical temperature differences of not
more than 5°F from a level of 4 to 67 inches from
the floor.

Humidity is the amount of water vapor within a
given space, and it is commonly measured as the
relative humidity (RH). Relative humidity is
defined as the percentage of moisture in the air
relative to the amount it could hold if saturated at
the same temperature. Humidity in the air has both
direct and indirect effects of people. Low relative
humidity (dry air) can dry the mucous membranes
and irritate the eyes, nose, and throat. Dry air can
also exacerbate respiratory infections and increase
problems with allergic and asthmatic symptoms.
Air that is too humid feels oppressive, especially if
combined with higher temperatures. Relative
humidities less than 30% and greater than 70% are
perceived as uncomfortable by many people.
Relative humidity above 50% can enhance micro-
biological growth.

Air movement will also affect perceptions of
comfort. Air movement less than 30 feet per
minute (fpm) in the winter and less than 50 fpm in
the summer is recommended (ASHRAE, 1981). If