United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/S2-90/001 May 1990
v>EPA Project Summary
Effects of Appliance Type and
Operating Variables on
Woodstove Emissions
P. G. Burnet, J. E. Houck, and R. B. Roholt
This project was conducted in
support of the Integrated Air Cancer
Project (IACP) to provide data on the
specific effects of appliance type and
operating variables on woodstove
emissions. Samples of particulate
material and volatile organic
compounds (VOCs) were collected.
Particulate samples were analyzed
for different organic fractions,
including specific polynuclear
aromatic hydrocarbon (PAH)
compounds. Inorganic matter on the
filters was also analyzed. Results
were calculated for pollutant
concentrations, emission rates, and
emission factors. Twelve test runs
were conducted on a conventional
stove, and two runs were conducted
on a catalyst-equipped stove.
Operating variables included fuel
type (oak and pine), altitude (80 and
800 m), and burn rate (high and low).
Test data were analyzed using
analysis of variance and linear
regression procedures. Although the
data do not show strong statistical
significance due to variability of
results, some general trends do
appear to be present and
conclusions can be drawn as to the
effects of various operating variables
on woodstove emission. At the 99%
confidence bound (CB), oak fuel
reduced emissions of total PAH
compounds relative to pine fuel.
Emisssions of carbon monoxide (CO)
showed a significant decrease from
low to high burn rates, and a small
decrease when oak, rather than pine,
fuel was used. The catalytic stove
(with a used combustor) reduced
emissions of CO, but did not show
significant reductions of total
particulate material at the 99% CB. No
altitude effects were noted at the 99%
CB.
At the 95% CB, oak fuel reduced
the concentration, emission rate, and
emission factor for many individual
PAH compounds, and reduced the
emission factor for total PAH
compounds. Marginal decreases in
benzene were also attributed to the
use of oak, rather than pine, fuel.
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 two
separate volumes of the same title
(see Project Report ordering
information at back).
Introduction
During the winter of 1986-87, the U.S.
Environmental Protection Agency (EPA)
conducted an emission measurement
program in Boise, Idaho, as part of the
Integrated Air Cancer Project (IACP). The
program was designed to identify the
potential mutagenic impact of residential
wood burning on ambient and indoor air.
One aspect of the field sampling effort
involved obtaining emission samples
from chimneys serving wood burning
appliances in Boise. This project was
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undertaken as a parallel project in an
instrumented woodstove test laboratory
to quantify woodstove emissions typical
of Boise conditions.
The purpose of this laboratory project
was to quantify the effect of several
variables on emissions from woodstoves
so that operational conditions of stoves in
the field could be inferred by existing
data bases. The variables included fuel
species, burn rate, and altitude
(barometric pressure). A conventional
woodstove, typical of many existing stove
models in the Boise area, was used as
the test appliance. Limited testing was
also conducted on a catalytic woodstove.
A modified half-factorial test matrix was
used to obtain test results most useful to
the IACP.
A woodstove dilution sampler (Wood-
stove Sampling System, or WS2) was
used to collect particulate samples, while
a modified ambient sampler was used to
collect aldehyde and volatile organic
compound (VOC) samples. Particulate
samples were analyzed for total mass,
polynuclear aromatic hydrocarbons
(PAHs), semicondensible organics (grav),
total chromatographical organic (TCO)
compounds, and inorganic compounds.
Concentrations of carbon monoxide (CO),
carbon dioxide (C02),and oxygen (02) in
flue gases were recorded. Samples of
wood fuel and residual ash were
analyzed for elemental composition.
Summary of Test Results
Total particulate capture values were
substantial, ranging from about 2-16g of
material. Although the grav-plus-TCO
values were expected to be similar to the
total capture values because of the high
organic content of woodsmoke, these
values were typically 45-70% of total
capture values. It is not clear why the
unextractable fractions from the filter
catches were so high.
Table 1 lists particulate emissions as
total capture, grav, and TCO fractions.
Total capture emission rates for the
conventional stove ranged from 10.9 g/hr
(pine fuel, low elevation, low burn) to 50.7
g/hr (pine fuel, high elevation, low burn).
