PM-10 AND CARBON MONOXIDE EMISSIONS
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PM-10 AND CARBON MONOXIDE EMISSIONS
FROM WOOD BURNING IN BUTTE, MONTANA
PRINCIPAL INVESTIGATOR:
DR.KUMARASwAMY GANESAN
Department of Environmental Engineering,
Montana College of Mineral Science and Technology
Butte, Montana 59701
PROJECT COORDINATORS:
BOB RAISCH BOB JEFFREY
State Air Quality Bureau
Department of Health & Environmental Sciences
Cogswel1 Building
Helena, MT
with assistance from:
P.V.RAJAN
Graduate Student
Montana Tech
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SUMMARY
The Environmental Protection Agency classified
Butte, Montana as a group I area because air quality data
indicated a 95 % probability that the community would
violate new PM-10 particulate matter standard. In order to
prepare a plan to reduce this ambient particulate
concentrations, the various sources, their strength,spatial
and temporal distribution must be evaluated. A possible major
source of particulates in Butte is residential wood burning.
This survey report details the emission inventory of
particulate and carbon monoxide emission^ in Butte for the
year 1987-88.
The ultimate use of this emission data is to serve
as input in a mathematical diffusion model to evaluate the
impact of wood burning on Butte's ambient particulate levels
under specific winter time meteorological conditions.
Therefore this emission inventory was based on a spatial
scale consisting of 1 km x 1 km grids.The study was conducted
by contacting 430 households by telephone with a
questionnaire to obtain the necessary data. The number and
selection of households was based on statistical methods. In
Butte, it was estimated that,there were 13,073 occupied
households for the survey year of 1988. It was estimated that
32 % or 4189 households burn wood emitting 632 tons of
particulates and 3624 tons of carbon monoxide per burning
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i i
season. The emission's by grid showed that the particulate
emissions varies from 0.18 to 45.64 tons per grid. It is
estimated that 30 % of the citywide particulate emissions,
;that jji__o_vejr 90 tonsy were emitted from 5 grids. Nine out of
ten highest particulate emitting grids are bounded by
continental drive on the north and east; Utah Avenue on the
west and Holmes and Elizabeth Warren Avenue on the south. The
spatial carbon monoxide emissions was very similar to that
for particulates.
Although the density of households in some uptown
grids is much higher than the grids in the flat area, the
emissions are lower in the uptown grids. This is mainly due
to a lower percentage of wood burners (14%-25 %) in the
uptown area except in one grid in Walkerville, where the
percentage of wood burners were 42.9 %. The percentage of
wood burners in the flat area varied from 26%-70 %. The
highest percentage of wood burners were in grids located
south of Butte (83 %). Similarly number of cords burned also
was found to differ for each grid. Thus the emission from a
particular grid is a function of its population, percent of
wood burners and the number of cords used in that grid.
Stoves and fireplaces (63% and 30 %) were the two
major wood burning devices used in Butte. Only 7.8 % of the
devices were low emission devices such as catalytic or
pellet stoves. In Butte, almost two thirds of the wood
burners depend on wood as their sole source of heat.
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i i i
Based on the grid survey for the winter of 1987-88
about 19,245 tons of wood or 14,192 cords of wood were used;
primarily for residential heating.
The emission inventory data provided in this report was
based on a statistical survey of the Butte area. It is
impossible to attain absolute numbers for any emission
s~-.
inventory/,^ it becomes even more difficult when one should
depend on the home owner to estimate critical variables such
as the number of cords of wood burned or how they operated
their wood burning device. However extra care was taken in
the preparation of this report in order to ensure development
of a quality emission data base for Butte.
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i v
TABLE OF CONTENTS
SUMMARY i
1. INTRODUCTION 1
2. SURVEY METHODOLOGY 2
2.1 Objective 2
2.2 Questionnaire 2
2.3 Sample selection 3
2.4 Telephone Survey and interview 4
3. SURVEY RESULTS 5
3.1 Number of wood burning households 5
3.2 Reasons for burning wood 5
3.3 Types of wood burning devices 6
3.4 Amount of wood burned 7
4. DEVELOPMENT OF EMISSION ESTIMATES 9
4.1 Emission factors 9
4.2 Spatial apportionment of emissions 12
4.2.1 Population distribution by grid.. 16
5. STATISTICAL DATA ANALYSIS 28
5.1 Age of wood burning devices 28
5.2 Replacement status 29
5.3 Safety inspection data 30
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5.4 Air quality acknowledgement 30
5.5 Burning days and times 36
5.5.1 Burning days per week 36
5.5.2 Times of wood burning 37
5.5.3 Two device households 38
5.5.4 Wood procurement 39
5.5.5 Wood collection trips 40
5.5.6 Time of collection 40
5.5.7 Wood storage technique 40
5.5.8 Non wood burning households
unused wood burning devices 41
5.5.9 Wood collection miles 42
APPENDIX A: SURVEY QUESTIONNAIRE 44
APPENDIX B: SAMPLE SELECTION 46
APPENDIX C: SURVEY CONTACT RESULTS 48
APPENDIX D: SUMMARY OF LOW EMISSION DEVICES 49
REFERENCES CITED 50
ACKNOWLEDGEMENT 52
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LIST OF TABLES
TABLE TITLE PAGE
1. Percent wood burning households 6
2. Reasons for burning wood 6
3. Types of devices 8
4. Average cords of wood used by
different devices 8
5a. Emission factors 12
5b. Effective emission factors 13
6. Grid emissions 14
7. Average age of different
types of devices 29
8. Cross tabulation of types of devices
by age of devices 31
9. Cross tabulation types of devices
by age (less than 5 years old) 35
10. Replacement status of devices 30
11. Fire inspection of devices 30
12. Response to warning 36
13. Wood burning days 37
14. Time of wood burning 37
15. Burning hours per day 38
16. Secondary wood burning devices 39
17. Method of collecting wood 39
18. Average trips for collection of wood 40
19. Time of collection 41
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VI 1
20. Storage method 41
21. Types of devices owned by non
wood burners 42
22. Average miles of collection 42
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v i i i
LIST OF FIGURES
FIGURE TITLE PAGE
1. Butte map with grid numbers 20
2. Occupied households in each grid in Butte 21
3. Percent wood burners in each grid in Butte 22
4. Wood burning households in each grid
in Butte 23
5. Particulate from wood burning in
eachgridinButte(tons) 24
6. Carbon monoxide emission from wood
burning in each Grid in Butte ( tons ) 25
7. Three dimesional view of particulate
emi ssi ons 26
8. Isopleth of partuiculate emissions 27
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1. INTRODUCTION
This report contains the details of the development of
an emission inventory for participate and carbon monoxide
from wood burning in Butte, Montana. The actual inventory
employed a 1 km x 1 km grid system to allow for spatial
apporti onment.
The U.S. Environmental Protection Agency (EPA)
promulgated ambient air quality standards for particulate
matter with diameter less than 10 micrometer(PM-10). The
standards become effective on July 31, 1987. For the new
PM-10 standard, the 24 hour ambient concentration should not
exceed 150 micrograms per cubicmeter and the annual average
should not exceed 50 micrograms per cubicmeter(1).
In assessing the severity of the PM-10 problem in different
communities EPA grouped communities based on their
probability of violating the standards. Communities that have
95 % probability of violating the standards were classified
as Group I areas. Due to past particulate data and recent
violations of the PM-10 standards, Butte was classified as a
Group I area. Each state must develop a state implementation
plan(SIP) which includes control measures to bring the
ambient particulate concentration into compliance with the
PM-10 standards. Identification of emission sources, their
strength, spatial and temporal distribution are essential to
develop effective and meaningful control strategies. The main
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2
purpose of this emission inventory is to identify and
quantify the particulate matter emissions from residential
wood burning in Butte. The particulate and carbon monoxide
are reported for a grid composed of 1 ki1ometer(km) x 1
ki1ometer(km) squares based on the UTM coordinate system. The
data will then be used as input to an air quality diffusion
model. Through air quality diffusion models the spatial and
temporal impacts of emission sources on the ambient air
quality be evaluated. The Air Quality Bureau (AQB) of the
Montana Department of Health and Environmental Sciences
intends to use the Wyndvalley, a two layer grid model, to
evaluate the impact of various emission sources on the Butte
ai rshed.
2. SURVEY METHODOLOGY
2.1 Objective
The major objective was to obtain quality, reliable
and accurate wood burning emission inventory for Butte. One
of the ways to obtain such data is to directly measure the
emissions from each and every source. For residential wood
burning this method is very time consuming and unreasonably
expensive. As a reasonable alternative this study, estimated
emissions based on a telephone survey.
2.2 Questionnaire
The questions for the telephone survey were
developed by the state AQB. A copy of the questionnaire is
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3
included in appendix (A). Some of the major questions asked
were:
i) number and types of wood burning devices (WBD),
ii) amount of wood burned per season,
iii) source of wood, type and amount of time the wood was
stored before use,
iv) burning practices such as day vs night; amount of wood
charged each time and the refuel time, and
v) use of wood burning device for primary space heating
or for pleasure.
