# Assessment of

Outdoor Wood-fired Boilers

Prepared by NESCAUM (Northeast States for Coordinated Air Use Managemen t)

March 2006 (revised June 2006)

### Members of NESCAUM

Arthur Marin, Executive Director

NESCAUM

Anne Gobin, Bureau Chief Connecticut Department of Environmental Protection, Bureau of Air Management

James P. Brooks, Bureau Director Maine Department of Environmental Protection, Burea u of Air Quality

Barbara Kwetz, Director Massachusetts Department of Environmental Protectio n, Bureau of Waste Prevention

Robert Scott, Director New Hampshire Department of Environmental Services, Air Resources Division

William O’Sullivan, Director New Jersey Department of Environmental Protection, Office of Air Quality Management

David Shaw, Director N e w Y o r k D e p a r t m e n t o f E n v i r on m e n t a l C on s e r v a t i on , D i v i s i on o f A i r R e s ou r c e s

Stephen Majkut, Chief Rhode Island Department of Environmental Management , Office of Air Resources

Richard A. Valentinetti, Director Vermont Department of Environmental Conservation, A ir Pollution Control Divisionii



# Assessment of Outdoor Wood-fired Boilers

Prepared by NESCAUM (Northeast States for Coordinated Air Use Managemen t)



## March 2006 (revised June 2006)iii



# Assessment of Outdoor Wood-fired Boilers

Project Manager

Lisa Rector, NESCAUM

Principal Contributors

George Allen, NESCAUM Philip Johnson, NESCAUM Lisa Rector, NESCAUM

Editor

Paul Miller, NESCAUMiv



## Acknowledgments

NESCAUM gratefully acknowledges the funding provide d by the Massachusetts Executive Office of Environmental Affairs and NESCA UM member states’ dues to complete this report. This report was developed by staff at NESCAUM with assistance from Air Quality Technical Services, Essex, Vermont

. NESCAUM also thanks the following individuals for c ontributing to this effort:

Peter Babich, Connecticut Department of Environment al Protection Patrick Bowe, Connecticut Department of Environment al Protection David Cash, Massachusetts Executive Office of Envir onmental Affairs Marc Cohen, Massachusetts Department of Environment al Protection James Doucette, Massachusetts Department of Environ mental Protection Phil Etter, Vermont Department of Environmental Con servation Jack Glenn, New Hampshire Department of Environment al Services Chris Jones, Vermont Department of Environmental Co nservation Glenn Keith, Massachusetts Department of Environmen tal Protection Barbara Kwetz, Massachusetts Department of Environm ental Protection Dave Manning, Vermont Department of Environmental C onservation Donald Squires, Massachusetts Department of Environ mental Protection

Printed: March 2006 Revised: May 2006 Revised: June 2006v TABLE OF CONTENTS

Acknowledgments....................................

................................................... ....................... iv Executive Summary..................................

................................................... ..................... vii Executive Summary..................................

................................................... ..................... vii 1. Introduction....................................

................................................... ......................... 1-1 1.1. OWB Description...............................

................................................... ............... 1-1 1.2. Report Overview...............................

................................................... ................ 1-2 2. Issues Unique to OWBs...........................

................................................... ............... 2-1 2.1. Unit Design ...................................

................................................... .................... 2-1 2.1.1. Combustion Cycle............................

................................................... ........ 2-1 2.1.2. Stack Height................................

................................................... ............. 2-1 2.1.3. Combustion Design...........................

................................................... ....... 2-1 2.1.4. Efficiency..................................

................................................... ............... 2-2 2.2. Use Patterns ..................................

................................................... .................... 2-2 2.3. Fuel Quality ..................................

................................................... .................... 2-2 2.4. Application of Current Regulations to Address OWBs....................................... 2-3 2.4.1. Federal Regulation..........................

................................................... ......... 2-3 2.4.2. State Regulations ...........................

................................................... .......... 2-3 3. Overview of OWB Industry........................

................................................... ............ 3-1 3.1. OWB Costs and Distribution ....................

................................................... ........ 3-1 3.2. Sales Trend Analysis..........................

................................................... ............... 3-2 4. Public Health Concerns..........................

................................................... ................. 4-1 4.1. Wood Smoke Composition........................

................................................... ....... 4-1 4.2. Particulate Matter Health Effects and Populati ons at Risk.................................. 4-1 4.3. Unique Factors Relating to OWB Emissions and P otential Public Health Threats4-4 4.4. Cause for Concern.............................

................................................... ................ 4-5 5. Emissions Information...........................

................................................... ................. 5-1 5.1. Previous Test Data ............................

................................................... ................ 5-1 5.2. Near-Source Ambient Emission Field Monitoring. ............................................. 5-4 5.3. Results of NESCAUM OWB “In Use” Stack Test.... .......................................... 5-6 5.3.1. Testing Methods.............................

................................................... .......... 5-6 5.3.2. Results and Discussion ......................

................................................... ...... 5-7 5.4. ASTM Test Protocol............................

................................................... ........... 5-18 5.5. Conclusions on Emissions Testing ..............

................................................... ... 5-18 6. OWB Control Strategies ..........................

................................................... ............... 6-1 6.1. Regulatory Action.............................

................................................... ................ 6-1 6.1.1. Ban/Removal of OWBs .........................

................................................... .. 6-1 6.1.2. Emission Standards..........................

................................................... ........ 6-1 6.1.3. Fuel Requirements ...........................

................................................... ........ 6-2 6.1.4. Mandatory Removal...........................

................................................... ...... 6-3 6.1.5. No Burn Days ................................

................................................... .......... 6-3 6.1.6. Nuisance Rules..............................

................................................... ........... 6-3 6.1.7. Opacity Rules...............................

................................................... ............ 6-3 6.1.8. Removal Prior to Sale or Transfer of Propert y ........................................... 6-4 6.1.9. Zoning Regulations..........................

................................................... ........ 6-5vi

6.2. Voluntary Programs............................

................................................... .............. 6-5 6.2.1. Change-out Programs.........................

................................................... ...... 6-5 6.2.2. Voluntary Industry Actions..................

................................................... .... 6-5 6.3. Court Actions.................................

................................................... ................... 6-5 6.4. Enforcement Actions ...........................

................................................... ............. 6-6 6.4.1. Connecticut .................................

................................................... ............. 6-6 6.4.2. Massachusetts ...............................

................................................... ........... 6-6 6.4.3. Vermont .....................................

................................................... .............. 6-9 7. Conclusions/Recommendations.....................

................................................... ......... 7-1

Appendix A: Outdoor Wood-fired Boiler Correspondenc e Appendix B: Outdoor Wood-fired Boiler Manufacturers Appendix C: Estimated National Sales of OWBs Appendix D: Michigan DEQ Modeling Appendix E: Field Report on Moisture Readings and O pacity Appendix F: Outdoor Wood-fired Boiler Regulations

FIGURES

Figure 1-1. Schematic of an OWB Installation......

................................................... ...... 1-2 Figure 3-1. States representing 95% of the OWBs sol d .................................................. 3-2 Figure 5-1. PM Emission Comparison (g/hr) .........

................................................... ..... 5-3 Figure 5-2. Field measurements of PM 2.5 near outdoor wood boiler.......................... .... 5-5 Figure 5-3. Field measurements of PM2.5 near outdo or wood boiler............................ 5-6 Figure 5-4a-e. VT Outdoor Wood Furnace Stack Sampl ing ........................................ 5-13 Figure 5-5. VT Outdoor Wood Furnace Stack Sampling Continuous PM.................... 5-19

TABLES

Table 3-1. Estimated Sales of OWBs since 1990 .....

................................................... ... 3-3 Table 5-1. Unevaluated OWB Emissions Data..........

................................................... ... 5-2 Table 5-2. Filter Measurements Idle Burn Mode.....

................................................... .. 5-10 Table 5-3. Filter Measurement Full Burn Mode......

................................................... .. 5-11 Table 5-4. Comparison of Filter Data and DataRam .. .................................................. 5 -12vii



## Executive Summary This report was undertaken by NESCAUM (Northeast St ates for Coordinated Air Use Management) to provide policymakers with an ass essment of concerns relating to the growing use of outdoor wood-fired boilers (OWB), al so known as outdoor wood-fired hydronic heaters or outdoor wood-fired furnaces. The increased use of OWBs in populated areas represents a potential public healt h problem in the Northeast because of the severity of health effects associated with resi dential wood smoke inhalation. This report 1) overviews unique features of OWB app liances, 2) estimates OWB appliance sales trends, 3) assesses emission consid erations and potential health concerns of residential wood smoke, 4) presents results of O WB ambient monitoring and stack testing conducted by NESCAUM, and 5) provides recom mendations for regulatory action. Findings from this study show that:

• OWBs, generally, do not use catalytic or non-cataly tic emission control devices that other residential, wood-fired combusti on devices, such as indoor wood stoves, commonly employ.

• OWB use has become more prevalent, commonly replaci ng indoor wood stoves, and continued increases in sales are likely

.

• OWBs emit significantly more particulate matter tha n other residential wood burning devices and short term particulate mat ter spikes can be extremely high.

• OWBs could contribute almost 900,000 tons of partic ulate matter by 2010.

• Local populations are likely subject to elevated am bient particulate matter levels from OWB smoke.

• Current regulations do not provide surrounding area s with adequate protection from the use of OWBs in residential appl ications.

• There is a lack of information relating to air toxi c emissions, such as polycyclic aromatic hydrocarbons (PAHs), polycyclic organic matter (POM) and dioxin.

OWBs present unique issues, unlike other residentia l wood burning devices, based on the following factors:

• Year Round Operation – OWBs are designed to provide heat and hot water year round. Owners often use them in the war mer months not only for domestic hot water but also to heat their swimm ing pools and/or spas.

• Cyclic Operation - The cyclic nature of OWB operations, unlike EPA certified wood stoves, does not allow for complete combustion and creates an environment conducive to increased toxic and par ticulate emissions.viii • Short Stack Heights – Stacks from OWBs, as per manufacturer’s installation instructions, are usually less than 12 feet from the ground, resulting in poor dispersion of smoke and are more likely to cause fumigation within surrounding areas.

• Oversized Firebox – An OWB’s large firebox is built such that a user could burn a variety of inappropriate materials tha t could not be burned in wood stoves or fireplaces. Enforcement programs ha ve discovered OWBs burning tires, large bags of refuse, and railroad t ies. Even when used properly, overall OWBs emissions are greater than o ther residential wood burning devices. With funding from the Massachusetts Executive Offi ce of Environmental Affairs (EOEA), NESCAUM measured emissions from an OWB unit in the field under real world conditions. The test data indicate that the smallest OWB is likely to have an average in-use emission rate of approximately 161 g rams of fine particulate matter per hour, which is twenty times higher than the average in-use emissions of an EPA certified wood stove. This report utilizes a gram per hour m easurement in order to understand the potential ambient impacts and to make comparisons t o other residential furnaces and heating units such as oil-fired furnaces, natural g as furnaces, and residential wood stoves. Furthermore, NESCAUM believes that given the health impacts associated with wood smoke and their use in residential locations (near at-risk populations such as children and the elderly), it is critical to assess particulate emissions from OWBs on a mass per unit time basis to fully understand potential health ris ks and appropriate protections. Based on the test results in this report, the aver age fine particulate emissions from one OWB are equivalent to the emissions from 22 EPA certified wood stoves, 205 oil furnaces, or as many as 8,000 natural gas furnaces. To put these emissions into perspective, one OWB can emit as much fine particul ate matter as four heavy duty diesel trucks on a grams per hour basis. Cumulatively, th e smallest OWB has the potential to emit almost one and one-half tons of particulate ma tter every year. Based on sales estimates, OWBs could emit over 233,000 tons of fin e particulate matter nationwide in 2005. Considering sales trends, NESCAUM estimates that there could be 500,000 OWBs in place nationwide by 2010. Based on that es timate, emissions from OWBs would reach 873,750 tons of fine particulate matter nationwide per year by 2010. The cumulative impact of OWBs to ambient air qualit y is only one part of the problem. Because OWBs are used primarily in reside ntial applications, they have the potential to emit fine particulate matter and air t oxics at levels that could create elevated risk to nearby populations. A second pilot study c onducted by NESCAUM measured ambient PM 2.5 within 150 feet of an OWB device. Relative to bac kground levels, the study documented high 15-second average values (>1, 000 micrograms per cubic meter (μg/m 3 )) with spikes greater than 8,000 μg/m 3 throughout the course of normal daily OWB operating modes. These data suggest that build ings located near OWBs can experience high PM 2.5 levels during typical boiler operating conditions. Health studies have found associations of acute and chronic exposu re to wood smoke with adverse health outcomes such as increases in respiratory sy mptoms, decreases in lung function, visits to emergency departments, and hospitalizatio n.ix States have requested several times that the U.S. E nvironmental Agency (EPA) develop federal regulations for OWBs but EPA has ye t to act. Critical to the development of a federal emissions standard is the need to develop a technology forcing standard that would require manufacturers to employ wood combustion controls commonly employed by other residential and industri al wood-fired devices. In addition, the increasing use of OWBs necessitates that action be taken as quickly as possible. Federal action would likely take five to seven year s to put protective measures into place.
In the absence of federal action, states will need to act on this emerging issue in a timely manner. Given the significant health effect s OWB emissions may pose and the lack of action on the federal level, NESCAUM believ es that states should take action immediately to control OWB emissions by establishin g technology-forcing standards that will lead manufacturers to develop cleaner burning OWBs.Assessment of Outdoor Wood-fired Boilers Page 1-1



## 1. INTRODUCTION As the price of home heating oil, natural gas and l iquefied petroleum gas (LPG) increases, many households are looking for heating alternatives. Increasingly, people are turning to wood-burning devices to replace oil and gas heating. 1 Wood-fired devices include masonry heaters, indoor wood stoves, indoor wood furnaces, pellet stoves and outdoor wood-fired boilers. The recent increase i n the use of outdoor wood-fired boilers (OWBs) are of particular concern to state environme ntal agencies because the cumulative stack emissions from these appliances are higher th an other wood burning appliances and, unlike other wood burning devices, currently a re unregulated. In the early 1990’s, states became aware of OWBs, although their use at that time was primarily limited to rural settings. However, states have noted an incr easing trend of OWB installation in suburban and urban neighborhoods to provide space h eating, year-round heating of hot water, and heating of swimming pools, Jacuzzis, and hot tubs. Use of OWBs in commercial applications is also increasing beyond t raditional use in agricultural operations.



### 1.1. OWB Description An OWB is a wood-fired furnace that is usually hous ed within a small insulated shed located some distance from a house. Manufactur ers design OWBs to burn large amounts of wood over long periods of time. 2 OWBs vary in size ranging from 115,000 Btu/hr up to 3.2 million Btu/hr, although residenti al OWBs tend to be less than 1 million Btu/hr. According to sales data, the size of the m ost commonly sold unit is 500,000 Btu/hr. OWBs heat buildings ranging in size from 1 ,800 square feet to 20,000 square feet. Typically, the dimensions of an OWB are thre e to five feet wide, six to nine feet deep, and six to ten feet tall, including the heigh t of the chimney. Inside the OWB is an oversized firebox that can accommodate extremely la rge loads. Firebox sizes will vary with each unit but tend to range in size from 20 cu bic feet up to 150 cubic feet. Industry literature indicates that a commonly sized resident ial unit can easily accommodate wood pieces that are 30 inches in diameter and 72 inches long. 3 Surrounding the firebox is a water jacket that can be heated to temperatures up to 190°F. The OWB cycles water through the jacket to deliver hot water to the buil ding. Water pipes run underground to deliver hot water for both space heating and domest ic use. Figure 1-1 provides a schematic of an OWB installat ion. OWBs have a cyclical operating pattern; when the water temperature in th e water jacket reaches a given temperature, an air damper closes off air to the un it until the temperature drops and the air damper opens, creating an on/off cycle.

1 http://www.usatoday.com/news/nation/2005-11-13-woodburn ing-pollution_x.htm
2 Schreiber, Judith et al. Smoke Gets in Your Lungs: Outdoor Wood Boilers in New Y ork State . Office of the Attorney General; Albany, New York, 2005. Available at http://www.oag.state.ny.us/press/2005/aug/August 2005.p df
3 http://www.centralboiler.com/eadvantage.phpAssessment of Outdoor Wood-fired Boilers Page 1-2

Figure 1-1. Schematic of an OWB Installation

Manufacturers advertise OWBs for operation with woo d fuel, however, many states have found that users sometimes fuel OWBs wi th yard waste, packing materials, construction debris, and domestic wastes. 4 While most manufacturers of OWBs instruct owners of OWBs to burn wood, anecdotal data suggest that distributors instruct purchasers of OWBs they can burn “whatever they wan t” -- even household garbage and tires. 5



### 1.2. Report Overview This report provides data on issues unique to OWBs, an analysis of sales and distribution of OWBs, an explanation of wood smoke pollutants and their associated public health risks, analysis of OWB emissions, an overview of regulatory options, and conclusions.

