PM-10 AND CARBON MONOXIDE EMISSIONS F8GM WfiGi) S(JKNL% IN BUuk, MONTANA 25»n i^**--j- -f?-**?-^-- -"'r-eY**"^ /.^-^i /^gBssMjeu ^|S-^ PRINCIPAL INVESTIGATOR: r.-tf 7 i f1 V. ;' >' ! .. " ' ", , i .' 0 'sv-. - t -.1 1 :- : i '':,<:. t?r;f:r- *,'-.; i -;:; ; ! <: f; ^ \ '., ' _ :'*,' i i". : .* ' '.: f » ' i ------- 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 ------- 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 ------- 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. ------- 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. ------- 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 ------- 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 ------- 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 ------- VI 1 20. Storage method 41 21. Types of devices owned by non wood burners 42 22. Average miles of collection 42 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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 ------- 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. ------- 12 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 ------- 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 ------- 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. ------- 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. ------- |