Environmental Engineering Reference
In-Depth Information
common substances detected in nonresidential U.S. buildings (frequency 81
to 100% in 56 BASE office buildings), with concentrations in the range of 0.2
to 2.8
µ
g/m3; in Danish buildings, concentrations were 1.45 to 5.9
µ
g/m
3
(
Table 4.11
)
.
2. Nonplasticizer SVOCs
A variety of nonplasticizer SVOCs are found in indoor air in measurable
concentrations (
Table 4.11
). Texanol, found in the highest concentration, is a
colorless liquid mixture, with 2,2,4-trimethyl-1,3-pentanediol monoisobu-
tyrate, a compound closely related to TXIB, the dominant compound present.
It is commonly added to latex-based paints and has a vapor pressure of
0.013 mm Hg.
3. PCBs
Polychlorinated biphenyls (PCBs) are a group of synthetic chemical com-
pounds (209) characterized by the attachment of one to 10 chlorine atoms to
a biphenyl moiety. They were produced in the U.S. from approximately 1930
to the mid-1970s and marketed under the trade name Arochlor™. Polychlo-
rinated biphenyls were used as: dielectric fluids in transformers and capac-
itors, heat transfer and hydraulic fluids, lubricating and cutting oils, and
plasticizers in adhesives. They were also used in paints, pesticides, inks,
caulking, and sealants. As a consequence, PCBs are ubiquitous contaminants
of many pre-1975 buildings.
Polychlorinated biphenyls represent a number of building contamina-
tion concerns. These include fluorescent light ballast leakage and failures
which result in air and surface contamination. Polychlorinated biphenyl
levels in buildings with PCB-containing transformers (191-888 ng/m
3
) have
been observed to be twice as high as those without such transformers.
Polychlorinated biphenyl contamination of building surfaces, as well as
air, is a particularly significant problem when a building has experienced a
structural fire. Fire can destroy dozens, if not hundreds, of PCB-containing
ballasts. Resulting surface contamination poses a significant challenge to
building owners and restoration personnel in their efforts to restore the fire-
damaged/contaminated areas and materials. Air and surface PCB levels must
be below guideline values to make the building acceptable for reoccupancy.
In one building subjected to a limited structural fire, elevated air and
surface PCB levels were reported to be associated with (1) PCB-containing
adhesive used to adhere fiberglass insulation to the exterior of metal supply
air ducts and (2) the adhesive of fiberglass duct board. The burned building
was also contaminated with polychlorinated dibenzofurans, polychlorinated
dibenzo-
p
-dioxins, and combustion products of PCBs.
4. Floor dust
Low-volatility, high-potency organic compounds and those with high polar-
ity can be expected to partition more to particles than to the vapor phase in