4 Conversations with representatives from enforcement staff at the New York Attorney General’s Office, Connecticut Department of Environmental Conservation, Maine De partment of Environmental Protection, and Massachusetts Department of Environmental Protection.
5 Staff from a variety of environmental agencies have spoken wi th distributors at fairs and other distribution venues to gather information on the units.Assessment of Outdoor Wood-fired Boilers Page 2-1



## 2. ISSUES UNIQUE TO OWBS While there are a variety of concerns surrounding w ood burning devices, several issues make OWBs unique. The largest number of com plaints voiced to Northeast state air quality enforcement programs relate to excessiv e smoke and nuisance conditions. These conditions arise due to the unique design and operating features of OWBs.



### 2.1. Unit Design The smoke from OWBs appears to be greater than othe r wood burning appliances for several reasons. Primarily, it is because of t he basic design of OWBs. Even when operated properly with seasoned wood, OWBs typicall y generate significant amounts of smoke. When an operator dampers down the unit, the lack of oxygen to support combustion creates a build up of materials such as creosote. When opening the damper, these materials burn and release immediately to the air. Excessive loading and/or low demand for heat further aggravates this problem. I n addition, OWBs emit more pronounced smoke than wood stoves due to the short stack height, which does not disperse smoke above living spaces in neighboring h omes. The addition of sophisticated combustion controls could address many of the smoke issues, however, the vase majority of units sold do not employ any catalytic or non-ca talytic emission controls.



### 2.1.1. Combustion Cycle The primary reason for the large amounts of smoke i s the cyclic nature of the device. When an OWB is in the “off” cycle and does not need to generate heat, the air damper closes to cut off the air supply. This crea tes an oxygen-starved environment in which the fire smolders, creating smoke and creosot e that condenses on the internal steel surfaces. When heat needs to be produced, the air damper opens and natural draft forces air into the firebox, pushing the smoke and air pol lutants out the stack. Measured emissions peak when the unit has received a fresh l oad of fuel and the wood has not yet reached a charcoal stage. In the field test conduc ted by NESCAUM, the unit’s internal stack temperature never reached levels that would h ave resulted in complete combustion (see Section 5.3).



### 2.1.2. Stack Height Another contributing factor to OWB smoke is the sho rt stack height of OWBs. Manufacturer installation literature specifies stac k heights that are generally eight to twelve feet from the ground. Stack heights this sh ort typically fail to disperse smoke adequately, resulting in excessive ground level smo ke. Because OWBs rarely provide stovepipe fans to increase the upward velocity of t he smoke, there is only limited vertical dispersion of OWB emissions. Certain weather condi tions aggravate this situation, such as cold weather inversions when the smoke does not rise but stays close to the ground.



### 2.1.3. Combustion Design Most OWBs do not have any combustion controls, such as catalytic devices and secondary combustion. Incorporating these features could significantly reduce particulate emissions. Almost all indoor wood stoves sold toda y use catalytic or secondaryAssessment of Outdoor Wood-fired Boilers Page 2-2

combustion to reduce emissions. NESCAUM’s review o f OWB manufacturers’ data finds that only a limited number of manufacturers u tilize common wood burning combustion controls. Discussions with wood combust ion experts indicate that these units could incorporate combustion controls into their de sign in a relatively short period of time, which would result in reduced emissions, incr eased efficiency and an overall improvement in OWB performance.



### 2.1.4. Efficiency Review of available data indicates that the operati ng efficiencies of OWBs are extremely low, often half the efficiency of other r esidential wood burning devices such as wood stoves. Several manufacturers have made claim s that their OWBs are up to 95 percent efficient. Review of the data, however, sug gests that heating efficiencies range from as low as 28 percent to not higher than 55 per cent. 6 Test results obtained by Freedom of Information Act (FOIA) requests to EPA i ndicate that, in general, most units will have operating efficiencies in the range of 30 to 40 percent. A comparison with wood stove efficiencies finds that their efficienci es range from 60 to 80 percent efficient. 7
Low efficiencies translate into increased amounts o f wood burned to generate heat, which in turn increases emissions.



### 2.2. Use Patterns Unlike indoor wood stoves and fireplaces, manufactu rers design OWBs for use year round. OWBs not only heat space but provide d omestic hot water and heat swimming pools and spas. In the summer months, the smoke may seem more apparent because the smoke may be less likely to disperse as the lower flue velocities from the stack may keep the smoke closer to the ground. NES CAUM observed this condition during its stack test conducted in June 2005. Another critical difference in OWB operations from other wood burning devices relates to long burn times. Manufacturers instruct owners that they can completely fill the OWB firebox and leave it burning for as long as 96 hours. However, completely filling the combustion chamber creates a smoldering fire that burns inefficiently, especially when warm weather or a depressed thermos tat during mid-day or nighttime hours reduces demand for heat. The lack of tending for long periods of time compounds the problem, leading to inefficient burning conditi ons over extended periods. In contrast, owners of conventional indoor wood stoves tend them more often to optimize combustion.



### 2.3. Fuel Quality While most manufacturers provide OWB owners with be st burn practices and instruct users that they should only burn dry seaso ned wood, the design of the OWBs encourages burning of inappropriate materials. Sta te agencies have documented the burning of wet, large, unsplit wood, wood waste, ya rd waste, refuse, tires and railroad

6 Schreiber, Judith et al. Smoke Gets in Your Lungs: Outdoor Wood Boilers in New Y ork State . Office of the Attorney General; Albany, New York, 2005. Available at http://www.oag.state.ny.us/press/2005/aug/August%202005 .pdf

. 7 http://www.epa.gov/woodstoves/efficiently.html

.Assessment of Outdoor Wood-fired Boilers Page 2-3

ties. In fact some manufacturer’s websites state t he ability to burn green or scrap wood as one of the benefits of OWBs. For example, the P acific Western website states that their unit, “easily burns junk wood including palle ts.” 8



### 2.4. Application of Current Regulations to Address OWBs Enforcement programs have attempted to use existing regulations to address OWB complaints. A detailed description of various regulatory options can be found in Section 6.1 of this report. This section provides a more general overview of the current efforts used by states to address OWBs.



### 2.4.1. Federal Regulation While EPA requires indoor wood stoves, pellet stove s, and small wood-fired industrial boilers to adhere to federal air polluti on standards of 7.5 g/hr for non-catalytic appliances and 4.1 g/hr for catalytic appliances, t here are no federal standards for OWBs. To date EPA has received several requests from stat e agencies to develop federal standards. EPA has yet to act on these requests an d a June 2005 letter sent by EPA to OWB manufacturers, and an EPA statement provided to the Clean Air Act Advisory Committee (CAAAC) on August 11, 2005, indicates tha t any action in the near-term is unlikely (see Appendix A). The August 11, 2005 st atement to the CAAAC advised that EPA was reviewing the state petitions and did not e xpect a decision on action until spring 2006. In this same statement, EPA also indicated t hat it would take a minimum of five to seven years to develop and implement a federal stan dard.



### 2.4.2. State Regulations In the absence of federal standards, the states hav e attempted to use several avenues to address OWB problems. Two states and se veral municipalities have attempted to address OWBs by adopting regulations l imiting emissions or banning the sale of OWBs. Regulations in the state of Washingt on limit emissions from all solid fuel burning devices rated less than one million Btu/hr. Sales data obtained from manufacturers show that only a small number of OWBs have been sold in Washington. It is unlikely that the OWBs sold in Washington could meet the standard. Correspondence between Central Boiler and the Washington Departmen t of Ecology indicates that the manufacturers dispute the application of Washington ’s regulation on OWBs (see Appendix A). In 1997, Vermont adopted regulations t hat require setback and stack height standards for OWBs. This regulation has not elimin ated the OWB problem; and in fact the VT DEC continues to receive complaints. Many states have opacity regulations that could app ly to OWBs (a detailed explanation of opacity regulations can be found in Section 6.1.7.). Based on the experience of state enforcement staff, it is unlike ly that an OWB could meet most states’ opacity requirements even under ideal operating con ditions. In fact, several states have attempted to work with homeowners to find methods t o operate OWBs within state opacity limits but none to date have been able to c omply. Given this scenario, the only solution is removal, which comes at great cost to t he homeowner because it requires

8 http://www.outdoorfurnaces.com/article/pacific-western-details- 6.asp

.Assessment of Outdoor Wood-fired Boilers Page 2-4

removal of the OWB and installation of a new heatin g system. Opacity regulations place a significant burden on the homeowner who, often un wittingly, purchases a unit that cannot meet the state regulatory opacity requiremen ts. Further compounding the problem is the limited ability of many state enforcement ag encies to enforce against residential OWBs. Most state enforcement methods aim towards m itigating conditions at industrial facilities, leaving the states reticent and ill-equ ipped to enforce opacity requirements at residential OWBs.Assessment of Outdoor Wood-fired Boilers Page 3-1



## 3. OVERVIEW OF OWB INDUSTRY NESCAUM has identified twenty-seven manufacturers o f OWBs (see Appendix B). Manufacturers are located throughout the Unite d States with eight in Minnesota, three in Pennsylvania, two in Wisconsin, two in Nor th Carolina, and one each in Missouri, Nebraska, New Hampshire, New York, Tennes see, and Washington. In addition, NESCAUM identified six manufacturers base d in Canada. These companies range in size from one to over 140 employees. Some of these manufacturers participate in the Hearth, Patio and Barbecue Association (HPBA ), which is an industry trade association that represents wood stove, pellet stov e and fireplace manufacturers as well.

The Northeast states have focused attention on OWB s since the late 1990’s. Several states have attempted to work with manufact urers to address complaints and nuisance issues with little success. The New York State Department of Environmental Conservation held a meeting with manufacturers in 2 003 to gain a better understanding of the industry and to determine the direction of manu facturers. At these meetings, manufacturers stated that cleaner OWBs would be on the market in the near future. Almost three years later, there has been little cha nge in OWB design. In fact, recent statements from the largest producer of OWBs indica te that it does not believe that OWBs emit significant amounts of pollution. Testim ony prepared by Central Boiler for the Vermont draft OWB regulations 9 and statements by its vice-president Rodney Tolufsen declared that its OWBs pollute no more tha n EPA-certified wood stoves. 10



### 3.1. OWB Costs and Distribution The total cost to purchase and install the smallest OWB can range from $8,000- $10,000, with costs increasing with the size of the unit. The OWB itself costs approximately $5,000, excluding installation. Inst allation usually includes laying a concrete foundation, putting in a power source, ins talling underground piping from the unit to the house, and other additional piping. Commonly, manufacturers sell OWBs directly or throu gh a national distribution network. Distribution venues commonly include hard ware stores, fairs, and direct sales. Typically, stores that sell indoor wood stoves or f ireplaces do not sell OWBs. Marketing literature from manufacturers typically claims that OWBs have many advantages over gas, oil and other wood burning devices, including:

• Eliminating heating bills

• Improving indoor air quality

• Reducing the incidence of asthma or allergies

• Benefiting the environment by reducing the greenhou se emissions

• Increasing safety of heating by removing the heatin g unit from the building

• Requiring less time to operate than other wood burn ing devices

• Reducing dependence of fossil fuels 11

9 Transcripts from public hearings on Vermont’s proposed r egulations.
10 http://groups.yahoo.com/group/woodheat/message/6422

. 11 http://www.shol.com/mahoning/reason.HTM and http://www.centralboiler.com/eadvantage.php.Assessment of Outdoor Wood-fired Boilers Page 3-2

In its review of emissions and efficiency data, NES CAUM found limited or no documentation to support manufacturers’ claims. Ma nufacturers often claim that their OWBs have relatively high efficiency ratings. Some manufacturers have made claims that their units are up to 95 percent efficient. H owever, review of the data suggests that heating efficiencies range from 28 to 55 percent 12 (Section 2.1.4 contains a more detailed discussion of OWB efficiency).



### 3.2. Sales Trend Analysis With the recent increase in the price of heating fu els, the use of wood for residential and commercial heating is on the rise. 13 As part of this trend, there has been a rapid increase in the number of OWBs installed. Ma ny of the OWB manufacturers began selling OWBs in the early 1980’s but sales began to rise substantially after 1999. Using sales data gathered by the New York Attorney Genera l’s Office via subpoena of 21 manufacturers and by EPA from nine manufacturers vi a a Clean Air Act Section 114 request, NESCAUM estimates that over 155,000 OWBs h ave been sold nationwide since 1990 (see Table 3-1). Appendix C contains estimate s of sales by state. Of the estimated 155,000 OWBs sold nationwide, 95% have been sold in nineteen states, as illustrated in Figure 3-1. These states include Connecticut, Indi ana, Illinois, Iowa, Kentucky, Maine, Massachusetts, Michigan, Minnesota, Missouri, New H ampshire, New York, North Carolina, Ohio, Pennsylvania, Vermont, Virginia, We st Virginia, and Wisconsin.

Figure 3-1. States representing 95% of the OWBs sol d

National sales have been growing in the past five y ears at rates of 30 to 128 percent. In October 2005, one manufacturer, Centra l Boiler, stated that its production

12 Schreiber, Judith et al. Smoke Gets in Your Lungs: Outdoor Wood Boilers in New Y ork State . Office of the Attorney General; Albany, New York, 2005. Available at http://www.oag.state.ny.us/press/2005/aug/August%202005 .pdf

. 13 http://www.usatoday.com/news/nation/2005-11-13-woodburn ing-pollution_x.htm

.Assessment of Outdoor Wood-fired Boilers Page 3-3

was “double what it’s ever been before.” 14 In December 2004, the same manufacturer stated its peak production at that time was 200 uni ts a week, and it had the room to make 1,000 a week, which would mean a capacity to produc e over 50,000 annually. 15 The number of OWBs sold in 2003 and 2004 equals the num ber OWBs sold in the previous fourteen years. Given the continued rise in the co st of natural gas and petroleum fuels, it is likely that an increasing sales trend will conti nue. EPA has estimated that it would take a minimum of five years for rules to be put in place, at which time over 500,000 OWBs could be in place. New construction uses OWBs as primary furnaces and OWBs are also replacing conventional indoor wood stoves and oil or gas-fire d furnaces. To promote the use of EPA certified wood stoves through the Wood Stove Ch ange Out Campaign, EPA is educating the public about the dangers of using old non-certified wood stoves. Many homeowners, however, may be choosing to install OWB s instead of certified indoor wood stoves. One manufacturer, Central Boiler, est imated that about 50% of the OWBs sold replace indoor wood stoves. 16 Therefore, while EPA’s change out effort is important, it may be resulting in increased install ation of OWBs due to the absence of education about OWBs relative to certified wood sto ves. This will lead to greater wood smoke pollution if consumers erroneously believe OW Bs are a cleaner option than noncertified indoor wood stoves.

Table 3-1. Estimated Sales of OWBs since 1990 17

Year US 1990 195 1991 278 1992 398 1993 568 1994 811 1995 1,159 1996 1,656 1997 2,366 1998 3,380 1999 4,828 2000 6,865 2001 15,330 2002 10,552 2003 15,342 2004 24,560 2005 67,546 Total 155,834

14 Rutledge, R. Milwaukee Journal Sentinel, Burning to Save a Buck , Oct. 7, 2005 http://www.jsonline.com/news/gen/oct05/361678.asp
15 Bakken, R. Grand Forks Herald, Business Heats Up, December 6, 2004

. 16 Ibid.
17 Sales estimates derived from state specific sales data from nin e manufacturers, national sales data from 21 manufacturers, and trend analysis to forecast 1990-1998 and 2005 data. Appendix C provides state specific sales estimates.Assessment of Outdoor Wood-fired Boilers Page 4-1



## 4. PUBLIC HEALTH CONCERNS Wood smoke emissions represent a potential threat t o the health of persons living in proximity to OWB devices. Scientific studies ha ve found associations between the inhalation of wood smoke or wood smoke constituents and adverse health effects. These findings are of notable concern because a large fra ction of the population is susceptible or at increased health risk from exposure to wood smok e. In addition, physical and operational factors unique to OWBs heighten the pos sibility that people are exposed to wood smoke in both outdoor and indoor environments.



