Environmental Engineering Reference
In-Depth Information
Table 4.12
Concentrations of Phthalate Compounds Measured in 125
California Residences
Concentration (ng/m
3
)
Indoor/outdoor
ratio
Compound
Median
90th percentile
Diethylphthalate
340
840
4.3
Di-
n
-butylphthalate
420
1300
14.0
Butylbenzyl phthalate
34
240
4.3
Di-2-ethylhexyl phthalate
110
240
1.7
Di-
n
-octyl phthalate
BLD
9.7
1.4
Source:
From Sheldon, L. et al.,
Proc. Indoor Air '93
, Helsinki, 3, 109, 1993.
flexible and typically comprise 25 to 50% of the weight of products such as
vinyl floor covering. As plasticizers slowly vaporize with time, vinyl products
lose their desirable soft properties, become hard and brittle, and crack.
Commonly used plasticizers include phthalic acid esters such as dieth-
ylhexyl phthalate (DEHP), dibutyl phthalate (DBP), diisobutyl phthalate
(DiBP), benzyl butyl phthalate (BBP), and diethyl phthalate (DEP). A com-
monly used nonphthalate plasticizer is TXIB (2,2,4-trimethyl-1,3-pentanediol
diisobutryate).
Because of their low vapor pressures, concentrations of individual vapor-
phase plasticizer compounds in indoor air are generally very low. Neverthe-
less, significant vapor-phase concentrations may be associated with the
installation of new building products such as vinyl floor covering or wall
paper where the loading factor is high (high surface to volume ratio). Such
high loading factors also occur in new automobiles where the volatilization
and subsequent condensation/deposition of plasticizers is reportedly
responsible for the “greasy window” phenomenon which is exacerbated by
greenhouse-type heating of automobile interiors on sunny days.
Measurable levels of both vapor- and particulate-phase phthalic acid esters
have been reported in buildings. Concentrations of DEHP as high as 110 to 230
µ
g/m
3
have been associated with emissions from vinyl wall covering, with mean
concentrations of DBP and DiBP in the range of 2 to 16
g/m
3
. Air concentrations
(vapor and aerosol phase) of phthalate compounds in 125 California residences
are summarized in
Table 4.12
.
These concentrations are approximately half of
those reported for Danish nonresidential buildings (
Table 4.11
)
.
Phthalates associated with airborne and settled dust have been reported
for Norwegian residences. Total phthalate concentrations in suspended par-
ticulate matter ranged from 450 to 2260 ppm (w/w) with an average con-
centration of 1180 ppm. The settled dust concentration of phthalates was 960
ppm, with DEHP comprising approximately two thirds of this level. Sus-
pended and settled dust levels were strongly correlated, particularly for
DEHP and DBP. As such, resuspended settled dust appears to be the major
route of human exposure.
TXIB, a nonphthalate plasticizer, has been reported in the concentration
range 100 to 1000
µ
µ
g/m
3
in problem buildings. It was one of the most
