Environmental Engineering Reference
In-Depth Information
symptoms. Only a few complaint investigations have been conducted. How-
ever, a variety of substances are emitted from vinyl flooring. These include
benzyl and benzal chloride, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate
(TXIB), dodecene, methyl phenol, ethylhexyl acrylate, 2-butanone, toluene,
trichloroethane, cyclohexanone, butanal, hexanol, benzaldehyde, phenol,
benzyl butyl ether, decanol, and the plasticizers, dibutyl phthalate and
diisobutyl phthalate. The health significance of exposure to vinyl floor cov-
ering emissions is unknown. Danish human chamber exposure studies, how-
ever, indicate that vinyl floor covering has the potential to cause a variety
of SBS-type symptoms. Exposure to plasticizers has been suggested as a
potential contributing factor to asthma.
G. Exposure to specific vapor- and particulate-phase contaminants
Exposure to specific vapor- and particulate-phase contaminants has been
evaluated as a potential risk factor for SBS-type symptoms. These include
HCHO, TVOCs, biological contaminants, and airborne particles (dust).
Although they have yet to be evaluated in a systematic way, vapor-phase
human bioeffluents are suspected of contributing to SBS-type symptoms.
The potential relationships between individual exposure to HCHO, TVOCs,
and biological contaminants, and SBS-type symptom responses in nonres-
idential buildings, have been discussed in previous chapters. The reader is
directed to Chapter 4 for discussions related to HCHO and TVOCs and
Chapters 5 and 6 for biological contaminants. The discussion here is limited
to human bioeffluents and dust (airborne and surface) as risk factors for
SBS-type symptoms.
1.
Human bioeffluents
Contaminants generated by humans, described as bioeffluents, have long
been a major IAQ/IE concern which has focused primarily on odor and
comfort.
Since metabolically produced CO
is emitted at high rates by humans,
levels in occupied buildings are commonly greater than those outdoors.
Because of these concentrations and ease of measurement, CO
2
has served
as an indicator of total bioeffluent levels and a crude indicator of ventilation
adequacy (see Chapters 8 and 9). Carbon dioxide in buildings may vary from
the approximate ambient (outdoor) concentrations of 360 to 370 ppmv to
>4500 ppmv. The wide range of CO
2
levels observed in buildings is due to
differences in occupant density and ventilation rates. Other bioeffluents
reported in indoor air include acetone, acetaldehyde, acetic acid, alkyl alco-
hol, amyl alcohol, butyric acid, diethyl ketone, ethylacetate, ethyl alcohol,
methyl alcohol, phenol, and toluene. Substances such as toluene, and possibly
phenol, may be secondary bioeffluents, as their exhalation may be associated
with previous inhalation exposure. A systematic characterization of bioefflu-
ent emissions from humans has yet to be conducted. There is, however,
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