2 . 3 Sample selection
The number of residences to be contacted and their
addresses were selected based on a statistical approach. The
proportion of residences to be contacted was obtained by
using the Binomial distribution approach. For a finite sample
population and for a confidence level, the proportion of a
sample from which valid data should be collected to achieve
the desired level of confidence a is given by(2,3) :
t * J p x a x(N-n)/n(N-l) < limit of error 1
P \
Explanation of each term and a model calculation of
sample selection is shown in appendix B.
Based on the above equation, sample sizes for various levels
of confidence were estimated. Based on data from the 1980
census the number of residences in Butte, was estimated to be
14,240. The sample size for this population was determined to
be as high as 2,131 to achieve a 95 % confidence level and
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4
430 to achieve a 90 % confidence level. Since the sample size
(430) for a 90 % confidence level was about 5 times less than
the number of samples (2,131) to obtain a 95 % confidence
level a sample size of 430 was chosen.
The next step was to select the specific residences to
be contacted. This list was developed using a random number
generator. These random numbers correspond to page and line
numbers in the Butte telephone directory, and were generated
by a Digital Equipment VAX-8530 computer using an SPSSX
software package. From each page number and line number a
list of addresses and corresponding telephone numbers were
-obtained. Blank lines, business addresses, and street names
were skipped until a valid residential address was
identified. Using this procedure a list of 650 residences was
developed this list served on the basis for the telephone
survey.
2.4 Telephone survey and interview
Most of the residences were contacted by telephone
during the month of April 1988. Four Montana Tech students
conducted the telephone interviews. Upon completing a call
the students identified themselves, attempted to verify the
name and address of the respondent and explained the reason
for the survey. Five contacts were attempted before that
particular residence was classified as a miss. If the
respondent answered "yes" to the question "Do you burn
wood ?" then the rest of the questionnaire was completed. If
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5
the answer was "no", then they were only asked about their
future plans for new installation or reactivation of wood
burni ng devi ces.
A total of 643 contacts were attempted in order to
obtain the 430 successful contacts'.3 The unsuccessful contacts
were attributed to: disconnections(48), misses(91), refusal
to participate(71), and the address selected falling outside
the study area(3). A breakdown of this data is provided in
appendix(C).
3. SURVEY RESULTS
The data from the questionnaire was transferred
manually to a IBM compatible personal computer for
convenience of data handling and analysis. The results of
some of the major analysis are discussed in this section.
3.1 Number of wood burning households
Out of the 430 successful contacts, 156(36.3 %)
respondents burned wood. The overall survey result of 36.3%
is comparable to 38 % reported in a similar survey conducted
in Butte in the spring of 1985(4). The small decline could be
an actual decline in the number of residences burning wood or
could be due to differences in survey methods. These results
are reported in table 1.
3.2 Reason for burning wood
Of the 156 respondents burned wood, useful
information regarding their reason for burning wood could be
obtained from 151. Out of these 151 respondents, 57 % burned
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wood as a primary heat source for space heating, and 26.5%
burned wood for secondary or supplementary heat.
TABLE 1: PERCENT OF WOOD BURNING HOUSEHOLDS
TOTAL NUMBER OF RESPONDENTS IN THE SURVEY
NUMBER OF RESPONDENTS BURNING WOOD
PERCENT OF WOOD BURNING HOUSEHOLDS
URBAN AREA HOUSEHOLDS
NUMBER OF WOOD BURNING HOUSEHOLDS
430
156
36.3
13,073
4,745
About 14.5 % of the 151 respondents burned wood for
enjoyment and only 2 % used wood to heat a garage or out
building. Thus over 83 % of the respondents that burned wood
did so for the purpose of primary or secondary space heating
The detailed results are shown in Table 2.
TABLE 2 : REASONS FOR BURNING WOOD
TOTAL NUMBER OF WOOD BURNING HOUSEHOLDS = 4,745
REASON
PRIMARY
SECONDARY
ENJOYMENT
OUT BUILDING
NUMBER OF
RESPONDENTS
86
40
22
3
% BURNING
WOOD
57.0
26.5
14.5
2.0
PROJECTED
HOUSEHOLDS
2,705
1,257
688
95
TOTAL 151 100.0 4,745
3.3 Types of wood burning devices
Wood stove make up 63 % of the of wood burning
devices(WBD) in Butte while fireplaces accounted for only
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7
very 30.3% . A small percentage (2 %) of the WBD were home
made stoves such as barrel stoves etc. Of the total WBD's
36.8 % of them were air tight stoves and about 18.7 % of them
were non air tight stoves. Only 7.8 % of the total were
reported to be low emission devices such as catalytic
combustor equipped stoves or pellet stoves. About 4.5 % of
the stoves were modified wood furnaces.
In summary the majority of the WBD in Butte are wood
stoves, followed by fireplaces. The detailed information on
the types of devices is provided in table 3.
3.4 Amount of wood burned
The types of wood burning devices, the amount of
wood burned and the number of residents burning wood were the
major survey variables used to estimate the emissions from
wood burning. Respondents were asked how many cords of wood
they used in the winter of 1987-88. Most of the respondents
knew the amount of wood in a cord. Whenever necessary it was
explained to them that a cord of wood contains 128 cubicfeet
or that a cord is a stack of wood 8 ' x 4' x 4' in size.
Analysis of the data showed that the average amount of wood
burned during the above season was about 3.63 cords per
respondent. The details of the data are shown in Table 4. The
amount of wood used in a fireplace, 1.69 cords, was much less
than the 5.37 cords, used in a non airtight stove. This is
mainly due to the fact that the fireplaces are generally for
aesthetics and used for a shorter periods of time, whereas
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8
stoves are used for space heating and consequently for longer
periods of time. As one would expect, the airtight stoves
used less amount of wood than the non airtight stoves.
TABLE 3:TYPES OF DEVICES
Type of
devi ces
FIREPLACE
MODIFIED FP
NON AT STOVE
AT STOVE
CATALYTIC STOVE
PELLET STOVE
MOD WOOD FURNACE
HOME MADE
VALID RESPONSES
TOTAL
155
Number of
respondents
37
10
29
57
6
6
7
3
155
NO RESPONSE
Valid
percent
23.9
6.5
18.7
36.8
3.9
3.9
4.5
1.9
100.1
1
TABLE 4:AVERAGE CORDS OF WOOD USED BY DIFFERENT DEVICES
Types of
devi ces
FIREPLACE
MODIFIED FP
NON AT STOVE
AT STOVE
CATALYTIC STOVE
PELLET STOVE
MOD WOOD FURNACE
HOME MADE
For the entire
population
NO RESPONSE
TOTAL RESPONSES
Number of
respondents
36
10
26
52
5
5
5
3
= 14
= 142
Mean
cords
1 .6944
3.3000
5.3654
4.1212
2.5600
2.2000
4.7000
6.6667
Std Dev
1 .8386
3.2762
2.6289
2.8626
2.1138
1.7536
3.0332
1.5275
3.6275
2.8601
The catalytic and pellet stoves used the least amount of
wood, 2.6 cords(wood) and 2.2 tons(pel1ets) per burning
season per device respectively. This interpretation stands
valid only under the presumption that all the above stoves
were used for the same amount of time. The home made stoves
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9
such as barrel stoves, consumed the largest amount of wood,
6.6 cords per device per burning season. In total, based on
survey projections, Butte used 15,472 cords (21,043 tons) of
wood in the burning season of 1987-88.
Information on the type of wood burned in Butte area was
scarce and for this report, data from a previous report(4)
was used. This report used 80 % lodgepole pine and 20 %
Douglas fir based on information obtained from the U.S.
Forest Service. Assuming a moisture content of 25%, and the
density for lodgepole and fir being 30 and 35 Ibs/cft,
respectively(5,6), each cord of wood burned weighs 1.356 tons
(2,7201bs/cord) . This conversion of cords to tons is
necessary because the emission factor is provided in Ibs of
particulate/tons of wood burned.
4. DEVELOPMENT OF EMISSION ESTIMATES
4.1 Emission Factors
An emission factor relates the quantity of pollutants
emitted per unit level of activity such as amount of
particulate generated per quantity of wood burned. Emission
factors are statistical averages, and are not an absolute
measurement of emission from a particular source. However,
reasonable estimates of total emissions can be obtained using
emission factors.
Emissions from wood burning devices could depend upon
several factors, some of the factors influencing emissions
from wood burning are type of device, wood piece size, charge
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10
size, moisture content, type of wood and wood burn rate.
