Joel Schwartz, Harvard School of Public Health, 2002
Australian Environmental Protection Agency
When I think about it, it amazes me how many things we do in our society involve fire. We sing around the campfire toasting marshmallows. We use bonfires big and small as rites of passage. We build a fire in the fireplace for that romantic evening get together or build a fire in the woodstove to keep warm. We fire up the charcoal grill for the backyard barbeque with our friends. We burn leaves on a cool autumn day just to dispose of them. And some of us even burn garbage in a 50-gallon drum out back. All of these activities have their characteristic smell, which many of us find pleasant. They also produce harmful pollutants that get into the air and into the lungs of those who are exposed to them.
It figures doesn't it? Something that smells good is bad for us. But just how bad is it? I suppose it might depend on your perspective. If you're a healthy adult you probably perceive it as less of a threat than if you're a small child with asthma. Of course if you smoke two packs of cigarettes a day you may not even notice the effects of all of the smoke dumped into the air by your neighbor's woodstove. The point is that it doesn't matter who you are, the smoke from burning wood, leaves, garbage, tires or anything else is not a good thing to take into your lungs. Health problems associated with smoke include but certainly aren't limited to such things as asthma, respiratory tract inflammation, mouth cancer, cancer in pets, meningitis, heart attack, lung disease and many others.
The problem is all of the particulate matter (and associated pollutants) produced by the inefficient burning. In general, particulate matter has been defined as those particles less than 10-microns in diameter (and designated PM10) or in other words smaller than a particle of talcum powder. This definition would include red blood cells, bacteria and wood smoke. Of more recent concern are particles less than 2.5-microns in diameter (i.e. PM2.5) because those particles are more likely to be taken deep into the lungs. Particles from wood smoke average about 1-micron in size. In addition to the particulate carbon found in wood smoke, substances such as dioxins, radioactive cesium and heavy metals have also been found. While there is some disagreement among scientists as to how harmful dioxins are to humans, there is little doubt that exposure to radioactive compounds and heavy metals is harmful.
One argument in favor of burning wood is that it is generally considered to be a renewable resource; burn a tree, plant a tree. If I plant a tree for every tree I burn, net carbon dioxide production should theoretically be zero. Unfortunately that logic is a little faulty and the real picture isn't quite as simple as it sounds. Add to the picture all of the particulate matter that burning wood produces and the overall picture gets even more complicated. So what do we do? It's not an easy question to answer, unless of course we stop burning biomass altogether, which isn't likely.
- Choose a human activity that involves burning of biomass and determine how much pollution from particulate matter is produced in a year. For example if you choose wood burning and know how much wood smoke is produced in an hour's time by one stove, you can then estimate how many stoves there are in the U.S. and how many hours they operate, etc.
- Burning wood for energy is steadily becoming more popular. Compare burning wood for home heating to burning oil or natural gas for the same process. You'll need to take into consideration such things as the cost of each fuel, the efficiency of the furnace and typical amounts of energy per unit of fuel.
- How does burning wood, leaves and garbage affect the global carbon cycle? Do you think there would be a net increase in atmospheric carbon dioxide?
- Burning Issueshttp://burningissues.org/welcome.html
This is a very informative site with lots of useful information. The site deals primarily with wood smoke.
- Smoke Gets In Your Eyes by Diane M. Martyhttp://www.emagazine.com/september-october_2002/0902gl_home.html
This is an interesting article on the effects of wood smoke.
- Australian Environmental Protection Agency - Why Is Wood Smoke A Problem?http://www.epa.nsw.gov.au/woodsmoke/index.htm
This is one page out of many at the New South Wales, Australia, Environmental Protection Agency. They have a good amount of information related to wood smoke and its health effects.
- Biomass Burning: Wood, Leaves, Grass, Forests, Crops and Trashhttp://www.webcom.com/~bi/lukebiomass.html
This article is a reprint of an article, which appeared in a special edition of Burning Issues in November 2002. It is very informative with many references.
- Frequently Asked Questions About Open Burninghttp://www.dnr.state.wi.us/org/aw/air/hot/faq.htm
This site, at the Wisconsin Department of Natural Resources, is filled with a lot of useful information. Information on burning trash is located toward the lower third of the page.
- EREC Brief: Air Pollution from Wood-Burning Appliances and Fireplaceshttp://www.eere.energy.gov/consumerinfo/refbriefs/ja3.html
This article discusses the U.S. Environmental Protection Agency's woodstove regulations and methods for reducing pollution from wood burning appliances.
- Energy Fact Sheet: Woodhttp://www.iclei.org/EFACTS/WOOD.HTM
Sponsored by the International Council for Local Environmental Initiatives, this site discusses the advantages and disadvantages of using wood as a fuel source.
- Agency for Toxic Substances and Disease Registry - U.S. Department of Health and Human Serviceshttp://www.atsdr.cdc.gov
This is an excellent site for finding information on all of the toxic substances found in smoke from burning biomass.
All material (except for some code and external links) © Jeffery A. Schneider, 2003