Environmental Engineering Reference
In-Depth Information
In advanced countries, increasing concern has developed in the past
several decades about contaminants in our building environments and
potential exposure risks to occupants. These have grown out of previous
and contemporary concern for the health consequences of ambient (outdoor)
air pollution, water pollution, hazardous waste, and the general pollution
of our environment and food with toxic substances such as pesticides, PCBs,
dioxin, etc.
Other factors have also “conspired” to increase our awareness that con-
tamination of built environments (particularly indoor air) poses potentially
significant public health risks. These have included: (1) recognition of the
health hazards of asbestos and its widespread presence in schools and many
other buildings, and the regulatory requirements for inspection of public
and private schools for asbestos as well as its removal prior to any building
renovation/demolition; (2) recognition of the significant exposure to form-
aldehyde (HCHO) experienced by residents of mobile homes, urea-formal-
dehyde foam-insulated (UFFI) houses, and conventional homes in which a
variety of formaldehyde-emitting urea-formaldehyde resin-containing
products were used; (3) recognition that residential buildings and some
schools have elevated radon levels (thought high enough to carry a signifi-
cant risk of lung cancer); (4) the apparent consequences of implementing
energy-reducing measures in response to increased energy prices in the mid
1970s, including reducing ventilation air in mechanically ventilated build-
ings, using alternative space heating appliances such as wood-burning
stoves and furnaces and unvented kerosene heaters, and reduced air infil-
tration into buildings; (5) an eruption of air quality complaints in hundreds
of buildings in the U.S. following changes in building operation practices;
(6) progressive awareness of the problem of childhood lead poisoning and
its association with house dust from lead-based paint; and (7) an increasing
understanding that biological contaminants of the indoor environment, e.g.,
mold, dust mites, pet danders, cockroach excreta, etc., play a role in causing
human asthma and chronic allergic rhinitis.
I. Indoor contamination problems
The contamination of indoor air and horizontal surfaces (by dusts) is com-
mon to all built environments. Such contamination is most pronounced in
industrial environments where raw materials are processed and new prod-
ucts manufactured. These environments pose unique exposure concerns and
are subject to regulatory control and occupational safety and health pro-
grams in most developed countries. Though industrial and other occupa-
tional exposures are significant, they are not included in discussions of
indoor air quality and indoor environmental (IAQ/IE) contamination con-
cerns in this topic.
Indoor air quality as it relates to residential, commercial, office, and
institutional buildings, as well as in vehicles of transport, is its own unique