### 4.1. Wood Smoke Composition Wood smoke contains a complex mixture of particles and gases, many of which have been shown to produce acute and chronic biolog ical effects, as well as deleterious physiologic responses in exposed humans. The abund ance of fine particulates in wood smoke presents perhaps the most serious health risk to exposed populations, and will be discussed in more detail in the following section. Wood smoke also contains numerous gases, including carbon monoxide, nitrogen and sulf ur oxides, volatile organic compounds (VOCs), PAHs, and chlorinated dioxins. C arbon monoxide can cause respiratory and cardiac distress because it compete s with oxygen on the hemoglobin molecule, forming carboxyhemoglobin. Studies have associated exposure to nitrogen oxides with toxicological effects including pulmona ry edema, bronchoconstriction, and increased infection rates. Studies have also assoc iated VOCs, such as aldehydes, with upper airway irritation, headaches, and other neuro physiologic dysfunctions, and possibly cancer. Studies have shown that polycyclic aromati c hydrocarbons, such as benzo(a)pyrene, are carcinogenic in animals and may cause cancer in humans. Toxicologic evidence also suggests that certain dio xin congeners commonly found in wood smoke are human carcinogens. 18



### 4.2. Particulate Matter Health Effects and Populations a t Risk The severity and variety of adverse health effects attributed to exposure to fine particulate matter suggests that the aerosol compon ent of wood smoke plays a large role in the observed health effects associated with wood combustion. Because of its physical structure, PM 2.5 can bypass conductive airways and deliver exogenou s materials into the deep lung. These materials include reactive organi c chemicals that adsorb onto the particle. Over the past 30 years, scientific evide nce has found that short- (e.g., daily) and long-term (e.g., annual and multiyear) exposure to airborne PM is associated with

18 Pierson WE, Koenig JQ, Bardana Jr EJ. Potential adve rse health effects of wood smoke. West J Med 1989; 151:1-6. Larson TV, Koenig JQ. A summary of the emissions c haracterization and noncancer respiratory effects of wood smoke. EPA-453/R-93-036. U.S. EPA, Office of Air Quality Planning and Standards: Research Triangle Park, NC, 1993. Maynard RL, Waller R. Carbon Monoxide. In: Holgate, S T, Samet, JM, Koren, HS, Maynard, RL, eds. Air Pollution and Health. Academic Press: New York, NY 199 9; pp. 749-796. Zelikoff JT, Chen LC, Cohen MD, Schlesinger RB. T he toxicology of inhaled woodsmoke. J Toxicol Envron Health 2002; Part B,5:269-282. Steenland K, Bertazzi P, Baccarelli A, Kogevinas M. Dioxi n revisited: developments since the 1997 IARC classification of dioxin as a human carcinogen. Environ Health Perspect 2004; 112:1265–1268.Assessment of Outdoor Wood-fired Boilers Page 4-2

cardiopulmonary health effects, including increased respiratory and cardiac symptoms, hospital admissions and emergency room visits, and premature death. Other harmful health effects include aggravated asthma, decreased lung function, and chronic bronchitis. Recent studies suggest that chronic ex posure to air pollution may actually result in the development of new cases of asthma an d atopy. 19 A review of adverse health effects of short-term exposure to particulat e matter in study areas where residential wood combustion was considered a major source of am bient PM found higher health risk associations than those found in areas dominated by other sources of PM, especially for children. 20
Population subgroups susceptible or most affected b y PM 2.5 exposure comprise upwards of 50% of the general population, including children, asthmatics, persons with preexisting respiratory disease or cardiac problems , older adults, and healthy adults who work or exercise outdoors. 21 Children’s exposure to air pollution is of specia l concern because their immune system and lungs are not fully developed when exposure begins. For example, the number of alveoli in the human lun g increases from 24 million at birth to 257 million at age four. As the lung epithelium is not fully developed, there is greater permeability of the epithelial layer in young child ren. Also, under normal breathing, children breathe 50% more air per kilogram of body weight than adults. In addition, children’s high activity levels can result in incre ased ventilation, increasing exposure to air pollutants such as particulate matter. These f actors suggest that there is a critical exposure time for children when air pollution may h ave long-term effects on respiratory health. 22 However, PM exposure can adversely affect both su sceptible and general populations, including healthy adults. The exact l evel where an individual might become ill or sensitized is unknown because of the inabili ty of scientists to determine whether a threshold level exists or does not exist below whic h exposure to PM is safe. 23
Even hourly exposures to fine particulate matter ma y result in acute health responses within susceptible subgroups. Clinical a nd epidemiological evidence now suggests cardiac health effects, including increase d risk of myocardial infarction and decreases in heart rate variability, which may be a ssociated with PM exposures with

19 Pope CA, Burnett RT, Thurston GD, Thun MJ, Calle EE, K rewski D, Godleski JJ. Cardiovascular mortality and long-term exposure to particulate air polluti on: epidemiological evidence of general pathophysiological pathways of disease. Circulation 2004;109:71-77. Review of the National Ambient Air Quality Standards fo r Particulate Matter: Policy Assessment of Scientific and Technical Information. EPA-452/R-05-005. U.S. EPA, Office of Air Quality Planning and Standards: Research Triangle Park, NC, 2005. Peters JM, Avol E, Berhane K, Gauderman WJ, Gillilan d F, Jerrett M, et al. 2004. Epidemiologic investigation to identify chronic effects of ambient air po llutants in southern California. Contract No. 94- 331. Los Angeles, CA:University of Southern Californi a. 20 Boman BC, Forsberg AB, Järvholm BG. Adverse health eff ects from ambient air pollution in relation to residential wood combustion in modern society. Scand J Work Environ Health 2003;29:251-260.
21 Johnson PRS, Graham JJ. Fine particulate matter National Am bient Air Quality Standards: public health impact on populations in the northeastern United States. Environ Health Persp 2005;113:1140–1147.
22 Schwartz J. Air pollution and children’s health. Pediatrics 2004;113: 1037-1043.
23 Daniels MJ, Dominici F, Zeger SL, Samet JM. 2004. The Nati onal Morbidity, Mortality, and Air Pollution Study, Part III: PM10 Concentration–Response Curves and Threshold for the 20 Largest US Cities. Research Report 94. Boston, MA:Health Effects Insti tute.Assessment of Outdoor Wood-fired Boilers Page 4-3

averaging times less than 24 hours (e.g., one to se veral hours). 24 These findings, in combination with associations between daily changes in PM and cardiovascular deaths and hospitalizations, indicate that short-duration exposures to wood smoke emissions could have serious health effects, especially for s usceptible members of the population, such as those with preexisting heart disease and ol der persons. While the above evidence regarding the severity of health effects and magnitude of populations affected by PM has led health scient ists to conclude that exposure to wood smoke should be avoided, 25 residential wood combustion (RWC) remains one of t he largest sources of PM 2.5 emissions to the atmosphere in North America. 26 Studies in urban and rural areas have found that wintertime re sidential wood smoke contributes significantly to ambient concentrations of PM 2.5 as well as VOCs. 27 This can be aggravated in areas subject to persistent temperatu re inversions, located in valleys, or which have a high percentage of wood burning househ olds. 28 Wood smoke PM is dominated by particles with average mass diameters generally between 0.1 and 0.6 μ m. Submicron particles readily penetrate residential s tructures as a result of the normal exchange of air. 29 Particles in wood smoke emitted from chimneys hav e been found to be a major source of indoor particles and thus a sourc e of exposure to residents, even in homes without wood stoves. 30 Given the infiltration capacity of PM 2.5 , exposure to wood

24 Brook RD, Franklin B, Cascio W, Hong Y, Howard G, Lips ett, M. Air pollution and cardiovascular disease: a statement for healthcare professionals from the expert p anel on population and prevention science of the American Heart Association. Circulation 2004;109: 2655-2671.
25 Pierson WE, Koenig JQ, Bardana Jr EJ. Potential advers e health effects of wood smoke. West J Med 1989; 151:1-6. Koenig JQ, Larson TV, Hanley QS, Rebolledo V, Dum ler K, Checkoway H, et al. Pulmonary function changes in children associated with particulate matter air poll ution in a wood burning community. Environ Res 1993:63;26-38. Larson TV, Koenig JQ. Wood smoke: emissions and no ncancer respiratory effects. Annu Rev Public Health 1994; 15:133-156. Zelikoff JT, Chen LC, Cohen MD, Schlesinger RB. The toxicology of inhaled woodsmoke. J Toxicol Envron Health 2002; Part B,5:269-282. Bates DV, Koenig J, Brauer M. Health and Air Quality 2002 – Phase I: Methods for Estimating and Applying Relationships between Air Pollution and Health E ffects. Final Report. British Columbia Lung Association. May 2003.
26 Fine PM, Cass GR, Simoneit BRT. Organic compounds in bio mass smoke from residential wood combustion: emissions characterization at a continental scale. J Geophys Res-Atmos 2002; 107(D21):8349.
27 Johansson LS, Tullin C, Leckner B, Sjövall P. Particle emissions from biomass combustion in small combustors. Biomass Bioenerg 2003; 25:435-446. McDonald JD, Zielinska B, Fujita EM, Sagebiel JC, Ch ow JC, Watson JG. Fine particle and gaseous emission rates from residential wood combustion. Environ Sci Technol 2000; 34:2080-2091. Polissar AV, Hopke PK, Poirot RL. Atmospheric aero sol over Vermont: chemical composition and

sources. Environ Sci Technol 2001; 35:4604-4621.
28 Sexton K, Spengler JD, Treitman RD, Turner WA. Winter air quality in a wood-burning community: a case study in Waterbury, Vermont. Atmos Environ 1984; 18:1357-1370.
29 Boman BC, Forsberg AB, Järvholm BG. Adverse health eff ects from ambient air pollution in relation to residential wood combustion in modern society. Scand J Work Environ Health 2003; 29:251-260. Abt E, Suh HH, Catalano P, Koutrakis P. Relative cont ribution of outdoor and indoor particle sources to indoor concentrations. Environ Sci Technol 2000; 34:3579-3587.
30 Anuszewski J, Larson TV, Koenig JQ. Simultaneous indoor and outdoor particle light-scattering measurements at nine homes using a portable nephelometer . J Exposure Anal Environ Epidemiol 1998; 8:483-493.Assessment of Outdoor Wood-fired Boilers Page 4-4

smoke indoors—where individuals typically spend the majority of their time—can occur across large residential areas.



### 4.3. Unique Factors Relating to OWB Emissions and Potent ial Public Health Threats Outdoor wood boilers are a unique emission source w ith operational and design factors not typically found in other residential wo od burning appliances. First, the design of OWBs is to operate intermittently following the heat load of a building. This design enables boilers to burn wood in low temperature and oxygen-starved conditions to prolong the fuel source. In general, PM 2.5 mass concentration increases during unsatisfactory operating conditions, especially whe re lower excess air ratios or lowquality fuel can yield more condensable gas and org anic condensation nuclei. 31 Reduced combustion air supply favors the emission and forma tion of especially harmful pollutants, as inefficient smoldering conditions can result in high emissions of particles and unoxidized gaseous compounds, leading to the format ion of particle-bound PAHs. 32 Unlike EPA-certified residential wood stoves, the d esign of many OWBs do not provide for the oxidation of incomplete combustion vapors. As a result, these are available for formation of PM 2.5 rich in relatively high molecular weight organic co mpounds. Second, in addition to poor combustion properties, the relatively short stack height of OWBs creates dangerous dispersion conditi ons to nearby buildings, including an increased likelihood of worst-case emission scen arios such as fumigation and impingement. In contrast to indoor wood stove stac ks that extend through the roof of a home to heights of 20 to 30 feet, OWBs come with sh ort stacks typically between 8 to 10 feet tall. In addition, the regular use of OWBs fu rther exacerbate the potential impact of their emissions on nearby buildings because the app liances supply hot water for domestic consumption and heating every day, all year long—no t just during wintertime. In-field ambient PM 2.5 monitoring recently conducted by NESCAUM illustrat e the potential for OWBs to affect nearby ambient air quality as discus sed in Section 5.2 of this report. Finally, the use of OWBs for trash burning increase s potential emission and public health problems related to these devices. T he sizeable firebox capacity and large loading door dimensions characteristic of OWBs faci litate the loading and combustion of non-wood materials, such as household waste (e.g., paper, plastic, and packaging). The combustion of these materials in devices that have low stacks, lack emissions control systems, and operate under low temperature conditio ns creates the potential for generating hazardous air pollutants in close proxim ity to homes, schools, businesses and other areas where people spend significant amounts of time. Using OWBs without emission controls to burn trash is analogous to the use of burn barrels and burn piles,

31 Barrefors G, Petersson G. Volatile hydrocarbons from do mestic wood burning. Chemosphere 1995; 30:1551-1556. Johansson LS, Tullin C, Leckner B, Sjövall P. Par ticle emissions from biomass combustion in small combustors. Biomass Bioenerg 2003; 25:435-446.
32 Hueglin C, Gaegauf C, Kunzler S, Burtscher H. Characterizati on of wood combustion particles: morphology, mobility and photoelectric activity. Environ Sci Technol 1997; 31:3439-3447. McDonald JD, Zielinska B, Fujita EM, Sagebiel JC, Ch ow JC, Watson JG. Fine particle and gaseous emission rates from residential wood combustion. Environ Sci Technol 2000; 34:2080-2091

.Assessment of Outdoor Wood-fired Boilers Page 4-5

which many states and local governments have banned because they emit a variety of pollutants, including acidic gases, heavy metals, a nd dioxin. Inhaling these substances has the potential to cause health problems includin g eye and throat irritation, respiratory problems, and an increased risk of cancer. 33



### 4.4. Cause for Concern Because OWBs are conducive to the formation of high PM emissions relative to background levels during routine operating conditio ns, OWBs may present a potential health risk to nearby populations. Should the use of OWBs become more prevalent in populated areas, OWB wood smoke particulate emissio ns could result in short- and longterm ambient and indoor air quality impacts on near by neighbors, in light of the ability of fine aerosols to permeate readily into dwellings. These impacts likely would also affect populated areas subject to pollution loading arisin g from terrain and meteorological conditions favorable to inversion formation. This raises public health concerns because of the known health effects associated with exposur e to PM, including a suite of respiratory and cardiac morbidity outcomes as well as premature mortality. Susceptible populations, such as the elderly, children, and per sons with preexisting cardiopulmonary disease, may be at higher health risk and therefore disproportionately affected. Consideration of operating and design features typi cal to OWBs that can influence emissions supports these public health co ncerns, including poor combustion design, low stack height and poor dispersion, four- season utility, large firebox chamber capacity, and the potential to burn trash. Current ly, few field assessments of OWB ambient emissions have been conducted, thereby limi ting regulatory efforts to evaluate this potential public health problem, especially wi thin the context of whether 24-hr and annual PM standards are suitably protective in area s with heavy wood burning. It is reasonable and prudent to assume that OWBs can pres ent a public health risk to populations in proximity to these devices.

33 Lemieux PM. Evaluation of Emissions from the Open Burnin g of Household Waste in Barrels. EPA Project Summary. EPA/600/SR-97/134. U.S. Environmental Protection Agency, National Risk Management Research Laboratory: Cincinnati, OH, 1998.Assessment of Outdoor Wood-fired Boilers Page 5-1



## 5. EMISSIONS INFORMATION This section reviews previous studies of OWB emissi ons and describes the results of two studies conducted by NESCAUM.



### 5.1. Previous Test Data
A search of available data revealed limited informa tion on OWB emission characterizations. Below are the results of this r eview.

• EPA funded an OWB study conducted by Valenti and Cl ayton in 1998. 34 The comparisons detailed within this study primarily pr ovide data based upon a heat input basis. For reasons cited earlier in this rep ort, the data have been converted to grams per hour measurements where possible. The testing was performed using a modified Method 28 fueling protocol and a m odified Method 5G for measuring particulate matter, PAHs, and POMs. The OWBs tested under this effort exhibited PM emission levels as high as 143. 2 g/hr for high heat removal firing and 55.4 g/hr at low heat removal. The appl ication of a prototype catalyst on one device lowered PM emissions to 53.8 and 37.8 g/hr respectively. Table 4-5 of the study compared PM emissions in milligrams PM per megajoules heat output for two OWB units; Furnace A produced 1,048 mg/MJ and Furnace B 35 produced 681 mg/MJ. Table 4-5 indicated that non-c atalytic wood stoves built in the 1990’s tested at 383 mg/MJ, catalytic stoves at 425 mg/MJ and pellet stoves at 110 mg/MJ.

Testing for total chromatographable organics (TCOs) showed emission rates as high as 5.4 g/hr at high heat removal to 8.31g/hr f or low heat removal. The PAH emissions were as high as 2.8 g/hr for high heat re moval and 0.64 g/hr at low heat removal. Surprisingly, the catalyst runs generated substantially higher levels of TCO and PAH compounds. The study did not provide c omparison data on a grams per hour basis for TCOs or PAHs, however, it provided comparison data in micrograms per megajoules input basis. This data s howed that PAH emissions for Furnace A were 15.6 mg/MJ, Furnace B 16.1 mg/MJ , non-catalytic wood stoves 28 mg/MJ, catalytic stoves 24 mg/MJ and cert ified pellet stoves 0.082 mg/MJ. However, EPA caveated these data due to the different test methods, stating that only differences of an order of magnitude should be considered significant. The only publicly availabl e data to compare PAH emissions on a grams per hour basis (total stack em issions) between OWBs and wood stoves is from an EPA wood stove field study o n Phase 2 units in Klamath Falls and Portland, Oregon. 36 This study found that the average “in-use” PAH

34 Valenti JC, Clayton RK. Emissions from Outdoor Wood-Burning Residential Hot W ater Furnaces. EPA Project Summary , EPA/600/SR-98/017. U.S. EPA, National Risk Management Research Laboratory: Cincinnati, OH 1998.
35 Furnace B is a Central Boiler Model CL 17 (letter from Rober t C. McCrillis, EPA, to Rodney Tollefson, Central Boiler, November 23, 1998).
36 Fisher, L, Houck, J, Tiegs, P. Long Term Performance of EPA Phase 2 Woodstoves, Klamath Falls and Portland, Oregon, 1998/1999. EPA NRMRL RTP-195 (R3-27-00).Assessment of Outdoor Wood-fired Boilers Page 5-2

emissions for Phase 2 wood stoves, which had been i n-use for over five years, was 0.149 g/hr for non-catalytic stoves and 0.165 g /hr for catalytic stoves. Based upon these data, OWBs may emit 4.3 to 18.8 times mo re PAHs than non-catalytic wood stoves and 3.9 to 16.9 times more than catalyt ic wood stoves.

