United States
Environmental Protection
Agency
Environmental Monitoring
Systems Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/S4-88/028 Sept. 1988
&EPA Project Summary
Field Evaluation of Sampling
and Analysis for Organic
Pollutants in Indoor Air
J. C. Chuang, G. A. Mack, J. W. Stockrahm, S. W. Hannan, C. Bridges, and
M. R. Kuhlman
The objectives of this study were
to determine the feasibility of the use
of newly developed indoor air sam-
plers in residential indoor air sam-
pling and to evaluate methodology
for characterization of the concen-
trations of polynuclear aromatic
hydrocarbons (PAH), PAH deriv-
atives, and nicotine in residential air.
Residential air sampling was
conducted in Columbus, Ohio, during
the winter of 1986/87. The residences
were selected on the basis of these
characteristics: electric/gas heating
system, electric/gas cooking appli-
ances, and amount of cigarette
smoking in the home. The indoor air
sampler was equipped with a quartz
fiber filter to collect particles
followed by XAD-4 resin to trap
vapors. A modified EPA medium
volume sampler with an identical
sampling module was used for
outdoor air sampling. Eight homes
were sampled; two homes were
sampled twice. The indoor air was
sampled in the kitchen and the living
room over consecutive 8-hr periods.
Each outdoor sample was a single
16-hr sample taken simultaneously
with the indoor samples.
The levels of PAH detected in
outdoor and indoor air samples
ranged from 4000 ng/m3
(naphthalene) to less than 0.1 ng/m3
(cyclopenta[c,d]-pyrene). The PAH
derivatives were found at much lower
levels than their parent PAH. Higher
average indoor levels of all but three
target compounds were found
compared to outdoor levels. The
higher outdoor levels of these three
compounds (naphthalene dicar-
boxylic acid anhydride, pyrene
dicarboxylic acid anhydride, and 2-
nitrofluoranthene) are probably due
to atmospheric transformation. Cig-
arette smoking was identified as the
most significant contributor to indoor
levels of PAH and PAH derivatives.
Homes with gas heating systems
appeared to have higher pollutant
levels compared to homes with
electric heating systems. However,
homes with electric cooking
appliances were associated with
higher pollutant levels than homes
with gas appliances, but the true ef-
fects of heating and cooking systems
cannot be accurately known because
of the small sample sizes and the
lack of statistical significance for
most pollutant differences.
This Project Summary was
developed by EPA's Environmental
Monitoring Systems Laboratory,
Research Triangle Park, NC, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
Recently many research and
monitoring efforts have focused on
assessing and improving the quality of
air. Several studies have demonstrated
that some polynuclear aromatic
hydrocarbons (PAH) and nitrated PAH
(NO2-PAH) found in ambient and indoor
air are potent carcinogens, mutagens, or
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both There is an increasing concern over
human exposure to these compounds in
indoor air from the home, workplace, and
school, because we spend more than 80
percent of our time indoors.
Generally, the sampling method-
ology used for indoor air sampling has
not been fully established. The existing
sampling devices used in outdoor
ambient air sampling are not suitable for
indoor sampling applications because of
size, lack of portability, and noise. In a
pilot residential indoor air study, the
sampler pumping unit was located
outside the house in an insulated housing
to minimize the noise level. Depending
upon the structure of each house
sampled, there were different modifi-
cations made to allow the tube
connecting the sampling module to the
pumping unit to pass through an open
window. This sampling device
significantly added to the sampling costs
and to the levels of inconvenience
experienced by the residents of the
sampled house. Therefore we have
developed a prototype indoor air sampler
that is quiet, transportable, and relatively
unobtrusive. This prototype device can
be operated at a flow rate (8 cfm)
sufficient to collect enough particulate-
bound and vapor phase organic
compounds over a period of eight hours
for chemical analysis and microbioassay
analyses.
