Review of Wood Heater and Fireplace Emission Factors

James E. Houck

OMNI Consulting Services, Inc., 5465 SW Western Avenue, Beaverton, OR 97075

houck@OMNI-Test.com

John Crouch

Hearth Products Association, 7840 Madison Avenue, Fair Oaks, CA 95628

crouchpa@ix.netcom.com

Roy H. Huntley

U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards (MD-14)

Research Triangle Park, NC 27711

huntley.roy@epa.gov

ABSTRACT

Wood heater and fireplace air pollutant emissions factors that are generally used in the 

calculation of emission inventories are those compiled in the U.S. Environmental Protection Agency’s 

AP-42 and Locating and Estimating (L &E) documents. For a number of pollutants the AP-42/L& E 

emission factors for wood heaters and fireplaces are based on a limited number of tests on few models. 

In addition, much of the data making up the wood heater emission factor database are from older 

models.

In particular, two significant emission factor categories, which have a wider and more current 

database than is represented in the EPA documents, are polycyclic organic matter (POM) from wood 

heaters, and particles and carbon monoxide from fireplaces. Residential wood combustion (RWC) has 

been implicated as a major source of POM. New POM data for Phase 2 certified stoves and another 

conventional stove are now available that allow for the revision of POM emission factors.

Fireplace emissions are becoming of increasingly more importance due to the fact fireplaces are 

installed in the construction of new homes. The number of fireplaces is growing more rapidly in 

comparison with the number of wood stoves. Already, in the South and West census regions nearly one 

quarter of the total cordwood used for RWC is burned in fireplaces. By using data from reports that 

were not widely distributed and from new reports, particulate and carbon monoxide emission factors for 

fireplaces were developed based on a largely expanded number of individual fireplace tests.

The appropriateness of expressing particulate emissions as “5H equivalent” was also evaluated. 

Method 5H is a wood heater certification method not a method designed to provide real-world 

particulate emission values.

A large number of fireplaces use manufactured wax/sawdust firelogs for fuel. No emission 

factors for wax/sawdust firelogs have been included in AP-42. Emission data for the use of 

manufactured wax/sawdust firelogs are provided here. These emission data are significant not only 

because manufactured firelogs are widely used but because they also provide emission reductions when 

used in lieu of cordwood.

INTRODUCTION

Air pollution emission factors for residential wood combustion (RWC) need to be revised for 

three primary reasons: (1) Limited data have been used to represent a large number of appliances and 
variables. There are many hundreds of types or models of wood burning devices in use, many dozens of 

tree species are commonly used for wood fuel, draft characteristics vary from home to home (chimney 

conditions), household altitude is variable, there are variations in fuel wood seasoning and storage 

practices (wood moisture), and there are wide variations in the home occupants operation of wood 

burning devices (burn rate, burn duration, damper setting, kindling approach, etc.). Each of these 

parameters have significant impacts on combustion conditions and will change emissions. The 

measurement of emissions from a very limited number of models and burning conditions to represent 

the estimated 9.8 million wood stoves, 7.3 million wood burning fireplace inserts, 27 million wood 

burning fireplaces without inserts, and 0.3 million pellet stoves in homes (1999) in the United States has 

the potential of producing very non-representative emission data. (2) Semi-volatile organic compounds 

as well as water soluble organic compounds, such as alcohols, aldehydes and organic acids, make up a 

very large fraction of RWC emissions. The choice of sampling approaches changes the capture 

efficiency of emissions and the partitioning between gas and particulate phases. For example, there 

have been a number of different particulate sampling approaches which will produce different emission 

factors for the same set to test conditions., and, (3) Since 1990 there has been considerable 

improvement in new RWC appliance performance, i.e., lower emission factors, which is not represented 

adequately in the EPA emission factor compilations simply due to the age of many studies. Related to 

this is the fact that the federal wood heater certification manufacturing and sale requirements were put in 

place between 1988 and 1992. Studies prior to this generally did not evaluate current state-of-the-art 

appliances. In addition, there is general recognition that there has been improvement in both cordwood 

and pellet stoves since the first introduction of high technology models in the late 80's and early 90's.

