THREE BASIC STRATEGIES

THREE BASIC STRATEGIES

Source Control

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 section.

Ventilation Improvements

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 permits.

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) 5232929.



Air Cleaners

There are many types and sizes of air cleaners on the market,
ranging from relatively inexpensive tabletop models to
sophisticated and expensive whole house systems. Some air
cleaners are highly effective at particle removal, while others,
including most tabletop 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. Tabletop
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 house plants 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. EPA s booklet, Residential Air
Cleaning Devices, provides further information on air cleaning
devices to reduce indoor air pollutants



For most indoor air quality problems in the home, source control
is the most effective solution. This section takes a source by
source look at the most common indoor air pollutants, their
potential health effects, and ways to reduce levels in the home.
(For a summary of the points made in this section, see the chart
in the middle of this booklet titled Reference Guide to Major
Indoor Air Pollutants in the Home. )