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Clemson University Cooperative Extension Service
South
Carolinians want their homes to be free from indoor air pollutants
and toxic substances that can affect the health of children
and other family members. You spend 80 to 90 percent of your
time indoors, and you may have family members with health
conditions which are affected by pollutants.
While
pollutant levels from a single source may not be a health
risk, some homes have many sources which contribute to indoor
air pollution. Fortunately, there are ways to control or eliminate
most pollutants at a relatively low cost. These control measures
will help you to achieve a healthy house.
This
publication answers common questions about indoor air pollutants
and discusses ways to reduce or eliminate the problems. For
additional information about radon, contact the Clemson University
Housing Institute or your County Extension Office for copies
of "A Citizen's Guide to Radon," "How to Reduce Radon Levels
in Your Home," and "Home Buyers and Sellers Guide to Radon."
Indoor
air pollution results when man-made and natural chemicals,
gases, particles, and other substances are produced or released
in or near the home. Common pollutants found in homes are
volatile organic compounds, formaldehyde, particulates, radon,
asbestos, and combustion gases and by-products.
These
pollutants come from a variety of sources such as household
cleaning products, wood or fuels that are burned, building
materials and products, furnishings, paint strippers, pesticides,
the soil under a house, and human activities.
Some
sources, like air fresheners, release pollutants almost continuously.
Others, like unvented space heaters, produce pollutants occasionally
or when they are used.
Pollution
standards exist for outside air and for the work place, but
there are no standards for pollutant levels in the home. However,
when homes have been monitored, pollutant levels indoors have
sometimes exceeded "safe" outdoor or work levels.
An "acceptable"
pollution level in your home may depend on such varied factors
as:
- whether
or not family members have chronic illnesses - especially
respiratory or illnesses aggravated by pollutants
- whether
there are children or elderly family members who may be
more sensitive to pollutant effects
- whether
products or materials used in the home produce pollutants
and how often they are used
- the
effectiveness of your home ventilation system and the distribution
of air throughout the house
You
may feel the effects of exposure to an indoor pollutant immediately
after exposure, or the problem may not show up until years
later. Immediate effects include irritation of the eyes, nose,
and throat; headaches; dizziness and fatigue. Age, preexisting
conditions, and sensitivity to the pollutant can all affect
whether a person reacts to a pollutant.
Other
health effects may show up years after exposure or after repeated
or long exposure. These effects can include central nervous
system damage, chromosomal damage, and cancer. Health effects
associated with some indoor air pollutants are summarized
in following table.
Table
I: Common Indoor Air Pollutants, Sources, Health Impacts,
Controls and Detection
Pollutant |
Sources |
Health
Impacts |
Controls* |
Detection |
Asbestos
|
Insulation on pipes and ducts, wood stove gaskets, ceiling
tiles, resilient flooring and tiles, thermal insulation;
deteriorating, damaged or disturbed insulation, fireproofing,
or acoustical material |
Lung cancer, asbestosis, mesothelioma |
Do not disturb existing asbestos containing materials;
for asbestos-containing materials that are friable (flaking
or crumbling), coat with a sealant, enclose with airtight
structure or have removed by a professional asbestos abatement
contractor. |
Bulk sample sent to lab for analysis: contact your county
Extension office or DHEC for a list of laboratories; air
sample taken by industrial hygienist using special equipment.
|
Biological
contaminants |
Molds, mildews, fungi, bacteria, viruses, dust mites;
wet or moist walls, ceilings, carpets and furniture; poorly
maintained humidifiers, dehumidifiers, and air conditioning;
bedding, household pets |
Allergies, respiratory irritation, infectious diseases;
eye, nose and throat irritations; fever; humidifier fever;
influenza |
Control relative humidity in house; ventilation and use
of outside vented exhaust fans; if humidifiers are used,
clean reservoir daily with chlorine bleach or disinfectant,
or follow manufacturer's instructions for cleaning; seal
ductwork, especially those located in crawl spaces.
|
Air sample taken by industrial hygienist using special
equipment; odor of mold and mildew; relative humidity
can be checked with sling psychrometer or humidity sensor.
|
Combustion
Products |
Unvented space heaters (natural gas, kerosene, fuel oil,
and charcoal), unvented gas stoves, wood stoves and fireplaces;
tobacco smoke; human respiration; outside air
|
Headaches, drowsiness, dizziness (carbon dioxide); impairment
of vision and brain functioning, irregular heart functioning,
nausea, mental confusion, death (carbon monoxide); respiratory
distress and lung damage (nitrogen dioxide) |
Supply adequate combustion air for appliances, especially
by use of outside air for combustion; have gas or oil
furnaces and exhaust systems checked annually; use exhaust
fans vented to outside; use catalytic converters on wood
burning heaters; air cleaners. Eliminate use of kerosene
space heaters. |
Inexpensive carbon monoxide monitors available; check
with county Extension office, county health department.
