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List of State Officials - Robert Ehrlich, Governor; Michael Steele, Lt. Governor; Kendl Ehrlich, MDE Secretary 

Volume 1, Number 7

November 2005

​eMDE is a monthly publication of the Maryland Department of the Environment. It covers articles on current environmental issues and events in the state. Additional monthly features include: MDE public meetings and hearings schedule, enforcement and compliance notes, and permitting activity.

Learn Before You Burn Wood

By Bob Maddox

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Woodburning Stove 

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The home heating season is quickly approaching, and it’s time to prepare your home for cold weather. For many, this may include having the heating system serviced, getting the oil tank filled, or doing weatherproofing projects. For others, it involves stockpiling wood and cleaning a fireplace or wood stove and chimney. Marylanders should know that there are environmental concerns with wood burning.

While many people enjoy the aesthetics of a fireplace, many homes, especially in rural areas, use wood as primary heating fuel. With the anticipated price increases for home heating oil and natural gas, many consumers may resort to more wood use for heat, or opt to install woodstoves to heat portions of homes. According to the industry group, Hearth, Patio and Barbeque Association, over a half million new wood-burning units were sold each year in the U.S. between 1998 and 2003.

Smokey Aroma Means Noxious Fumes
That wood smoke aroma you smell on a crisp autumn evening may seem harmless. But wood smoke contains fine particle matter with numerous chemicals and “compound groups’ that can enter the lungs and pose a threat to the cardiopulmonary system. These fine particles can remain in the lungs for long periods, harming delicate tissue and causing permanent damage. People with respiratory illnesses – such as asthma – may be particularly sensitive to wood smoke. If the user is not using a wood stove or fireplace properly, more pollution can occur, both indoors and outdoors.

As a fuel, wood is dirtier than oil or natural gas. Wood smoke is actually a result of incomplete combustion. Wood smoke can pollute outdoor air from the chimney and pose household hazards. Approximately 100 chemicals or compounds have been associated with wood smoke, including carbon monoxide (CO), nitrogen oxide (NOx), and polycyclic aromatic hydrocarbons (PAHs). CO is colorless and odorless. It may cause fatigue, headaches and even death. NOx can irritate the lungs and cause bronchitis. PAHs can irritate eyes, throat and sinuses.

In some areas of the country, wintertime air pollution from wood smoke has become so bad that governments have had to curtail the use of wood stoves and fireplaces under certain weather and pollution conditions. For instance, the Puget Sound Clean Air Agency in Washington imposes temporary burn bans for outdoor and indoor wood burning when a weather phenomenon know as a thermal inversion is forecasted. A thermal inversion tends to occur under clear, cold stagnant conditions at night. It is a direct result of the earth’s surface radiating heat into space – allowing the air just above the surface to become colder than the air higher up.

“The warm air above the cold air acts as a lid and causes the wood smoke and its associated pollutants to become trapped at the surface,” according to MDE meteorologist Michael Woodman. “These burn bans include fireplaces and woodstoves, unless wood fuel is a house’s only source for heat.”

Some communities received assistance from the U.S. Environmental Protection Agency (EPA) to “changeout” older wood stoves for cleaner EPA-certified wood stoves.

Tips for Cleaner Burning
There are several things to do for your fireplace or wood stove to burn cleanly, efficiently, and safely. The most important way to assure little or no smoke is to use dry, well-seasoned hardwood. Wood with high moisture content creates more smoke. Wood usually takes nine months or longer to become dry enough for use as heating fuel. Never use evergreen wood (from pines or spruces) as they contain resins that can cause chimney fires.

Other advice to keep stoves and fireplaces safe:

  • Do not burn treated wood. It has chemicals added that can cause damage to the catalytic converters in newer stoves.
  • Remove excess ash from vents and hearth to optimize the fuel/air ratio.
  • Do not use a wood stove or fireplace to burn trash.
  • Inspect the stove and chimney yearly and have chimney cleansed as needed.

For more information about wood stoves and wood smoke, contact the following organizations: EPA’s Clean Burning Wood Stoves and Fireplaces website at: www.epa.gov/airprogm/oar/woodstoves/index.html. A citizen’s group that provides information and education about the health effects from wood smoke is Burning Issues at www.burningissues.org. A wood stove industry trade group is the Hearth, Patio and Barbeque Association at www.hpbapacific.org.


©2005 Copyright MDE

Editorial Board
Maryland Department of the Environment
1800 Washington Boulevard, Baltimore, MD 21230