Page 441 - Fundamentals of Air Pollution 3E

V. Control of Indoor Air Pollutants 391

vidual to the federal government, can do to improve indoor air quality.
Many of these efforts focus on education, improved materials, and better
design of products and structures.
The technological control strategies are related back to Fig. 23-1. If the
hazard is the result of elevated concentrations, then the technological solu-
tion is to reduce or remove the sources or dilute or remove the agent.
Control techniques are discussed for agents mentioned earlier—radon,
ETS, and biological agents—and also for volatile organic compounds
(VOCs). Radon enters the residence by two principal routes: infiltration
from soil beneath the structure and outgassing from well water during
showers. Elevated levels of radon are generally observed in basements or
first-floor rooms. The mitigation techniques available include increased
ventilation of the crawl space beneath the first floor, soil gas venting from
beneath a basement floor, and sealing of all openings to the subsurface
soil. These steps reduce the entry of radon into the home. Elevated levels
of radon in well water can be removed by aeration or filtration by absorbent-
filled columns.
Control of ETS is more complicated because of the personal behavior of
individuals. For public buildings and facilities like offices, restaurants, and
malls, many governmental bodies are placing restrictions on smoking in
these areas, which can range from complete bans to requiring a restaurant
to have a portion of a dining area for smokers and the remainder for
nonsmokers. The difficulty for the restaurant owner is ensuring that the
nonsmoking section is free of ETS. Education is the primary approach to
"control" in the home. Information about the effects of ETS on family
members has modified the behavior of some smokers.
Control of biological agents is multifaceted. In the case of Legionnella,
cleaning and maintenance of heating and air-conditioning systems are gen-
erally sufficient to reduce the risk of this disease. In home heating and air-
conditioning systems, mold and bacteria may be present and controlled
with maintenance procedures. Growth may be inhibited by lower humidity
levels. Keeping a house clean lowers the presence of dust mites, pollen,
dander, and other allergens.
For VOCs, control options are multiple. Source reduction or removal
includes product substitution or reformulation. Particleboard or pressed
wood has been developed and used extensively in building materials for
cabinet bases and subflooring and in furniture manufacturing for frames.
If the product is not properly manufactured and cured prior to use as a
building material, VOCs can outgas into the interior of the residence or
building. Other sources of VOCs may be paints, cleaning solutions, fabrics,
binders, and adhesives. Proper use of household products will lower vola-
tile emissions.
In many of the industries associated with building or household products,
efforts are under way to reduce the potential for subsequent VOC release