Wood fires still help keep many Americans warm during the winter. But if indoor wood fire burning -- whether open hearth or wood stoves -- aren't built or set up properly, they can negatively affect air quality and lead to health risks.

The Environmental Protection Agency -- in addition to drafting new rules -- has offered fire-burners a series of tips to avoid excessive exposure to the air particulates produced by burning wood.

The EPA advises fire-burners to season their wood outdoors for at least six months before burning it. Along with a list featuring several other pieces of advice, the agency insists that fires always be sourced with "dry, well-seasoned wood that has been split properly."

Fires should always burn hot, officials say. Hot, dry fires minimize the amount of smoke and ash that filter into the air. The full array of recommendations can be found on EPA's website.

The new rules, which the EPA is expected to finalize in February, would be the first new regulations on indoor heaters since the 1980s. The updated emissions standards would require new wood stoves to burn 85 percent cleaner.

"Residential wood smoke causes many counties in the U.S. to either exceed the EPA's health-based national ambient air quality standards (NAAQS) for fine particles or places them on the cusp of exceeding those standards," EPA officials wrote in a statement last year, when they first announced the newly proposed regulations.

Particulate pollution, which includes soot and other small airborne particles, has been proven to negatively affect human health, leading to heart disease, respiratory problems, cancer and other complications.

In cold and damp cities like Denver, San Francisco and Seattle, local regulators are occasionally forced to ban wood burning fires when weather systems stagnate and trap pollution.

Such is the case in King County -- the county which encompasses Seattle-Tacoma-Bellevue -- where environmental regulators recently banned wood burning stoves and open fires (outdoors and indoors) until air conditions improve. Only those who don't have alternative sources of heat are exempt.