No simple test for carbon dioxide; check with county health
department. Dosimeters available for nitrogen dioxide
available from industrial health and safety supply companies;
check with county Extension office, county health department;
consult gas utility supplier. |
Formaldehyde
|
Pressed wood products (hardwood plywood wall paneling,
particle board, fiberboard) and furniture made with these
pressed wood products; ureaformaldehyde foam insulation
(UFFI) and furnishings made with ureaformaldehyde; finishes
on home textiles, durable press drapes, and some glues
|
Irritation of skin, eyes, nose and throat; respiratory
irritation, respiratory function impairment; cancer; chromosome
damage |
Use building materials with little or no formaldehyde;
seal formaldehyde-containing floor and wall surfaces with
vinyl flooring, vinyl wallpaper and formaldehyde- absorbent
paint; air cleaners; ventilate area of house where formaldehyde-containing
products are in use. House ventilation, outside-vented
exhaust fans, air filters and cleaners; restrict use of
products or equipment; use alternative products.
|
Dosimeters available; check with county Extension office,
county health department. Visual identification by source
and location; personal exposure meters, microenvironment
samplers; check with county Extension office, county health
department. |
Particulates
|
Dust, pollen, cleaning and cooking sprays; environmental
tobacco smoke; fireplaces, wood stoves, kerosene heaters,
unvented gas or space heaters |
Eye, nose, throat irritation; respiratory infections and
bronchitis; lung cancer (long term risk) |
Regularly change filters on heating/cooling systems and
air cleaners; vent all furnaces to outdoors; eliminate
unvented space heaters and gas appliances; have trained
professional inspect, clean, and tune-up central heating
system; repair leaks promptly. |
Bulk sample sent to lab for analysis: contact your county
Extension office or DHEC for a list of laboratories; air
sample taken by industrial hygienist using special equipment.
|
Radon
|
Soil, well-water from private supplies |
No immediate symptoms; lung cancer (long term risk); smokers
at higher risk of developing radon-induced lung cancer
|
House ventilation; seal cracks in floors, walls and ceilings;
soil ventilation; house pressure control; seal ductwork.
|
Test your home to determine radon level. Test kits available
from county Extension offices in South Carolina. Monitors
or detectors available: check with county Extension office,
county health department for sources. |
Volatile
Organic Compounds |
Household chemicals and products (including pesticides,
painting supplies, solvents, adhesives, cleaners and waxes,
moth crystals, air fresheners, fabric protectors, chlorine
bleach), aerosol propellants; dry cleaned products; tobacco
smoke and combustion processes |
Range of possible effects from headaches, eye and respiratory
irritations to central nervous system disorders; liver/kidney
effects; cancer; chromosome damage |
Follow use and storage instructions on labels. Use outside
vented exhausts; increase ventilation in house; use solvents
and paint products outside when possible; use alternative
products; air cleaners. |
Dosimeters to test for specific chemicals and materials
available from industrial health and safety supply companies;
check with county Extension office, county health department
for sources; air sample taken by industrial hygienist
using special equipment. |
* Controls other than those mentioned may be suitable for individual
houses; not all controls listed may be appropriate for individual
houses
You and
your doctor may not be sure of the cause of an illness. Most
pollutants can't be seen, smelled, tasted or felt, and pollutant-related
illnesses may mimic the effects of a cold or virus. Also,
with many pollution sources in the house, it may be difficult
to single out which ones are causing the problem. In addition,
since some health effects take years to develop, a person
may be unaware of a pollutant that may be contributing to
future health problems.
If you
are concerned about air quality in your house, you can make
a common-sense diagnosis by documenting health complaints.
You can also have tests done or samples taken to test for
various pollutants. Professionals often use the following
questions when considering the possibility of indoor air pollution:
- What
health complaints have been experienced by you or members
of your family?
- Are
complaints reported by more than one family member?
- When
were these complaints first noticed?
