Wood Burning in Vermont Schools

Why Burning Wood Chips to heat and power Vermont schools is a bad idea.

October 31, 2006: Dear Members of the Norwich School Board: from A.A. Member of the community and neighbor to the project.

The dangerous pollution you are proposing to introduce into the community is of significant concern, especially in light of the very small savings of $17,000 out of the $4,300,000 annual school budget. This is .004 of the budget, less than half of one percent. Given that this technology is in its infancy and improvements and cost reductions may well be on the horizon, it could save more and give Norwich a healthier solution to hold off on the proposed Wood Chip Heating Plant Building.

To examine the issue of dangerous pollution more closely, consider the following information.

The latest spreadsheet from John Aubin reports that BERC estimates our Wood Chip Boiler Plant will burn 325 tons of woodchips annually.  The estimated BTU produced by woodchips range from 7,600,000 to 10,800,000 BTU/ton.  This is a range of 2,470,000,000 to 3,510,000,000 BTU annually from burning woodchips.

The emission rate of PM10s from an uncontrolled wood fired boiler is .3 to .7 pounds per million BTU according to RSGÕs data. This results in 1,729 to 2,457 lbs of total PM10 of which at least 76% (some say more than 90%) are below 2.5 micrometers and 67% are below 1 micrometer. Since the latest data refers to PM2.5 and how it is the most dangerous size, letÕs focus there.

 .76 (1,729) = 1,314 and .76(2,457) = 1,867

Downtown Norwich will get from 1,314 to 1,867 POUNDS of dangerous ultrafine particulate matter each year coming from a smokestack that is 40 feet in the air only 100 feet or so from the school and closest residential property. 

  If this doesn't impress you, remember 67% of these particles are below 1 micrometer which is .0000394 (approximately 1/25,000th) of an inch, or one thousandth of a millimeter.  It takes about 70 to equal the width of a hair.  These tiny particles are jagged and can imbed deeply in lung tissue and there are a lot of them in 1,843 pounds.  Many fewer could cause serious harm in your lungs, if you live close enough or spend time at the school.

  The boiler plant is surrounded by tall trees which could exacerbate the trapping of particulates, already socked in by the bowl effect of the close hills and susceptible to cold weather inversions. This is intensified in the very coldest months with the worst inversion patterns and highest level of burning, increasing the risks by much higher exposure levels for periods of time, not evenly stretched over the months.

 Telling us this is the equivalent of two houses using woodstoves is not accurate.  Here is the more accurate calculation. The national average cordwood usage per year in a conventional stove is 2.5 cords. We live in a cold area so make that 4 cords to be conservative. The weight of dry cord is 1.163 tons.  So 4 x 1.163 =4.652 tons of wood.  If there were two, then that would be 9.304 tons.  The emissions factor for woodstoves is 34.6 lbs of PM10/ton of wood burned so the result equals 322 lbs.  To compare apples to apples, the PM10 emissions from the Wood Chip plant could be 2,457 lbs (The smaller PM2.5 could be 1,847 lbs.)

  To be very clear, 2,457 lbs is a much bigger number than 322 lbs.  Do not continue to allow misinformation to be disseminated to the people of Norwich.   You could say that this Wood Boiler plant will be emitting the same PM10 as 15 woodstoves, all in the exact same location, right next to the playground.  Saying this is equal to two houses using woodstoves no  longer constitutes an answer from the school board to the public about how safe this is and why we shouldn't be alarmed. 

  I just spoke to a contact at the Vermont Department of Pollution Control who corroborated that a few houses using woodstoves can in fact generate quite a lot of dangerous emissions.  And that wood chip boilers used in places where the inversions occur can be a serious problem.  (Remember we can't afford the taller safer smoke stack.)

After talking to this expert on modeling wind and temperature inversion patterns in Vermont, at the Vermont Department of Air Pollution Control, I am very concerned about the models and the data which RSG will be using to put the stamp of approval on our wood chip boiler plant. 

  The following is taken from the RSG Project Summary of the Wood-Fired Boiler Permitting Study done for SAU #70 concerning the Richmond Middle School:

á                Developed a computer-based air pollutant dispersion model, based on EPA simulation software and methods, to estimate air pollutant concentrations at air exchange locations on the building and at ground locations proximate to the building.

á                Compared model-predicted results with National Ambient Air Quality Standards (NAAQS), Prevention of Significant Deterioration (PSD) standards and known odor thresholds, to determine if the stack location and height would provide sufficient dispersion of air pollutants.

I assume from this excerpt that RSG will do modeling on the MCS project using the same EPA based software, methods and standards.

At this point, it would be very relevant to note that the current EPA standards (NAAQS) regulating PM issued in Sept 06 are quite below the levels that the scientific advisors to the EPA recommended in order to protect health. This is a matter of public record.

  The EPA has bowed to industrial and corporate pressure in this matter and ignored the opinions of their own scientific advisors (an alarming precedent but not surprising under the current administration.)

So the NAAQS numbers that the data will be compared to are inadequate and outdated in determining whether this will be safe for the village.

The weather data being used by RSG is only useful in proving this plant "safe" to be built on the wide open spaces of the Keene or Concord airports instead of in a nook of tall trees in a river valley in a residential village only a hundred or so feet away from the school playground and houses. 

  Even though it was announced at the first informational meeting that a contact at RSG would be provided to interested people, my request for the contact name was refused when I asked for it.  So, none of these concerns about inappropriate modeling inputs can be discussed with the people running the models. 

In the discussion of whether there is a health risk, the lack of a state permit requirement due to size of the project is not actually relevant. The lack of requirement is an economic concession to smaller entities, not a green light on health risks. Please understand this important distinction.