In this study three variables were considered for
estimating wood burning emissions; the stove type,wood
moisture content and wood burning rate. The WBD's were
classified according to the types mentioned earlier. The wood
moisture content for calculation purposes in this report was
assumed to be 25 %. Moisture content much above or below
20-25 % results in higher emissions. The third major
factor,the wood burn rate, was analyzed based on the
following categories:
(i) high (refuel time less than 2 hrs),
(ii) medium( refuel time between 2 to 4 hrs),
(iii) low (refuel time greater than 4 hrs).
The emission factors used in this emission inventory are
listed in Table 5A (7). Emission factors are provided for
each WBD type and burn rate. Air tight stoves with a low burn
rate (greater than 4 hours between refuelling) generate the
highest amount of particulates (125 Ibs of particulates/ton
of wood)and carbon monoxide (700 Ibs of carbon monoxide/ton
of wood). Based on survey projections approximately 70 % of
the air tight stoves in Butte are operated with a low burn
rate and they are contributing almost half of the particulate
emissions. Table 5B presents the emissions data generated by
WBD type and burn rate.
Wood burning stoves contribute approximately 86 % of the
total particulate emissions in Butte. The pellet and
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11
catalytic stoves excluded from the above stove group
contribute only 0.5 % of the total emissions even though they
account for 7.9 % of the total number of WBD's in Butte. It
appears that the air tight stoves,operating on low burn
rates, generate 50 % of the total particulate emissions from
wood burning in Butte. Low burn rates are generally used
overnight when people fully charge the stove before they go
to bed, the next refueling takes place in the morning. Over
night the stove operates under starved air mode, smoldering
through the night resulting in higher particulate emission
rate. It is also during these hours that the poor
meteorological conditions of low wind speeds and stable
atmospheric conditions prevail, increasing the impact of
these particulate emissions on the ambient air quality .
Butte would not have ambient air quality problem if the
meteorological conditions allowed effective and efficient
diffusion and dispersion of air pollutants. But the
meteorological conditions in Butte, especially during the
winter, become very unfavorable and they restrict the amount
of pollutants that could be discharged in the Butte airshed
without violating ambient air quality standards. The Butte
meteorological conditions are discussed in a separate section
of this report.
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TABLE 5A: EMISSION FACTORS:
[POUNDS
WBD TYPE
FIREPLACE
NON STD FP
NON AT STOVE
NON AT STOVE
NON AT STOVE
AT STOVE
AT STOVE
AT STOVE
CAT STOVE
PELLET STOVE
FURNACE
OF POLLUTANT P
BURN RATE
N/A
N/A
LOW
MED
HIGH
LOW
MED
HIGH
N/A
N/A
N/A
4.2 Spatial aoporti onment of
ER TON OF WOOD
PARTICULATE
30
30
75
65
50
125
90
50
12
2
40
emissions
BURNED]
CO
200
200
340
340
340
700
430
355
100
60
340
Emissions were assigned to individual 1 Km x 1 Km
grids based on the proportion of the wood burning households
in each grid and the amount of wood burned. An aerial
photograph of Butte was divided into 1 km x 1 km grids based
on UTM coordinates, and for identification purposes, the
grids were numbered in increasing order from south to north
and from west to east. The number after the decimal
indicates the distance of the grid in kilometers from the
first grid in the direction of west. Similarly the numbers
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TflBLE 5B = EMISSION BflSED ON THE TYPE OF DEVIC
TOTflL URBRN nREfl 13073
PERCENT WOOD BURN 36.3
NUMBER OF WOOD BU 4189
PflRTICULflTE
CRRBON MONOXIDE
MERN TOTflL EMISSION EMISSION CO/DEV
NR '/. WBP WB HOU CORDS TONS EF EMF1 TONS EF EMF2 TONS PflRT/DEV
FIREPLRCE
MOD FIRE PLfl
NON flT STOV
LOW
MED
HIGH
flIR TIGHT ST
LOW
MEDIUM
HIGH
CRT STOVE
PELLET
FURNRCE
HOME MflDE
37 23.9 1000 1.69 2,297.50
10 6.5 270 3.30 1,209.35
12 7.7 324 5.37 2,359.51
12 7.7 324 5.37 2,359.51
5 3.2 135 5.37 983.13
30 7.161 34.46 200 47.74 229.75 .00047 .00310
30 1.935 18.14 200 12.90 120.94 .00091 .00605
75 5.806 88.48 340 26.32 401.12 .00369 .01671
65 5.032 76.68 340 26.32 401.12 .00320 .01671
50 1.613 24.58 340 10.97 167.13 .00246 .01671
40
10
7
6
6
7
3
25.8
6.5
4.5
3.9
3.9
4.5
1.9
1081
270
189
162
162
189
81
4.24
4.24
4.24
2.56
2.20
4.70
6.67
6,209.47
1,552.37
1,086.66
562.90
483.74
1,205.69
732.94
125 32.26
90 5.806
50 2.258
12 .4645
2 .0774
40 1.806
75 1.452
===========
388.09
69.86
27.17
3.38
.48
24.11
27.49
700
430
355
100
60
340
340
180.65 2
27.74
16.03
3.87
2.32
15.35
6.58
,173.31
333.76
192.88
28.14
14.51
204.97
124.60
. 00485
.00349 .
.00194 .
.00028 .
.00004 .
.00172 .
.00458 .
01669
01378
00235
00121
01464
02077
155 100 4189
EFFECTIVE EMISSION FflCTOR
21043 65.67 782.92 376.81 4,392.23
LBS/TON 782.92TONS LBS/TON 4,392.23TONS
NR= NUMBER OF DEVICE OF THRT TYPE FOUND IN SURVEY .0328TON/TON OF WO .18840
/. WBP= '/. OF WOOD BURNING POPULfiTION
WB HOU = WOOD BURNING HOUSEHOLDS USING PflRTICULRR DEVICE
TONS = TOTRL TONS OF WOOD USED
RVG CORDS = flVERRGE CORDS OF WOOD USED
EF1= PRRTICULflTES EMISSION FflCTOR
EF2= CO EMISSION FflCTOR
EMF1 = CONTRIBUTION TO PRRTICULRTE EMISSION FflCTOR DUE TO THflT PflRTICULflR DEVICE
BflSED ON THE PROPORTION OF THflT DEVICE
EMF1 = CONTRIBUTION TO CO EMISSION FflCTOR DUE TO THflT PflRTICULflR DEVICE
BflSED ON THE PROPORTION OF THflT DEVICE
CONVESION FRCTOR= 2000 POUNDS = 1 TON
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GRID EMISSIONS
.ISSION FACTOR = PARTICULATE 65.67LBS/TON .0328 TON/TON OF WOOD
CARBON MONXI 376.8LBS/TON .1884 TON/TON OF WOOD
GRID #
89.3
89.4
89.5
90.3
90.4
90.5
90.6
91.2
91.3
91.4
91.5
91.6
91.7
92.1
92.2
92.3
92.4
92.5
92.6
92.7
92.8
93.1
93.2
93.3
93.4
93.5
93.6
93.7
93.8
94.1
94.2
94.3
94.4
94.5
94.6
94.7
95.1
95.2
95.3
95.4
95.5
95.6
96.1
96.2
96.3
96.4
97.1
97.2
97.3
98.1
98.2
98.3
I OF GRID
430 13073 4187 186.06 14,186.46 631.64 3,624.32
CORDS TONS TONS
GRID # = GRID NUMBER PARTICUL CARBON
SAMPLES = SAMPLES PER GRID MONOXIDE
%WB = % OF WOOD BURNING HOUSEHOLDS IN THE GRID
H = APPROX. NUMBER OF HOUSEHOLDS IN THAT GRID
WBH = NUMBER OF WOOD BURNING HOUSEHOLDS IN THAT GRID
MEAN CORDS = AVG NUMBER OF CORDS BURNED BY HOUSEHOLDS IN THAT GRID
TOTAL CORDS OF WOOD = TOTAL TONS OF WOOD BURNED BY HOUSEHOLDS IN THAI GR
SAMP
0
6
2
4
6
0
1
0
2
4
0
12
16
0
1
2
19
6
20
10
0
0
2
8
17
20
28
3
0
0
2
4
27
35
13
2
15
11
20
2
9
7
29
29
2
0
16
5
0
1
7
0
%WB
44.8
16.7
44.8
44.8
83.3
44.8
44.8
44.8
44.8
44.8
44.8
25
56.3
18.8
18.8
18.8
42.1
33.3
70
60
42.4
18.8
18.8
25
41.2
30
46.4
42.4
42.4
18.8
18.8
18.8
25.9
40
46.2
42.4
33.3
18.2
15
42.4
44.4
57.1
17.2
13.8
18.8
42.4
25
20
18.8
18.8
42.9
18.8
H
25
116
18
12
126
10
82
10
38
127
69
226
247
49
43
42
388
115
388
145
82
24
75
309
429
498
642
95
22
35
143
91
847
712
545
71
212
573
666
290
501
327
671
1220
528
23
335
383
208
7
96
137
WBH
11
19
8
5
105
4
37
4
17
57
31
57
139
9
8
8
163
38
272
87
35
5
14
77
177
149
298
40
9
7
27
17
219
285
252
30
71
104
100
123
222
187
115
168
99
10
84
77
39
1
41
26
MEAN TOTAL CORDS
CORDS OF WOOD
3.30
3.30
3.30
3.30
2.00
3.30
3.30
3.30
3.30
3.30
3.30
3.30
3.30
4.15
4.15
4.15
3.44
3.44
2.10
2.16
3.44
4.15
4.15
4.15
3.44
1.58
3.44
3.44
3.44
4.15
4.15
4.15
3.44
3.31
3.44
3.44
4.15
4.15
4.15
3.44
3.44
3.44
4.15
4.15
4.15
3.44
4.15
4.15
4.15
4.15
4.15