It is beyond the scope of this limited paper to provide revised emission factors for all air 

pollutants for all RWC appliance types. Four topics were selected to illustrate the revisions and 

improvements possible in RWC emission data. These were: (1) POM emissions from wood heaters, (2) 

particles and carbon monoxide from fireplaces, (3) emission data from manufactured wax/sawdust 

firelogs burned in fireplaces, and, (4) an evaluation of the effects of particulate sampling approaches on 

emission factors.

POLYCYCLIC ORGANIC MATTER FROM WOOD STOVES

Residential wood combustion has been identified as a source of polycyclic organic matter 

(POM). Polycyclic aromatic hydrocarbons (PAH) are a subset of POM. Sixteen (and seven) specific 

PAH compounds have been used as indicators of POM emission levels and they are generally used in 

emission inventories in that role. They are referred to as 16-PAH and 7-PAH. The seven compounds 

that make up the 7-PAH group are carcinogens.

Emission factors for a number of PAH compounds for conventional, catalytic and high 

technology non-catalytic stoves have been compiled in AP-421. 16-PAH and 7-PAH emission factors 

based on that PAH data are provided in EPA’s Locating and Estimating (L & E)document2. Review of 

the references used to develop the AP-42 PAH emission factors revealed that no references published 

more recently than 1986 were used to develop the high technology non-catalytic emission factors and 

that no references published more recently than 1990 were used to develop the catalytic emission 

factors. Consequently, no certified stoves were among the stoves that were used to develop the high 

technology non-catalytic emission factors and only one phase 2 certified stove, along with uncertified 

models and one Oregon certified model, was used to develop the catalytic emission factors. In addition, 

the conventional stove emission factors in AP-42 were based only on one stove.

Two new studies (one sponsored by the U.S. EPA3 and one by Environment Canada4) have 

recently been published that contain data for phase 2 stoves and therefore contain data more 

representative of stoves now manufactured and sold than the AP-42 data. (All wood stoves sold after 

July 1, 1992 have had to be phase 2 certified.) The EPA sponsored study measured emissions from 

phase 2 stoves that were used at least seven years in homes to take into account normal performance 
degradation. A total of 16 used phase 2 stoves were tested for multiple one-week periods for a total of 

43 runs for that study. 

The Environment Canada study tested a new phase 2 certified stove in the laboratory under 

realistic burn conditions (six runs). This study also tested one more conventional stove under realistic 

use conditions (six runs).

The test results from the two new studies were combined with part of the AP-42 referenced data5

containing the one phase 2 stove and the one conventional stove to produce more realistic 7-PAH and 

16-PAH results. A comparison between the updated and currently published emission factors is shown 

in Table 1. As can be seen, the updated emission factors for all three stove categories, for both 7-PAH 

and 16-PAH, are lower than the currently published emission factors. In addition, the difference in the 

emission factors between conventional stoves and phase 2 certified stoves is larger than the difference 

shown for conventional stoves and older model catalytic or high technology non-catalytic stoves.

FIREPLACE PARTICULATE AND CARBON MONOXIDE EMISSIONS

A comprehensive literature review was conducted to establish the range and distribution of 

fireplace carbon monoxide and particulate emissions. Twenty four unique sources (not including 

multiple reports and publications based on the same tests)were found to contain relevant data. Sixteen 

of these6-21 are not included in the particulate or carbon monoxide calculations used to derive the values 

tabulated in AP-42. Some of these sources are recent publications or had limited distribution.

The tests used to develop the database represent a “cross section” of fireplace types and fireplace 

usage characteristics. The tests have been conducted over a 32-year period. Tests were conducted on 

masonry and metal manufactured fireplaces of various sizes, various sizes and styles of grates were 

used, some tests were conducted without grates, different chimney heights and types were used, some 

tests employed hot starts, some tests employed cold starts, and a variety of cordwood and dimensional 

lumber fuel types were used.