To determine the feasibility and
advantages of using this newly-
developed prototype air sampler in
residential sampling, a pilot field study
was conducted in eight homes in
Columbus, Ohio, during the winter of
1986/1987. The objectives of this study
were to determine the effectiveness of
the prototype sampler in collecting
residential air samples and to evaluate
methodology for characterization of the
concentrations of nicotine, polynuclear
aromatic hydrocarbon (PAH), and PAH
derivatives in residential air. An
investigation of the correlations among
levels of PAH, nicotine, and numbers of
cigarettes smoked was performed. The
correlations between three potential PAH
markers phenanthrene, pyrene, and
fluoranthene and other PAH were also
investigated. This study consisted of the
following subtasks:
1. Developing a study design for the
field study,
2. Performing the field study in the
winter of 1986/1987 according to the
study design,
3. Conducting chemical analyses of the
collected samples and preparing
samples for microbioassay analyses,
4. Conducting statistical analyses of the
collected data.
Procedure
A newly developed prototype indoor
air sampler was used for the indoor air
sampling, and a modified EPA medium
volume sampler was used for the outdoor
air sampling. The sampler was equipped
with a quartz fiber filter followed by an
XAD-2 trap to collect organic particles
and vapors. The indoor samples were
collected from the kitchen from approx-
imately 0700 to 1500 eastern standard
time (EST) and from the living room from
1500 to 2300 (EST). During the entire
indoor air sampling, a single outdoor air
sample was collected in the backyard of
each house. The sampler flow rate was
approximately 12.5 m3/hr, which
collected 100 m of air over 8 hr.
The sampling design is as follows:
Smoking Heating Cooking No. of Homes
Yes gas gas 2
electric 2
Yes
No
No
electric
gas
electric
electric
gas
electric
electric
2
2
1
1
The homes selected were chosen to
give the greatest variation in the number
of cigarettes smoked. In addition, homes
were selected so that nearly equal
number of samples could be taken from
each available combination of type of
heating system and type of cooking
appliance. The order in which the homes
were sampled was randomized to
remove potential source of bias that
could result if some systematic order
were used. No sampling was done either
during or immediately following rain. No
sampling was performed while the tem-
perature was above 60°F. By not
sampling during such periods of time we
avoided gross inconsistencies due to the
cleaning of the air by the rain or due to
the shutting off of the heating system'
due to warm weather. All the homes are
located in Columbus, Ohio, and the
sampling was conducted in early March
1987.
The filter and XAD-4 samples were
combined and extracted with dichloro-
methane for 16 hr. The extract was
further extracted with ethyl acetate for an
additional 8 hr. The dichloromethane
extract and ethyl acetate extracts were
combined and concentrated by
Kuderna-Danish evaporation.
The extract was analyzed by positiv
chemical ionization and negative chen
ical ionization, gas chromatography/mas
spectrometry to determine PAH, nitroge
heterocyclic compounds. nitro-PAH ar
oxygenated-PAH. Statistical analysis i
the data included the generation <
summary statistics, the comparison i
indoor and outdoor pollutant
concentrations, and statistical modelin
to assess the separate influence of tr
individual experimental factors.
Results
The extractable organic mas
concentrations found in the XAD-4 ar
filter combined extracts ranged froi
0.077 mg/m3 to 0.57 mg/m3 indoors ar
0.0091 mg/m3 to 0.047 mg/m3 outdoor
Generally, higher levels of organic rrratti
were found in the indoor air sample
compared to that from the correspondir
outdoor air samples. It appeared th,
cigarette smoking contributes to th
higher levels of extractable organ
matter found in the indoor air sample
The highest concentrations of organ
mass were found in home 5 in the livir
room location where the highest numbei
of cigarettes were smoked during th
sampling period.
Concentrations of the individual PA
measured in homes ranged from 0.1
ng/m3 to 4200 ng/m3; naphthalene w<
most abundant and cyclopentc
[c,d]pyrene, in general, was the lea
abundant. The carcinogenic PAH such i
benzo[a]pyrene and indeno[1.2.;
c,d]pyrene were present individually
concentrations from 0.18 to 3.3 ng/m
The concentration of nicotine range
from 45,000 ng/m3 to 24 ng/m3. Indoi
concentrations of quinoline an
isoquinoline were 8.1 ng/m3 to 11C
ng/m3. The NO2-PAH and OXY-PA
concentrations found indoors were 0.0(
to 1.3 ng/m3 and 0.021 to 40 ng/rr
respectively. For most of the targi
compounds, higher indoor concentratior
were detected compared to the outdoi
concentrations.
