United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/S7-90/006 June 1990
SEPA Project Summary
Comparison of Measurement
Techniques for Quantifying
Selected Organic
Emissions from Kerosene Space
Heaters
G.W. Traynor, M. G. Apte, H. A. Sokol, and J. C Chuang
A study was performed to compare
the "hood" and "chamber-
techniques for quantifying pollutant
emission rates from unvented
combustion appliances and to
assess the semivolatile and
nonvolatile organic-compound
emissions from unvented kerosene
space heaters. In general, the hood
and chamber techniques yielded
similar emission-rate results for CO,
NO, and NO2. However, when
differences were observed, it was
concluded that the chamber-
technique value was more realistic
because this technique allows the
oxygen level supplied to the
appliance to decrease as it would in
residences. A well-tuned radiant
heater and a maltuned convective
heater were tested for semivolatile
and nonvolatile organic pollutant
emissions. Each heater was operated
in a 27-m-3 chamber with a prescribed
on/off pattern. Organic compounds
were collected on Teflon-
impregnated glass filters backed by
XAD-2 resin and analyzed by gas
chromatography/mass spectrometry.
Pollutant source strengths were
calculated using a mass-balance
equation. The results show that
kerosene heaters can emit polycyclic
aromatic hydrocarbons (PAHs);
nitrated PAHs; alkyl benzenes;
pentachlorphenol; phthalates; hydro
naphthalenes; aliphatic hydrocar-
bons, alcohols, and ketones;
and other organic compounds, some
of which are known mutagens.
This Project Summary was
developed by EPA's Air and Energy
Engineering Research 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
The sales and use of unvented
kerosene space heaters over the past
decade have increased dramatically in
the U.S. Unvented kerosene space
heaters have been found to emit a wide
variety of pollutants including carbon
monoxide (CO), carbon dioxide (CO2),
nitric oxide (NO), nitrogen dioxide (NO2),
sulfur dioxide (802), formaldehyde
(HCNO), and suspended particles. Other
studies using a kerosene-fueled
turbulent-diffusion continuous-flow
combustor showed that many polycyclic
aromatic hydrocarbons (PAHs) are
emitted during kerosene combustion. Still
other studies also showed that kerosene
soot is indirectly mutagenic: one showed
that essentially all of the indirect
mutagenic activity of kerosene soot was
due to unnitrated PAH compounds, and
another showed that kerosene heaters
emit dinitropyrene. Kerosene soot has
also been shown to be directly mutagenic
and that most of the direct mutagenic
activity could be attributed to
dinitropyrenes.
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The above studies have shown that: 1)
kerosene combustion products can be
mutagenic, 2) kerosene combustion can
produce PAHs and nitrated PAHs, and 3)
it is likely that much of the mutagenic
activity of kerosene soot is due to the
PAHs and nitrated PAHs. However, it is
not known whether the unvented portable
kerosene space heaters commonly used
indoors in the U.S. produce emissions
similar to those emitted by the kerosene
combustors used in several earlier
studies or whether these portable space
heaters produce other potentially harmful
organic pollutants.
Two Major Goals
Of the two major goals of this study,
the first was to measure selected organic
pollutant emissions (including PAH and
nitrated PAH emissions) from portable
kerosene heaters commonly used in the
U.S.
The second, but chronologically first,
goal of this study was to compare two
techniques for assessing pollutant
emissions from unvented combustion
appliances. One technique, henceforth
called the "chamber" technique, involves
placing the unvented combustion
appliance in a room-size or large
chamber, operating the appliance for a
representative period of time, and
monitoring the increase in the chamber
pollutant concentrations. The pollutant
emission rate, expressed as mass of
pollutant emitted per unit of fuel
consumed often ng/kJ, is then calculated
from the chamber and outside pollutant
concentrations using a single-equation,
mass-balance model. The chamber
technique has been used to quantify
pollutant emission rates from kerosene
heaters. The other technique, henceforth
called the "hood" technique, involves
placing the unvented combustion
appliance under a hood large enough to
capture all of the pollutant emissions and
measuring the ratio of the concentration
of each pollutant under investigation to
the concentration of CO2 in the hood
exhaust flue. After correcting for
background dilution air, the theoretical
COg emission rate is used to calculate
the emission rate of the pollutant of
concern. The hood technique has been
used to measure pollutant emission rates
from kerosene heaters.
The Tests
For the evaluation of the hood and
chamber measurement techniques, one
unvented radiant kerosene heater and
one infrared unvented (natural) gas space
heater (UVGSH) were used. Radiant and
infrared combustion space heaters
generally have more repeatable
emission-rate characteristics than do their
convective counterparts; therefore, using
such heaters allowed hood vs. chamber
technique emission-rate differences to be
more easily detected.