• Vermont Department of Environmental Conservation (V T DEC) determined, pursuant to litigation, that a unit produced by Cen tral Boiler (Model CL-7260) had an “adjusted emission rate” of 93.76 g/hr for P M. This number was derived by state review of laboratory testing conducted by the manufacturer. Central Boiler claims in their submission of the tests that the actual rate was 3.6 g/hr. However, after thorough review, the Vermont DEC Air Pollution Control Agency concluded that Central Boiler incorrectly interpret ed the data and believes that the state’s calculations of 93.76 g/hr are accurate.

• US EPA and the New York Attorney General’s Office h ave obtained sales and emissions data from manufacturers. Table 5-1 conta ins emissions data made public by the New York Attorney General’s Office. OWB manufacturers have claimed that these data are Confidential Business I nformation and therefore NESCAUM has not been able to review the test report s or underlying test procedures 37 and therefore cannot confirm the test results nor determine the amount of emissions that may not have been measured in the condensable portion of the emissions. However, the data do show high e mission rates and indicate that manufacturers are aware of these high emission rate s from their OWBs.

Table 5-1. Unevaluated OWB Emissions Data 38

Unit PM Emissions

g/hr PAH Emissions

g/hr Heating

Efficiency Number of

Test Runs OWB 1* 84 Not Available 30% 5 OWB 2* 60 Not Available 37% 4 OWB 3* 108 Not Available 28% 2 OWB 4* 18 Not Available 31% 2 OWB 5* 49 Not Available 55% 7 OWB 6* 33 Not Available 37% 2 OWB 7** 147 Not Available 55% 2 OWB 8** 118 Not Available 53% 2 OWB 9*** 179 Not Available 45% OWB 10*** 269 Not Available 46%

* Intertek Laboratories 2004 ** Omni Laboratories 2004 *** Intertek Laboratories 2004 from ASTM subcommittee, older model not currently being sold.

37 Correspondence with EPA Region 1 in response to NESCAUM’s FOIA request of data submitted to EPA as a result of a Section 114 action.
38 Schreiber, Judith et al. Smoke Gets in Your Lungs: Outdoor Wood Boilers in New Y ork State . Office of the Attorney General; Albany, New York, 2005. Available at http://www.oag.state.ny.us/press/2005/aug/August%202005 .pdfAssessment of Outdoor Wood-fired Boilers Page 5-3

While there is only limited data at this time, the data show that PM emissions from OWBs are very high. One study concluded that OWB emissions are 10 to 20 times higher than certified indoor wood stoves. 39 Such high emissions result from low efficiency and incomplete combustion of fuel. The Connecticut Department of Environmental Protection completed a comparison of homes heated with natural gas, oil, and OWBs, and concluded that emissions from one OWB are equivalent to emissions from four non-certified wood stoves, 18 certified wood stoves, 205 oil fur naces or 3,000 to 8,000 natural gas furnaces. 40 To put these emissions into perspective, one OWB can emit as much PM as four heavy duty diesel trucks. Figure 5-1 provides a chart comparing particulate emissions from various source s. 41

Figure 5-1. PM Emission Comparison (g/hr)

39 Schreiber, Judith et al. Smoke Gets in Your Lungs: Outdoor Wood Boilers in New Y ork State . Office of the Attorney General; Albany, New York, 2005. Available at http://www.oag.state.ny.us/press/2005/aug/August%202005 .pdf

. 40 CTDEP. Connecticut Department of Environmental Protection. Connecticut DEP Fact Sheet: Outdoor Wood Burning Furnaces. State of Connecticut, Connecticut Depart ment of Environmental Protection. July 2004; available at: http://www.dep.state.ct.us/air2/consumer/index.htm ; accessed June 14, 2005.
41 Based upon an average emission rate of 36 g/hr for diesel t rucks; http://www.burningissues.org/compemmis-part-sources.htm

. 0 20 40 60 80 100 120 140 160 180

gas furnace oil furnace pack of cigarettes pellet stove certified
wood stove diesel

truck OWBAssessment of Outdoor Wood-fired Boilers Page 5-4



### 5.2. Near-Source Ambient Emission Field Monitoring Currently, few assessments exist of OWB impacts to ambient air quality, limiting regulatory efforts to evaluate exposure conditions and the potential health risks posed to nearby populations. 42 In order to characterize ambient PM 2.5 emissions near an OWB, NESCAUM performed a screening level evaluation in M arch 2005. Pilot field monitoring was conducted in Central New York State at a site within 50-150 feet of a Hardy H5-1-07 “Economy” boiler. 43 The device had a fire chamber 22.6 cubic feet in size, maximum capacity of 180,00 0 Btu/hr, and stack height of about 10 feet. Fuel usage during monitoring was a mix of green oak logged 11/01/04 and split 12/04 (stored dry) and maple/cherry/other hardwood seasoned about one-year (stored dry). The PM 2.5 monitoring interval was a 15-second averaging time in order to capture high temporal resolution during different boiler op erating modes and fuel loads. A Thermo Electron DataRAM 4000 performed the monitori ng of PM 2.5 . This is a portable nephelometric monitor that employs light scattering to measure the fine particle fraction of airborne pollutants. The DataRAM has the abilit y to estimate particle size below PM 2.5 and is an ideal instrument for portable and highly time-resolved applications.

Results indicate that areas within 150 feet of an O WB can experience high PM 2.5 concentrations relative to background levels. Cont inuous sampling recorded periodic values >1,000 μg/m 3 and frequent values >400 μg/m 3 throughout the course of routine OWB operating conditions, including damper open (ox ygen rich) and damper closed (oxygen starved) modes and within about 1 hour and 24 hours after fuel loading. The monitor found high PM 2.5 levels at all sampled distances, recording values upwards of 4,000 μg/m 3 over distances of 50, 100, and 150 ft. The monito r observed a peak value of 8,880 μg/m 3 at 50 ft. The time-series plotted in Figures 5-2 and 5-3 show selected results. Figure 5-2 displays fine particle values that the monitor obta ined about 24 hours after the OWB had been loaded with a wheelbarrow of wood fuel. (Wind was calm and variable/southerly, temperature about 8 °C, and relative humidity about 44% with light snow.) As shown in Figure 5-3, the study also conducted PM 2.5 monitoring before and within 1 hour after OWB loading with 1⁄2 wheelbarrow of wood fuel. (Wind was calm and variable/southerly, temperature about 6 °C, and re lative humidity about 50% with light snow.) In both figures, the monitor recorded high PM 2.5 readings during both damper open and damper closed modes at all distances along the monitoring transect. It found the highest values within 1 hour after fuel loading , with damper open. General observations of wind direction and speed indicate t hat changes in monitored PM 2.5 concentrations occurred when the measurement device was directly downwind or not directly downwind of the OWB plume. While this screening level pilot study was not inte nded to quantify 24-hour or longer-term average exposures (e.g., a complete hea ting season), such information would be useful to collect in order to compare typical am bient OWB PM levels to current 24-

42 The Michigan Department of Environmental Quality modeled t he impacts of an OWB based on theoretical emissions (see Appendix D).

43 A detailed presentation of findings has been submitted for peer-reviewed publication to the Journal of Health and Ecological Risk Assessment by Philip RS Johnso n, NESCAUM.Assessment of Outdoor Wood-fired Boilers Page 5-5

hour or annual PM national ambient air quality stan dards. There are no health-based benchmarks for PM 2.5 for 15-second averaging times. However, the high PM 2.5 15- second concentrations observed in this study could indicate the potential for elevated 24- hour average concentrations relative to current hea lth-based standards. 44 EPA’s current national ambient air quality 24-hr and annual PM 2.5 standards are 65 μg/m 3 (98 th percentile form) and 15 μg/m 3 , respectively. EPA recently proposed a revised 24 -hr PM 2.5 standard of 35 μg/m 3 (98 th percentile form) with no proposed revision of the annual standard. 45 Canada’s more stringent PM 2.5 24-hr objective is 30 μg/m 3

. 46 Because of this study’s findings of high PM 2.5 concentrations in proximity to an OWB under routin e operating conditions, NESCAUM recommends further re search to quantify the nature and magnitude of OWB ambient emissions in populated areas.
Figure 5-2. Field measurements of PM 2.5 near outdoor wood boiler

0 200 400 600 800 1000 120015:56:0815:59:2316:02:3816:05:5316:09:0816:12:2316:15:3816:18:5316:22:0816:25:2316:28:3816:31:5316:35:0816:38:2316:41:3816:44:5316:48:0816:51:2316:54:38

time (15 sec intervals)PM2.5 (ug/m3) DR 150' from OWB DR 100' from OWB

OWB damper open Damper open Damper closed Damper closed

44 Because the monitored data NESCAUM obtained was from an econo my-sized OWB (180,000 Btu/hr), there is the potential that other OWB devices emit higher PM2.5 concentrations; OWB models can range from about 115,000 to 3,200,000 maximum Btu/hr output

. 45 US Environmental Protection Agency. Revisions to the Nat ional Ambient Air Quality Standards for particulate matter. Final rule. Fed. Reg. 1997;62:38652–38760

. Review of the National Ambient Air Quality Standards fo r Particulate Matter: Policy Assessment of Scientific and Technical Information. EPA-452/R-05-005. Offi ce of Air Quality Planning and Standards, US Environmental Protection Agency: Research Triangle Park, N C, 2005. US Environmental Protection Agency. National Ambient A ir Quality Standards for particulate matter. Proposed rule. Fed. Reg. 2006;71:2620–2708.
46 Canadian Council of Ministers of the Environment. Human Health Effects of Fine Particulate Matter: Update in Support of the Canada-wide Standards for Particul ate Matter and Ozone. Health Canada: Ottawa, Canada, 2004. URL for CWS is www.ccme.ca/publications/

.Assessment of Outdoor Wood-fired Boilers Page 5-6

Figure 5-3. Field measurements of PM2.5 near outdo or wood boiler

0 1000 2000 3000 4000 5000 6000 7000 8000 900017:19:0817:20:2317:21:3817:22:5317:24:0817:25:2317:26:3817:27:5317:29:0817:30:2317:31:3817:32:5317:34:0817:35:2317:36:3817:37:5317:39:08

time (15 sec intervals)PM2.5 (ug/m3) DR 100' from OWB

OWB damper closed OWB loaded with wood

Damper open Damper closed ~17:35



### 5.3. Results of NESCAUM OWB “In Use” Stack Test In June 2005, NESCAUM completed stack testing on a 250,000 Btu/hr Central Boiler unit to gain a better understanding of OWB o perations. NESCAUM made pilot measurements on an "in-use" (field, not laboratory) residential OWB to determine emission rates for different burn scenarios using r eal-time measures and short duration filter samples. In addition, the test also obtaine d data on particle size, stack temperature and flue velocity. The results from these measurem ents are anecdotal in nature because NESCAUM tested only a single furnace and wood type. Nevertheless, combined with other laboratory emissions data, these tests provid e a better understanding of the potential impact of these sources on air quality. The experi ence gained from these tests in how to better characterize the real-world emissions from O WBs will be useful in guiding the design of future testing programs.



### 5.3.1. Testing Methods NESCAUM performed testing in June 2005 on an OWB, C entral Boiler CL-17, rated at 250,000 Btu/hr that was installed in 2000 to heat a residence, provide hot water, and heat a swimming pool. For this test, the heat load was the swimming pool; the damper was manually controlled to simulate moderate heating loads observed in NESCAUM’s previous test. The wood used was from th e furnace owner’s wood pile. The wood consisted of mixed hardwoods with moisture contents ranging from 20 to 40%. Appendix E contains information on the moisture con tent along with opacity readings taken by USEPA Method 9-certified staff from the VT DEC. On day one of testing, the OWB received an initial load of wood with no coal b ed that was not disturbed until the end of the test runs that day. On day two, the OWB started with a full load of wood on a bed of coals. The loading door was opened once dur ing the second day of testing toAssessment of Outdoor Wood-fired Boilers Page 5-7

check the load and rake the coals. Nothing else wa s done to the wood load in the OWB during the testing period.

A Thermo Electron DataRAM 4000 made continuous stac k PM concentration measurements using light scattering to estimate PM 2.5 concentrations. The OWB stack sample was diluted with ambient air by a factor tha t varied between approximately ten to twenty times (the actual dilution ratio was repeate dly measured and applied to the reported data). The dilution air was added within the stack to minimize water vapor condensation problems. The sample train provided s ufficient residence time (several seconds) and near-ambient temperatures to allow org anic gases in the sample to condense to particle phase. Thus, this method should be con sidered to be measuring both the “hot” and “cold” (condensed organic vapor) fractions of t he stack PM emissions. Observed stack PM concentrations were five to ten times high er than expected, so there were some problems with the continuous PM measurements. The inlet probe clogged (partially or completely) several times, and concentrations excee ded the DataRAM’s useful range a significant amount of the time. Data from these pe riods have been excluded from this report, with the exception of a few brief periods t hat are noted as “saturated” on the continuous data plots. The continuous PM data have been converted into emission rate data (grams per hour) based on the average dry flow for each of the two burn modes (idle fire or damper closed mode and full fire or damper open mode). For the scatter plot comparing data from the DataRAM continuous PM metho d with the filter gravimetric method (see below), mass concentrations of PM in th e stack are used. The DataRAM also reports a semi-quantitative measurement of the volume (mass) median particle diameter (an approximate estimate of particle size)

. A modified EPA Method 17 sampling system (using 0.3 μm pore-size glass fiber filters) collected short-term (3 to 20 minute) filt er gravimetric PM samples. The stainless steel filter holders were preheated to 275 ° F prior to sampling, but were outside the stack and unheated during sampling (no hot-box was used), so the actual temperature of the filter varied with the furnace burn mode resulting in a substantial variation in the amount of “condensable” (semi-volatile organic) PM collect ed on the filters. “Full fire” mode (damper open) stack temperatures were usually above 400 ° F; this resulted in substantial under-measurement of PM due to the inability to mea sure the condensable PM. “Idle fire” mode stack temperatures were as low as 130 ° F, and much of the condensable PM was collected under these conditions even though th e filter holders were preheated.



### 5.3.2. Results and Discussion The following sections provide specific details on the testing results using the DataRam and filter test methods.


### Results from DataRam Measurements Figures 5-4a through 5-4e are time series plots of continuous PM emission data, particle mass median diameter, and stack temperatur e. Times and values of gravimetric filter sampling are also indicated on these plots. Missing time periods are when the DataRAM data are invalid for various reasons as not ed above.Assessment of Outdoor Wood-fired Boilers Page 5-8

The continuous PM emission data demonstrate the sho rt-term dynamics of emission rates in more detail than filter sample da ta. In some cases, changes in emission rates can be related to changes in burn conditions (damper state changed), but often the rates change dramatically for no obvious reason. O ne possible explanation is settling of the wood load inside the furnace, but this could no t be observed without interrupting the testing process. The wide range of PM emission rat es even under similar conditions demonstrates the need for more extensive testing to properly characterize sources. The mean emission rate from the continuous monitor was 161 g/hr. 47 This rate does not include start up emissions (worst case scenario) an d represents mid-range emissions, operating through several operating cycles. This r ate is higher than the mean of filter emission rates for either mode (93 g/hr for full fi re mode and 64 g/hr for idle fire mode), which is likely due to the filter sampling method’s inability to measure condensibles.


### Results from filter samples Table 5-2 gives a summary of filter test results fo r damper open or full fire, and Table 5-3 gives results for damper closed or idle f ire. The mean PM emission rate for all full fire filter runs is 93 grams per hour (g/hr) w ith a range of 13 to 237 g/hr. For idle fire conditions, the mean is 64 g/hr with a range of 13 to 148 g/hr. To put these emissions into a hypothetical ambient PM concentration contex t, if the maximum rate of 237 g/hr were emitted into a totally stagnant air mass of 10 0 cubic meters (for example, an area of 100x100 meters and a height of 100 meters), the amb ient PM concentration would be 237 μg/m 3 after one hour. We must note that caution should be taken in making relative comparisons of emission rates from the two burn modes based on the filter data. These data imply that on average, full fire PM emission rates are approxi mately 50% higher than idle burn rates. As noted above, and discussed in detail bel ow, the filter data from full fire samples is likely to be biased low by a large factor becaus e of the loss of condensable PM from the hot filter. This implies that the actual full fire emission rate is much higher than the idle rate. An additional uncertainty in calculatio n of idle fire emission rates is the stack flow measurement; the flows were very low in that m ode and thus difficult to measure accurately.