Carbon monoxide emission factors (g/dry kg) were compiled. The emission factor data are 

based on 277 tests on 70 fireplace models. The mean was 64.1 g/dry kg and the standard deviation was 

40.7 g/dry kg. The results are compiled in Table 2 and plotted in Figure 1. For comparison purposes, 

the carbon monoxide emission factor value listed in AP-42 is 126 g/dry kg.

Particulate emission factors (g/dry kg) were compiled. Because there have been a number of test 

methods used to measure particulate emissions, results were all converted to Method 5H equivalent 

values to put them on the same basis. Conversion of data collected with the Automated Woodstove 

Emission Sampler (AWES), the Virginia Polytechnic Institute (VPI) sampler and Method 5G-like 

dilution sampling systems to Method 5H equivalent values was conducted with equations developed for 

the U.S. Environmental Protection Agency22. Data collected with the Emission Sampling System (ESS) 

developed for the Washington state certification program14 and for the Northern Sonoma County 

method

21 were converted to Method 5H equivalent values with the relationship developed with 

simultaneous testing with Method 5H and the ESS21 Historical data collected with a Method 5 sampler 

were converted to Method 5H equivalents by developing a relationship between the values obtained with 

a Method 5H sampler and the same sampler with the particulate material collected on the back filter 

removed from the calculation. (The key physical difference between a Method 5H sampler and a 

Method 5 sampler is that the Method 5 sampler does not have a back filter but the Method 5H does). 

Based on 20 data points, the relationship between Method 5H and Method 5 was determined to be: 

Method 5H = 1.11898 (Method 5) - 0.9374, R2 = 0.9815.
The emission factor data are based on 388 tests on 112 models. The mean was 11.8 g/dry kg and 

the standard deviation was 11.6 g/dry kg. The results are compiled in Table 3 and plotted in Figure 2. 

For comparison purposes, the particulate emission factor value listed in AP-42 is 17.3 g/dry kg23.

MANUFACTURED FIRELOGS

It has been estimated that 100 million wax-sawdust firelogs or 0.8 million wood cord equivalents 

are burned each year24. Based on survey data, wax-sawdust firelogs were burned some of the time in 

30% of fireplaces and exclusively in 12% of the fireplaces during the 1994-1995 heating season25.

Wax-sawdust firelogs are composed of approximately 40% to 60% wax with the remaining 

portion sawdust. Waxes obtained from petroleum refineries are typically used. The heat content of 

wax-sawdust firelogs is much higher than that of cordwood (15,700 Btu/lb. for wax-sawdust firelogs as 

compared to 8900 Btu/lb. for Douglas fir) and their moisture content is much lower (3% as compared to 

20% for well-seasoned cordwood). There are two types of manufactured firelogs, densified firelogs and 

wax-sawdust firelogs. Wax-sawdust firelogs, discussed here, are used in much greater numbers than 

densified logs and are for use exclusively in fireplaces. They require no kindling, and are designed for 

one-at-a-time use. While several sizes of firelogs are commercially available, those with a burn duration 

of about three to four hours, which is the typical fireplace usage period, are most popular.

There have been a number of studies that have evaluated the reduction in particulate and carbon 

monoxide emissions achievable with wax-sawdust firelogs as compared with cordwood9,12,17 & 26. These 

studies used emission rates (g/hr) rather than emission factors (g/kg fuel) or emissions per unit of heat 

(g/Mj) to compare emissions. This was done since the heat content is different for wax-sawdust firelogs 

than for a cordwood and their prescribed usage (one log burned at a time without the use of kindling) is 

also different than for cordwood. That is, the average emission rates over a normal burn cycle for both 

cordwood and firelogs provide the best measure for comparison of the total amount of air pollutants that 

are released into the environment when a standard fireplace is used in a normal fashion with either fuel 

type. The results of all studies showed substantial reduction in particulate matter (PM) and carbon 

monoxide (CO) emissions. The average reduction in particulate emissions for the studies was 69% and 

the average reduction in carbon monoxide emissions was 88%. Because virtually all particles emitted 

from cordwood and firelogs burned in fireplaces are sub-micron in diameter, reductions documented for 

total particulate matter (PM) emissions are also representative of reductions in PM10 and PM2.5 particles. 

