United States
Environmental Protection
Agency
Research and Development
Air and {Energy Engineering
Research Laboratory
Research Triangle Park, NC 27711
November 1994
EPA/600/SR-94/141
r EPA Project Summary
i
Characterization of
Emissions from Carpet Samples
Using a 10-Gallon
Aquarium as the Source
Chamber
Zhishi Quo and Nancy Roache
As part of Phase I of a carpet
bioresponse study sponsored by the
U.S. Environmental Protection Agency
(EPA), a study was conducted to evalu-
ate the emissions from carpet samples
that had previously shown toxic effects
on experimental mice as reported by
Anderson Laboratories, Inc., Dedham,
MA, in 1992. The full report describes
the major findings of the chemical char-
acterization work conducted at the In-
door Source Characterization Labora-
tory of EPA's Air and Energy Engineer-
ing Research Laboratory. All other re-
sults (animal testing, microbial testing,
chemical analysis by sample extrac-
tion, and pesticide analysis) are re-
ported separately.
The experimental system used in this
study was first developed by Anderson
Laboratories and was identical to the
system that EPA's Health Effects Re-
search Laboratory (HERL) used in car-
pet bioresponse testing. Duplicate tests
were conducted for each of three -
samples received from the Consumer
Product Safety Commission: two previ-
ously used carpet samples plus mock
(empty bags) samples.
An emissions characterization team
from Acurex Environmental Corpora-
tion evaluated the experimental sys-
tem and concluded that the test sys-
tem developed by Anderson Laborato-
ries was not suitable for carpet chemi-
cal emisisions characterization because
of poor reproducibility, nonuniform
thermal conditions, and emissions from
the source chamber itself. The 1-h bake
cycle prior to the dynamic mode is not
typical of indoor air characterization
methods.
This Project Summary was developed
by EPA's Air and Energy Engineering
Research Laboratory, Research Tri-
angle Park, NC, to announce key find-
ings of the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
In 1992, researchers at Anderson Labo-
ratories, Inc., of Dedham, MA, reported
toxic effects in experimental mice exposed
to emissions from selected carpet samples
Because of the potential public health sig-
nificance of their reported findings, the
U.S. Environmental Protection Agency
(EPA) and the Consumer Product Safety
Commission (CPSC) initiated studies in
1993 to evaluate Anderson's experimen-
tal method and to replicate the reported
findings. In addition to a comprehensive
toxicity screen and microbial characteriza-
tion, the EPA test plan (Phase I) called for
a thorough chemical characterization of
emissions from carpet samples collected
by CPSC. This report summarizes the find-
ings of the carpet emissions characteriza-
Printedon Recycled Paper
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tion performed by Acurex Environmental
Corporation under EPA Contract 68-DO-
0141 at the Indoor Source Characteriza-
tion Laboratory of EPA's Air and Energy
Engineering Research Laboratory (AEERL).
The experimental system used in this
work was based on a protocol provided
by Anderson Laboratories and was identi-
cal to that used by EPA's Health Effects
Research Laboratory (HERL) for replicat-
ing Anderson Laboratories' tests.
The objectives of the study were two-
fold. First, emissions tests were performed
to Identify potential toxic volatile organic
compounds in the emissions from carpet
samples and to determine the concentra-
tion levels during the exposure. Second,
because of the unconventional nature of
the method, the experimental system was
characterized to determine test conditions
and the background emissions from the
source chamber.
Method
Test System and Protocol
The test system consisted of four func-
tional parts: air supply system, source
chamber, exposure chamber, and air flow
control. During a test, the carpet sample
was placed in the source chamber (a 10-
gal — 38 L—glass aquarium) and heated
to elevated temperatures. Humidified zero-
grade air was then introduced to the cham-
ber to carry the emissions to the exposure
chamber, where the experimental animals
are tested. Air samples were collected for
* chemical analysis from the source cham-
ber after the 1-h static period and from
the exposure chamber during the dynamic
period.
Duplicate tests were conducted on each
of the three carpet samples randomly re-
ceived from CPSC. Samples A and C
were previously used carpet samples col-
lected by CPSC, and Sample B was re-
ceived as an empty bag to indicate an
empty chamber test. The samples were
received as follows: Sample A for tests 1
and 6; Sample B for tests 2 and 3; and
Sample C for tests 4 and 5. Each test
consisted of four 1-h exposure periods
and took two days to complete.