4.15
36.30
62.70
26.40
16.50
210.00
13.20
122.10
13.20
56.10
188.10
102.30
188.10
458.70
37.35
33.20
33.20
560.72
130.72
571.20
187.92
120.40
20.75
58.10
319.55
608.88
235.42
1,025.12
137.60
30.96
29.05
112.05
70.55
753.36
943.35
866.88
103.20
294.65
431.60
415.00
423.12
763.68
643.28
477.25
697.20
410.85
34.40
348.60
319.55
161.85
4.15
170.15
107.90
EMISSION IN^ONS
PART CO
1.62
2.79
1.18
.73
9.35
.59
5.44
.59
2.50
8.38
4.55
8.38
20.42
1.66
1.48
1.48
24.97
5.82
25.43
8.37
5.36
.92
2.59
14.23
27.11
10.48
45.64
6.13
1.38
1.29
4.99
3.14
33.54
42.00
38.60
4.59
13.12
19.22
18.48
18.84
34.00
28.64
21.25
31.04
18.29
1.53
15.52
14.23
7.21
.18
7.58
4.80
9.27
16.02
6.74
4.22
53.65***
3.37
31.19
3.37
14.33
48.06
26.14
48.06
117.19
9.54
8.48
8.48
143.25
33.40
145.93***
48.01***
30.76
5.30
14.84
81.64
155.55
60.14***
261.89
35.15
7.91
7.42
28.63
18.02
192.47
241.00***
221.47
26.37
75.28
110.26
106.02
108.10
195.10
164.34
121.93
178.12
104.96
8.79
89.06
81.64
41.35
1.06
43.47
27.57
-------
PART= PARTICULATE EMISSION BASED ON EFFECTIVE EMISSION FACTOR
CO= GABON MONOXIDE EMISSION BASED ON EFFECTIVE EMISSION FACTOR
*** = GRIDS IN WHICH ACTUAL SURVEY CORDS WERE USED
1 CORD = 1.36 TONS OF WOOD 15
-------
16
before the decimal indicate the vertical position of the
grid, the southernmost grid for Butte being 89. Butte was
divided into ten grids South to North and 7 grids West to
East, totalling 70 grids of 1 km x 1 km. Thus the Southwest
corner grid was identified by a numeric 89.1, the Northeast
corner was identified by 98.7. (Refer Fig.l).
4.2.1 Population distribution by grid
The household distribution in each grid is
necessary to estimate the grid emissions. At present, there
is no such data available for Butte. This is the first
attempt to develop such a grid population data base.
The basic data for the grid population distribution was
taken from census data from the Butte-Silver Bow County
Planning Department, Montana Department of Commerce and
actual counts taken from an aerial photograph of Butte. The
latest census data available for Butte was for 1980. The^
number of occupied households reported for the Butte in 1980
was 14,177 and the population in 1980 was 38,092. The
predicted population for 1990 was 35,360 and the population
in 1984 was estimated to be 34,655. Assuming a linear
relationship between population and households and assuming
that the growth or decline of the population between years
was linear, the total number of occupied households in Butte
was estimated to be 13,073 for 1988. The Department of
Commerce provided information on occupied households for the
six areas of the census tract map, furthermore each of the
-------
17
six areas was broken down into blocks with occupied household
data supplied for each block. This block data was overlaid on
a 1 km x 1 km grid map of Butte and the number of occupied
households in each grid was distributed accordingly. Although
the block data was for 1980 a proportional decline in number
of households was assumed and uniformly adopted throughout
the grid to account for the estimated 13,073 occupied
households. In addition residential units were also counted
manually from an aerial photograph of Butte taken in 1984.
This counting showed several new residential housing units,
particularly in the " flat", which were absent in the block
data. Where ever necessary these were added to the grid
population to obtain a more realistic household distribution
in Butte.
The grid map of occupied households in the Butte
study area is shown in Figure 2. For purpose of emissions
calculations, the Butte study area was arbitrarily divided
into three zones. Zone I being uptown, Zone II being the
flat area around Greely School and Zone III being the
developing area south of 190. Zone I consists of 21 grids to
the northwest, Zone II consists of the grids to the northeast
and Zone III includes all the grids south of Zone I, and
Zone II
The grid with the highest number of occupied
households is located in Zone I, more specifically 1,220
occupied households were located in grid 96.2. This grid is
-------
18
in the uptown residential area near Park Street. Total
households were 5,847, 6,120 and 1,106, respectively, for
Zones I,II and III. In Zone I grids 95.1 to 95.3, 96.1 to
96.3 and 97.1 to 97.3 accounted for 82 % of the population in
that zone, whereas the Zone II households are more or less
uniformly distributed. The grids on the boundaries of Zone
III are sparsely populated with new housing units.
One variable affecting grid emissions is the number of
households burning wood in a grid. Figure 3 and 4 show grid
distribution for the number of and percentage of wood burning
households respectively. If 5 or more samples were collected
from a grid then the percentage of households burning wood in
that grid was calculated from the grid samples. For those
grids less than 5 samples the percentage of wood burning
households was the average from the zone in which the grid
was located.
In Zone I, 12 out of 21 grids used the zone average
for the percentage of households burning wood. In Zone II, 6
out of 17 grids used the zone average and in Zone III, 8 out
of 12 grids did. The percentage of households burning wood in
zones 1,2, and 3 was 18.8, 42.4 and 44.8, respectively. The
low percentage in zone I is probably due to the number of
households there that are located in apartment buildings in
the older uptown area.
Another parameter affecting grid emissions is the
number of cords of wood burned per household. Adequate and
-------
19
representative samples from each grid are needed and by using
student t-test it was possible to determine the minimum
number of samples necessary to represent a grids population
at the 90% confidence level. For those grids meeting the
t-test the average amount of wood burned per household grid
was calculated using the survey results of that grid. If the
t-test failed then the amount of wood burned per a household
in that grid was calculated from that grid's zone average
ie.,the average cords burned from all the grids in that zone.
Only five grids passed the t-test; those grids were:
90.4, 92.6, 92.7, 93.5 and 94.5. the average number of cords
burned in those grids was 2.0, 2.1, 2.16, 1.58, and 3.31,
respectively. The rest of the grids used zone averages which
were 4.15, 3.44, and 3.30 cords burned per household far
zones 1, 2, and 3, respectively.
The particulate and carbon monoxide emissions in each
grid were calculated using the above data and are shown in
Figure 5 and 6, respectively, and in Table 6. Figure 7 and 8
gives the particulate emissions in three dimensional view and
in the form of isopleth lines. The total particulate and
carbon monoxide emissions were 631.64 and 3,624.32 tons,
respectively, for the 1987-1988 burning season.The
particulate emissions in Zone I ,Zone II and
Zone III were 202.70, 362.43 and 66.52 tons,respectively. The
Zone II area contributed the highest percentage, 57.5%,of
particulate emissions and it contains the two highest
-------
3UTTE MAP WITH GftID
-------
7
335
671
212
35
24
49
-XXX-
-XXX-
-XXX-
FTP, \
96
383
1220
573
143
75
43
1C
-XXX-
-XXX
> nccuf
137
20*
528
666
91
309
42
38
12
25
TED HOIISJ
-XXX-
-XXX-
23
29C
1847
429
388
127
126
116
HOLDS If
-XXX-
-XXX-
-XXX-
501
N.
712
498
115
69
10
18
| EACH GR
-XXX-
-XXX-
-XXX-
327
545
! 642
388
V
226
82
-XXX-
ID IN BIT
i
-XXX-
-XXX-
-XXX-
-XXX-
71
95
145
247
-XXX-
-XXX-
TE
-------
18.8
25
-/
17.2
33.3
18.8^
18.8
18.8
-XXX-
-XXX-
-XXX-
R
42.
