Environmental Engineering Reference
In-Depth Information
public health and policy issue, as is the contamination of building surfaces
by lead, pesticides and other toxic, hazardous substances. As such, IAQ/IE
concerns are, by definition, limited to nonindustrial indoor environments.
Indoor environment problems, as they are experienced in residential and
nonresidential structures, tend to have their own unique aspects. In non-
residential buildings, occupants have little or no control over their environ-
ments, which are owned and managed by others. In theory, homeowners
and lessees have some degree of freedom to modify (for better or worse) the
environments in which they live. Because of the nature of activities con-
ducted within, and how buildings are constructed and maintained, residen-
tial and nonresidential buildings often differ significantly in the nature of
IAQ/IE problems and associated health risks. These building types also
differ in how problem investigations are conducted and, in many cases, who
conducts such investigations. Because of the differences described above,
IAQ/IE problems treated here are described in the context of both residential
and nonresidential built environments.
II. Characteristics of residential buildings
Residential buildings can be characterized in the context of (1) the population
they serve, (2) ownership status, (3) building types, (4) construction charac-
teristics, (5) heating and cooling systems, (6) site characteristics, (7) occupants
and occupant behavior, and (8) exposure concerns.
A. Population served
Residential dwellings are different from other built environments because
they must provide shelter for everyone, i.e., an enormous population. This
includes individuals ranging in age from infants to the elderly, individuals
whose health status varies from healthy to a variety of ailments, illnesses,
and infirmities, and who spend anywhere from a few to 24 hours per day
indoors. In the U.S., on average, individuals spend 22 hours/day indoors,
with approximately 14 to 16 hours at home.
Those who spend the most time at home are the very young, very old,
ill or infirm, or those not employed outside the home.
B.
Ownership status
Approximately 70% of the U.S. population resides in occupant-owned dwell-
ings, while 30% lease their residence from private individuals or government
agencies. This significant private ownership of individual dwellings is
unique among nations.
Ownership status is an important factor as it relates to IAQ/IE concerns.
It is widely accepted that home ownership carries with it both individual
responsibility and pride. Such responsibility and pride can be expected to
result in better building maintenance, reducing the potential for problems