Test Parameters
The major test parameters were
Size of carpet sample: 2,900 cm2
Observed sample
temperature: ~50°C
(at the surface of the carpet backing)
~70°C
(hot spot on the fiber side)
Target air temperature in source
chamber: 37 ± 3°C
Observed average air temperature
in source chamber: -41 °C
Volume of source chamber:
Source chamber air flow rate:
Target relative humidity of inlet
air:
38 L
, 7 L/min
45 + 5%
Volatile Organic Compound
Analysis
The volatile organic compounds (VOCs)
were collected on multisorbent traps dur-
ing chamber testing and analyzed by ther-
mal desorption-capillary gas chromato-
graph (GC) equipped with a mass selec-
tive detector (MSD) for compound identifi-
cation and a flame ionization detector (FID)
for compound quantification. Individually
identified compounds were quantified, and
the emissions of total volatile organic com-
pounds (TVOCs) were estimated.
The VOCs were measured using sam-
pling and analysis procedures developed
and implemented in previous emissions
testing at AEERL. These procedures in-
cluded daily tuning of the MSD for identifi-
cation, five-point calibration of the GC/FID
for quantification, analysis of daily check
samples, analysis of field and laboratory
blanks, and verification of sorbent trap
background concentrations (blanks).
Measurements of Particle
Concentrations
The instrument used for monitoring par-
ticle concentration was a model 8010
PortaCount particle counter (TSI). The in-
strument was operated in the "Count
Mode," in which the instrument directly
counts the aerosol drawn through the
sample port and gives the concentration
in particles per cubic centimeter (P/cm3).
Particle concentrations between 0 and 5 x
10s P/cm3 can be measured with this in-
strument. For comparison purposes, the
particle concentrations in the laboratory
air were measured before and after each
exposure.
Results
Characterization of Physical
Parameters
Tracer gas measurements showed that
the air in the exposure chamber was well
mixed. The inlet and outlet air flow rates
were measured with an electronic bubble
flowmeter at the start of each test to make
sure the difference between the two flow
rates was within 10%. Comparison of the
outlet air flow prior to each exposure and
after the completion of the test indicated
increased leakiness of the system during
testing due to heated duct tape and poor
seals in the system. The pressure differ-
ence between exposure chamber and the
laboratory air was negligible.
The source chamber was heated with
heating pads from outside, creating a
poorly controlled thermal environment.
Temperature data from 12 locations were
collected at a frequency of one reading
every minute and logged by a computer.
Figure 1 shows an example of tempera-
ture profiles in the source chamber.
Total Volatile Organic
Compounds
Peak TVOC concentrations found in the
source chambers at the end of the initial
1-h static heating period were approxi-
mately 10 mg/m3 for each carpet sample.
The background contribution to the TVOC
concentration from the source chamber
was <1 mg/m3 arid represented <10% of
the TVOC during the carpet test. Peak
TVOC concentrations averaged 2-8 mg/
m3 in subsequent samples collected from
the source chamber after the 1-h static
periods with the same carpet sample. Each
exposure followed a pattern of an initially
high concentration followed by a continu-
ous decay in concentration during the 1-h
exposure period 'because of the dilution
by clean air (Figure 2). During subse-
quent 1-h exposure periods, the source
strength was lower and variable (Figure
3).
Individual and Classes of
Compounds in Carpet
Emissions
More than 200 compounds were ob-
served in the carpet emissions. About 15%
were identified and confirmed by
interlaboratory comparison of GC/MS
analysis, another 70% were tentatively
identified, and the remaining 15% were
not identified. The identified compounds
fell into the following classes: alkanes,
alkenes, cycloalkanes, cycloalkenes, oxy-
genated hydrocarbons, one- or two-ring
aromatic hydrocarbons, siloxanes, and
phenols. Oxygenated hydrocarbons, aro-
matic hydrocarbons, and siloxanes were
also emitted from an empty source cham-
ber. Table 1 lists compounds identified by
Acurex for each test sample. Table 2
shows the classes of compounds found in
the emissions from each sample.
Concentrations of the predominant com-
pounds, including those identified by HERL
as potentially toxic for each sample, are
listed in Table 3. The data are the aver-
age concentration from a 60-minute
sample during Exposure 2 of each test.
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80'
70-
60-
O 50-
O
£
i 40 H
CD
Q.
£> 30-
20-
10-
—1—
50
100
Carpet Fiber
Carpet Backing
Air in Aquarium
Second
Exposure
150
200 250
Elapsed Time (min)
300
350
—i—
400
450
Figure 1. Typical temperature profiles in the source chamber.
10000
10 15
20 25 30
Elapsed Time (min)
35 40 45 50
Figure 2. Observed TVOC emissions from Sample A (Exposure 1, Test 1).
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5000-
Exp1
Exp 2 Exp 3
Exposure \D
Exp 4
I I Sample A RSSJ Sample B
Sample C
Figure 3. Average TVOC concentrations in the exposure chamber during four 1-h exposure periods of a test.
Particles
The particle concentrations in the cham-
ber air were one to two orders of magni-
tude lower than those found in laboratory
air.
