Wood or Gas:
Which Fuel is Better for the Environment?

Q: I would appreciate your sending me any information you may have about the differences between burning wood in an open fireplace and installing a set of gas logs, in terms of the amount of pollution each produces.

  I don't have the comparison data you request available in one document, but can give you a quick overview of the debate concerning the environmental impact of the two fuels as I understand it:

The combustion of natural gas doesn't produce significant particulate pollutants; it is the gaseous elements contained in gas exhaust, particularly the so-called Greenhouse Gases such as methane (CH4) and carbon dioxide (CO²), that are of environmental concern. Natural gas exhaust contains over twice the amount of greenhouse gases per quad of heat delivered as wood exhaust. Thus, burning natural gas is considered by scientists to be a much more significant contributor to the environmental threat known as Global Warming than burning wood.

Along with CO2 and trace amounts of various other gases, an open wood-burning fireplace emits between 40 and 60 grams of particulate waste into the airshed per hour. The gaseous emissions from a wood fire are considered by scientists to be environmentally benign, as a fallen tree will emit the same amount of CO2 into the atmosphere whether it is burned or left to rot. The main environmental concern with regards to wood burning is the inhalation of the exhaust particulates, especially those known as PM-10's, which are particles small enough to lodge in the lungs. Today's EPA approved woodstoves were created to address this issue; they are required by law to produce fewer than 4.5 grams of particulate emissions per hour.

Environmentalists seem to have formed two camps regarding the relative environmental impact of the two fuels. The anti-particulate emissions extremists would ban wood fires altogether, while those who view global warming as the larger environmental threat strongly disagree, and also point out that wood is a renewable resource, while natural gas is in limited supply.

Both camps would agree that neither fuel should be burned frivolously: wood fires and decorative gas logs in open fireplaces waste the fuel resource and contribute needlessly to airborne pollution. If you are deciding how best to use your fireplace, consider installing an EPA approved wood insert or a high-efficiency gas insert.