### Comparison of two testing methods To assess the comparability of the two PM measureme nt methods used (continuous and filter-based), Figure 5-5 shows sca tter plots of matching time periods when collecting both filters and valid continuous P M data. Data from the two burn modes are compared separately because of the substa ntial difference in how much condensable PM was presumably collected with the fi lter method between the two modes. Table 5-4 presents the data used in Figure 5-5. Note that Table 5-4 presents these data as concentrations (grams per cubic meter ) rather than emission rates. The difference in both numerical agreement and corr elation between the two PM measurement methods between the two burn modes is c onsistent with the differences in

47 This measurement came from a mostly contiguous 3.5 hour pe riod on day two of testing after two initial modulations of the unit running a period beginning 2.5 hours after the fuel charge and ending six hours after fuel charge.Assessment of Outdoor Wood-fired Boilers Page 5-9

filter temperature between the two modes. In the i dle burn (damper closed) mode, stack (and therefore filter) temperatures are relatively low, allowing collection of much of the condensable organic PM. In this mode, the two meth ods correlate well and the mean PM is within 30%. In the full burn (damper open) mode , the stack (and filter) temperatures are much higher, so the filter is not collecting mu ch of the condensable PM. In this mode, the two measurement methods do not correlate, and the filter PM data are much lower than the continuous PM data. In the damper o pen mode, the continuous data range is approximately a factor of 10; the filter data ra nge for this mode is small, with five of the six samples between 0.13 and 0.21 g/m 3 . The mean of the continuous DataRAM PM is nearly seven times higher than the mean of the f ilter PM for this sample subset period. These differences between the two PM methods are no t unexpected, because the modified method 17 used for the filter measurements does not attempt to efficiently collect the condensable organic PM fraction.



### Stack Conditions Stack temperatures varied widely, from as low as 13 0 ° F (idle burn) to 600 ° F (full burn). Median particle size also varied widely, fr om 0.1 to over 1 μm in diameter. Smaller sizes were generally associated with full ( hot) burn modes, with larger sizes during idle (cooler) burns. This is consistent wit h what could be expected; hotter burns would have less organic carbon material because the higher temperatures combust more of the organic carbon.



### Conclusions
While it would be reasonable to assume that a “fres h” load of burning wood in the OWB would result in higher emission rates compared to an “aged” load that is more charcoal-like, this was not the case. The idle bur n mode filter test results were insufficient to show this and the full burn mode te sts would not be appropriate to use because the filter measurements did not capture the majority of PM emissions. Idle burn filter PM data from June 21 were too limited (2 sam ples, both 2-3 hours after loading) for this assessment. On June 22, six idle-fire filter measurements were made from about 1⁄2 hour after the OWB was loaded to almost 6 hours aft er. The successive idle burn filter PM emission rates were 51, 83, 109, 148, 27, and 13 grams/hour. Although the two lowest PM emission rates were at the end of the tes t sequence, the highest value of 148 g/hr occurred almost five hours after the wood was loaded. Thus, no clear conclusion from these limited data can be made rega rding emissions and age of load.Assessment of Outdoor Wood-fired BoilersPage 5-10Table 5-2. Filter Measurements Idle Burn ModeTest Run 3 5 7 10 12 14 16 17Date6/21/2005 6/21/2005 6/22/2005 6/22/2005 6/22/2005 6/22/2005 6/22/2005 6/22/2005Clock Time (24 hour)15:08 – 15:23 16:15 – 16:3110:03 –10:2211:21 – 11:40 12:47 – 12:50 14:18 -14:21 15:08 – 15:11 15:18 – 15:21Test Duration (minutes)15 16 19 19 3 3 3 3Sample Volume (dscf)4.583 4.838 6.09 5.416 0.865 0.862 0.862 1.014Test MeasurementsMeansIsokinetics (%)88.9 87.9 92.2 82.1 101.6 95.5 91.6 97.8 92.2Moisture Content (%)7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5Temperature (F)200 200 200 200 356 280 250 140 228.25Gas Composition –CO2(%)6.4 6.4 6.4 6.4 6.4 6.4 6.4 6.4 6.4O2(%)13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3 13.3CO (%)0 0 0 0 0 0 0 0 0N2(%)80.3 80.3 80.3 80.3 80.3 80.3 80.3 80.3 80.3Gas Velocity (fps)2.4 2.4 2.4 2.4 2.6 2.5 2.5 2.3 2.4375Gas VolumetricFlow (dscfm)37 37 37 37 32 34 36 39 36.125(acfm)50 50 50 50 54 52 52 48 50.75PM Emission DeterminationsConcentration(grains/dscf)0.268 0.2705 0.354 0.5804 0.8778 1.1171 0.1933 0.0852 0.468288Emission Rate (lbs/hr)0.08 0.09 0.11 0.18 0.24 0.33 0.06 0.03 0.14Concentration(grams/meter3)0.614 0.619 0.811 1.329 2.010 2.558 0.443 0.195 1.072378Emission Rate(grams/hour)38.56 38.92 50.93 83.50 109.22 147.69 27.06 12.92 63.60Assessment of Outdoor Wood-fired BoilersPage 5-11Table 5-3. Filter Measurement Full Burn ModeTest Run1 2 4 6 8 9 11 13 15Date6/21/2005 6/21/2005 6/21/2005 6/22/2005 6/22/2005 6/22/2005 6/22/2005 6/22/2005 6/22/2005Clock Time(24 hour)14:11 –14:1914:38 –14:4515:37 –15:5609:44 –09:4910:43 –10:5010:59 -11:00:3012:16 –12:3113:50 –14:0614:39 –14:55Test Duration (minutes)8 7 19 5 7 1.5 15 16 16Sample Volume (dscf)2.583 3.701 4.662 1.586 1.946 0.36 4.06 4.223 4.198Test MeasurementsMeansIsokinetics (%)134 95.3 99.3 133.4 116.7 193.4 102.3 101.6 101.1 119.6778MoistureContent (%)21.7 21.7 21.7 21.7 21.7 21.7 21.7 21.7 21.7 21.7Temperature (F)450 590 630 360 455 455 478 500 500 490.8889Gas Composition –CO2 (%)8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3 8.3O2 (%)11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8CO (%)0 0 0 0 0 0 0 0 0 0N2 (%)79.9 79.9 79.9 79.9 79.9 79.9 79.9 79.9 79.9 79.9Gas Velocity (fps)6.4 6.9 7 6 6.4 6.4 6.5 6.5 6.5 6.511111Gas VolumetricFlow (dscfm)60 56 55 63 60 60 60 58 58 58.88889(acfm)134 144 147 126 130 134 136 136 136 135.8889PM Emission DeterminationsConcentration(grains/dscf)0.9965 0.0763 0.0755 0.9691 0.2244 0.9774 0.0908 0.0771 0.0588 0.393989Emission Rate (lbs/hr)0.51 0.04 0.04 0.52 0.12 0.06 0.05 0.04 0.03 0.156667Concentration(grams/meter3)2.282 0.175 0.173 2.219 0.514 2.238 0.208 0.177 0.135 0.902235Emission Rate(grams/hour)232.49 16.61 16.15 237.40 52.35 228.03 21.18 17.3913.26 92.76336Assessment of Outdoor Wood-fired BoilersPage 5-12Table 5-4. Comparison of Filter Data and DataRamFull Burn Data6/21/20056/21/20056/22/20056/22/20056/22/20056/22/200514:38 – 14:45 15:37 – 15:56 10:43 – 10:50 12:16 –12:31 13:50 – 14:06 14:39 – 14:55PM Concentration, g/m3DR3.070 0.340 1.355 1.174 1.900 1.532Idle Burn Data6/21/2005 6/22/2005 6/22/2005 6/22/2005 6/22/200516:15 – 16:31 12:47 – 12:50 14:18 -14:21 15:08 – 15:11 15:18 – 15:21PM Concentration, g/m3DR0.661 2.586 2.956 1.269 0.501Filter0.619 2.010 2.558 0.443 0.195Assessment of Outdoor Wood-fired BoilersPage 5-13Figure 5-4a. VT Outdoor Wood Furnace Stack SamplingContinuous PM (Data RAM) 21-June 200514:28 to 15:08

28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 0 1 2 3 4 5 6 7 8

Condensable PM Emissions (grams/hour)0100200300400500600 Temperature (F)550575600625650 Particle Mass Median Diameter (microns)0.00.20.40.60.81.0Emissions g/hTempDiameter

filter starts filter ends

damper open (full burn) damper closed (idle burn)--- filter = 16.6 g/h ---Assessment of Outdoor Wood-fired BoilersPage 5-14Figure 5-4b. VT Outdoor Wood Furnace Stack SamplingContinuous PM (Data RAM) 21-June 200515:31 to 16:40

31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Condensable PM Emissions (grams/hour)050100150200 Temperature (F)100200300400500 Particle Mass Median Diameter (microns)0.00.51.01.52.02.53.0Emissions g/hTempDiameter

damper open (full burn) damper closed (idle burn)

filter starts filter starts

filter ends filter ends--- filter = 16.1 g/h ------ filter = 38.9 g/h ---Assessment of Outdoor Wood-fired BoilersPage 5-15Figure 5-4c. VT Outdoor Wood Furnace Stack SamplingContinuous PM (Data RAM) 22-June 200510:32 to 10:54

32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53

Condensable PM Emissions (grams/hour)050100150200250300 Temperature (F)100200300400500 Diameter (microns)0.00.20.40.60.81.01.2Emissions g/hTemp (F)Diameter (μm)DataRamSaturated

damper closed (idle burn) damper open (full burn) filter end

filter start--- filter = 52.3 g/h ---Assessment of Outdoor Wood-fired BoilersPage 5-16Figure 5-4d. VT Outdoor Wood Furnace Stack SamplingContinuous PM (Data RAM) 22-June 200511:50 to 13:42

50 52 54 56 58 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42

Condensable PM Emissions (grams/hour)0200400600800 Temperature (F)0200400600800 Diameter (microns)0.00.51.01.52.02.5PM emissions (g/h)Temp (F)Diameter (μm)

damper closed (idle burn) damper open (full burn) filter start filter end damper closed (idle burn) open owb door to check fuel

filter start filter end (109 g/h)filter = 21.2 g/hAssessment of Outdoor Wood-fired BoilersPage 5-17Figure 5-4e. VT Outdoor Wood Furnace Stack SamplingContinuous PM (Data RAM) 22-June 200513:44 to 15:23

44 46 48 50 52 54 56 58 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 0 2 4 6 8 10 12 14 16 18 20 22

Condensable PM Emissions (grams/hour)0200400600800 Temperature (F)0200400600 Diameter (microns)0.00.51.01.52.02.53.0PM Em issions (g/h)Tem p (F)Diam eter (μ)SaturatedSaturated

damper open (full burn) filter start filter end damper closed (idle burn) filter start filter end (147.7 g/h) damper open (full burn) filter start filter end damper closed (idle burn) filter start filter start

filter end (27.0 g/h) filter end (12.9 g/h)--- filter = 17.4 g/h ---filter = 13.3 g/hAssessment of Outdoor Wood-fired Boilers Page 5-18



### 5.4. ASTM Test Protocol In June 2004, the ASTM sub-committee was formed to develop a standardized, replicable laboratory method to measure particulate emissions from OWBs. The goal of this process is to develop a laboratory-based test method that evaluates emissions between different OWBs and measures particulate emi ssions and delivered heating efficiency at a minimum of four heat output rates. This will provide accurate and reliable data on the performance of OWBs as an aid in develo ping cleaner technology. There are currently thirty voting members on the committee; n ineteen are manufacturers, three are from OWB testing companies, two are from state envi ronmental agencies, one is from a state attorney general’s office, one is a consultan t, one is a coordinator for the HPBA trade association, one is from a state economic dev elopment agency, one is from Environment Canada, and one is from EPA. 48



### 5.5. Conclusions on Emissions Testing Both the ambient and stack testing conducted by NE SCAUM on smaller OWBs burning appropriately seasoned hardwood showed high PM 2.5 emissions, suggesting that people living near OWBs may be affected by unhealth y levels of PM 2.5 . Because manufacturers are selling OWBs primarily for use in residential settings, NESCAUM believes a single PM emission limit expressed in gr ams per hour should be developed to reduce emissions and assure public health protectio ns. NESCAUM also concludes that it may be appropriate to use newer, continuous PM measurement methods to measure emissions from OW Bs and other wood burning devices. In order to accurately quantify emissions for OWBs, the testing method must have the capability to provide accurate results giv en the likelihood of filter loading and excessive moisture content. In addition, it is cri tical that any robust measurement of OWB emissions be capable of measuring the condensab le fraction of PM because the majority of wood smoke emissions are in the condens able fraction. Traditional “backend” techniques (such as method 202) are not design ed for wood smoke and may not efficiently capture the condensable fraction. Unli ke power plant stack aerosols, wood smoke is not water soluble, and the small particle sizes generated in full fire mode are difficult to collect using inertial techniques. Th erefore, the use of alternative technologies and test methods such as continuous PM measurement may be more appropriate for OWBs. Such alternatives already ex ist and EPA has conditionally approved them as alternatives to traditional Method 5 testing. Continuous PM monitors allow for PM measurement throughout the burn cycle rather than averaging several runs in a burn cycle. These methods would allow for acc urate, continuous measurements in both low and high firing modes throughout the entir e fuel charge, resulting in an accurate average emission rate for an entire burn cycle. S econd, these methods overcome many

48 Information regarding the ASTM work can be found at http://www.astm.org/cgibin/SoftCart.exe/DATABASE.CART/WORKITEMS/WK5982.htm?L +mystore+kltm0898

.Assessment of Outdoor Wood-fired Boilers Page 5-19

Damper closed (Idle burn):

Mean DR: 1.59 g/m 3 Mean Filter: 1.17 g/m 3

R 2 = 0.93

Filter PM (g/m 3 ) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5DataRam PM (g/m3)

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Damper open (full burn):

Mean DR: 1.56 g/m 3 Mean Filter: 0.23 g/m 3

R 2 = 0.02 (not significant)

Filter PM (g/m

3 ) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5DataRam PM (g/m3)

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Both methods measuring most of condensables (filter T is ~120 to 180 F) Dataram measuring most of condensables; filter is losing most (filter T is ~300 to 550 F) of the issues associated with filter-based testing including filter loading, excessive moisture content and condensable losses.

Figure 5-5. VT Outdoor Wood Furnace Stack Sampling Continuous PM

(Data RAM) vs. Filter PM 21-22 June 2005Assessment of Outdoor Wood-fired Boilers Page 6-1



## 6. OWB CONTROL STRATEGIES Policy makers often face challenges in determining emission control and exposure reduction requirements with uncertain and often con flicting scientific and toxicological opinions before them. However, there is mounting e vidence to support the need for action to reduce emissions from OWBs in order to ma intain public health protections. The options government agencies should consider are to rely on existing regulations, adopt new requirements, or invest in voluntary init iatives. This section outlines these options and provides an overview of relevant judici al rulings and enforcement actions.



### 6.1. Regulatory Action Regulatory agencies can institute one or more strat egies to address emissions from OWBs. These strategies include setting emissi on standards for OWBs, requiring permits for OWB installation, requiring the removal of non-certified appliances, establishing no burn days, instituting and implemen ting nuisance rules and/or opacity rules, and developing standards for fuels. The fol lowing section provides a brief overview of the options available to regulatory age ncies.



### 6.1.1. Ban/Removal of OWBs One strategy would ban the sale of all new OWBs and establish a timeline for removal of all existing OWBs. This strategy would address the installation of new OWBs by placing an immediate ban on the sale of new OWBs, and would address existing OWBs by establishing a timeline to remove them. Several states and municipalities have attempted to put bans into effe ct but only a few municipalities have succeeded. In 2004, Connecticut considered legisla tion that would ban the sale of OWBs until a federal emission standard had been adopted but this legislation was defeated under strong lobbying efforts from OWB manufacturers. A similar strategy would prohibit the sale of OWBs until clean burning units come to the market. These strategies are the only avenue that would immediately address emissions fro m all OWBs.



### 6.1.2. Emission Standards Another strategy would create a PM emission limit f or OWBs and prohibit the sale or installation of any unit that did not meet the standard. There are three potential approaches to creating a standard for OWBs:

• a simple mass emission rate limit (grams/hour) rega rdless of an OWB’s rated output or actual thermal output,

• an emission rate limit that is tied to an OWB’s rat ed output or actual average thermal output (grams of PM/Btu/hr or mg PM /megajoule), or

• a limit on the concentration of the PM in an OWB’s stack (grams/cubic meter or grains/cubic foot of exhaust gas).