The emission reductions for the most representative use scenarios provide the best assessment of the 

level of pollutant reductions that can be reasonably expected in an airshed through the use of firelogs.

Research was conducted on the most realistic use scenarios for both cordwood and firelogs and 

emission measurements of particles, carbon monoxide and air toxics were made for them13. The most 

representative fireplace scenario for cordwood consists of seasoned oak fuel, 3-hour wood addition

period, a standard factory-supplied grate and an approximately 3 kg/hr burn rate. The most 

representative firelog scenario consists of burning a “4-hour” firelog following manufacturer’s 

instructions (one at a time on a grate with bar spacing less than 3 inches) and tapping the log with a 

fireplace poker when visible flames start to flicker out. In both cases the most common/typical fireplace 

and chimney set-up which consisted of a 36- inch radiant fireplace, no glass doors, and a 16.5 ft 

chimney height was used. 

The overall results of the study are illustrated in Figure 3 and can be simply stated. Emissions of 

key air pollutants (particles, carbon monoxide, formaldehyde, benzene, and 16-PAH) were reduced in 

the range from 69% to 90% through the use of wax-sawdust firelogs in fireplaces. Emission rates for 

both oak cordwood and firelogs are shown in Figure 3. Since the nominal weight of firelogs used in the 

test was 6 lbs. (2.7 kg), emission factors (g/kg) and perhaps more importantly total emissions per six 

pound log can be calculated from the data. (The weighted average weight of firelogs sold in the U.S. is 

estimated, based on sales numbers, as 4.95 lbs.). It should be noted that since the overwhelming 
majority of particles emitted from both cordwood and firelogs are less than 2.5 :, the values for PM, 

PM10 and PM 2.5 for a given test were within the uncertainties of the methods and also that the values as 

shown in Figure 3 are essentially 5G equivalents. The corresponding PM 5H equivalent for the 46.1 

g/hr value shown in Figure 3 for cordwood is 51.9 g/hr and the corresponding PM 5H equivalent for the 

12.4 g/hr value for a firelog is 15.8 g/hr (based on the conversion factor used for AP-42).

PARTICULATE COLLECTION AND REPORTING

As previously noted, particulate emissions have been measured by a variety of methods (viz., 

EPA methods 5, 5G and 5H, with the AWES, VPI and ESS samplers, and with various custom dilution 

systems) and equations have been developed to relate results from each method to a “5H equivalent” 

value to allow for comparisons. The correlation between methods is generally not good primarily 

because of the organic makeup of RWC emissions27 and the various uses of filters, resins and impingers 

by the different methods to collect emissions. Figure 4, for example, shows the poor correlation 

between Methods 5G and 5H data generated independently by three laboratories in the emission rate 

range characteristic of new and used phase 2 wood heaters. Table 4 shows the magnitude of the 

difference between results directly obtained with Method 5G and the corresponding equivalent Method 

5H values obtained by two standard conversion equations

In addition to the “scatter” seen in the correlations between methods, the selection of 5H equivalent 

values as the format for compiling particulate emissions is inappropriate since Method 5H is a 

certification method (not a method for collecting representative real-world emissions) and is designed 

for wood heaters only. (It is not for appliances with high amounts of excess air such as fireplaces.) It is 

generally believed that a dilution tunnel with the tunnel and filter temperatures near a given wintertime 

ambient temperature would produce the most representative particle emission factors for RWC.

CONCLUSIONS

$ 16-PAH and 7-PAH values for phase 2 stoves are lower than the values currently compiled for 

high technology catalytic and non-catalytic stoves. The revised values for the conventional stove 

category are also lower and the difference between conventional stoves and phase 2 stoves is 

greater than the difference between conventional stoves and the published values for high 

technology catalytic and non-catalytic stoves.

