Residential Construction: Indoor Air Quality
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Green building is resource efficient, contributes to a healthy environment,
and provides a healthy home for occupants. According to the EPA, most
Americans spend up to 90% of their time indoors. Home design includes
many amenities people feel they need to make them happy and comfortable
in their home. A home should also ensure that sources of indoor pollutants
are limited, and those that exist will be diluted or removed from the
Because of the amount of time people spend inside, indoor air quality
is important. Indoor air problems are usually caused by gases or particles.
Many building materials and building designs contribute to indoor air
problems. Outside sources can also become indoor pollutants if carried
in on shoes or located next to fresh air returns for the house. Ventilation
provides fresh air to dilute concentrations of pollutants and to carry
them outside. Inadequate ventilation can add problems by allowing moisture
and temperature levels to rise.
Reasons to Change
Some people, especially children, elderly, and those with allergies are
particularly sensitive to indoor pollutants. Adverse health effects may
include respiratory, neurological, and skin conditions, impairment of brain
function (mental retardation in children), lung disease and cancer. To reduce
these effects, apply a "systems approach" where the interaction
of all elements of the building site, building envelope, mechanical systems,
and occupants are considered.
Primary Indoor Air Pollutants
||Primary source in homes is particle-board, hardwood
plywood paneling, and medium density fiberboard. Also various sources
including smoking, household products, and the use of unvented, fuel-burning
appliances, glues and adhesives, and preservative in some paints and
||Radioactive breakdown of soil and rock, occurs virtually everywhere
||These include carbon monoxide, carbon dioxide, sulfur
dioxide, nitrogen dioxide. Unvented kerosene and gas space heaters,
woodstoves, fireplaces, gas stoves, water heaters and appliances;
improperly installed or maintained chimneys and flues, and cracked
furnace heat exchangers; "back-drafting" of fireplaces,
woodstoves and gas appliances with no dedicated outdoor air supply.
||Smoke coming from burning end of cigarette, pipe or
cigar or exhaled by smoker
||Fireplaces, woodstoves, kerosene heaters and secondhand
|Volatile Organic Compounds (VOCs)
||Fuels, paints, varnishes, adhesives and wax. Household
cleaning, disinfecting, cosmetic, degreasing, and hobby products containing
||(Including: dust mites, mold, pet dander, pollen, etc.)
Various plant, animal, human and mechanical sources, typically enhanced
through moisture and relative humidity over 30 - 50%.
||Mineral fiber used for insulation and as a fire-retardant
in pipe and furnace insulation materials, asbestos shingles, millboard,
textured paints and other coating materials, and floor tiles.
|Old lead-based paint improperly removed from surfaces
by dry scraping, sanding, or open-flame burning.
||Insecticides and disinfectants used in the home, carried
in from contaminated soil, or stored.
Builders can reduce the risks of poor indoor air quality. Reduced liability
and increased community relations will result from homes built with indoor
air quality considerations. Homeowners and the community at large will
benefit from reduced health impacts caused by poor indoor air quality
in homes. Money spent on insurance, medication, remediation activities,
and lost productivity is money often taken from expenditures that keep
local economies strong.
P2 in Action: Eliminate Sources
It is cheaper and easier to avoid pollutants than to cover or
clean them up. For unavoidable pollutants, and those created by the homeowner,
plan for fresh air exchange through mechanical ventilation and air cleaning
Eliminate toxic materials and pollutant breeding grounds as often
- Select easy to clean floorings and those that don't "offgas"
(e.g. ceramic tile, linoleum, wood, short fiber carpet or area rugs) to avoid pollutant
- Vent bathrooms and other fans and the dryer outdoors, not in attic
or other interior space.
- Provide sufficient water management around the foundation, attic and
walls (waterproof system, drain tile or vapor retarder) to reduce moisture,
mold and humidity.
- Select only no or low VOC paints, and for flooring, non-toxic adhesives
or mechanical fasteners.
- Avoid cabinets and furnishings made from particleboard that may contain
formaldehyde in the glue or seal particleboard components with no or
low VOC sealant.
Separate potential pollutants from the living space.
- Build an airtight structure to keep insulating materials sealed away
- Select sealed combustion or power vented heating appliances (own air
supply and vent to exterior).
- Encapsulate or permanently cover potential pollutants such as asbestos
or lead paint.
P2 in Action: Ventilate
Provide adequate mechanical ventilation within the home to ensure enough
fresh air intake for dilution of pollutants, removal of pollutants and efficient
operation of appliances. Organizations working in the fields of building energy,
green buildings, heating, refrigeration, and ventilation provide criteria
for mechanical ventilation system rates and parameters, i.e. American Society
of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) http://www-epb.lbl.gov/publications/lbnl-42975.pdf. Guidelines often
include requirements for testing of the system.
If installing or using products that may contribute to unhealthy indoor
air, take extra precautions to reduce exposure to the interior of the
home, e.g. lay carpets and draperies out to vent or offgas
in a clean, dry area outside of the home for at least 24 hours before
P2 in Action: Be Proactive
Consider installing monitoring and remediation systems during new construction,
when they can save lives, prevent illness, and add very little additional
cost. For example:
- Install a carbon monoxide detector near combustion appliances.
resistant construction reduces moisture levels and associated problems
and only costs $100 - $300 while increasing the value of the home. Nearly
one in15 homes in the U.S. is estimated to have elevated radon levels. It
is much easier and less expensive to provide this type of system during
new construction activities.
|"The key to designing and building a healthy house
is to choose the construction materials that are most benign, and put
them together in a manner that enhances your health rather than compromises
John Bower, author of Healthy House Building:
A Design and Construction Guide, and internationally recognized healthy