While some replicate runs showed close
agreement (Runs 1 and 3, and 7 and 8),
other runs showed considerable
differences: Runs 2 and 4, 6 and 14, and
9 and 10 varied by factors of 3 to 4
(Figure 1). Agreement and discrepancies
between the replicate runs were similar
when reported as grams per kilogram.
Most of the measured PAH compounds
were lower-molecular weight compounds,
with low emission rates of high molecular
weight compounds. Naphthalene
accounted for almost half of the
emissions of measured PAH compounds
in many samples (Runs 4, 6, 14, 16, 10,
7, 8, 12, 13). ,A very large fraction of total
PAH compounds were recovered from
the filter and XAD-2 resin extract
fractions, with a relatively small
contribution from the probe rinse fraction.
Total VOC emissions (C-|-C7
hydrocarbons) ranged from 9 g/hr (Runs
4 and 6) to 40 g/hr (run9). Replicate VOC
samples for Runs 5 and 16 and Runs 7
and 8 were in relatively close agreement.
Other replicate tests showed
considerable variation. Methane was the
largest single fraction of most samples,
although Run 1 had no reported methane.
-C
0>
05
(C
QC
20
10
SOLL-1 SOLH-1 SPLL-1 SPLH-1 SPHL-1 SPHH-1 EPHL-1
SOLL-2 SOLH-2 SPLL-2 SPLH-2 SPHL-2 SPHH-2 EPHH-1
Test Code
Figure 1. Emission rates for particulate capture fractions.
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Table 1. Paniculate Matter Emissions
Particulate Concentration
Paniculate Emission Rate
Paniculate Emission Factor
Run
No.
1
3
21
4
6
14
5
16
9
10
7
8
12
13
Sample
Code3
SOLL-1
SOLL-2
SOLH-1
SOLH-2
SPLL-1
SPLL-2
SPLH-1
SPLH-2
SPHL-1
SPHL-2
SPHH-1
SPHH-2
EPHL-1
EPHH-1
Flue Gas
Flow
(dscmh)b
15.368
14.042
18.872
17.248
11.589
10.642
14.535
20.252
11.077
12.018
18.986
18.652
10.305
13.384
Sample
Volume
(1)c
3,315.6
3,330.8
1,590.0
3,385.6
3,080.9
3,344.0
2,979.3
2,965.9
3,579.0
2,870.0
2,800.6
2,821.5
3,661.4
3,518.8
Totals
2.052
2.471
2.309
0.919
0.941
2.886
k
1.113
4.574
0.928
0.678
0.608
0.601
0.601
\yiiu /
Grav.h
1.218
1.687
1.522
0.445
0.430
1.634
k
0.599
2.844
0.510
0.341
0.351
0.344
0.166
TOO'
0.306
0.220
0.312
0.166
0.190
0.668
0.339
0.334
0.817
0.303
0.188
0.198
0.140
0.367
Total9
31.5
34.7
43.6
15.6
10.9
30.7
k
22.5
50.7
11.2
12.9
11.3
6.2
8.0
[yini r
Grav.h
18.7
23.7
28.7
7.7
5.0
17.4
k
12.1
31.5
6.1
6.5
6.5
3.5
2.2
TOO'
4.7
3.1
5.9
2.9
2.2
7.1
4.9
6.8
9.0
3.6
3.6
3.7
1.4
4.9
Totals
23.3
27.1
16.8
7.5
6.6
18.4
k
7.7
43.0
6.9
4.1
3.6
4.7
4.1
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P. Burnet, J. Houck, and R. Roholt are with OMNI Environmental Services, Inc.,
Beaverton, OR 97005.
Robert C. McCrillis is the EPA Project Officer (see below).
The complete report, entitled "Effects of Appliance Type and Operating
Variables on Woodstove Emissions,"
Volume I. Report and Appendices AC: (Order No. PB90 151457 'AS; Cost:
$23.00, subject to change).
Volume II. Appendices D-F: (Order Nc. PB90 151465/AS; Cost: $31.00, subject
to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
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 Center :or Environmental Research
Environmental Protection Information
Agency Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S2-90/001
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