20
13.8
18.2
18.8
18.8
18.8
44.8
-XXX-
-XXX-
G 3 : PERCJ
3 18.8
-XXX-
18.8 -XXX-
18.8
15
18.8
25
18.8
44.8
44.8
44.8
42.4
42.4
25.9
41.2
42.1
44.8
83.3
16.7
LNI WUUU ^fl-RNERS IN~E
-XXX-
-XXX-
-XXX-
44.4
+
40
30
33.3
44.8
44.8
44.8
-XXX-
-XXX-
-XXX-
57.1
46.2
46.4
70
^,
25
44.8
-XXX-
RCH O3ID 1M cunt
i
22
-XXX-
-XXX-
-XXX-
-XXX-
42.4
42.4
60
56.3
-XXX-
-XXX-
-------
^^^^^_
1
84
V
115
71
7
5
9
-XXX-
-XXX-
-XXX-
4!
7
168
104
27
14
8
4
4
-XXX
FTG
26
39
99
100
17
77
8
17
5
11
WOOD
-XXX-
-XXX-
10
123
219
177
163
57
105
L
BURNING
-XXX-
-XXX-
-XXX-
222
\-
285
149
38
31
4
8
40USEHOL
-XXX-
-XXX-
-XXX-
187
252
298
272
r
57
37
-XXX-
iS IN EA(
i
23
-XXX-
-XXX-
-XXX-
-XXX-
30
40
87
139
-XXX-
-XXX-
:H GRID
-------
0.18
15.52
21.25
13.12
1.29
0.92
1.66
-XXX-
-XXX-
-XXX-
FIG 5 :
7.58
14.23
31.04
19.22
4.99
2.59
1.48
.59
-XXX-
-XXX-
PARTICULAT
4.80
7.21
18.29
18.48
3.14
14.23
1.48
2.50
0.73
1.62
E PROM WOQE
-XXX-
-XXX-
1.53
18.84
33.54
27.11
24.97
8.38
9.35
2.79
piPMTMf; Tl
-XXX-
-XXX-
-XXX-
34.00
42.00
10.48
5.82
4.55
.59
1.18
i FArw r»in
-XXX-
-XXX-
-XXX-
28.64
38.60
45.64
25.43
8.38
5.44
-XXX-
(TONS)
24
-XXX-
-XXX-
-XXX-
-XXX-
4.59
6.13
8.37
20.42
-XXX
-XX
-------
«»,
^B
1.06
88.06
121.93
75.28
7.42
5.30
9.54
-XXX-
-XXX-
-XXX-
43.47
81.64
178.12
110.26
28.63
14.84
8.48
3.37
-XXX-
-XXX-
6 : eo EMISSION
»*: V»TTT 1 TLJTV *-_» .-».^« M * SM*i
27.57
41.35
104.96
106.02
18.02
81.64
8.48
14.33
4.22
9.27
/
>'hHUM wugu
-XXX-
-XXX-
8.79
108.10
192.47
155.55
143.25
48.06
53.65
16.02
BURNING I
-XXX-
-XXX-
-XXX-
195.10
241.00
60.14
33.40
26.14
3.37
6.74
rEACH GRH
-XXX-
-XXX-
-XXX-
164.34
221.47
261.89
145.93
48.06
31.19
-XXX-
rlN BUI lb(
25
-XXX-
-XXX-
-XXX-
-XXX-
26.37
35.15
48.01
117.19
-XXX-
-XXX-
ws) -
-------
26
FIGURE 7 THREE DIMESIONAL VIEW OF PARTICULATE EMISSIONS
-------
FIGURE 8 ISOPLETH OF PARTICULATE EMISSIONS
10.00
9.17 (b
8.33
7.30
6.67
5.83
5.00 -
0.83
10.00
- 9.17
- 8.33
- 7.50
- 6.67
- 5.83
- 5.00
- 4.17
3.33
- 2.50
1.67
- 0.83
0.00
n nn n R9 164. 9.45 3.27 4.09 4.91 5.73 6.55 7.36 8.18 9.00
0.00
-------
28
the ambient air monitoring site that has recorded numerous
exceedences of the PM-10 National Ambient Air Quality
Standards.
5. STATISTICAL DATA ANALYSIS:
Several statistical data analyses and interpretations
were done on the data obtained from the questionnaire. This
section details some of the results.
5.1 Age of wood burning devices
There were 134 respondents who provided information
regarding the age of their WBD's. The results are reported in
Table 7 and in a statistical cross tabulation in Table 8. The
average age of a WBD in Butte is about 6.4 years. The highest
being fireplaces with an average age of 9.4 years and a
standard deviation of 4.5 years and pellet stoves being the
lowest with an average age of 2 years and standard deviation
of 0.9 years. The majority (54.5 %) of all WBD's were less
than 6 years old, 31.1 % were 6-10 years old, and only 7.5 %
of the WBD's were less than one year old. Airtight stoves
were the most common WBD (38.8%) with 69% of them less than
6 years old. Conversely non airtight stoves makeup only 19.4%
of all WBD,s and 31% of them are less than 6 years old. All
the catalytic stoves (3.7 % of all WBD,s) reported were less
than 6 years old and all six pellet stoves reported (4.5 % of
all WBD,s) were less than 4 years old. Thus the data clearly
indicates that Butte wood burners have bought mostly air
tight stoves in recent years.
-------
29
Analysis of data on all WBD's less than 6 years
old ,presented in Table 9, showed that 60.3 % of them were
stoves (49.3 % airtight stoves and 11 % non airtight stoves).
Catalytic and pellet stoves contribute to 15 %. During the
last year 4 out of 10 WBD's were either catalytic or pellet
stoves as compared to 5 years ago when only 1 out of 21 were
low emission WBD's. This seems to indicate that low emission
devices are becoming popular among the Butte wood burners.
TABLE 7: AVERAGE AGE OF DIFFERENT TYPES OF DEVICES
Types of
devi ces
FIREPLACE
MODIFIED FP
NON AT STOVE
AT STOVE
CATALYTIC STOVE
PELLET STOVES
MOD WOOD FURNACE
HOME MADE
For Entire
populati on
No Response
Total Cases =
Number of
Respondents
27
9
26
52
5
6
E 6
3
Mean
age
9.4074
5.8889
7.5000
5.2692
2.8000
2.0000
6.8333
4.3333
Std Dev
5.2861
2.5712
3.3377
4.0055
1.7889
.8944
6.6758
3.0551
134
6.3881
4.4837
22 or 14.1 Pet
156
5.2 Replacement status
Of the Wood burning devices that were less than five
years old 66.7 % of them were installed new and the remaining
33.3 % of them were retrofits, mostly fireplace inserts as shown
in Table 10.
-------
30
TABLE 10: REPLACEMENT STATUS OF DEVICES (LESS THAN 5 YEARS OLD)
Device type Number of Valid
respondents Percent
RETRO 6 11.1
NEW 36 66.7
FP-INSERT 12 22.2
TOTAL 54 100.0
VALID RESPONSES 54 NO RESPONSE 19
TOTAL CASES 73
5.3 Safety inspection data
About 56.6 % of new installation in the past five years
were reported to have been inspected for fire safety. As high as
24.5% of the respondents reported that they were not aware of the
fire safety inspection program. The detailed data on the safety
inspection of wood burning devices in Butte is given in
Table 11.
TABLE 11 : FIRE INSPECTION OF DEVICES (LESS THAN 5 YEARS OLD)
Type of Number of Valid
response respondents Percent
YES 30 56.6
NO 10 18.9
UNKNOWN 13 24.5
TOTAL 73 100.0
VALID RESPONSES 53 NO RESPONSE 20
TOTAL CASES 73
5.4 Air quality acknowledgement
The wood burning respondents were asked whether they
respond to warnings issued by the Butte-Silver Bow health
department during air alerts. Data analyses showed that 63.1 %
-------
TABLE 8: CROSS TABULATION OF TYPE OF DEVICE BY AGE
31
COUNT
ROW PCT
COL PCT
TOT PCT
TYPE DEVICE
1
FIREPLACE
2
MODIFIED FP
3
NON AT STOVE
4
AT STOVE
5
CATALYTIC STOVE
7
PELLET STOVE
9
MOD WOOD FURNACE
11
HOME MADE
.1
COLUMN
(CONTINUED) TOTAL
1
L
1
3.7
10.0
.7
| ..
L J
1
3.8
10.0
.7
2
3.8
20.0
1.5
2
40.0
20.0
1.5
2
33.3
20.0
1.5
1
16.7
10.0
.7
1
33.3
10.0
.7
10
7.5
AGE
2
1
3.7
7.7
.7
10
19.2
76.9
7.5
2
33.3
15.4
1.5
13
9.7
IN YEARS
3
2
7.4
13.3
1.5
1
11.1
6.7
.7
1
3.8
6.7
.7
8
15.4
53.3
6.0
1
1
20.0
6.7
.7
2
33.3
13.3
1.5
15
11.2
4
2
7.4
14.3
1.5
.
