Environmental Engineering Reference
In-Depth Information
Table 7.2
Problem Types Identified in NIOSH Building Investigations
Problem type
Buildings investigated
%
Contamination from indoor sources
80
15
Contamination from outdoor sources
53
10
Building fabric as contaminant source
21
4
Microbial contamination
27
5
Inadequate ventilation
280
53
Unknown
68
13
Total
529
100
Source:
Proc. Indoor Air Qual. Internatl. Symposium: The Practi-
tioner's Approach to Indoor Air Qual. Investig.,
From Seitz, T.A.,
American Industrial Hygiene As-
sociation, Akron, 163, 1989. With permission.
Outdoor sources of indoor contamination included entrainment/re-
entry problems associated with motor vehicle exhaust, boiler flue gases,
rooftop and building side exhausts, dusts and solvents from road and
parking lot asphalt work, and gasoline vapors infiltrating basements or
sewage systems.
Contamination associated with building products and materials
included HCHO emissions from urea-formaldehyde-bonded wood prod-
ucts, fiberglass particles eroded from duct liners, organic solvents from adhe-
sives, and PCBs from fluorescent light ballast failure.
Microbial contaminants were identified as the major cause of complaints
in approximately 5% of NIOSH investigations. Hypersensitivity pneumoni-
tis associated with high levels of exposure to spores of fungi or thermophilic
actinomycetes was the major health problem in buildings with microbial
contamination.
NIOSH health hazard evaluations represent a significant resource of
documented building investigations. NIOSH investigations differ in quality
from many early investigations conducted without benefit of a systematic
investigative protocol. NIOSH reports provide a general overview of the
type of problems observed by field staff. They are not likely to be represen-
tative of the frequency of problems found in U.S. buildings because the
building population is biased toward institutional buildings and to buildings
with problems that are likely to be more difficult to identify and resolve.
NIOSH investigations are often conducted when other government investi-
gators or private consultants have failed to identify and resolve reported
problems. The relatively high percentage of building cases with hypersen-
sitivity pneumonitis is likely due to NIOSH expertise in this area.
III. Systematic building investigations —
symptom prevalence
Field investigations have served to initially identify and define the nature
of problem building phenomena. However, they have limited scientific use-
