You Asked, We Answered: How Come No One Knows Wood Smoke Is Bad For You?

Oct 20, 2017

Summer lingered a little longer than usual this year, with a string of hot and humid days in September and October. Now, temperatures have dipped below freezing and folks are lighting up their wood stoves and fireplaces.

Which brings us to our Only in NH question this week: Evan asked “Why does no one know or care that wood smoke is as bad for you as diesel smoke or cigarette smoke?

Virginia Prescott asked Outside/In host Sam Evans-Brown to help us smoke out the facts.

So Sam, have you lit up the wood stove yet?

We have not! No, we have not had the need.

Well quick answer first – are wood stove smoke, diesel smoke, and cigarette smoke all equally bad for you.

Stories like this were made for gratuitous fire gifs

In fact, wood smoke might be worse for you than cigarette smoke - but that's only if you were to smoke it like you were to smoke a cigarette. And the infamous study on which this is based basically did just that.

[Researchers] burned a piece of wood, then burned some tobacco, and analyzed the fumes coming off of both of them. And, yes, the wood smoke seemed to be worse for you than the cigarette smoke.

However, you don't smoke wood the way you smoke a cigarette. You burn it, and you get the smoke away from you as quickly as possible. And so the health impacts of wood stoves are much fuzzier than the health impacts of cigarette smoke.

Well let's talk about the stuff that's in there. What in particular is detrimental to the body in these varieties of smoke?

I’m sure you remember all the doctors who would go on TV and talk about the 7,000 chemicals that are in cigarettes. There are also a ton of chemicals in a chunk of wood, and when you burn it you get all sorts of very standard pollutants that you hear about - nitrogen oxide, sulfur oxide – [pollutants that are also] in power plant emissions.

Dioxins and formaldehyde too – but the most damaging thing that's in wood smoke is particulate matter. And we're just talking about little tiny pieces of stuff that are so small that they get way down deep into your lungs, get lodged there, and then your body has to deal with them - which it can do in small doses, but it gets overwhelmed very easily.

What about nicotine? That is not in wood smoke.

No, indeed not. Nicotine is more like caffeine. It's an addictive substance that makes it so that you're coming back to cigarettes over and over - and therein lies the health risk. And wood smoke does have things that are absorbed into your lungs [like nicotine]but those aren't really the large health risk. We're really talking about this big dose of tiny little chunks of stuff, that you get in your lungs from breathing it in.

So if you were not very well ventilated room, for example.

Yeah. One of the things you can do is try to minimize the amount of time that you smell wood smoke in your house. Try to light your stove really efficiently so you don't get smoke in the house, or try to stoke the stove less frequently so you're not opening the door as much. If you smell smoke, that's a good indication that you're doing something bad for your lungs.

How about wood pellet stoves? They are supposed to be so much better environmentally.

Here's an animated pellet stove. You're welcome.

Wood pellet stoves are much cleaner burning than wood stoves. In fact I brought a handy dandy little visual aid for you to react to here. This shows the amount of particulate matter that is put out by the various types of things you can burn. If you look on the far left of that graph, you see you see a traditional fireplace. They're incredibly dirty.

A new wood stove [puts out] 28 times less particulate matter than that, and a pellet stove is about half of what a new wood stove puts out. And the reason for that is that pellets are a uniform fuel – you can control how the combustion happens and it burns completely. And that's really what the particulates are - they're un-combusted wood, tiny pieces of it floating in the smoke and into your lungs.

OK, so you said you don't smoke a burning piece of wood the same way that you take in a cigarette, like suck it in. But how about what's hanging in the atmosphere? You walk out of a house where people have been burning wood and you can actually smell wood smoke on them.

And in fact, if you're smelling wood smoke, you are getting some of that particulate matter into your lungs. And this is why organizations like the American Lung Association want to transition away from burning wood as a source of home heating, and it also gives you sort of an indication of [how you can be] a little more responsible with some of the things that you do.

For instance, this time of year is a really bad time of year to burn wood because the air is warm, smoke comes out of the chimney and it's about the same density as the air outside - so starts to sink back down. You'll see this time of year where you go past a house that's burning wood, and there's a sort of pall of smoke that's hanging around the house.

When you get to winter, the air is colder and dense so the smoke rises up and away from the house and you're not breathing as much of it. So not burning wood in the shoulder seasons, the spring and the fall, is a good way to be a little more responsible. Also… buying yourself a new wood stove is a way to be more responsible.

But what about our listener Evan, who phrased his question in a particular way : why does no one care about this issue? Is there an awareness problem, Sam? Do you think he's right to phrase it that way?

Well I think what he's responding to is that we have a culture of burning wood up here in the colder parts of the United States. Wood heat for a lot of people is considered “free”, because it’s coming from your property, you're cutting it yourself, you're only paying for it with your time and labor. And so it's part of the Yankee identity.

And there is push back to these campaigns to get people off of wood heat. So that's what I detect in the tenor of his question - why does no one care about this these public health campaigns that have been going on for decades now?

It might be dangerous, but man is it cozy.

Well there is something psychological though that the look of wood burning in a stove isn't there. You know there's this sense of the hearth especially on a cold winter day.

There's nothing more pleasant than standing next to a warm wood stove when it's cold outside. And I will confess I heat with wood at my home, but knowing about these issues, I try to do it at times when there are going to be fewer people outside and around. I try to do it at times when the smoke's not going to hang around. And I bought myself a new, cleaner burning wood stove.

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