1
11.1
7.1
.7
2
7.7
14.3
1.5
7
13.5
50.0
5.2
1
20.0
7.1
.7
1
16.7
7.1
.7
14
10.4
5
1
3.7
4.8
.7
3
33.3
14.3
2.2
4
15.4
19.0
3.0
9
17.3
42.9
6.7
1
20.0
4.8
.7
2
33.3
9.5
1.5
1
33.3
4.8
.7
| j
21
15.7
ROW
TOTAL
27
20. 1
r
9
6.7
26
19.4
52
38.8
5
3.7
6
4.5
6
4.5
3
2.2
L
134
100.0
-------
TABLE 8 CONT.
CROSS TABULATION OF TYPE OF DEVICE BY AGE
COUNT
ROW PCT
COL PCT
TOT PCT
TYPF DFVTTF --
1
FIREPLACE
"
2
MODIFIED FP
3
NON AT STOVE
4
AT STOVE
5
CATALYTIC STOVE
7
PELLET STOVE
9
MOD WOOD FURNACE
11
HOME MADE
COLUMN
(CONTINUED) TOTAL
6
2
7.4
14.3
1.5
2
22.2
14.3
1.5
5
19.2
35.7
3.7
h_ _ - - _ - J
4
7.7
28.6
3.0
h__-_----J
h_-_-----4
1
16.7
7.1
.7
1
1
14
10.4
AGE
7
1
11.1
20.0
.7
1
3.8
20.0
.7
hi
1
2
3.8
40.0
1.5
h_ j
H_ _ _ _ _ _ j
_-
.----.--.4
----------
1
33.3
20.0
.7
- ----- 4
----------
5
3.7
IN YEARS
8
1
3.7
14.3
.7
3
11.5
42.9
2.2
hi
3
5.8
42.9
2.2
h -J
H_ - _ - - - -J
. J
._-_____-J
7
5.2
9
4
14.8
80.0
3.0
hi
1
1.9
20.0
.7
h ________ J
u I
L _ J
h_-___-__J
5
3.7
10
.
4
14.8
36.4
3.0
.
4
15.4
36.4
3.0
Hi
3
5.8
27.3
2.2
h_ ______ J
_______J
,_________J
L __-
11
8.2
ROW
TOTAL
27
20. 1
9
6.7
26
19.4
52
38.8
5
3.7
.
6
4.5
.
6
4.5
.
3
2.2
,.
134
100.0
-------
TABLE 8 CONT.
CROSS TABULATION OF TYPE OF DEVICE BY AGE
COUNT
ROW PCT
COL PCT
TOT PCT
TYPF DEVICF -i
1
FIREPLACE
2
MODIFIED FP
3
NON AT STOVE
4
AT STOVE
5
CATALYTIC STOVE
7
PELLET STOVE
9
MOD WOOD FURNACE
11
HOME MADE
j
COLUMN
(CONTINUED) TOTAL
11
2
7.4
66.7
1.5
H- - - -
---------
1
3.8
33.3
.7
h_
.........
i
3
2.2
AGE
12
1
3.7
20.0
.7
1
11.1
20.0
.7
---------
3
11.5
60.0
2.2
H -
5
3.7
IN YEARS
13
1
3.7
100.0
.7
H,
---------i
Hi
h i
---------
1
.7
14
1
1
3.7
50.0
.7
H.
1
hi
_ -j
L _ _ . J
1
1.9
50.0
.7
L _ _ _ _ _ - - -1
L _ J
2
1.5
15
_ .
1
3.7
50.0
.7
hi
hi
_____ __,
1
3.8
50.0
.7
h ........ J
| _ J
2
1.5
ROW
TOTAL
27
20. 1
9
6.7
26
19.4
52
38.8
5
3.7
6
4.5
.
6
4.5
.
3
2.2
.
134
100.0
-------
TABLE 8 CONT.
CROSS TABULATION OF TYPE OF DEVICE BY AGE
COUNT
ROW PCT
COL PCT
TOT PCT
TYPF DFV T f F - - - -i
lire, u L v i L, L 1
1
FIREPLACE
2
MODIFIED FP
3
NON AT STOVE
4
AT STOVE
5
CATALYTIC STOVE
7
PELLET STOVE
9
MOD WOOD FURNACE
11
HOME MADE
j
AGE If
20
Hi
3
11.1
50.0
2.2
H- - - - J
2
3.8
33.3
1.5
1
H--------J
1
16.7
16.7
.7
1
L J
< YEARS
ROW
TOTAL
27
20.1
9
6.7
26
19.4
52
38.8
5
3.7
6
4.5
6
4.5
3
2.2
COLUMN 6 134
TOTAL 4.5 100.0
NUMBER OF MISSING OBSERVATIONS = 22
-------
TABLE 9: CROSS TABULATION OF TYPE OF DEVICE BY AGES
( LESS THAN 6 YEARS) or ( < 5 yrs old)
COUNT
ROW PCT
COL PCT
TOT PCT
TYPE DEVICE
1
FIREPLACE
2
MODIFIED FP
3
NON AT STOVE
4
AT STOVE
5
CATALYTIC STOVE
7
PELLET STOVE
9
MOD WOOD FURNACE
11
HOME MADE
j
COLUMN
TOTAL
1
f- - _ _ - -
1
14.3
10.0
1.4
L .
L
1
12.5
10.0
1.4
h-___----J
2
5.6
20.0
2.7
2
40.0
20.0
2.7
2
33.3
20.0
2.7
_l
1
25.0
10.0
1.4
-j
1
50.0
10.0
1.4
-f
10
13.7
AGE IN Y
2
L- - - -
1
14.3
7.7
1.4
L___.___ 1
h_______-J
10
27.8
76.9
13.7
h- - - - J
h___-_---J
2
33.3
15.4
2.7
13
17.8
EARS
3
2
28.6
13.3
2.7
1
1
20.0
6.7
1.4
h ____-- _ J
1
12.5
6.7
1.4
8
22.2
53.3
11.0
1
20.0
6.7
1.4
h_-___-_-J
2
33.3
13.3
2.7
15
20.5
4
2
28.6
14.3
2.7
1
20.0
7. 1
1.4
2
25.0
14.3
2.7
7
19.4
50.0
9.6
1
20.0
7.1
1.4
h-_-~ ___J
1
25.0
7.1
1.4
14
19.2
5
1
14.3
4.8
1.4
3
60.0
14.3
4.1
h_ _ _ _ _ _ _ J
4
50.0
19.0
5.5
H --_-_-___]
9
25.0
42.9
12.3
H________J
1
20.0
4.8
1.4
L _ __ _ _ _ J
2
50.0
9.5
2.7
1
50.0
4.8
1.4
21
28.8
ROW
TOTAL
7
9.6
5
6.8
8
11.0
L
36
49.3
5
6.8
L
6
8.2
L
4
5.5
L
2
2.7
73
100.0
NUMBER OF MISSING OBSERVATIONS =
-------
36
of the respondents usually do stop burning during air quality
alerts and 36.9% of them usually keep burning all the time. The
alert program was started in the wood burning season of 1987-88 .
Based on the air quality and meteorological conditions in Butte,
the county health department alerts the public of the hazardous
air quality. People are asked to voluntarily stop burning wood
during these alert periods.
5.5 Burning days and times
5.5.1 Burning days per week
Information was collected on how many days per week and
hours per day that a respondent usually burned wood. About 57.4 %
of the households burn wood on all 7 days, and only about 6.8% of
the households burn wood less than 1 day a week. As reported
earlier about 57 % of wood burning households in Butte use wood
for primary heat. From these results it could be assumed that
wood burners who burn wood for their primary heat burn wood on
all 7 days.The data is given in Table 13.
TABLE 12: RESPONSE TO WARNING
Type of Number of Valid
response respondents percent
ALWAYS STOP 10 9.0
USUALLY STOP 60 54.1
USUALLY KEEP BURN 22 19.8
ALWAYS KEEP BURNING 19 17.1
TOTAL 111 100.0
VALID RESPONSES 111 NO RESPONSES 45
TOTAL CASES 156
-------
37
TABLE 13: WOOD BURNING DAYS
Number of Valid
respondents percent
Burn days
<10D/YR
1 DAY
2 DAYS
3 DAYS
4 DAYS
5 DAYS
6 DAYS
7 DAYS
< ID/WEEK
VALID RESPONSES
TOTAL CASES
In order to obtain this information the wood burning
respondents were asked at what times of the day they most likely
burned wood.
Table 14 shows that 54.8 % of the respondent's in this
category usually burned 24 hrs a day and 36.8 % of them burned
either on evening or night time.