- Can
you associate these complaints with certain events or activities,
like moving to a new house, remodeling, or adding new furnishings,
carpeting or draperies?
- Do
the health complaints occur seasonally, at a particular
time of the day, or when a family member is in a particular
part of the house?
- How
often do the complaints occur and how long do they last?
- Do
the complaints or reactions go away when you are away from
the house? Do they return when you return home?
- Do
visitors have the same reactions or health complaints?
- Are
the complaints or reactions less severe when you ventilate
the house?
Sampling
techniques that detect and measure pollutants in your house
vary in difficulty and expense. Testing for some pollutants,
like volatile organic compounds (VOC), carbon dioxide and
asbestos, may require a certified industrial hygienist using
special equipment. These tests can cost up to several hundred
dollars. You can purchase inexpensive monitors or detectors
which measure for formaldehyde, radon, nitrogen dioxide, water
vapor and other pollutants. The devices can be installed and
left in your house for a certain period of time. Usually you
must return them to a laboratory for analysis. You'll receive
test results and follow-up information from the laboratory.
The cost of analysis is often included in the purchase price
of the monitor or detector.
One exception
is asbestos. A homeowner can send a sample of a suspected asbestos-containing
material to a lab for "bulk analysis." Ask the laboratory about
how to take the samples and what safety precautions to observe.
If you
suspect that there may be asbestos fibers circulating throughout
your house, a different process is used. A sample for airborne
asbestos fibers requires special equipment and the skills
of a trained asbestos removal contractor or certified industrial
hygienist. You may find these listed in the yellow pages or
business section of your telephone directory.
Some
people who have made homes more energy efficient wonder if
they've made the house too "tight." Symptoms associated with
a "tight" house can be high relative humidity, interior mildew
and molds, frequent condensation on windows or stale air.
Energy
conservation measures do not cause indoor air pollution. But
when you weatherize a house, you seal up cracks and openings
and reduce the natural air flow through the house. When you
add storm windows, weather stripping or caulking, concentrations
of indoor air pollutants that are already in the home can
increase. On the positive side energy conservation measures
increase your comfort and usually result in lower heating
and cooling costs. You don't have to give up the benefits
of weatherization. You can take steps to minimize pollution
from sources inside the home. You can also dilute or remove
the pollutants.
There
are three basic strategies to improve the air quality in your
home.
Source control is usually the most effective. Some sources,
like an unvented kerosene space heater, can be eliminated
or replaced with a more efficient, nonpolluting space heater.
Other sources, like carpets and enamel paints which contain
high levels of VOCs, or furniture which can contain high levels
of formaldehyde can be replaced by materials with much lower
levels, like latex paints or low-formaldehyde upholstery.
Ask for these kinds of products where you normally buy the
items. Other sources of pollutants, like the propellants in
aerosol spray cans, can be eliminated by using a pump sprayer
instead.
Improving ventilation may lower the concentration of pollutants
in your home. Simply opening windows and doors will usually
increase the natural ventilation rate. Turning on bathroom
or kitchen exhaust fans, which are vented to the outside,
can remove pollutants from these rooms. If you have a radon
problem, keep a window open when using fans so that more radon
is not drawn through the soil and into the house.
NOTE:
Exhaust fans can cause backdrafting of combustion appliances
if there isn't enough replacement air entering the house.
When this happens, combustion exhaust products may spill into
the house. If your house is very tight, use a balanced system
which includes both exhaust and intake of air.
Larger
mechanical ventilation systems can be expensive to install
and operate. Whole-house ventilation can be a part of the
heating and cooling system or it can be totally separate.
An exhaust-only system draws replacement air through various
openings throughout the house. A balanced system adds fresh
air intakes to supply the same amount of air which is exhausted
from the house. The system might include some types of heat
recovery which use outgoing warm air to preheat incoming cold
winter air.
If you
look into a whole-house ventilation system, be sure that:
- the
system supplies fresh air to bedroom(s) and living areas,
- exhaust
air is removed from the kitchen and bathroom(s), and
- the
distribution system is effective to all other rooms in the
house. Sometimes source control can be less expensive than
increasing ventilation which can also increase energy costs.
Air
cleaners can be effective for removing some pollutants.
Air cleaners are generally designed to remove particles and
some gases from the air.
