Earthcore Industries: The Isokern modular pre-fabricated fireplace is equipped with the HearthCat Emission Control System, allowing the manufacturer to develop what it says is the world’s cleanest burning open-hearth masonry fireplace. It uses a catalytic converter and a hood that drags in combustion air, reducing particulate emissions from an open-hearth wood-burning fire by as much as 90%. www.earthcoreindustries.com.