How to Improve
These three basic strategies should be utilzed:
Usually the most effective way to improve indoor air quality
is to eliminate individual sources of pollution or to reduce
their emissions. Some sources, like those that contain asbestos,
can be sealed or enclosed; others, like gas stoves, can be
adjusted to decrease the amount of emissions. In many cases,
source control is also a more cost-efficient approach to protecting
indoor air quality than increasing ventilation because increasing
ventilation can increase energy costs. Specific sources of
indoor air pollution in your home are listed later in this
Another approach to lowering the concentrations of indoor
air pollutants in your home is to increase the amount of outdoor
air coming indoors. Most home heating and cooling systems,
including forced air heating systems, do not mechanically
bring fresh air into the house. Opening windows and doors,
operating window or attic fans, when the weather permits,
or running a window air conditioner with the vent control
open increases the outdoor ventilation rate. Local bathroom
or kitchen fans that exhaust outdoors remove contaminants
directly from the room where the fan is located and also increase
the outdoor air ventilation rate.
It is particularly important to take as many of these steps
as possible while you are involved in short-term activities
that can generate high levels of pollutants--for example,
painting, paint stripping, heating with kerosene heaters,
cooking, or engaging in maintenance and hobby activities such
as welding, soldering, or sanding. You might also choose to
do some of these activities outdoors, if you can and if weather
Advanced designs of new homes are starting to feature mechanical
systems that bring outdoor air into the home. Some of these
designs include energy-efficient heat recovery ventilators
(also known as air-to-air heat exchangers). For more information
about air-to-air heat exchangers, contact the Conservation
and Renewable Energy Inquiry and Referral Service (CAREIRS),
PO Box 3048, Merrifield, VA 22116; (800) 523-2929.
There are many types and sizes of air cleaners on the market,
ranging from relatively inexpensive table-top models to sophisticated
and expensive whole-house systems. Some air cleaners are highly
effective at particle removal, while others, including most
table-top models, are much less so. Air cleaners are generally
not designed to remove gaseous pollutants.
The effectiveness of an air cleaner depends on how well it
collects pollutants from indoor air (expressed as a percentage
efficiency rate) and how much air it draws through the cleaning
or filtering element (expressed in cubic feet per minute).
A very efficient collector with a low air-circulation rate
will not be effective, nor will a cleaner with a high air-circulation
rate but a less efficient collector. The long-term performance
of any air cleaner depends on maintaining it according to
the manufacturer's directions.
Another important factor in determining the effectiveness
of an air cleaner is the strength of the pollutant source.
Table-top air cleaners, in particular, may not remove satisfactory
amounts of pollutants from strong nearby sources. People with
a sensitivity to particular sources may find that air cleaners
are helpful only in conjunction with concerted efforts to
remove the source.
Over the past few years, there has been some publicity suggesting
that houseplants have been shown to reduce levels of some
chemicals in laboratory experiments. There is currently no
evidence, however, that a reasonable number of houseplants
remove significant quantities of pollutants in homes and offices.
Indoor houseplants should not be over-watered because overly
damp soil may promote the growth of microorganisms which can
affect allergic individuals.
At present, EPA does not recommend using air cleaners to
reduce levels of radon and its decay products. The effectiveness
of these devices is uncertain because they only partially
remove the radon decay products and do not diminish the amount
of radon entering the home. EPA plans to do additional research
on whether air cleaners are, or could become, a reliable means
of reducing the health risk from radon.