Although all three of these approaches could reduce PM emissions from OWBs, only the first approach (grams/hour) specifically a ddresses both the regional and local aspect of OWB smoke. If the goal of a standard is in part to protect against local (50 to 1000 feet from source) high PM concentrations, then the total PM emitted from a givenAssessment of Outdoor Wood-fired Boilers Page 6-2

stack must be controlled without regard to OWB size . The second and third approaches above would not accomplish this because they allow a unit’s overall emissions to increase as the unit’s output increases. Both the second and third approaches address PM emi ssions from a relative efficiency perspective (PM emissions per unit heat produced). The second approach creates additional hurdles when developing and impl ementing a test protocol. First, it requires a clear definition on how to define Btu/hr – heat input, heat output as it leaves the OWB or heat output as it reaches the area to be heated. In addition, it will require that the testing precisely measure this additional feature. Another disadvantage to this method is that measurement would allow for dilution to minimize emissions when OWBs are tested in a laboratory setting. In addition, th is method does not normalize with different fuel sources. The third approach, a grai n loading standard, is similar to measurement based on heat ratings. However, a grai n loading standard with a correction for carbon dioxide would ensure that the measuremen ts in the testing are not diluted to reduce emissions. Furthermore the grain loading me asurement that mandates a correction for carbon dioxide levels minimizes variability tha t may arise due to inconsistency in the fuel source. The state of Washington has adopted a mass emission rate regulation that requires all solid fuel burning devices, including OWBs, to meet an emission limit of 4.5 g/hr PM for non-catalytic appliances and 2.5 g/hr for catal ytic appliances. The state of Vermont has proposed a regulation based on the third approa ch. The proposed Vermont standard would limit OWB emissions to 0.20 grains per dry st andard cubic foot of exhaust gas corrected to 12% CO 2 . Calculations based on testing data estimate that the mass emission limit for smaller OWBs would approximate 2 2-36 g/hr PM, assuming a 50% duty cycle. Because the Vermont standard is a conc entration-based standard, a residential wood boiler larger than the 250,000 Btu /hr used for these tests could have higher PM emission rates (assuming similar duty cyc les). Appendix F includes copies of the Vermont and Washington regulations. Establishing an OWB emission standard would reduce PM emissions from new OWBs and place the burden for reductions on manufac turers rather than homeowners. This option would allow the sale of clean burning O WBs while prohibiting the sale of dirty units. This strategy, however, would not add ress existing installations, but when combined with another strategy to address existing OWBs, it could present the best option to address OWB emissions.



### 6.1.3. Fuel Requirements Another strategy would require that all wood burnin g devices burn seasoned wood and eliminate any state loopholes that would a llow the burning of trash, yard waste or other waste materials. Several municipalities i n Colorado, California, Washington, and Canada have this type of regulation. However, this strategy has several disadvantages. First, even under ideal conditions, burning seasoned cordwood, OWBs emit extremely high levels of particulate matter an d air toxics. Second, enforcement of this rule would be a challenge. Finally, using woo d that is too dry, such as pallets, may also cause excessive smoke and air emissions due to the increased likelihood of explosive incineration.Assessment of Outdoor Wood-fired Boilers Page 6-3



### 6.1.4. Mandatory Removal Mandatory removal requires removal of any wood burn ing appliance that is not certified by a certain date and/or rendered permane ntly inoperable by a certain date. This strategy would reduce emissions from the older, dir tier OWBs and significantly reduce particulate emissions from these devices. However, it also would encumber the homeowner with substantial costs and require extens ive enforcement.



### 6.1.5. No Burn Days No Burn Days would prohibit the use of any wood bur ning device during episodes when the likelihood exists for high PM lev els. New Mexico and municipalities in Alaska, California, Colorado, Oregon, South Dako ta, Utah, and Washington have instituted a no burn day program. This strategy wo uld address high emission events but would not address the day to day contribution of po llution from OWBs to ambient air quality. In addition, it does not address the seve re local impacts that may occur. It also could be difficult to implement and enforce statewi de no burn days.



### 6.1.6. Nuisance Rules Nuisance rules would establish new regulations or m ore aggressively enforce existing regulations that limit or prohibit actions from causing or contributing to a nuisance condition. Many states have such regulati ons, however, using these rules to protect neighboring properties have proven difficul t. Connecticut’s rule calls any visible emission crossing the property line at ground level a nuisance violation. Once the agency documents a violation, it issues a notice of violat ion (NOV) giving the OWB owner thirty days to remedy the violation. In the past, OWB own ers have attempted to burn smaller loads, use dry wood, raise the stack height of the unit and install baffles without resolution of the underlying problem. Connecticut DEP has issued several NOVs for nuisance situations where the conditions causing th e nuisance were not mitigated but none has resulted in the elimination of the issue. After many attempts to modify fuel use (using seasoned wood), add-on equipment (catalysts or baffles) and limit use, enforcement programs have indicated that shutting d own or limiting OWB operation are the only viable remedies for nuisance and odor issu es.



### 6.1.7. Opacity Rules Many states, including Massachusetts, have requirem ents establishing smoke opacity limits. There is mounting evidence that su ggests that OWBs cannot meet current opacity standards. 49 A strategy to ensure that OWB’s comply with opaci ty regulations could require a permit to install and/or operate an OWB and require a demonstration that the unit meets the opacity limit before it can comm ence operation. This strategy would ensure that only clean OWBs are installed, but the burden of proof would be placed on the homeowner rather than the manufacturer. Furthe rmore, testing could only commence once the OWB owner had already invested in the purc hase and installation of a unit. Experiences within the NESCAUM states have shown th at once a unit is installed, it is very difficult for the state to remove the unit or prohibit operation. Therefore, even with

49 During NESCAUM’s stack testing, a certified smoke reader reco rded opacity readings. Appendix E includes a copy of the field report.Assessment of Outdoor Wood-fired Boilers Page 6-4

opacity regulations in place, states still face a h igh hurdle to enforce against OWBs based on opacity regulations. The following lists are the opacity regulations for the NESCAUM states:

• Connecticut’s air regulations (RCSA Section 22a-174 -18) limit opacity (except for periods of startup, shutdown, and malfu nction) to 20% during any six-minute block average or to 40% during any o ne-minute block
average.

• Maine’s regulations (ME DEP Chapter 101) limit visi ble emissions from any wood-waste or biomass unit to 30% opacity on a six-minute block average basis, except for no more than two six-minu te block averages in a three-hour period.

• Massachusetts’ regulations [310 CMR 7.06(1)] limit opacity to 20% for a period or aggregate period of time in excess of two minutes during any one hour, with a maximum of 40% at any time.

• New Hampshire’s air regulations (Env-A 2002.02) lim it average opacity from fuel-burning devices installed after May 13, 1 970 to 20% for any continuous 6-minute period, except for periods of s tartup, shutdown, malfunction, soot blowing, grate cleaning, and clea ning of fires.

• New York’s air regulations (NYCRR Section 211.3) re quire that no person shall cause or allow any air contamination s ource to emit any material having an opacity equal to or greater than 20% (six minute average) except for one continuous six minute perio d per hour of not more than 57% opacity.

• Rhode Island DEM’s Air Pollution Control Regulation No. 1 states that no person shall emit into the atmosphere from any sour ce any air contaminant for a period or periods aggregating more than three minutes in any one hour which is greater than or equal to 20% opacity.

• Vermont’s regulation (Section 5-211) limits opacity to 20% for an aggregate period of six minutes during any one hour with a maximum of 60% opacity for any two minute average; however the Vermont regulation exempts any wood-fuel burning equipment with a rate d output of less than 40 horsepower (1 boiler hp = 34,500 Btu/hr).



### 6.1.8. Removal Prior to Sale or Transfer of Property Another strategy would require a certification prio r to the completion of a sale or transfer of any real property on or after a certain date, that all wood burning appliances that are not certified would be required to be repl aced, removed or rendered permanently inoperable. This would require an investment from the homeowner as would the mandatory removal. This strategy relies on the str ength of the real estate market and the thoroughness of the home inspector. Enforcement of the program could be implemented via the building inspection process.Assessment of Outdoor Wood-fired Boilers Page 6-5



### 6.1.9. Zoning Regulations Another strategy would establish property line setb acks for OWBs to protect neighboring properties from nuisance smoke and odor s. Vermont and Connecticut both have such regulations. Connecticut’s rule requires a 200 foot setback and stack heights greater than the roofline of the neighboring proper ties. This rule was adopted in spring 2005 and therefore there is no experience to estima te the efficacy of this rule. Vermont adopted a “zoning” type regulation in 1997 that set s minimum setbacks, stack heights, and requires that purchasers of OWBs be notified ab out the Vermont rule requirements. Vermont has experienced many problems with this rul e and has found that it has not addressed the underlying public health, nuisance an d odor conditions created by OWBs. Setbacks and stack height requirements do not addre ss the overall emissions from OWBs. In August 2005, Vermont proposed a new regulation t hat would establish an OWB emission standard.



### 6.2. Voluntary Programs Voluntary programs rely on the consumer to purchase cleaner burning units or the manufacturer to make cleaner units. The section be low overviews two voluntary strategies.



### 6.2.1. Change-out Programs This strategy eliminates the use of old, dirty burn ing appliances by providing incentives for the public to purchase new, clean bu rning equipment. This strategy addresses PM 2.5 emissions generated by wood burning appliances and eliminates older, dirtier OWBs. Because the program is voluntary in nature, the program needs significant participation and a large amount of resources to be successful. It is likely that a changeout program will have a better chance of success if it is supported by a rule prohibiting the installation of wood-burning appliances that do not meet specified standards for low emissions.



### 6.2.2. Voluntary Industry Actions Another strategy would rely on manufacturers to vol untarily commit to developing cleaner OWBs. In 2001, New York held a meeting where manufacturers stated that they had plans to redesign their OWBs. Manufacturers once again made this claim to the Connecticut legislature during their r egulatory process in June 2004. In June 2005, EPA unsuccessfully asked for a meeting with m anufacturers. To date none of these efforts have led to cleaner burning OWBs. Appendix A includes a copy of EPA’s request and a response from one of the largest OWB manufact urers.



### 6.3. Court Actions
NESCAUM has identified six lawsuits in the Northeas t relating to OWBs. In every case, the end result has been the removal of, or prohibition to operate, the offending OWBs. In many cases, this has been the only option for neighboring properties to find adequate resolution to the nuisances created by OWB s. In Connecticut, five civil suits have been brought under Connecticut’s General Nuisance Laws. In every case, the outcome has been in the complainant’s favor. In atAssessment of Outdoor Wood-fired Boilers Page 6-6

least three of the Connecticut cases, the OWB manuf acturer provided an attorney at no cost to the OWB owner. In only one case did the O WB owner go to trial; the other cases were settled out of court, and required confidentia lity of the settlement. In all cases the OWB was either removed or prohibited from operating so long as the complainant resides in the neighborhood. In Stamford, Vermont, a landscape company that had improperly installed an OWB filed suit against the distributor and manufact urer (Central Boiler) of the OWB. In this case, the owner placed the unit within 200 fee t of a neighboring residence, in violation of the Vermont OWB regulation. The OWB o wner claimed that he had not been informed about the notification and setback re quirements. The unit was eventually removed, and the details are not available because the case was settled out of court.
In Grafton, Massachusetts, a resident made numerous complaints to the Massachusetts DEP about his neighbor’s OWB. The sm oke from the OWB was coming directly into the complainant’s house causing him t o have chronic bronchitis for the first time in his life. The Town of Grafton Board of Hea lth issued a cease and desist order until the unit had been inspected and had the prope r permits issued. The complainant ultimately took his neighbor to Housing Court and w on. The owner of the OWB is no longer allowed to use it in the summer, had to incr ease the stack height, adjust the air flow, and change burning practices. While individuals have been successful in bringing these suits under nuisance laws, it seems unreasonable to expect that all affe cted individuals have the financial resources and other wherewithal to pursue such acti ons for the vast majority of potential OWB nuisances. In addition, public health harm can arise from the collective impact of emissions from many OWBs even if no individual OWB can by identified as causing unique harm to a specific person, as may be require d under nuisance law. Therefore, it may not be an option available to all members of th e public nor broadly covering OWBs.



### 6.4. Enforcement Actions Several states have issued Notices of Violations (N OVs) for OWBs, however, enforcement actions against residential OWBs tend t o be resource intensive and difficult to resolve. The following provides an overview of the available data.



### 6.4.1. Connecticut Connecticut has issued approximately fifteen NOVs; none of these have resulted in assessed penalties, OWBs removed, or consent ord ers. OWBs complaints continue to increase. Implementation of Connecticut’s new rule requiring setback distances and stack heights has not eliminated complaints but has increased enforcement efforts and resources to address improperly installed units.



### 6.4.2. Massachusetts An overview of fourteen actions taken by Massachuse tts against OWBs:

• A residential property owner installed an OWB in th e spring of 2005 for heat and hot water. The smoke from the unit impacted th e nearest residential neighbor. The neighbor complained of smoke infiltr ating the house andAssessment of Outdoor Wood-fired Boilers Page 6-7

resulting health issues. The complainant also alle ged that the smoke in their yard was so thick that it is like fog and even fill ed up the garage and car. The Board of Health told the owner of the OWB to shut t he unit down for the summer. Before the unit can be restarted, the owne r must change the air mixture, increase the stack height, and change his wood burning practices. If these measures do not improve the excessive smoke, the unit will have to be closed down.

• Massachusetts DEP staff observed large amounts of s moke from the highway in Auburn, MA. They traced the smoke to an OWB ope rating at Brady Sunroom. The facility was burning glued boards in the unit for heat recovery. The facility entered into a consent order with pena lty and removed the unit.

• A company in Auburn, MA uses an OWB to heat their f acility. When the unit was first put in operation, the fire department rec eived many complaints about the unit. A trailer home park is located directly behind the company. The Massachusetts DEP staff have driven by this company on numerous occasions to try to verify excess smoke from this unit. The fire department has agreed to call the DEP this upcoming heating season if the un it is still causing a problem.

• Massachusetts DEP received anonymous complaints abo ut smoke and odors from an OWB. A daytime drive by on a cold day show ed an OWB operating on a small farm but no opacity was observed. The F ire Department worries that the unit is burning large amounts of cardboard . The Fire Department will continue to monitor the OWB and wait for further co mplaints.

• A residential property owner installed an OWB appro ximately six years ago and the neighbor has been having problems with smok e from that unit since the date of installation. The unit releases a grea t deal of smoke that goes all over the property and into their home. The homeown ers have expressed concern about the health effects, difficulty in bre athing by the neighbor, the inability of their daughter to visit them due to th e smoke, and their inability to use their yard. The homeowner worked with the Boar d of Health to try to resolve the situation but was informed that he woul d need to hire an attorney.

• A residential property owner installed an OWB to he at their home, pool and Jacuzzi. The large amounts of smoke from the unit were impacting the nearest neighbor who has two daughters with asthma. The smoke from the OWB was coming directly into their home and yard al legedly causing the children to have increased asthma attacks. The Boa rd of Health required the owner of the OWB to cease using the unit during the summer.

• A residential property owner installed an OWB to he at their home and provide hot water. Residents several miles downwind were g etting smoke coming into their homes in the middle of the night, thus waking them up and giving themAssessment of Outdoor Wood-fired Boilers Page 6-8

headaches. The neighbors traced the source of smok e and odor to the OWB. The Board of Health and the Groton Fire Department investigated the matter and have met with the owner of the OWB several time s but no formal action to date has been taken.

• In summer of 2003, a resident began complaining abo ut smoke from an OWB unit. A member of the town Board of Selectman was in the process of building a new home adjacent to the resident’s hous e and installed an OWB. The resident claimed that the owner of the OWB was also using the unit as an incinerator to burn construction debris. The resid ent complained about the large amounts of smoke coming from the OWB, the ina bility to use his lakeside property, and the inability to feed the nu merous song birds that no longer come to his house. The resident was 84 year s old, and reported that he had severe health issues. The resident has many ph otos of the OWB smoking. Visits by the Massachusetts DEP confirmed the prese nce of the OWB but did not observe it operating. The Board of Health took the lead in the matter.

• One municipality received numerous residential comp laints about an OWB located at a manufacturing facility. The facility purchased the OWB to burn pallets in order to reduce disposal costs and provi de building heat. The Board of Health and fire department made many visits to t he facility and witnessed excessive smoke from the OWB. The town eventually requested that the Massachusetts DEP provide some assistance in shutti ng down the unit. The DEP conducted an unannounced inspection and found t he unit to be operating with excessive smoke while burning pallets. It iss ued a notice of noncompliance to the company, which removed the uni t.

• In another municipality, residents contacted the Ma ssachusetts DEP and the town’s Board of Health regarding smoke complaints f rom their neighbor’s residential OWB. The unit was located in a histori cal district and operated without any town permit. The unit smoked so much t hat it obscured visibility several times on Main Street. The local paper even documented and published one of these instances. The complainant’ s wife has had numerous respiratory problems due to the operation of the OW B. The town’s historical commission had the owner remove the unit. It is cu rrently in the owner’s backyard and not hooked up. The town’s Board of He alth contacted the Massachusetts DEP about guidance on regulations to restrict the location and operation of OWBs. The town has held two of three public meetings on a proposed regulation.

• A residential property owner installed an OWB to he at the home and provide hot water. Five neighbors have complained to the B oard of Health and fire department that the smell from the OWB forces them to keep their windows shut at all times. Even so, the odor still seems t o seep through into their homes. The owner of the OWB was burning green pine in the unit. The Board of Health and fire department worked with the owner to improve theAssessment of Outdoor Wood-fired Boilers Page 6-9

smoke from this unit. Massachusetts DEP worked wit h the town in an advisory capacity.

• While visiting a facility, a Massachusetts DEP insp ector observed large amounts of smoke coming out of an OWB located at a land clearing company. The company burns waste wood to heat their building . At the time of the inspection, a 2.5 diameter by 3 foot long unsplit l og was being burned in the unit. The Department issued a Notice of Non-Complia nce (NON) requiring the source to stop the excessive smoke. The compan y could not meet the requirements in the NON and agreed to cease use of the unit.

