People with stoves live around other people with stoves. The air inside houses comes from somewhere. :) they hint at this in the study somewhere.

Even a small amount of smoke represents a thick concentration of particulate.

Lighting the fireplace causes some smoke to drift into the room, before the fire is hot/large enough to cause a strong draft.

There are also some times when the wood is a dud and takes a long time to start.

Specifically until the chimney is hot enough. You can speed up the process though by using a fresh air intake for the stove rather than it using the air in the house.

Perhaps some of the smoke leaks out of the stove into the room. Maybe a rocket mass heater[1] could help. It uses a thermal siphon to pull all the exhaust outside.

[1]https://en.wikipedia.org/wiki/Rocket_mass_heater

I mean wouldn’t you see it? I use my fireplace all the time in the winter and I would classify the amount of smoke that gets into the room as “negligible”. Especially compared to smoking a cigarette.Would love if this study actually followed up with some measurements and the “why” of actual fireplaces and stove setups.

You can measure. Buy an AQI meter. But I recommend buying an air filter with an AQI meter attached, as when you see what the supposedly negligible amount of smoke is actually doing to your air quality you are going to want the former.

Not all.

I grew up in a house that used wood as its primary means of heat (and two smoking parents but they smoked outside exclusively).

These days I live in a house primarily heated by a heat pump (in a region where it does get below 0F on a normal winter), but it has a wood stove.

I can't imagine a woodstove setup that doesn't leak some level of particulate to the inside. No matter what, you can tell there's wood burning inside. It is a pleasant smell (burning white/red oak), but probably not good for health.

So even though I grew up with a wood stove burning all winter every winter and have one now, I seriously appreciate the heat pump as a clean and efficient means of heat for 90% of the season.

To me, wood is a great emergency form of heat as we have plenty of deadfall where we live. But I would bot recommend it otherwise.

And don't get me started on firewood processing...

Wood with radon.

Radon's most stable isotope has a half life of only a few day, so if there's radon in the wood there must also be uranium or thorium in the wood to create that radon, and that must have come from the soil. Not impossible I guess, but I think if trees in your area have that much uranium/thorium in them, your primary concern would be radon coming up through the ground into your house.

If there's a correlation between burning wood and radon related health issues, I suspect it's not because of radon coming from the wood but rather smoke from the wood making residents particularly susceptible to injury from radon coming up from the ground. Such an effect is known to exist with tobacco smoke at least.

I am no scientist but I know radon is bad, and it comes from underground.

Underground water can contain radon, and it is an issue when it comes to wells and houses. Trees can suck that radon and when you burn wood a radon meter shows an increase.

A tree could suck up water containing radon, but after you cut down the tree and let it dry under a shed for a few weeks that radon will be gone. It will have all decayed away because the half life is only 3.8 days. For firewood to still contain radon a few weeks after the tree was cut down, it must have a fairly substantial amount of uranium or thorium in it (constantly producing new radon.)

Insighful, thanks. Then my radon meter must have been affected by something else.

If you can smell it, then is spreading through the room. There’s no rule of airflow which says air only flows upwards.

And once you can smell smoke the particulate levels are generally very high

> There’s no rule of airflow which says air only flows upwards.

When you are burning a fire there is a rule, it's called the stack effect, it is the very point of having a long (and ideally straight) chimney.

You’d be a fool to burn a fire in your home if your fireplace has no chimney. But that doesn’t mean all the smoke goes upwards.

Surprisingly I couldn’t find a single study which measured PM 2.5 from fireplaces with chimneys. However, a study on wood stoves (substantially better sealed) found a 30% rise.

Which is actually less than I would have predicted. I’d still expect a fire to be higher, but I’m open to being wrong. If I’m ever going someplace with a chimney and fire I’ll bring a pm 2.5 meter for fun.