$ Particulate and carbon monoxide emission factors for wood burning fireplaces based on an 

expanded database are lower than the values compiled in AP-42.

$ Emission data for wax/sawdust firelogs burned in fireplaces are important to include in RWC 

emission compilations due to the wide spread use of the fuel. Emissions from their use are lower 

than for cordwood.

$ The interconversion of particulate emission factors determined by different samplers has a high 

uncertainty associated with it. The use as of “5H equivalent” as measure of emission factors 

needs to be viewed with caution since Method 5H is strictly a certification method for wood 

heaters.

$ Upon review of existing reports and publications, a number of other revisions/updates in RWC 

emission factors are appropriate and possible using existing data. Notably, these include the 

revision of emission factors for pellet stoves to be representative of new models, the revision of 

conventional and certified stove particulate emission factors, the addition of emission factors for 

densified manufactured fuel, and the revision of volatile organic compound/ hazardous air 

pollutant emission factors for both wood stoves and fireplaces.

REFERENCES

1. U.S. Environmental Protection Agency, Compilation of Air Pollution Emission Factors –

Volume 1: Stationary Point and Area Sources, AP-42, Chapter 1.10, Research Triangle Park, 

NC, revised October 1996, pp 1.10-1-1.10-10.
2. U.S. Environmental Protection Agency, Locating and Estimating Air Emissions from Sources of 

Polycyclic Organic Matter, Research Triangle Park, NC, 1998, EPA-4545/R-98-014.

3. Fisher, L.H., Houck, J.E., Tiegs, P.E., and McGaughey, J., Long-Term Performance of EPACertified Phase 2 Woodstoves, Klamath Falls and Portland, Oregon: 1998/1999, Prepared for 

U.S. Environmental Protection Agency by OMNI Environmental Services, Inc., Beaverton, OR, 

2000, EPA-600/R-00-100.

4. Environment Canada, Characterization of Organic Compounds from Selected Residential Wood 

Stoves and Fuels, Ottawa, ON, 2000, report ERMD 2000-01.

5. Burnet, P.G., Houck, J.E., and Roholt, R.B., Effects of Appliance Type and Operating Variables 

on Woodstove Emissions, Prepared for U.S. Environmental Protection Agency by OMNI 

Environmental Services, Inc., Beaverton, OR, 1990, EPA-600/2-90-001.

6. Barnett, S.G., In-Home Fireplace Performance: Comparison of a Conventional Fireplace with a 

Retrofit Firecrest Masonry Insert in the Zagelow Residence Vancouver, Washington, Prepared 

for Mutual Materials Company, by OMNI Environmental Services, Inc., Beaverton, OR, 1991.

7. Barnett, S.G., Particulate and Carbon Monoxide Emissions from a Bellfire 28 Rosin Fireplace 

Using a Simulated Real-World Test Procedure, Prepared for Sleepy Hollow Chimney, Inc., by 

OMNI Environmental Services, Inc., Beaverton, OR, 1992.

8. Barnett, S.G., Summary Report of the In-Home Emissions and Efficiency Performance of Five 

Commercially Available Masonry Heaters, OMNI Environmental Services, Inc., Prepared for 

The Masonry Heater Association, by OMNI Environmental Services, Inc., Beaverton, OR, 1992.

9. Bighouse, R.D., and Houck, J.E., Evaluation of Emissions and Energy Efficiencies of Residential 

Wood Combustion Devices using Manufactured Fuels, Prepared for Oregon Department of 

Energy, by OMNI Environmental Services, Inc., Beaverton, OR, 1993.

10. Clayton, L., Karels, G., Ong, C., and Ping, T., Emissions from Residential Type Fireplaces, Bay 

Area Air Pollution Control District, San Francisco, CA, 1968.

11. DeAngelis, D.G., Ruffin, D.S., and Reznik, R.B., Preliminary Characterization of Emissions 

from Wood-Fired Residential Combustion Equipment, Prepared for U.S. Environmental 

Protection Agency, by Monsanto Research Corporation, Dayton, OH, 1980, EPA-600/7-80-040.

