Wood stoves are one of the most widely-used cooking implements on the planet — and also one of the most lethal, because they're often used inside poorly-ventilated houses. Smoke from them causes persistent health problems which knock decades off people's lives.
But smoke is simply a symptom of inefficient combustion: it's what happens when fuel is incompletely burned, and so bits of it are flying out of the exhaust. When fuel and oxygen are properly balanced, they burn completely, and while it still produces the ultimate combustion products (carbon monoxide, carbon dioxide, and so on) the smoke goes away.
A team of rocket scientists has been working on this, and designing a wood stove suitable for use in places like India (where the problem is particularly acute) that controls its airflow for optimal burning. It uses a fan and a control circuit, powered by thermoelectric power from the fire itself — and producing some spare electricity (to charge phones) as well. (For those versed in technologies for the developing world, this means that it's self-powering, although it can't be entirely field-maintained. But the key components in it are relatively inexpensive and the module is easy to swap, so it's still deployable) So while this doesn't solve all the problems, it's a very nice step forward.