TABLE 14 : TIME OF WOOD BURNING
2
4
19
9
9
9
3
85
8
TOTAL 148
SES 148 NO RES
156
Times of wood burning
1.4
2.7
12.8
6.1
6.1
6.1
2.0
57.4
5.4
100.0
PONSES
TIME OF THE DAY
MORNING
EVEN.&NIGHT
ALL DAY
NO PREF
NUMBER OF
RESPONDENTS
6
57
85
7
TOTAL 155
VALID RESPONSES 155
TOTAL CASES 156
VALID
PERCENT
3.9
36.8
54.8
4.5
100.0
NO RESPONSES
These data provided a general information on the tendency of wood
-------
38
burning households using wood on various times of the day.In
addition this data is used for calculating the total burning
hours in a burning week. The average number of burning hours are
also provided in table 15. In Butte, people who burn wood use
them for almost 15 hours a day in average.
5.5.3 TWO DEVICE HOUSEHOLDS
This survey collected information on households having
more than one WBD.
TABLE 15 : BURNING HOURS PER DAY
Number of
respondents
Burn days
Week day burners
1 DAY 1
2 DAYS 6
3 DAYS 2
4 DAYS 7
5 DAYS 9
6 DAYS 3
7 DAYS 85
< ID/WEEK 2
TOTAL 115
Weekend burners
1 DAY
2 DAYS
3 DAYS
4 DAYS
TOTAL 18
No preference burners
2 DAYS 3
3 DAYS 1
< ID/WEEK 1
TOTAL 5
For Entire
Population 138
Mean
Std Dev
hours/day hours/day
4.0000
6.0000
6.0000
8.5714
12.6667
8.6667
18.7882
5.0000
16.1652
.0000
.0000
.0000
6.8034
8.1854
3.0551
7.1947
1.4142
8.2045
3
9
5
1
9.6667
8.0000
7.0000
24.0000
6.3509
6.0000
2.8284
.0000
8.8889
12.0000
6.0000
6.0000
9.6000
14.9783
6.2109
10.3923
.0000
.0000
8.0498
8.3548
Total Responses = 156 No Responses = 18 or 11.5%
-------
39
About 14.1 % of the respondents had more than one wood burning
device. The majority of the 20 respondents used their secondary
WBD and the results are shown in Tables 16. About 65 % of the
respondents used fireplaces as their secondary WBD and 30% used
airtight or non airtight stoves.
Table 16: SECONDARY WOOD BURNING DEVICE
Number of Valid
Type of device respondents percent
FIREPLACE
NON AT STOVE
AT STOVE
OTHERS
TOTAL
VALID RESPONSES
TOTAL CASES 1
5.5.4 WOOD PROCUREMENT
13
3
3
1
20
20
56
65.0
15.0
15.0
5.0
100.0
NO RESPONSES
136
About 86 % (135 respondents) of the wood burning
households provided information in this category. Of the 135
respondents, 80 collected wood and 56 either purchased wood or
used wood left over from last winter.The results are represented
in Table 17.
Table 17: METHOD OF COLLECTION OF WOOD
Method of Number of Valid
Collection respondents Percent
PURCHASED OR LEFTOVER 56 41.2
COLLECTED 80 58.8
TOTAL 156 100.0
VALID RESPONSES 136 NO RESPONSES 20
TOTAL CASES 156
-------
40
5.5.5 WOOD COLLECTION TRIPS
The respondents who collected wood were asked how
many wood collection trips they made. The respondents who
collected wood for the purpose of primary heating, about
59%,averaged 6 trips with a standard deviation of 4 trips. The
entire population averaged 5.5 collection trips with standard
deviation of 5. The results are shown in Table 18.
Table 18: AVERAGE TRIPS FOR COLLECTION OF WOOD
Reason Number of Mean Std Dev
respondents
PRIMARY 33 6.2424 4.2429
SECONDARY 13 5.5385 6.1727
ENJOYMENT 8 3.1250 3.6815
OUT BUILDING 1 2.0000 .0000
For entire
population 55 5.5455 4.7212
Total Responses = 156, No Response = 101 or 64.7%
5.5.6 TIME OF COLLECTION
Respondents who collected wood on their own were asked
when they finished their wood collection. The results are shown
in Table 19.About 81.5% responded that they finished their wood
collection by Oct 1987.
5.5.7 WOOD STORAGE TECHNIQUE
The wood burning households were asked how they store
their wood and out of the 140 respondents, 59 of them (42%) store
wood in an open yard or under house eaves covered. This would
indicate that the wood burners may have a higher moisture content
than assumed in this report, resulting in higher emissions. The
results are shown in Table 20.
-------
41
Table 19: Time of Collection
Month
1987
BEFORE MAY
JUNE
JULY
AUG
SEPT
OCT
NOV
JAN 88 OR LATER
N
r
umber of
espondents
5
5
6
7
11
9
7
3
Val id
Percent
9.4
9.4
11.3
13.2
20.8
17.0
13.2
5.7
VALID RESPONSES 53
TOTAL CASES 156
TABLE 20 :STORAGE METHOD
TOTAL 156
NO RESPONSES 103
100.0
Method of storage
Number of Valid
respondents percent
WOODSHED 10
GARAGE 15
UNDER HOUSE EAVES COVERED 11
UNDER HOUSE EAVES NOT COVERED 4
YARD STACK COVERED 45
YARD STACKED NOT COVERED 55
7.1
10.7
7.9
2.9
32.1
39.3
VALID RESPONSES
TOTAL CASES
TOTAL 140 100.0
NO RESPONSES 16
140
156
5.5.8 NON WOOD BURNING HOUSEHOLDS WITH UNUSED WBD
All the non wood burners were asked if they had any
unused WBD's. 53 out of 274 respondents(19%) in this category
had one or more unused WBD's. The results showed that 13% of the
non wood burning households had fireplaces and 4% had airtight
stoves. The unused WBD types are shown in Table 21.
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42
5.5.9 WOOD COLLECTION HUES
Of the 80 respondents who collected wood
25 % of them provided information in this category. The average
number of miles a wood burner drives to collect wood is broken
down against the reason for burning and the results are shown in
Table 22. On an average, a wood burner travels about 34.2 miles
round trip to collect wood.
Table 21: TYPES OF DEVICES OWNED BY NON-WOOD BURNERS
Number of Valid
Type of device respondents percent
FIREPLACE 35 66.0
MODIFIED FP 1 1.9
NON AT STOVE 5 9.4
AT STOVE 10 18.9
PELLET STOVE 1 1.9
UNKNOWN 1 1.9
TOTAL 274 100.0
VALID RESPONSES 53 NO RESPONSES 221
TOTAL CASES 276
Table 22:AVERAGE MILES OF COLLECTION
Reason Number of Mean Std Dev
respondents miles miles
PRIMARY 11 29.7273 20.1796
SECONDARY 5 56.0000 40.8350
ENJOYMENT 4 19.2500 5.3774
For Entire
Population 20 34.2000 27.4525
Total Responses = 20 No Response = 136 or 87.2%
-------
43
APPENDIX A : SURVEY QUESTIONNAIRE
APPENDIX B : SAMPLE SIZE CALCULATION
APPENDIX C : SURVEY CONTACT RESULTS
APPENDIX D : SUMMARY OF LOW EMISSION DEVICES
-------
QUESTIONNAIRE # PHONE #
ADDRESS Grid #
1. Do you burn wood at this address? (1) Yes [Go to #2] (2) No [Next Quest] Burn
*** IF NO: "Does your home have any wood-burning devices that you don't currently use?"
(1) One Device [Next] (2) Two Devices [Next] (3) None [Go to #1}
***** what Kind(s)? [Note device type(s) under r2 (and #3), then go to #7]
MAKE SURE YOU ARE SPEAKING WITH THE PERSON WHO ORDINARILY OPERATES THE WOOD BURNING DEVICE BEFORE PROCEEDING
2. What is your PRINCIPAL wood-burning device? (1) Fireplace (2) Modified FP (3) Non-Airtight Stov
(4) Airtight Stov (5) Catalytic Stove Retrofit (6); (7) Pellet Stove Retrofit (8);
(9) Wood Furnace (10) Unknown
***If 4, 5 or 7, then: Is it an Oregon-certified low emission stove LED
(1) Yes (2) No (3) Unknown
*****!£ yes, then what is the: Brand Model t
*How old is this device? (1) One year or less; Actual years: Jlf <5 yr, Next 2 Quest's]
***Did device REPLACE an older unit (e.g., FP-INSERT), or was it a NEW installation?
(1) Retro (2) New (3) FP-INSERT
***Was this installation inspected for fire safety by a fire marshall or bldg. inspector?
(1) Yes (2) No (3) Unknown
*What is your main reason for burning this device? (1) Primary Heat (2) Auxiliary Heat
(3) Enjoyment (4) Out Building
*About how many days/week do you burn? 1234567 (8) <1 day/week (9) <10 days/yr
***IF <5 DAYS/WEEK: Are you more likely to turn on weekdays or on weekends? (1) WeekDAYS
(2) WeekENDS
*0n days you burn, what hours to you usually operate this device? WeekDAY TO ;
TO
SAME HOURS? ( ) WeekEND: TO ; TO
Weekday Slot
Weekend Slot
STOVES ONLY; About how long can you usually burn your stove between refuelings?