12. Hayden, A.C.S., and Braaten, R.W., “Reduction of Fireplace and Woodstove Pollutant 

Emissions through the Use of Manufactured Firelogs,” Presented at the 84th Annual Meeting and 

Exhibition of the Air and Waste Management Association, Vancouver, BC, 1991, paper 91-

129.1. 

13. Houck, J.E., Scott, A.T., Sorenson, J.T., Davis, B.S., and Caron,C., “Comparison of Air 

Emissions between Cordwood and Wax-Sawdust Firelogs Burned in Residential Fireplaces”, 

Presented at the Joint International Specialty Conference: Recent Advances in the Science and 

Management of Air Toxics, Banff, Alberta, 2000.

14. OMNI Environmental Services Inc., Reports on forty-five fireplace tests submitted to the 

Washington State Department of Ecology, Olympia, WA, pursuant to WAC 51-309-3102 and 

UBC Standard 31-2, 1995-2000.

15. OMNI-Test Laboratories, Inc., The Effects of Fireplace Design Features on Emissions, Prepared 

for the Fireplace Manufacturer's Caucus of The Hearth Products Association, Arlington VA, 

2000.

16. Shelton, J. W., and Gay, L, Colorado Fireplace Report, Prepared for Colorado Air Pollution 

Control Division by Shelton Research, Inc., Santa Fe, NM, 1987.

17. Shelton, J.W., Testing of Sawdust-wax Firelogs in an Open Fireplace, Prepared for Conros 

Corp., Duraflame Inc., and Pine Mountain Corporation by Shelton Research, Inc., Santa Fe, NM, 

1988.

18. Shelton, J.W., Sorensen, D., Stern, C.H., and Jaasma, D.R., Fireplace Emission Test Method 

Development, Prepared for Wood heating Alliance and Fireplace Emissions Research Coalition, 

by Shelton Research, Inc. Santa Fe, NM, and Virginia Polytechnic Institute, Blacksburg, VA, 

1990.
19. Stern, C.H., and, Jaasma, D.R., Study of Emissions from Masonry Fireplaces, Prepared for Brick 

Institute of America, by Virginia Polytechnic Institute, Blacksburg, VA 1991.

20. Stern, C.H., Jaasma, D.R., and Shelton J.W., Masonry Heater Emissions Test Method 

Development, Prepared for Wood Heating Alliance by Virginia Polytechnic Institute, 

Blacksburg, VA and Shelton, Research, Inc., Santa Fe, NM, 1990.

21. Tiegs, P.E., and Houck, J.E., Evaluation of an Emission Testing Protocol for Wood -Burning 

Fireplaces and Masonry Heaters, Prepared for Northern Sonoma County Air Pollution Control 

District, by OMNI Environmental Services, Inc., Beaverton, OR, 2000.

22. E.H. Pechan and Associates, Inc., Emission Factor Documentation for AP-42 Section 1.10, 

Appendix A, report to U.S. Environmental Protection Agency Research Triangle Park, NC, 

1993.

23. U.S. Environmental Protection Agency, Compilation of Air Pollution Emission Factors –

Volume 1: Stationary Point and Area Sources, AP-42, Chapter 1.9, Research Triangle Park, NC, 

revised October 1996.

24. Buckley, J.T. “A Steadily Burning Passion Gas Fireplaces Stoke Love of Hearth,” USA 

Today, January 5, 1998, pp. 1D and 2D.

25. Vista Marketing Research, Fireplace Owner Survey Usage and Attitude Report, Prepared for 

Durflame, Inc., Stockton, CA, 1996.

26. Aiken, M., Canadian Firelog Ltd. Emission Testing, Prepared for Canadian Firelog Ltd., by B.C. 

Research, Vancouver, BC, 1987.