• A residential property owner installed an OWB to he at his home and provide hot water. The smoke from the unit impacted severa l of his neighbors. The neighbors called the Board of Health and Massachuse tts DEP to complain about how the smoke was harming them (i.e., could n ot use yards, had to keep windows closed on beautiful days, etc.). The Board of Health required the owner of the OWB to cease using it for the summer.



### 6.4.3. Vermont Vermont has taken action against one unit not relat ed to their zoning regulation in Brandon, VT. In this instance, the Vermont Departm ent of Environmental Conservation (VT DEC) determined that a nuisance condition exist ed and required the owner to not to operate the OWB during the summer months and to inc rease the OWB stack height. Vermont has taken enforcement actions against deale rs and owners who have violated their setback and notification regulation. These actions have led to the shutdown or removal of six OWBs. In other instances, it req uired the unit owner to raise the stack height of the OWB. Currently, Vermont has four pen ding OWB violations.Assessment of Outdoor Wood-fired Boilers Page 7-1



## 7. CONCLUSIONS/RECOMMENDATIONS There is mounting evidence that supports the need f or action to reduce emissions from OWBs. Based upon the data, NESCAUM has reached the following conclusions:

• Sales of OWBs continue to increase by 25-50 percent annually. NESCAUM estimates that there are over 155,000 OWBs nationally. Recent manufacturer statements indicate that sales in 2005 increased by 200 to 350 percent. If sales trends continue, ther e is the possibility that there will be almost 5,000 OWBs in Massachusetts an d 500,000 OWBs nationally by 2010.

• State experience suggests that manufacturers are un likely to voluntarily improve OWB performance.

• EPA is unlikely to develop a federal standard and e ven if it were to act immediately, it would take a minimum of five to sev en years to enact a standard.

• EPA’s focus on wood stove change-outs could result in an increase in installation rates for OWBs.

• Without aggressive public policy to limit fine part icle and air toxic emissions from OWB sources, the number of potential ly exposed at-risk individuals will continue to grow.

• Emissions from OWBs are 22 to 40 times greater than EPA certified indoor wood stoves.

• Near-source ambient monitoring indicates that OWB e missions have the potential to create significant public health conce rns.

• Existing state regulations are inadequate to addres s OWBs and state environmental agencies lack the tools to effectivel y enforce against residential OWBs. Currently, the only viable route in some states to address OWB complaints is via state opacity require ments that are resource intensive to investigate and civil legal a ction, but this may not be equitable or broadly applicable.

• Complaints and enforcement actions against OWBs con tinue to increase, draining both state and local agency resources.
Based on these conclusions, NESCAUM recommends the following:

• Given that federal action is unlikely to take effec t in the near term, states should move quickly to address OWB emissions.

• States should adopt regulations that establish emis sion limits for OWBs, similar to those of other residential woodburning u nits, because this is the best strategy for addressing the elevated emissions of fine particles (and the cancer-causing substances associated with parti cles) from OWBs.Assessment of Outdoor Wood-fired Boilers Page 7-2

• Because OWBs are most often used in residential set tings and vary greatly in size, states should base an emission standard on a grams per hour basis to adequately protect public health.

• Additional studies should be conducted to assess im pacts and determine acceptable exposure levels.

• EPA should support additional testing to gain a bet ter understanding of the overall emissions profile of OWBs, specifically par ticulate matter and toxics.

• EPA should develop tools to assist states in addres sing OWBs. Tools could include model regulations, outreach materials , SIP credit, and research data.Assessment of Outdoor Wood-fired Boilers Page A-1



# Appendix A: Outdoor Wood-fired Boiler

Correspondence**July 29, 2004**

**Jeffrey R. Holmstead Assistant Administrator for Air and Radiation**  **U.S. Environmental Protection Agency Ariel Rios Building**  **1200 Pennsylvania Avenue, N. W. Washington, DC 20460** 

**Re: Outdoor Wood Boilers**

**Dear Mr. Holmstead:**

**Over the past several years, a number of state air pollution co ntrol programs, as well as**  **municipalities, have experienced a marked increase in the nu mber of complaints related**  **to Outdoor Wood Boilers (OWBs). The Northeast States for Coordinated Air Use Management (NESCAUM) believe the growing use of OWBs is a serious pro**  **blem and are therefore exploring ways to take immediate action to prevent the continued**  **proliferation of these sources until the units can be re-designed to ensure they meet**  **stringent emissions standards. Concurrently, we would like to work with EPA because**  **OWBs are sold nationwide and numerous states are facing similar problems with them. We believe a national regulatory approach is warranted, and we respectfully request that**  **your office consider adopting a national strategy to regulate OWBs. Inasmuch as we have been collaborating with other states on this issue, you may r**  **eceive similar correspondence from them.** 

**With recent increases in the price of heating fuels, th e use of wood for residential and**  **commercial heating is on the rise and the number of OWBs ha s increased to the point that**  **they constitute a significant compliance issue. While the nuisanc e smoke and odor**  **problem associated with OWBs is well documented, limited emission testing demonstrates that OWBs are also large generators of fine particulate matte**  **r. Exposure to particles can lead to a variety of adverse respiratory and cardiac health effects, espe**  **cially among people with heart or lung diseases who comprise a substantial percentage of the**  **population. Moreover, testing for Hazardous Air Pollut ants may demonstrate that OWBs**  **pose an additional threat to human health, suggesting a nee d to regulate these sources**  **under an area source MACT.**

**For a number of reasons, OWBs present problems not normally observed with indoor wood stoves, wood furnaces, or fireplaces. An OWB has a very short stack which emits** Mr. Jeffrey R. Holmstead Page 2

Outdoor Wood Boilers July 29, 2004

**smoke near the ground and allows for little dispersion. The majority of units are designed to provide long burn times and be loaded once a day, or less frequen**  **tly. The large fuel capacities and automatic damper controls,**  **typically combined with primitive combustion design, frequently result in poor combustion, heavy smoke, noxious odors,**  **and high concentrations of fine particulate and other air pollutants associated with low temperature combustion of wood fuel. Because they are also used to provi**  **de hot water for heating swimming pools, many OWBs are operated during summer months, when**  **windows in nearby residences are open.**

**Emission testing performed under the direction of the U.S. Environmental Prote ction**  **Agency in 1997 found particulate emissions from two common OWBs ranged from 1.5 – 3.1 pounds/mmBTU heat input. These tests were conducted on new units operating**  **under controlled conditions, at a fraction of rated capacity, while burning seasoned firewood. In practical application, particulate emissions are likely to be much higher.**  **However, OWBs were exempted from compliance with the national “Standards of Performance for New Residential Wood Heaters” (40 CFR Part 60, Subpart AAA) and**  **are currently regulated by only a few state and local governments. Therefore, we feel that it is critical that EPA take immediate action**  **to regulate these sources.**

**Thank you for your consideration of this timely and impo rtant concern.** 

**Sincerely,**

**Kenneth A. Colburn Executive Director** 

**cc: John DuPree, EPA Headquarters Fred Weeks, EPA Region 1**  **Denny Dart, EPA Region 1 Gil Wood, EPA OAQPS**  **Vinson Hellwig, Michigan DEQ The Capitol, Albany, NY 12224**  q **(518) 474-8096** q **Fax (518) 473-2534 S**  **TATE OF N**  **EW Y**  **ORK O**  **FFICE OF THE ATTORNEY G**  **ENERAL E**  **LIOT S**  **PITZER D**  **IVISION OF P**  **UBLIC A**  **DVOCACY Attorney General**  **E NVIRONMENTAL**  **P ROTECTION**  **B UREAU** 

**August 11, 2005**

**VIA OVERNIGHT MAIL**

**The Honorable Stephen L. Johnson Administrator, Environmental Protection Agency**  **Ariel Rios Building 1200 Pennsylvania Avenue, N.W.**  **Washington, DC 20460**

**Re: Petition for rulemaking under 42 U.S.C. § 7411( b)(1)**  **Regarding Outdoor Wood Boilers**

**Dear Administrator Johnson:**

**The States of New York, Connecticut, Maryland, Mass achusetts, Michigan, New Jersey**  **and Vermont, and the Northeast States for Coordinat ed Air Use Management (NESCAUM)**  **hereby petition the U.S. Environmental Protection A gency (EPA) to use its authority under**  **section 111(b)(1) of the Clean Air Act (the “Act”), 42 U.S.C. § 7411(b)(1), to list outdoor wood**  **boilers (OWBs) as a category of stationary sources under section 111(b)(1)(A) and to**  **promulgate standards of performance for OWBs under 42 U.S.C. § 7411(b)(1)(B). In the**  **alternative, after listing OWBs as a category of st ationary sources under section 111(b)(1)(A),**  **EPA could revise the existing standards for residen tial wood heaters, at 40 CFR §§ 60.530-**  **60.539b, to include standards for OWBs.**

**As explained in the attached report of the New York Attorney General’s Office,**  **Environmental Protection Bureau, entitled,** Smoke Gets in Your Lungs: Outdoor Wood Boilers in New York State **(the “New York Report”), OWBs are becoming increasi ngly common in rural**  **and suburban towns and villages throughout much of the nation. Emissions of fine particulate**  **matter (particulate matter with a diameter less tha n 2.5 microns [PM 2.5]) and toxic materials**  **from OWBs exceed those from indoor wood stoves (cal led wood heaters by EPA), both on a per**  **device basis and in proportion to the energy create d. Despite polluting at a significantly higher**  **rate than residential wood heaters, OWBs are exempt from the standard applicable to residential**  **wood heaters and are not required to meet any testi ng, performance, or emission standards.** **Petition to EPA by NY, CT, MD, MA, MI, NJ, VT and N ESCAUM** 

**August 11, 2005**

**Notable findings of the New York Report include:**

**• While advertised as a clean economical way to heat one’s house and water, OWBs may**  **be among the dirtiest and least economical modes of residential heating, especially when**  **improperly used;**

**• Even when used properly, OWBs emit, on an average per hour basis, about 4 times as**  **much PM 2.5 as conventional wood stoves, about 12 t imes as much PM 2.5 as EPA**  **certified wood stoves, 1000 times more PM 2.5 than oil furnaces, and 1800 times more**  **PM 2.5 than gas furnaces;**

**• When OWBs are used improperly to burn wet or treat ed wood, scrap, or garbage, they**  **generate even more smoke and emit additional toxic chemicals;** 

**• The pollutants emitted by OWBs can cause or contri bute to short-term health harms such**  **as eye, nose, throat, and lung irritation, coughing and shortness of breath, and long-term**  **health effects such as asthma, heart and lung disea se, and cancer;** 

**• The generally short chimneys and reduced draft of OWBs fail to disperse emissions**  **adequately and can cause smoky conditions at or nea r ground level;** 

**• OWBs are generally more expensive to install than comparable heating sources using oil,**  **or gas, or indoor wood stoves, and may be more expe nsive to operate depending on the**  **availability and price of dry seasoned wood;**

**• OWBs do not currently have to meet federal or stat e performance emission standards;** 

**• The absence of any federal regulations has led to various state and local efforts to**  **regulate OWBs.**

**Since the problems associated with OWBs are widespr ead and exist across much of the**  **northern U.S., it is sensible for the federal gover nment to enact federal standards of**  **performance, as it has with respect to indoor wood heaters, so as to avoid the development of a**  **patchwork of state and local regulations.**

**Section 111(b)(1)(A) requires EPA to include in the listing of categories of stationary**  **sources under section 111 a category that “causes, or contributes significantly to, air pollution**  **which may reasonably be anticipated to endanger pub lic health and welfare.” The findings in the**  **New York Report establish that OWBs should be liste d. Accordingly, the EPA should**  **promulgate regulations for OWBs under section 111(b )(1)(B), establishing standards of**  **performance that reflect the degree of emission lim itation achievable through the best system of**  **emission reduction that has been adequately demonst rated. 42 U.S.C. § 7411(a)(1). Consistent**  **with the general framework of the Act, such federal regulations should serve as a “floor,”**  **allowing states or municipalities to enact more str ingent regulations as necessary to combat**  **particularized local air quality problems. Petition to EPA by NY, CT, MD, MA, MI, NJ, VT and N**  **ESCAUM**

**August 11, 2005**

**The time has come for EPA to regulate emissions fro m OWBs in order to protect public**  **health and the environment. Therefore, please cons ider this letter to be a formal request pursuant**  **to the Administrative Procedure Act, 5 U.S.C. § 553 (e), for a rulemaking to list OWBs as a**  **category of stationary sources and to establish sta ndards for emissions from new OWBs.** 

**Sincerely,**

**ELIOT SPITZER Attorney General**  **State of New York**

**On behalf of: RICHARD BLUMENTHAL**  **Attorney General State of Connecticut** 

**THOMAS F. REILLY Attorney General**  **Commonwealth of Massachusetts**

**STEVEN E. CHESTER Director**  **Michigan Department of Environmental Quality**

**JOHN J. FARMER, JR. Attorney General**  **State of New Jersey**

**WILLIAM H. SORRELL Attorney General**  **State of Vermont**

**ARTHUR N. MARIN Executive Director**  **Northeast States for Coordinated Air Use Management (NESCAUM)** Assessment of Outdoor Wood-fired Boilers Page B-1



# Appendix B: Outdoor Wood-fired Boiler

ManufacturersAssessment of Outdoor Wood-fired Boilers Page B-2

Alternate Heating Systems, Inc 2395 Little Egypt Road Harrisonville, PA 17228 http://www.alternateheatingsystems.com/

Aqua-Therm LLC 48301 State Hwy 55 Brooten, MN 56316 www.aqua-therm.com

Alpha American 10 Industrial Blvd Palisade, MN 56469 http://www.yukon-eagle.com

Central Boiler, Inc. 20502 160 th Street Greenbush, MN 56726 www.centralboiler.com

Charmaster Products, Inc. 2307 Highway 2 West Grand Rapids, MN 55744 www.charmaster.com

Dectra Corporation 3425 33 rd Ave NE St Anthony, MN 55418 www.dectra.net/garn

Freedom Outdoor Furnace 7958 Curwensville Tyrone Hwy Olanta, PA 16863 www.freedomoutdoorfurnace.com

Global Hydronics Box 717 Winkler, Manitoba, CANADA R6W 4A1 www.globalhydronics.com Hardy Manufacturing 12345 Road 505 Philadelphia, MS 39350 www.hardyheater.com

Heatmor Inc. 105 Industrial Park Court NE Warroad, MN 56763 www.heatmor.com

Heat Innovations 499 Manitoba Road PO Box 989 Winkler, Manitoba, R6W 4B1 CANADA

Heatsource1 2201 Ridgeview Drive Beatrice, NE 68310 www.heatsource1.com

Hicks Waterstoves and Solar Systems 2541 South Main Street Mount Airy, NC 27030

Horstmann Industries, Inc. 301 Second Street Elroy, WI 53929 www.royalfurnace.com

Innotech Developments 2015 James Street South Thunder Bay, Ontario P7J1G6 CANADA www.outdoorfurnaces.com

Johnson Manufacturing PO Box 345, 8187 State Rte 12 Barneveld, NY 13304 www.hud-son.com/woodfurnaces.htmAssessment of Outdoor Wood-fired Boilers Page B-3

Mahoning Outdoor Furnace RD #1 Box 250 Mahaffey, PA 15754 www.shol.com/mahoning

Noonan’s Welding and Heating 105 1 st Street South Keewatin, MN 55753 www.northlandoutdoorwoodfurnace.com

Northwest Manufacturing 600 Polk Ave SW Red Lake Falls, MN 56750 www.woodmaster.com

Outside Heating Systems – Wood Doctor Box 567 Stewiacke, Nova Scotia B0N2J0 CANADA www.wooddoctorfurnace.com

Pacific Western Box 267 Atikokan, Ontario P0T 1C0 CANADA

Pro-Fab Industries Inc./Empyre/Cozeburn Box 112 Arborg, Manitoba R0C 0A0 CANADA http://www.burnsbest.com or www.profab.org

SFC Industries 2219 County Highway G Rhinelander, WI 54501

TARM USA, Inc. Main Street Box 285 Lyme, NH 03768 www.woodboilers.com Taylor Manufacturing, Inc. 1585 US HWY 701 South Elizabethtown, NC 28337 www.taylormfg.com

Timber Ridge, Inc. 2020 Highway 11-E Jonesborough, TN 37659 www.freeheatmachine.com

Turbo Burn, Inc. 4225 E Joseph Spokane, WA 99217 www.turboburn.netAssessment of Outdoor Wood-fired Boilers Page C-1



# Appendix C: Estimated National Sales of OWBsAssessment of Outdoor Wood-fired Boilers Page C-2

State Estimated number of OWBs sold since 1990 Alabama 74 Alaska 185 Arizona 24 Arkansas 574 California 182 Colorado 271 Connecticut 1,538 Delaware 77 District of Columbia 13 Florida 32 Georgia 50 Hawaii 0 Idaho 401 Illinois 4.798 Indiana 7,518 Iowa 2,762 Kansas 515 Kentucky 1,148 Louisiana 3 Maine 1,968 Maryland 872 Massachusetts 1,308 Michigan 29,568 Minnesota 13,936 Mississippi 0 Missouri 4041 Montana 350 Nebraska 190 Nevada 1 New Hampshire 1,981 New Jersey 215 New Mexico 12 New York 13,182 North Carolina 2,561 North Dakota 87 Ohio 13,605 Oklahoma 76 Oregon 555 Pennsylvania 11,836 Rhode Island 206 South Carolina 124 South Dakota 40 Tennessee 573 Texas 16 Utah 38 Vermont 2.033 Virginia 4.658 Washington 393 West Virginia 3,725 Wisconsin 27,452 Wyoming 66 US Total 155,834Assessment of Outdoor Wood-fired Boilers Page D-1



# Appendix D: Michigan DEQ Modeling

### Residential Wood Boiler Study
MAXIMUM PREDICTED 1-HR AVG CONCENTRATIONS

Four contour plots of the max 1-hr concentration at an emission rate of 1lb/hr. Since its 1 stack, the impacts can be scaled (linear relationship) to a different emission rate. Modeling is bas ed on the following: stack height = 8' temperature = 250F vel=1.5 m/s diameter = 6" 50' x 100' bldg 22' high Ran 25', 50', 75', and 100' set back distances from the bldg due north using 1983 KIS met data.Assessment of Outdoor Wood-fired Boilers Page E-1



# Appendix E: Field Report on Moisture Readings

and OpacityAssessment of Outdoor Wood-fired Boilers Page E-2

Vermont Department of Environmental Conservation

Air Pollution Control Division



## AIR POLLUTION TRIP REPORT

PROPERTY: Confidential DATES OF SITE VISIT: June 21 & 22, 2005

PURPOSE OF VISIT: To observe/assist with testing of an outdoor wood boiler.