The results of the statistical analyst
revealed that cigarette smoking was tr
most significant contributor to PAH ar
most PAH derivatives in indoor air. Tf
homes with gas heating systems a\
peared to have higher PAH and othi
pollutant concentrations in indoor air, b
the effect was not as important as tf
effect of smoking. The use of electr
stoves appeared to result in higher indo<
pollutant levels compared to the use
gas stoves. However, the true effect of <
electric cooking system is not well knov
due to the small sample sizes and tl
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lack of statistical significance of the
observed differences. In addition, further
.investigation of the data revealed that
most of the electric appliance mea-
surements were taken using Sampler C,
while the gas appliance measurements
were primarily taken using Sampler B.
Sampler bias could be responsible for
this difference. Comparisons of the effect
of sampling locations revealed that the
concentrations of the majority of the PAH
and PAH derivatives were higher in the
living room than in the kitchen, but the
difference was statistically significant for
only three of the compounds. Sources of
variation not included in the statistical
model constituted the largest single
source of random variation for most
target compounds. Home-to-home
variation was second-largest for most of
the compounds, while day-to-day
variation was the smallest.
Conclusions and
Recommendations
From this pilot field study, we
concluded that the newly developed
indoor samplers are quiet, transportable,
and acceptable for residential indoor air
sampling. The results of the current
study were, in general, consistent with
the results from the previous pilot study
using a different sampling method.
The results demonstrated that
cigarette smoking had the greatest effect
on the levels of indoor PAH and PAH
derivatives. However, the effect of
gas/electric heating and cooking systems
were not well established due to the
small sample sizes and the dominance of
the effects of cigarette smoking on PAH
levels.
The statistical analyses also showed
that there was strong evidence a
correlation among the potential PAH
markers (phenanthrene, pyrene and
fluoranthene) and the other PAH and
PAH derivatives. Phenanthrene and
pyrene appeared to be better marker
compounds than fluoranthene. It was
noted that relatively poor correlations
were found among PAH markers and
PAH derivatives naphthalene dicarboxylic
acid anhydride, pyrene dicarboxylic acid
anhydride, and 2-nitrofluoranthene. The
poor correlation may be because these
compounds can be formed through
secondary emission sources (e.g.
atmospheric transformation). The inves-
tigation of correlations among a potential
marker for cigarette smoking, nicotine,
and other pollutants revealed that all
correlations except one (naphthalene
Jicarboxylic acid anhydride) were
positive and statistically significant. It was
noted than quinoline indoor concen-
trations correlate very well with nicotine
indoor concentrations. Therefore, quino-
line can be a marker for the contribution
of cigarette smoke to indoor PAH levels.
The following recommendations are
based on the results of this study:
1. A study should be performed to
improve the acoustic performance of
the outdoor ambient samplers, be-
cause the noise levels produced by
these units was found to be a source
of irritation to the residents and
neighbors in this study and would
probably not be tolerated if sampling
were performed when windows of
the houses were open.
2. A pilot field study should be
performed in the summertime to
evaluate the sampler performance at
warmer temperatures and to collect
more data to assess the effect of
cooking systems on indoor pollutant
levels.
3. A small scale study of indoor PAH
concentrations should be performed
during a period of higher furnace use
so that the relationship between
amount of furnace use and PAH
levels can be determined. In any
such study it is important that the
amount of furnace use be measured.
4. In the design of future residential air
studies, it should not be necessary
to sample different locations within
the home. Fairly good air mixing
occurs in most homes so that
pollutant concentrations should be
fairly uniform throughout the house.
The samples are affected more by
the residents' activities during the
sampling period. Thus, "living room"
samples reported here are likely to
primarily reflect the cooking
associated with dinner preparation
while the "kitchen" samples reflect
breakfast and lunch preparation ac-
tivities. In future studies, the
"location" variables should either be
replaced by a "period of day"
variable or by other variables that
more specifically describe the res-
idents' activities conducted during
sampling.
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J.C. Chuang, G.A. Mack, J.W. Stockrahm, S.W. Hannan, C. Bridges, and M.R.
Kuhlman are with Battelle Columbus Division, Columbus, OH 43201-
2693.
Nancy K, Wilson is the EPA Project Officer (see below).
The complete report, entitled "Field Evaluation of Sampling and Analysis for
Organic Pollutants in Indoor Air," (Order No. PB 88-242 565/AS; Cost:
$19.95, 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:
Environmental Monitoring Systems 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/S4-88/028
0000329
*6ENCT
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