The
effectiveness of an air cleaner depends on:
- how
well it collects pollutants from the air (percentage efficiency
rate);
- how
much air it draws through the cleaning or filtering element
(cubic feet per minute) and
- whether
it removes particles, gases or both. The effectiveness of
air cleaners for radon reduction in the home has not been
established and at present is not recommended by the U.
S. Environmental Protection Agency.
Your
county Cooperative Extension Service office has additional
materials on indoor air quality, sources of monitoring devices
and names of local or county health agencies who can provide
assistance. They can also refer you to an Extension specialist
at Clemson University for general information as well as information
about research, technical studies, and state and federal agencies
who work with indoor air quality.
Your
local health department may also be able to help or refer
you to an appropriate state agency. Your telephone directory
yellow pages may also have listings for commercial firms which
supply testing devices or other services. Check under such
headings as "Industrial Hygienists," "Formaldehyde Dosimeters,"
"Asbestos Sampling/Removal," "Pesticide Sampling," "Radon
Dosimeters/ Samplers," and "Industrial Health and Safety Supply."
Backdrafting
- A condition in which the normal movements of combustion
gases up a flue is reversed, causing the combustion products
to enter the home. Backdrafting can occur when depressurization
in the house overcomes the natural tendency of the exhaust
gases to rise.
Exhaust
Fan - A fan which blows indoor air out of a house. Exhaust
fans can cause outdoor air and radon to leak in at other parts
of the house to make up for the air blown out by the exhaust
fan. Exhaust fans can also cause backdrafting.
Heat
Recovery Ventilators/Heat Exchangers -Equipment used to
transfer heat from one air flow to another. Heat from indoor
air being exhausted to the outside is transferred to incoming
air from the outdoors without the two air flows being mixed.
Infiltration
- The unplanned movement of outdoor air or radon into
a house through leaks and cracks in the house.
Radon
- Radon is the only naturally occurring radioactive gas.
The term is usually used to refer to radon 222, the radon
isotope which is present inside houses. Radon-222 is directly
created by the decay of radium-226 and has a half-life of
3.82 days.
Tight
House - A house with a low air exchange rate, often below
0.5 air changes per hour (ACH).
Ventilation
Rate - The rate at which outdoor air enters a house displacing
indoor air. The ventilation rate depends on the house construction,
weather conditions, and the use of appliances (like fans)
that affect air movement. The rate is commonly expressed in
terms of ACH or cubic feet per minute. It includes both natural
ventilation (infiltration) and mechanical ventilation.
Residential
Indoor Air Quality in North Carolina. 1985. American Council
for an Energy-Efficient Economy, Washington, D. C.
EPA
Indoor Air Quality Implementation Plan. Appendix A: Preliminary
Indoor Air Pollution Information Assessment.
EPA-600/8-87.
1987. U.S. Environment Protection agency, Washington, D. C.
EPA
Indoor Air Quality Implementation Plan. Appendix E: Indoor
Air Reference Data Base. EPA-660/8-87- 016. 1987. U. S. Environmental
Protection Agency, Washington, D.C.
The
Inside Story: A Guide to Indoor Air Quality. EPA/ 400/1-88/004.
September, 1988. U. S. Environmental Protection Agency and
U. S. Consumer Product Safety Commission, Washington, D. C.
Guidance
for Indoor Air Quality Investigations. January, 1987. Hazard
Evaluations and Technical Assistance Branch, Division of Surveillance,
Hazard Evaluations and Field Studies, National Institute for
Occupational Safety and Health, Cincinnati, Ohio.
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Disclaimer
and Reproduction Information: Information in NASD does not
represent NIOSH policy. Information included in NASD appears
by permission of the author and/or copyright holder. More
NASD Review: 04/2002
This
publication was adapted, with permission, by Craig Dewitt,
Clemson Extension Housing Specialist, from a similar document
published by North Carolina State University.
For
more information contact any of these numbers: Clemson University
Housing Institute (803) 656-0114 South Carolina Department
of Health and Environmental Control (800) 768-0362 United
States Environmental Protection Agency (800) SOS-RADON.
The
Clemson University Cooperative Extension Service offers its
programs to people of all ages, regardless of color, race,
sex, religion, national origin, or disability and is an equal
opportunity employer. Clemson University Cooperating with
U.S. Department of Agriculture, South Carolina Counties, Extension
Service, B.K. Webb, Director, Clemson, S.C. Issued in Furtherance
of Cooperative Extension Work in Agriculture and Home Economics,
Acts of May 8 and June 30, 1914
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