Environmental Engineering Reference
In-Depth Information
A. Sampling
In sampling, one attempts to identify or determine the concentration of a
substance or substances in a relatively small volume of indoor air or human
blood, on a limited surface area, or in a small mass of material. For purposes
of contaminant identification and quantification, a sample is assumed to be
representative of a larger volume of air (e.g., room), blood, or material surface
or mass. This assumption, when used in conjunction with an appropriate
sampling protocol, can be expected to provide reasonably reliable measure-
ments that can be used to confidently interpret sampling results.
B.
Sampling objectives
Environmental sampling is conducted in indoor environments for a number
of reasons. It has, as a consequence, one or more stated or inferred objectives.
These may include (1) general or specific measurements requested by a
homeowner/building owner/client, (2) routine screening measurements to
determine whether major identified contaminants are within guideline val-
ues or other acceptable limits, (3) measurements to confirm a hypothesis
relative to problem contaminants and health effects that may be associated
with such exposures, and (4) measurements to determine the effectiveness
of mitigation measures.
1.
Requests
Environmental sampling is often requested by building managers/owners
of both nonresidential and residential properties. These may be made in
response to regulatory requirements (asbestos, and in some cases, lead); as
a part of environmental site assessments; or as a condition of a real estate
transaction (asbestos, lead, radon). They may also be made in response to
problem building complaints in the case of nonresidential buildings and
general or specific health concerns expressed by occupants of residential
buildings. In the former case, environmental sampling may be requested (1)
in response to occupant requests, (2) to demonstrate empathy for occupant
concerns, (3) to allay occupant fears by demonstrating that an air/surface
contamination problem does not exist, and (4) to identify the potential cause
of occupant complaints.
Investigators have different professional responsibilities as they relate
to building manager/owner requests. Private consultants are obliged to
provide only the services requested and any additional services that may be
subsequently agreed upon. Public health and environmental agency staff
have an obligation to protect public health. In theory, they have more latitude
in conducting investigatory activities beyond simple requests for air or other
environmental sampling. In practice, public health/environmental agency
investigators acting in a nonregulatory mode generally respect the wishes
of building managers/owners relative to the scope of environmental sam-
pling and other building investigation activities.
