Do wood stoves really burn cleaner than those old reliable cast iron stoves of several decades ago?

You don't need a high tech lab to measure the pollution to find out. But it helps.

Omni Laboratories of Beaverton tests most of the woodstoves sold in the U.S., certifying them for the Environmental Protetction Agency.

In the early 1990's wood stoves emitted 40 to 50 grams of smoke per hour. Today, the E.P.A. will not allow more than 7.5 grams per hour to emerge from new wood stoves. The state of Washington has even stricter limits. As a result, most manufacturers strive to meet the Washington standard of 4.5 grams per hour.

You can see the difference for yourself. Look inside the stove and watch what's burning.

In old stoves, only the wood burns.

In new stoves, look through the glass front panel and you'll see the wood burning plus one or two more layers of roiling flames near that top of the stove. That's the stove burning its own pollution.

The technology really has changed in 15 years.

STOVE STATS:

- 420,000 Wood Stoves in Oregon

- More than 220,000 are old, high polluting