For the tests measuring organic
pollutant emissions from kerosene
heaters, two heater/tuning conditions
were chosen based, in part, on previously
reported participate emission data. The
previous study showed that particulate
emissions from a well-tuned properly
operated convective kerosene heater
were negligible, but that particulate
emissions from a radiant heater were not.
Therefore, it was/reasoned that significant
organic emissions would be more likely
to be observed from a radiant heater
rather than fronrua convective heater. A
well-tuned radiant heater was chosen as
the first heater/tuning combination to be
tested. The other heater/tuning
combination chosen for testing was a
maltuned convective heater. This choice
was based, in part, on conversations with
kerosene-heater users and testers, who
indicated that it was easier (more likely)
for a convective heater to soot (i.e., emit
a visible stream of particles) than it was
for a radiant heater. In fact, altering the
burner assembly itself was the only way
the radiant heater tested in this study
could be made to "soot." The convective
heater was maltuned by lifting the
exterior shell of the heater by
approximately 1 cm, thereby providing
excess air to the wick. Only two
heater/tuning combinations were tested
because each test had to be conducted
many timers to collect enough samples
for mutagehicity testing.
fAII experiments were conducted at the
Lawrence Berkeley Laboratory (LBL).
Battelle's Columbus Division prepared
and analyzed filters and resins used by
LBL to collect selected organic pollutant
emissions and provided sample extracts
to the Health Effects Research
Laboratory of the U.S. EPA.
Test Results
In general, the hood and chamber
emission-rate measurement techniques
yield similar results for CO, NO, and NO2.
However, when discrepancies were
observed, they were believed to be
caused by differences in combustion-air
oxygen jevels. The'chamber method
results were judged to be more accurate
since this method allows.,the oxygen
content of the combustion air\to drop, as
would occur in actual residences. The
hood method appears to be adequate for
quantifying CO, NO, and N02 emission
rates from appliances that are not oxygen
sensitive or from appliances that
marginally affect a residence's oxygen
level, such as a gas range. The chamber
method was preferable for measuring
total suspended particulate emissions
primarily because it was easier to
implement. No disadvantages to the
chamber method were discovered.
With regard to organic pollutant
emissions from kerosene heaters, this
study has confirmed the results of other
studies; i.e., that the kerosene
combustion process can emit PAHs and
nitrated PAHs. One-nitronaphthalene is
clearly emitted by well-tuned radiant and
maltuned convective kerosene space
heaters. One-nitronaphthalene was found
almost entirely in the semivolatile fraction
for the radiant-heater tests. For the
maltuned-convective-heater tests, 30% of
the nitronaphthalene was collected on the
filter. This is presumably due to the
heavy loading of fresh soot on the filter
during the maltuned-convective test.
Emissions of 9-nitroanthracene were
observed in the XAD fraction of one of
the radiant-heater tests and in the filter
fraction of the maltuned-convective test.
Emissions of 1-nitropyrene were also
observed in the filter fraction of both
radiant test samples, whereas only trace
amounts of 3-nitrofluoranthene were
observed in one of the two series of
radiant-heater tests in the filter-collected
fraction.
In addition, kerosene heaters were
found to emit many other organic
compounds, including aliphatic
hydrocarbons, alcohols, and ketones;
phthalates; and alkyl benzenes.
Additional analysis is needed to correlate
these results with health-effects data to
determine the risk associated with these
organic emissions. PAH and nitrated-PAH
emissions are sufficiently important to
justify additional quantitative studies;
furthermore, examinations of other
organic compounds of toxicological
significance and of unvented combustion
sources should be expanded.
One very important observation of this
study was that some estimates of the
indoor reactivity of SVOCs were higher
than 2 rr1. This implies that reactivity
rates for some SVOCs are more
important than ventilation rates for
determining indoor concentrations.
Clearly, this indicates that future studies
must quantify the indoor reactivity
process for individual SVOCs in order to
gain insight into potential indoor
exposures to these compounds.
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G. W. Traynor, M. G. Apte. and H. A. Sokol are with Lawrence Berkeley
Laboratory, Berkeley, CA 94720, and J. C. Chuang is with Battelle
Columbus Laboratories, Columbus, OH 43201.
James B. White is the EPA Project Officer (see below).
The complete report, entitled "Comparison of Measurement Techniques for
Quantifying Selected Organic Emissions from Kerosene Space Heaters,"
(Order No. PB 90-187 0221 AS; Cost: $15.00, 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 S300
EPA/600/S7-90/006
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