LOCATION OF SITE: Vermont

PEOPLE PRESENT: Lisa Rector, NESCAUM George Allen, NESCAUM John Jasko, Air Quality Technical Services Chris Jones, Vermont DEC (6/21/05) Philip Etter, Vermont DEC

WEATHER: Temperature: Highs generally 80s ° F Wind: 0-15 mph, Direction variable Cloud Cover: Clear to Partly Cloudy Precipitation: None

INVESTIGATOR: Philip L. Etter, Environmental Analyst

We attended the emissions testing of an outdoor woo d boiler (OWB) to assist with the testing and observe the operation of the OWB unit. While on site I made some measurements of the moisture content of the wood fu el being used during the test using a Delmhorst moisture meter and conducted some visible emissions observations for general informational purposes. I also took numerous digit al photos during the testing on 6/22/05.



### Wood Moisture Measurements
All wood moisture measurements were done on 6/22/05 . The wood supply consisted of mixed hardwoods but mainly maple and r ed oak in two to three foot lengths. Most of the wood had been split, but some of the wo od was in the round. The wood was uncovered and stacked in a semi sunny location. I checked the moisture content of three pieces of maple and two of red oak. One of the map le pieces was round but all the others had been split. I tried to choose pieces of larger size from various places in the small pile that had been designated as the fuel for the test. Using wedges and a sledge hammer, IAssessment of Outdoor Wood-fired Boilers Page E-3

split each piece roughly in the center just before taking measurements. I then took three measurements on the inside split surface, one in th e center and one on either side of center roughly halfway from the center to the ends of the piece. The upper moisture content limit of the meter is 40%. Moisture readin gs above this limit were recorded as greater than 40%, but were treated as 40% when calc ulating averages. Readings are documented in the following table.



### PERCENT MOISTURE IN WOOD FUEL
Species Rough Size

(inches) Reading 1

% Reading 2

% Reading 3

% Average

%M Maple 5” split 26.8 29.3 24.3 26.8 Maple 5” round 28.5 28.5 25.6 27.5 Maple 7” x 4” split 30.5 27.7 32.6 30.3 Red Oak 5” split >40 37.5 >40 >39.2 Red Oak 8” x 3” split >40 >40 >40 >40

Note that the moisture content measurements were do ne for general information only. No attempt was made to weigh the fuel charge d to the unit or to count the chunks of various species of wood being charged. Some of the wood charged on the second day was taken from another part of the pile that had be en recently rained on. Overall, the moisture content appeared to be fairly high. Oak g enerally takes longer to dry than many other hardwood species but the history of particula r pieces of wood is unknown so it may be that the oak was cut later than the maple.



### Visible Emissions In an attempt to determine how the visible emission s vary over time and the burn mode cycling of the OWB, I evaluated visible emissi ons for 24 minutes on 6/21/05 and for nearly two hours on 6/22/05 (see attached VE ev aluation forms). These observations were purely informational. Currently, OWBs are exe mpt from Vermont’s visible emissions standards due to their small size. The g reen foliage of the woods behind the OWB provided a good contrasting background for the light colored smoke. The sun was always well within appropriate angles for Method 9 observations. I ceased making observations on 6/22/05 at about 1140 hours as the sun’s vertical angle was becoming potentially inappropriate. During midday hours in late June, the vertical angle of the sun is inappropriate for observations in most situation s. Observations were made difficult by the highly variable wind speed and direction, the p lume often down washing, looping or blowing away from the observer making proper readin gs impossible. The nature of the plumes also made VE evaluation mo re difficult. Much of the time, especially during the open damper mode, the p lume appeared to be largely condensed organics; with the densest part of the pl ume a few to several feet beyond the top of the stack. On 6/21 I tended to read the plu me a couple feet above the stack before the densest smoke formed. On 6/22/05 I was reading the opacity in the densest part of the plume, a few to several feet above the stack. I did not notice any indications of aAssessment of Outdoor Wood-fired Boilers Page E-4

condensed water vapor component in the plume althou gh I can’t rule-out with absolute certainty that some moisture condensation was occur ring. Meteorological conditions would have caused any condensed water vapor in the plume to rapidly dissipate leaving a less dense trailing particulate plume. This was no t apparent during the test burns as the dense plumes carried for a considerable distance, g radually dispersing. I also found evaluating the opacity during the idle mode to be difficult due to the very low gas flows emanating from the stack. Often the plume seemed to narrow beyond the top of the stack perhaps causing the plume to a ppear denser than if it were spread over the full width of the stack. The idle mode pl umes appeared to be fully condensed as they exited the stack, which isn’t surprising given the very low stack gas temperatures recorded during the idle mode. The observations on the morning of 6/22/05 represen t the worst case, as they were made during the beginning of the burn cycle. The O WB was loaded before the beginning of the test in the morning but not later. Although I didn’t conduct formal observations later in the day during the charcoal stage of the b urn cycle, informal observations indicated that visible emissions were greatly reduc ed with opacities more in the 40-50% range during the charcoal stage operating modes rat her than the 90-100% opacities near the beginning of the burn cycle. The observations done on 6/21/05 were later in the day but I am uncertain how long it had been since the O WB was charged.


### Summary
These visible emissions observations indicate that the smoke from this OWB was densest during the first hours of the burn cycle an d less dense during the latter charcoal phase burning. The opacities and total volume of v isible smoke (i.e. the overall size or volume of the plumes) were also heaviest following the opening of the damper. Opacities and total smoke volume were much reduced during the idle mode and were greatly reduced as the duration of the idle mode in creased probably due to the cooling of the fire greatly reducing combustion gas production . Opacities also seemed to decrease somewhat as the stack temperatures increased with t he length of the open damper operating mode.Assessment of Outdoor Wood-fired Boilers Page F-1



# Appendix F: Outdoor Wood-fired Boiler

RegulationsPROPOSED RULE (ver.7/28/2005) Page 1

AGENCY OF NATURAL RESOURCES Waterbury, Vermont

ENVIRONMENTAL PROTECTION REGULATIONS

CHAPTER 5

AIR POLLUTION CONTROL

Subchapter II. Prohibitions

5-204 SITING AND STACK HEIGHT STANDARDS FOR OUTDOOR WATERSTOVES WOOD FIRED

BOILERS; NOTIFICATION TO PURCHASERS

(a) Applicability.

(1) This section shall apply to all outdoor waterstoves installed after October 1, 1997 except outdoor waterstoves with weighted average particulate matter emissions of less than 4.1 grams per hour. Compliance with th is standard shall be determined in accordance with federal test method 28 for establishing test condit ions and weighted emission values and federal test methods 5G or 5H for determ ining particulate emission concentrations (40 CFR Part 60, Appendix A), or

o ther methods approved by the Air Pollution Control Officer

.
This section shall apply to each outdoor wood-fired boiler installed after October 1, 1997, except those outdoor wood-fi red boilers that are subject to and compliant with Section 5-205 herein.

(b) Definitions. For the purpose of this section and Section 5-205 herein

, the following definitions apply, in addition to tho se of Section 5-101 of this chapter.

“Outdoor Waterstove” means any individual hand

- fed furnace designed to burn wood and used fo r the purpose of heating water where the furnace is located outside the structure into which the hot water produced thereby is piped.

“ Outdoor Wood-Fired Boiler ” means a fuel burning device designed: (1) to burn primarily wood by hand-firing; (2) not to b e located inside structures ordinarily occupied by humans; and, (3) to heat spaces or water by the distribution through pipes of a fluid heated in the device, typically water. Examples of common uses of outdoor wood-fired boilers include: residential or commercial space he ating, heating of domestic hot water, and heating of water for swimmi ng pools, hot tubs or whirlpool baths.

(c) Prohibition.

No person shall install or allow the installation of an outdoor
waterstove wood-fired boiler subject to the requirements of this section unless the outdoor waterstove wood-fired boiler :PROPOSED RULE (ver.7/28/2005) Page 2

(1) Is located more than 200 feet from any residenc e other than a residence served by the outdoor waterstove wood-fired boiler or owned by the owner or lessee of the outdoor waterstove wood-fired boiler ;

(2) Has an attached permanent stack extending higher than the roof line peak of the roof of the structure(s) being served by the outdoor waterstove wood-fired boiler, if any residence is located more than 200 but less than 500 feet from the outdoor waterstove wood-fired boiler other than a residence owned by the owner or lessee of such outdoor waterstove wood-fired boiler ; and,

(3) Complies with all applicable laws, including bu t not limited to local ordinances, but excluding Section 5-205 of th is chapter

, and its operation does not create a public nuisance.

(d) Notice to Buyers

**.**

(1) No outdoor waterstove wood-fired boiler subject to the requirements of this section shall be sold or offer ed for retail sale or lease within the State unless prior to any sales or lease agreement, the seller or dealer provides the prospe ctive buyer or lessee with written notice stating that:

(i) Only untreated natural wood may be burned in an outdoor
waterstove wood-fired boiler ;

(ii) Installation of the outdoor waterstove wood-fired boiler is subject to the distance and stack height requirements provided in this section. [Each notice shall expres sly disclose each such requirement];

(iii) Use of an outdoor waterstove wood-fired boiler that meets the distance and stack height requirements provided in this section is not appropriate in some areas due to ter rain that could render the operation of an outdoor waterstove wood-fired boiler to be a nuisance or a public health hazard.

(2) The written notice specified above shall be sig ned by the prospective buyer or lessee to indicate receipt of notification of the requirements of this section. Prior to makin g delivery of

an outdoor waterstove wood-fired boiler into the possession of any buyer or lessee, the seller or dealer shall mai l or otherwise provide a copy of the signed notice specified above to the:

Air Pollution Control Division 103 South Main Street Building 3 South Waterbury, Vermont 05671-0402.

Said notice shall contain the name, address and tel ephone number of both the seller or dealer and the buyer or lesse e, the location where the outdoor waterstove wood-fired boiler will be installed and the make and model of the outdoor waterstove woodfired boiler

.PROPOSED RULE (ver.7/28/2005) Page 3

5-205 CONTROL OF PARTICULATE MATTER FROM NEW OUTDO OR WOOD-FIRED BOILERS

(a) Applicability

This section shall apply to any outdoor wood-fired boiler that is distributed or sold in Vermont or for installation in Vermont on or after January 1, 2006, except that this section doe s not apply to any outdoor wood-fired boiler that: (1) is or has been owned by an individual for his or her own personal use and is d istributed or sold to another for his or her own personal use; or (2) was purchased and received by any person other than the manufacturer before January 1, 2006.

(b) Definitions. For the purposes of this section, the following definitions apply, in addition to those of Sections 5-101 and 5-204 of this chapter.

“ Distribute or Sell ” means to distribute, sell, advertise for sale, offer for sale, hold for sale, ship, deliver for sh ipment, release for shipment, or receive and (having so received) deliv er or offer to deliver. This term also includes conditional sales and long-term leases. This term does not include the distributio n or sale by a manufacturer of an outdoor wood-fired boiler that i s installed outside
Vermont.

“ Manufacturer” means any person who constructs or imports an outd oor wood-fired boiler.

“ Model line ” means all outdoor wood-fired boilers offered for distribution or sale by a single manufacturer that, in the judgment of the Air Pollution Control Officer, are similar in a ll material respects.

(c) Standard for Particulate Matter; Certification

(1) No person shall distribute or sell an outdoor wood- fired boiler in Vermont or for installation in Vermont unless th e Air Pollution Control Officer has issued a certificatio n to the manufacturer that the boiler, or the boiler model l ine to which it belongs, complies with the following particulate matter emission limit: An outdoor wood-fired boiler shall not emit, or cause or allow to be emitted, any gases that contai n particulate matter in excess of 0.20 grains per dry standard cu bic foot of exhaust gas corrected to 12% CO 2, as determined in accordance with the test methods and procedures in subsection (d) o f this section.

(2) Unless revoked sooner by the Air Pollution Control Officer, a certification issued under this subsection shall be valid for five years from the date of issuance.

(3) The distribution or sale of each outdoor wood-fired boiler subject to this section that has not been certified by the Air Pollution Control Officer as meeting the particulat e matter emission limit in this subsection shall constitute a separate violation and be subject to civil or criminal penal ties as provided in 10 V.S.A. Chapters 201 and 211, or 10 V .S.A. §568.PROPOSED RULE (ver.7/28/2005) Page 4

(d) Emission Test Methods and Procedures

(1) In order to obtain certification of an outdoor wood -fired boiler under subsection (c) of this section, the manufacturer of any such boiler shall have emission test(s) conducted t o determine compliance with the particulate matter emission lim it under subsection (c) of this section and furnish the Air Pollution Control Officer a written report of the results of such tests, including a detailed description of the operating c onditions of the boiler during the tests. Said written report s hall contain such documentation and other information and follow such format as may be specified by the Air Pollution Control Of ficer. In the discretion of the Air Pollution Control Officer, a manufacturer of an outdoor wood-fired boiler subject to this sec tion may have emission testing conducted of a representative boil er within a model line of outdoor wood-fired boilers and may us e those tests to demonstrate compliance of all units manufactured in that model line.

(2) All emission testing required under this section sh all be conducted by independent testing consultants who ha ve no conflict of interest and receive no financial benefit from t he outcome of the testing. Manufacturers of outdoor wood-fired bo ilers shall not involve themselves in the conduct of any emissi on testing under this section nor in the operation of the unit being tested, once actual sampling has begun.

(3) Emission tests shall be conducted and data reduc ed in accordance with 40 CFR Part 60, Appendix A, Test Methods 1 thr ough 5, and 40 CFR Part 51, Appendix M, Test Method 202, or altern ative methods approved by the Air Pollution Control Officer. All tests shall be conducted in accordance with Vermont’s “Source E mission Testing Guidelines” (January 2002 revision, as amen ded) and under a test protocol which has received the prior approv al of the Air Pollution Control Officer. Emission tests shall be conducted under such conditions as the Air Pollution Control Officer shall specify, based on representative performance of the outdoor woodfired boiler under actual field operating condition s.

(4) The manufacturer of the outdoor wood-fired boiler s hall provide the Air Pollution Control Officer with at least 30 days prior notice of any emission test to afford the Air Pollu tion Control Officer the opportunity to have an observer present . The manufacturer of an outdoor wood-fired boiler(s) bei ng tested as required by this section shall reimburse the state of Vermont for the reasonable expenses incurred by any such Agency observer for out-of-state travel to observe such testing, includ ing among other items the costs of transportation, lodging an d meals.

(e) Notification by Manufacturers

(1) By March 1 st of each year and as necessary when an outdoor wood

fired boiler is certified, each outdoor wood-fired boiler manufacturer shall provide the following informatio n in writing to any person to whom the manufacturer has distribu ted or sold, intends to distribute or sell, or actually distribu tes or sellsPROPOSED RULE (ver.7/28/2005) Page 5

outdoor wood-fired boilers in Vermont or for instal lation in
Vermont:

(i) A list of all the models of outdoor wood-fired boil ers it manufactures; and

(ii) An identification of which, if any, of said mo dels or boilers has received a certification of compliance under subsection (c) of this section and thus may be dist ributed or sold in Vermont or for installation in Vermont.

(2) By March 15 th of each year, a copy of all written information provided to comply with paragraph (1) of this subse ction and a list of persons to whom it was provided shall be su bmitted to the Air Pollution Control Officer.