27. Purvis, C.R., McCrillis, R.C., and Kariher, P.H., “ Fine Particulate Matter (PM) and Organic 

Speciation of Fireplace Emissions,” Environ. Science Technol., 2000, 34, 1653-1658.

Table 1. Comparison of updated 16-PAH and 7-PAH emission factors with values derived from 

L&E/AP-42 Documents.

Catalytic Stoves High-Technology NonCatalytic Stoves

Emission Conventional Stoves

Factor 

Category 7-PAH 

(g/kg)

16-PAH

(g/kg)

7-PAH

(g/kg)

16-PAH

(g/kg)

7-PAH

(g/kg)

16-PAH

(g/kg)

L&E/AP-42 0.024 0.314 0.024 0.314 0.022 0.359

Updated 0.0051

(phase 2)

0.1611

(phase 2)

0.0032

(phase 2)

0.1272

(phase 2)

0.02030.2233

1. Average of 5 used phase 2 certified stoves (13 tests) and one new phase 2 certified stove (2 tests), 

references 3 & 5.

2. Average of 11 used phase 2 certified stoves (30 tests) and 1 new phase 2 stove (6 tests), references 3 

& 4.

3. Average of 2 conventional stoves ( 18 tests) using 4 wood types, 4 burn rate categories, 2 altitude 

categories, references 4 & 5.
Table 2. Distribution of fireplace carbon monoxide emissions factors (g/dry kg)

Comments Maximum Value of 

Interval (g/dry kg)

Cumulative Number 

of Data Points

Cumulative 

Percentage

Number of Data 

Points in Interval

10 16 6% 16

22 34 12% 18

Mean - SD 23.4 42 15% 8

30 59 21% 17

40 73 26% 14

50 112 40% 39

60 135 49% 23

Mean 64.1 150 54% 15

70 160 58% 25

80 192 69% 32

90 221 80% 29

100 236 85% 15

Mean + SD 104.7 240 87% 4

110 246 89% 10

120 257 93% 11

130 262 95% 5

140 266 96% 4

150 270 97% 4

175 272 98% 2

200 274 99% 2

225 275 99% 1

250 275 99% 0

275 276 100% 1

300 277 100% 1

Number of models=70

Number of tests=277

SD=Standard Deviation= 40.7 g/dry kg
Table 3. Fireplace particulate emission factors (expressed as 5H equivalents)

Comments Maximum Value of 

Interval (g/dry kg)

Cumulative Number 

of Data Points

Cumulative 

Percentage

Number of Data 

Points in Interval

Mean - SD 0.3 0 0 0

1.2 8 2 8

3.5 46 12 46

4 58 15 50

6 104 27 46

8 148 38 44

10 198 51 50

Mean 11.8 235 61 37

14 275 71 40

16 304 78 29

18 328 85 24

20 346 89 18

Mean + SD 23.4 361 93 15

25 366 94 20

30 378 97 12

35 381 98 3

45 383 99 2

50 385 99 2

55 385 99 0

60 385 99 0

65 386 99 1

80 387 100 1

170 388 100 1

Number of models=112

Number of tests=388

SD=Standard Deviation=11.6 g/dry kg
Table 4. Conversion of 5G to 5H particulate values

Measured Calculated Difference % Difference

5G (g/hr) 5H (g/hr)15H (g/hr)25G-5H15G-5H25H1-5H2

5G-5H1

 