Conclusions
The objective of this study was to char-
acterize the physical parameters of the
test system and the chemical emissions
from two specific carpet samples and the
empty source chamber under test proto-
col conditions. The experimental system
used for the physical and chemical char-
acterization was identical to the system
used by HERL in their bioresponse test-
ing. Although the experimental systems
were identical in design and materials, the
emissions generated during testing with
individual systems could be different based
on the following observations:
• Nonuniform heating of chamber sur-
faces, chamber air, and carpet
samples
• Development of air leakage in cham-
bers during testing
• Emissions of pollutants from the
source chamber
• Inadequate temperature control be-
cause of low precision manual tem-
perature controls
The study results indicate that environ-
mental conditions could not be precisely
controlled or reproduced. Therefore, there
is no assurance that identical systems
would produce identical emissions.
More than 200 compounds were emit-
ted by the two carpet samples that were
tested. Of the 200 compounds, 29 (15%)
were identified by GC/MSD and confirmed,
and another 70% were tentatively identi-
fied. Of the 29 compounds that were con-
firmed, 58% were found in both carpet
samples tested, and five of the confirmed
compounds were observed in all three of
the test samples (two carpets and empty
chamber). Most of the emissions from the
empty source chamber were siloxane iso-
mers with most of the emissions being
less than the quantification limits of the
analytical instruments.
Quantitative differences of some of the
individual compounds were observed dur-
ing an exposure, between the four suc-
cessive exposure cycles of a single test,
and between replicate tests using differ-
ent subsets of the same carpet sample.
Although the same flow rate and tempera-
ture protocols were followed throughout
this study and replicate subsets of the
same carpet samples were tested, no two
exposures produced the same emission
profile. During the exposure period, the
TVOC concentration and concentrations
of some individual compounds decreased
with time but did not exhibit an exponen-
tial decay. Some of the predominant highly
volatile compounds observed in Exposure
1 were below the detectable limits of the
analytical systems in subsequent expo-
sures. The emissions from these tests
were a function of the exposure protocol
and the time during the exposure at which
the samples were collected.
No evidence was found to support the
hypothesis that the carpet samples could
generate a significant amount of particles
under the experimental conditions.
The data reported in this document are
representative only of the two carpet
samples tested during this study. The car-
pet samples evaluated were not new;
some of the emissions may have been of
chemicals adsorbed onto the samples dur-
ing previous use. ,
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Table 1. Individual Compounds Identified in the Three Samples
Compound
Sample A
Sample B
Sample C
Acetone
Isopropanol
Benzene
Acetic Acid
Toluene
Hexanal
Ethylbenzene
m,p-Xylene
N,N-Dimethyl-acetamide
Styrene
o-Xylene
a-Pinene
Benzaldehyde
Decane
Trimethylbenzene
Limonene
Acetophenone
Terpene
Undecane
n-Dodecene
Camphor
Naphthalene
Dodecane
Dodecamethylcyclohexasiloxane
4-Phenylcyclohexene
Butylatedhydroxytoluene
Hexadecane
Butanoic acid
2,3-Dihydro-1,1,3-trimethyl-3-phenyl-1H-indene
Table 2. Classes of Compounds Identified in the Three Samples
Class Sample A
Sample B
Sample C
Alkanes
Alkenes
Cycloalkanes
Cycloalkenes
Oxygenated hydrocarbons
Siloxanes
Substituted benzene
Substituted phenol
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Tsbte 3. Predominant Emissions by Test
(Concentration unit: iig/rrf)
Compound
Sample'/Test A/1
A/6
B/2
B/3
C/4
C/5
Butylatedhydroxytoluene (BHTf
Acetic Acid*
Naphthalene1
Toluene
Nonanal
Tri(t-butyl) phenol
Phenol
Siloxane isomer
(retention time 59.9 min)
386
14
19
134
49
48
ND
25
407
27
22
10
108
55
ND
32
29
ND
ND
44
ND
ND
ND
6
18
ND
ND
21
ND
ND
ND
4
2
ND
ND
4
53
ND
15
73
21
2
3
7
1693
ND
73
39
TVOCs
1737
2198
182
115
1890 3181
'Samples: A and C = carpet; B » empty chamber used as a control.
'Identified as potentially toxic by HERL.
"Coelution of nonanal and siloxane isomer.
ND • not detectable by analytical system.
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Zhishi Quo and Nancy Roache are-with Acurex Environmental Corp., Research
Triangle Park, NC 27709.
Mark A. Mason is the EPA Project Officer (see below). t^mnloa
The complete report, entitled "Characterization of E™ss™s*ro™C
Using a 10-Gallon Aquarium as the Source Chamber," (Order No.
Cost: $27.00, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use $300
EPA/600/SR-94/141
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT NO. G-35
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