(1) <2 hours (2) 2-4 hours (3) >4 hours
*How many cords of wood have you burned this winter? cords Other
NOTE: A cord of firewood is a stack of wood 4 feet wide by 4 feet high by 8 feet long.
It takes approximately two half-ton, long-bed pickup truckloads with wood piled
even with the top of the bed to make one cord.
ftWhen the Butte/Silver Bow Health Department declares hazardous air quality and asks the
public to voluntarily stop burning wood, do you: (1) Always stop burning
(2) Usually stop burning (3) Usually keep burning (4) Always keep burning
-------
3. Do you have a SECONDARY wood-burning device? (1) Fireplace (2) NON-Airtight Stov
(3) Airtight Stov (4) Other
4. Did you buy or collect wood for this winter? PURCHASED: (1) Yes (2) No (3) Some % GIFT ( )
COLLECTED: (1) Yes (2) No (3) Some %
ftft*IF COLLECTED: How many wood collection trips did you make? ( )No Coll Trips per se
What was the approximate round trip mileage of each collection trip?
When did you finish collecting the wood you have burned this winter?
(1) May 1987 or before (2) June (3) July (4) Aug (5) Sept (6) Oct (7) Nov
(8) Dec (9) Jan 1988 or later
5. Where do you store your firewood? [USE PERCENTS IF NECESSARY] (1) Woodshed/Carport % [Main #]
(2) Garage % (3) Under house EAVE COVERED % (4) Under house EAVE NOT COVERED % [Main %]
(5) Stacked in YARD COVERED % (6) Stacked in YARD NOT COVERED % [2nd #]
[2nd %] .
6. Do you plan to stop burning wood for good after this winter?
(1) Yes, definitely (2) Probably (3) Probably not (4) No Stop
***IF YES OR PROBABLY [Next Question, then go to #8]: What is your MAIN reason for
stopping? (1) Tired of collecting, splitting, stacking, hauling ashes, etc.
(2) Safety reasons; e.g., small children getting burned, risk of chimney fires
(3) Concerned about Butte's poor wintertime air quality (4) Economics; e.g.,
cheaper to heat with natural gas, etc. (5) Other Why Stop
7. Do you plan to install a wood-burning device (OR REACTIVATE AN UNUSED ONE) in the Install
next 2 years? INSTALL: (1) Yes, definitely (2) Probably (3) Probably not (4) No
REACTIVATE: (1) Yes (2) No React
***IF YES OR PROBABLY: What type of device are you considering installing: ><
(1) Fireplace (2) FP-Insert (3) NON-Airtight Stove (4) Airtight Stove (I)Type
(5) Catalytic Stove ~ Catalytic Retrofit (6), (7) Pellet Stove Pellet Retro (8) (R)Type
(9) Wood Furnace (10) Other (11) Unknown Brand
***IF YES OR PROBABLY: Are you considering installing a wood-burning device that is
eligible for a Montana income tax credit? Credit
XXXX NOTE ONLY: Had to explain tax credit? (1) Yes (2) No Explain
8. (OTHER THAN WOOD) what is your home's primary kind of heating system? (1) GAS;
(2) CENTRAL SPACE (3), (4) ELECTRICAL: (5) CENTRAL BASEBOARD (6); (7) FUEL OIL:
(8) CENTRAL SPACE (9); (10) OTHER
-------
46
SAMPLE SIZE CALCULATION
The distribution of expected results while sampling a population
to determine the proportion of people who burn wood is generally
Bi nomi al i n nature.
The a-level of confidence limit experimentally observed
proportion of wood burning(when sampling a finite population)
is given by (2)
p
± tcn- * 7p*q(N-n)/n(N-l)
where p+q =1
p= Proportion of wood burners in the sample
q= proportion of wood burners who do not burn wood
n= sampl e size
N= The size of the population
ta n.l is the student's t statistic corresponding to a level of
significance with (n-1) degrees of freedom.
Requiring that true proportion of wood burning population be
within a specified percent of the experimentally observed
proportion requires that the term
t * /p x q (N-n)/n(N-l)
when expressed as percent of estimated value of wood burners be
less than a specified limit,given by the relationship:
-------
47
t *7 p x a xfN-n)/n(N-l) < limit of error
P
Assuming p = proportion of wood burners = 0.38
q = 1-p = 1-0.38 = 0.62
Assuming N = Number of families who burn wood as 14240
We have t = 1.96 for confidence level of 95% i.e at 5% level
of significance
Error = 0.05
1.96 * 70.38 x 0.62 x(14240-n)/n(14240-1) < 0.05 x 0.38
solving for n gives a value of 2131 samples to be chosen for
survey. The size of sample seems to be impractical.
Choosing a confidence level of 90 % (10 % level of significance)
the size of sample is 430. Therefore total number of samples
chosen for survey will be 430.
-------
48
SURVEY CONTACT RESULTS
TOTAL SAMPLE DRAWN 643
DISCONNECTIONS 48 7.47 %
OUTSIDE STUDY AREA 3 0.47 %
TOTAL POSSIBLE CONTACTS 592 92.07 %
MISSES 91 15.37 %
REFUSED TO PARTICIPATE 71 11.99 %
TOTAL SUCCESSFUL CONTACTS 430 72.64 %
-------
SUMMARY OF DEVICE TYPE
I. CLASS I CERTIFIED STOVES
DEVICE TYPE
BLAZE KING
FISCHER TECH IV
RUSSO
ARROW
EARTH STOVE
ROCKER
NUMBER
FOUND
7
1
1
1
6
1
17
% OF DEVICE
25.0
3.5
3.5
3.5
21.5
3.5
60.5
UNCERTIFIED STOVES
STOVE
FIREVIEW
CELGENNIA
DAKA
MAGNOLONI
STOVEKING
AFCO
SCHRAEDER
HOME MADE
TOTAL
NUMBER FOUND
1
1
1
2
1
1
1
3
11
% OF WBH
3.5
3.5
3.5
7.0
3.5
3.5
3.5
11.0
39.5
-------
50
REFERENCES CITED:
1. ENVIRONMENTAL REPORTER 7-10-87 (CURRENT DEVELOPMENTS)
PP 763-766
2. Robert G.D. Steel & James H.Torrie.Princioles and Procedures
of Statistics, McGraw-Hill Book Company, 1960, pp 415-420.
3. Cochran G.William. Sampling Techniques, John Wiley & Sons,Inc.
New York, 1963, pp 74-76
4. K.Ganesan. IMPACT OF WOOD BURNING IN A VALLEY AIRSHED Paper
presented in 48 TH Annual Meeting. MONTANA ACADEMY OF
SCIENCES Butte.MT. March 1988.
5. Ted Otis, James H.Carlson. R.G.Samel, Gerald. Cator. Wood
Burning and particulate Air Pollution in the Missoula
Valley,Sept 1977, Missoula City county Health Dept.
6. Hazen, Brenner, The wood heat handbook, Oregon, Department of
Energy.
7. SteffeT. Richard.Eco Resources systems.222 E.Backwith
Ave.Missoula.Montana. 1986 Missoula Wood survey ,Residential
wood burning and pollutant Emissions.
8. Paul G.Bunet. Norman G.Edmisten. Paul E.Tiegs. James E.
Houck.Rachel A. Yoder. Particulate, Carbon Monoxide and Acid
Emission Factors For wood Burning, JAPCA Vol 36; No 9
Sept 1986, PP-1012- 1018.
9. Western Montana Scientist committee. Survey of residential
wood use in Helena, Bozeman,Great Falls and Kalispell,
Montana,
-------
51
A Report to the Air quality Bureau, Dept. of Health and
Env.sciences, June 1981.
10. Technical support Document of Residential Wood Combustion,
U.S. EPA FEB 1986.
11. Preliminary Characterization of Emission from Wood Fired
Residential Combustion Equipment, Interagency Energy /
Environmental R & D Program report....EPA-600/7-800409..
U.S. EPA MAR 1980.
12. "Compilation of Air Pollution Emission factors, 3rd edition"
AP-42 Supplement 14, U.S. Environmental Protection agency,
Research Triangle Park, NC, May 1983.
13. S.S.Butcher and E.M Sorenson, "A Study of Wood Stove
Particulate Emissions", Journal of the Air Pollution Control
Association. 24(9) : 724-728, July 1979.
14. National Oceanic and Atmospheric Administration,
Climatological Data. Dec 1984,1985,1986,1987, Jun 1985,
1986,1987, 1988.
-------
ACKNOWLEDGEMENTS
The principal investigator is grateful to Mr. Jeff Chaffey.-
chief, Air Quality Bureau and his department for sponsoring this
study. Also he likes to thank the students of the Environmental
Engineering Department, Montana College of Mineral Science and
Technology, for having helped in conducting the telephone survey.
The cooperation and facilities provided by the Department of
Environmental Engineering is greatly appreciated.
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