We celebrated New Year’s Eve at my dad’s, including a fire in the fireplace. I was curious how much the wood smoke went up the chimney vs collecting in the room, and decided to take some measurements. I used the M2000 that I got when investigating whether a ceiling fan could be repurposed as an air purifier.
Here’s what I found:
I started the meter running at 4:30pm, and we started the fire at about 5:30pm. I didn’t write down the specific time because I thought it would be evident from the chart [1] but actually I can’t see it at all.
Then at 6:45pm we lit Hanukkah candles, and the smoke from the matches being blown out had a very sharp effect. Particulate levels stayed high for the rest of the time, with both the fireplace and candles, which I attribute to the candles.
[1] Several years ago I remember reading Sam Harris’ blog post The
Fireplace Delusion, which argues that while we consider wood fires
to be wholesome they’re actually worse than smoking. And argues that
this feeling of “wait, but wood fires are good!” is useful for
understanding what religious folks are thinking when presented with
atheism. Several years later his post had gotten jumbled in my head
into saying that fireplace fires cause bad air quality in your own
home, and so when I ran this experiment I was expecting to see quite
high levels. On rereading, however, he spends a lot of time talking
about externalities: the wood smoke that goes up my chimney goes, in
part, into many other people’s houses, causing a small bit of harm in
each. So no conflict there.
This is really interesting! And lines up with my own anecdotal experience of watching candles make my walls sooty over the course of just a couple of years.
Out of curiosity, are there any studies on the effects of wood fires at the community level? How far apart do housing units need to be for the effect of smoke from the chimney on other houses to be negligible?
Interesting that the fire in the fireplace seemed to have no effect. This post gives a pessimistic estimate of 25,000 (pm2.5 I believe) in worst possible conditions and 2-3 orders of magnitude better (25-250?) under ideal conditions. Interesting that you found essentially no effect. Maybe good conditions/a flue with good draw reduces it to essentially zero?
It seems like your measurements for the candles match theirs as well “a spike to around 50-200 with particles hang in the air for 3-5 hours”. Obviously, an airtight lid (as they suggest) is not possible for Hanukkah candles (or the matches themselves), but I would be curious to see how running them under water or using a snuffer changes things (or just taking them outside to blow them out).
I’d also be curious to see how different types of lighters perform vs matches. I would guess that any type of lighter would be a lot better, but perhaps running the matches under water to extinguish them would be almost as good—though I would guess that a significant portion of their emissions comes from just lighting them.
I’d be interested to know what type of fireplace your dad has. Is it open, or a wood burner with a door?
We have a wood burner with a door, and after reading several articles about the dangers of woodsmoke, my understanding is that burners with doors don’t negatively impact air quality until you open the door to refuel them, at which point they flood the room with airborne particles. So, you may get higher readings at refuel times if his fireplace has a door.
We’ve never really used our burner due to the health impacts: we have small kids who would be especially vulnerable. I haven’t seen the externalities highlighted as much as the linked article before, this was an interesting read, thanks.
It’s open; no door.