 5G

5G-5H2

 5G

0.2 0.48 0.38 -0.28 -0.18 0.10 -139% -89%

0.4 0.85 0.71 -0.45 -0.31 0.14 -113% -77%

0.6 1.19 1.02 -0.59 -0.42 0.17 -99% -70%

0.8 1.51 1.32 -0.71 -0.52 0.19 -89% -65%

1 1.82 1.62 -0.82 -0.62 0.20 -82% -62%

2 3.24 3.03 -1.24 -1.03 0.20 -62% -52%

3 4.53 4.38 -1.53 -1.38 0.15 -51% -46%

4 5.75 5.68 -1.75 -1.68 0.07 -44% -42%

5 6.92 6.95 -1.92 -1.95 -0.03 -38% -39%

6 8.05 8.19 -2.05 -2.19 -0.14 -34% -37%

7 9.15 9.42 -2.15 -2.42 -0.27 -31% -35%

8 10.22 10.63 -2.22 -2.63 -0.41 -28% -33%

9 11.27 11.83 -2.27 -2.83 -0.55 -25% -31%

10 12.30 13.01 -2.30 -3.01 -0.70 -23% -30%

15 17.23 18.78 -2.23 -3.78 -1.55 -15% -25%

20 21.87 24.36 -1.87 -4.36 -2.49 -9% -22%

25 26.32 29.81 -1.32 -4.81 -3.49 -5% -19%

30 30.63 35.16 -0.63 -5.16 -4.53 -2% -17%

35 34.81 40.42 0.19 -5.42 -5.62 1% -15%

40 38.88 45.62 1.12 -5.62 -6.73 3% -14%

45 42.88 50.75 2.12 -5.75 -7.87 5% -13%

50 46.80 55.82 3.20 -5.82 -9.03 6% -12%

55 50.65 60.85 4.35 -5.85 -10.20 8% -11%

60 54.44 65.84 5.56 -5.84 -11.40 9% -10%

65 58.18 70.78 6.82 -5.78 -12.60 10% -9%

70 61.87 75.69 8.13 -5.69 -13.82 12% -8%

75 65.52 80.57 9.48 -5.57 -15.05 13% -7%

80 69.13 85.42 10.87 -5.42 -16.29 14% -7%

85 72.69 90.23 12.31 -5.23 -17.54 14% -6%

90 76.22 95.02 13.78 -5.02 -18.80 15% -6%

95 79.72 99.79 15.28 -4.79 -20.07 16% -5%

100 83.19 104.53 16.81 -4.53 -21.34 17% -5%

110 90.04 113.95 19.96 -3.95 -23.91 18% -4%

120 96.78 123.28 23.22 -3.28 -26.50 19% -3%

130 103.43 132.55 26.57 -2.55 -29.12 20% -2%

140 109.99 141.74 30.01 -1.74 -31.75 21% -1%

150 116.47 150.87 33.53 -0.87 -34.40 22% -1%

160 122.88 159.95 37.12 0.05 -37.06 23% 0%

170 129.22 168.97 40.78 1.03 -39.74 24% 1%

1

 40CFR: 5H = 1.820(5G)0.830 (g/hr) 2

 AP 42: 5H = 1.619(5G)0.905 (g/hr)
Figure 1. Cumulative fireplace carbon monoxide emissions factor distribution.

(x = mean, — = mean ± SD)

Figure 2. Cumulative fireplace particulate emissions factor distribution.

(x = mean, — = mean ± SD)

0%

20%

40%

60%

80%

100%

0 50 100 150 200 250 300

g/dry kg

Cumulative Percent

0%

20%

40%

60%

80%

100%

0 50 100 150

g/dry kg

Cumulative Percent
12.4

46.1 46.9 48.2

11.3 11.7

0

10

20

30

40

50

60

Oak Firelog

PM, g/hr PM10, g/hr PM2.5, g/hr

253

42

0

50

100

150

200

250

300

Oak Firelog CO, g/hr

4.99

1.18

0.57

0.049

0.61

0.31

0.00

1.00

2.00

3.00

4.00

5.00

Oak Firelog

Formaldehyde, g/hr Benzene, g/hr 16 PAH, g/hr

Figure 3. Comparison of air emission rates for representative cordwood and firelog use

scenarios
Figure 4. Method 5G-5H correlation

5H = 1.820(5G)0.830

r squared = 0.52

5H = 1.333(5G)

r squared = 0.52

0

3

6

9

12

15

0 3 6 9 12 15

5G (g/hr)

5H (g/hr)

Lab 1 Data

Lab 2 Data

Lab 3 Data

5H (All Data)

Power (40 CFR Correlation)

Linear (Best Fit)