Vermont's push to move schools to wood-chip burners through subsidy is an effort to prop up and grow the wood industry in the face of declining economic success of pulp mills and a misinformed "green" push concerning the carbon neutrality of using wood.  Please pay attention to the viewpoint put forth by Jim Merkel from the Office of Sustainability at Dartmouth Collage and the document he provided to Mary Sachsse of the school board and Alison May of the selectboard.  There is not a consensus in the "green" community as to whether these wood chip boilers systems achieve a truly "green" solution!!!  So don't appoint yourselves green just yet.  He is not alone in this viewpoint by any means.  I will provide more on this issue in an email to follow this letter. As stewards of this process I know you will not want to appear to be partisan on this topic in the face of a truly vigorous and undecided ongoing scientific debate.

 It is interesting that Adam Sherman's title is Business Development/Project Manager.  Although BERC is a nonprofit, they have a vested interest in being chosen as general contractor for the project.  Much of the data that you are relying on so far comes from or through this entity. 

It is incumbent on you to accept other information outside of this one source that will benefit financially from this project. Seek out information from the Vermont Air Pollution Control division. Consider the reactions of EPA scientific advisors to the latest PM standards and the research upon which their strong opinions are based. Search for current breaking research before you commit the town to a 30-40 year project that could do serious damage to the health of the local population.

  Just the titles of these studies found on MEDLINE and PUBHEALTH from various medical journals should give you pause, even before reading the conclusions and implications:


The effect of air pollution on lung development from 10 to 18 years of age.

Ultrafine particle deposition in humans during rest and exercise.

Ultrafine particle deposition in subjects with asthma.

Inhalation of ultrafine particles alters blood leukocyte expression of adhesion molecules in humans.

Pulmonary function, diffusing capacity, and inflammation in healthy and asthmatic subjects exposed to ultrafine particles.

Effects of exposure to ultrafine carbon particles in healthy subjects and subjects with asthma.

Carbon in airway macrophages and lung function in children.

Carbon loading of alveolar macrophages in adults and children exposed to biomass smoke particles.


Consider this statement:


Even hourly exposures to fine particulate matter may result in acute health responses within susceptible subgroups. Clinical and epidemiological evidence now suggests cardiac health effects, including increased risk of myocardial infarction and decreases in heart rate variability, which may be associated with PM exposures with averaging times less than 24 hours (e.g., one to several hours).* 


* Brook RD, Franklin B, Cascio W, Hong Y, Howard G, Lipsett, M. Air pollution and cardiovascular

disease: a statement for healthcare professionals from the expert panel on population and prevention

science of the American Heart Association. Circulation 2004;109: 2655-2671.


Or this one:


Children's exposure to air pollution is of special concern because their immune system and lungs are not fully developed when exposure begins. For example, the number of alveoli in the human lung 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 children. 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 increased ventilation, increasing exposure to air pollutants such as particulate matter. These factors suggest that there is a critical exposure time for children when air pollution may have long-term effects on respiratory health.*

* Schwartz J. Air pollution and children's health. Pediatrics 2004;113: 1037-1043.

  And this one:

Over the past 30 years, scientific evidence has found that short- (e.g., daily) and long-term (e.g., annual and multiyear) exposure to airborne PM is associated with 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 exposure to air pollution may actually result in the development of new cases of asthma and atopy.*


* Pope CA, Burnett RT, Thurston GD, Thun MJ, Calle EE, Krewski D, Godleski JJ. Cardiovascular

mortality and long-term exposure to particulate air pollution: epidemiological evidence of general

pathophysiological pathways of disease. Circulation 2004;109:71-77.

  Just two more:

Some of the components in wood smoke are free radicals, which steal electrons from the body, leaving cells unstable or injured. Some of these cells may die, while others may be altered and take on different functions. These changes lead to inflammation, which causes stress on the body. EPA researchers suggest that the lifetime cancer risk from wood smoke may be 12 times greater than the lifetime cancer risk from exposure to an equal amount of cigarette smoke. (Rozenberg 2001, What's in Wood Smoke and Other Emissions)

The elderly, newborns, children, adults who exercise rigorously and those with existing heart and lung disease are most at risk for premature death due to particle pollution exposure. (American Lung Association, "The Perils of Particulates", 1-800-LUNG-USA)

Now how do you feel about those 1,867 lbs of ultrafine particulate matter settling in and around the school?  Do these few quotes make you hesitate in the rushed determination to commit to this industrial plant?   I have many more for you if you are interested.

  Did you know particulates infiltrate buildings at 50-70% of the outdoor levels?  We are not just talking about children on the playground.  This will be a danger for the entire time they are at school.  Does it make you think, O Maybe those tall trees and the valley inversion WILL cause these particles to hang in the air both inside and outside the school and inside neighbor's houses all day and all night?Ó 

  I realize this letter is dense with material – believe me I am swimming in information. There is only so much one can take at one time.  An email will follow with more background material, such as evidence of the inversion phenomena in northern New England river valleys.  

  Please consider that this is basically a technology and industry in its infancy, developing in the face of breaking research on the topics of both environmental impact and health risks.    There are uncertainties unfolding in the wood chip supply chain as people jump on this new wagon. It is very likely that IF this proves to be something that is actually sound practice, the costs of the technology will come down and the quality and reliability will go up. 

  Also consider that the very best cost-effective pollution mitigation device, the Core Separator, was made by a company that is now out of business.  The only options that are both available and affordable are not efficient at removing the smaller particles (PM2.5) which are the bulk of the emissions, so really don't address the true dangers.

  Surely another good solution will be produced, but by rushing this decision you may find that had you waited you would have ended up with something that is truly good for Norwich.  You will lock in the town and its people to a very expensive capital project with an expected life of 40 years in a very rushed process. And perhaps make us sick.

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