Asthma and Modern Wood Stoves

[BronxMatt]

Hi,

We’re getting close to purchasing and installing an Ashford 25 insert. This forum has been incredibly helpful.

Is there any research (or just experience-based knowledge) out there on how using a modern wood stove might effect people with Asthma? Growing up I had a lot of experience with a VC Defiant. We often had it open and always smelled of smoke! My assumption is that with these new, cleaner, tighter, and for the most part, closed stoves, there isn’t a whole lot that comes out of the stove and into the living space other than heat.

Thanks again, and as always!

-Matt, father of 3 asthmatic* kids!

*our kids asthma is triggered by a cold virus, not really dust/pollen. But we’re still learning a lot about the condition.

 

[stoveliker]

Make sure your chimney is tall enough. Smoke roll out is often related to too short chimneys. And elbows in the flue (too close to the stove).

Wood stoves do give dirt/dust: bringing wood in is just not a clean thing.

Ashes can be mostly prevented from spreading by emptying them with a warm stove that still has coals. The ashdrawer on a BK stove likely will help contain ash dust. But I like to shovel and don't use the ashpan.

 

[stoveliker]

@Poindexter has medical expertise and has particle measurements from his home when using a BK. He has a thread about this.

 

[mikey]

I”ve had asthma all my life and been around wood stoves most of that life, I think more than anything it’s the dryness of the air that gets to me. I found that keeping a pot of water on the stove keeps the air humid, I also have a humidifier going when the stove is getting a lot of use. I have a Jotul 601cb burns clean with no smoke.

Mike

 

[ABMax24]

Having a proper chimney setup that achieves enough draft is a big part of it. Keeps the stove under vacuum and prevents any smoke from leaking into the house, also helps pull the smoke up the flue when the door is opened.

Another factor is sufficient combustion air for the appliance, and makeup air for the house itself. Again prevents back drafts and puffing when the door opens.

 

[bikedennis]

For added insurance, I have a high quality air filter. Also a humidifier and a cast iron pot on the stove filled with water.

 

[Poindexter]

Good advice so far. The main thing I can think of is to flip the big lever into bypass and go "do stuff" for several minutes before you open the loading door. Make coffee, go pee, let the cat out, pour a cup of coffee.

I would guess smoke roll out is going to be your biggest enemy. The main way to combat that is to wait a little bit longer after flipping the lever to bypass before you open the loading door. Check the sports scores. When you flip out of an overnight burn with the combustor engaged you got to wait (longer) to let the new airflow get established inside the firebox now that the combustor is bypassed.

I think (as of last year) the 25 series inserts and the Boxer (freestanding) 24 had no ashdump in the floor of the firebox. You will probably have to shovel ashes off the floor of the firebox into a container to carry the ashes outdoors. You might check your local secondhand/ antique stores for cooking pots with lids in the roughly 2 gallon size for this chore. I picked up a 2 gallon graniteware item, with lid, for $10 within the last couple years.

Your big variables are how many glowing coals you have in the firebox, how tall your chimney pipe is, and outdoor ambient temperature. Learning curve here, your house, your install, your weather. Given "Bronx" as your location and late Oct 2022 as the time, start with 10 minutes as your bypass time before you open your loading door and proceed. If the asthmatics in your home have reactive airway disease they will (likely) react to smoke rollout you cannot even see. If the first reload at 10 minutes has you passing around albuterol MDIs try 20 minutes bypass time next time around. It is really hard to perceive smoke rollout when I am squatting on the floor in front of my stove trying to reload.

BRB, I have some meat in the smoker that needs attention.

 

[begreen]

@Poindexter has medical expertise and has particle measurements from his home when using a BK. He has a thread about this.

Homemade air filters - Good indoor air quality, cheap

This is pre-pub. I have a lot of documentation to do after I collect a bale of data. I wasn't expecting to post here for another 6-8 weeks, but check this out. This is in my living room, about 10 feet from my wood stove that has been running 24/7 for days. I also have a geriatric long...

www.hearth.com

 

[stoveliker]

I also note that sometimes wood has some mold on it from when it was still wet. I don't know if that can still spread spores that you are bringing into the house.

 

[Poindexter]

So I am back.

I bought 4 of the $60 air quality meters in this thread, and 2 of the Dylos 1100s last fall. The cheap AQ counters do fine from 6 mcg/m3 up to 200 mcg/ m3. If you really want to know how "excellent" your AQ is at under 6 mcg or how unhealthy it is above 200mcg, you will need to spend the money on Dylos and do math.

For perfectly adequate resolution between excellent and unhealthy AQ, the $60 meter from amazon does perfectly well and correlates adequately with the more expensive Dylos in the relevant range - in my testing at my house.

This thread hereby incorporated by reference: https://www.hearth.com/talk/threads/homemade-air-filters-good-indoor-air-quality-cheap.188986/

I do now explicitly point out the inexpensive amazon counter is made in Asia and calculates "AQI" (air quality index) on a different model than that currently utilized by USA EPA. If you buy the $60 particle counter you will have to take your raw particle counts in mcg/m3 to the current EPA table to find your current USA EPA AQI. With a woodstove inside your home you will very likely find your controlling variable is invariably PM2.5. During wildfire season (if you have forest fires in your area) PM2.5 and PM10 will be your controlling variables for AQI at about a 50:50 mix.

I have now built three boxes that allow a 20" box fan to draw through three 20x20 furnace filters, and I don't think it is worth the trouble. Better, I think, to simply duct tape one MERV13 filter furnace filter onto the intake side of a 20" box fan, and use the savings to buy an IR thermometer. If your fan motor is more than 1-2 degrees F hotter than ambient air I would be grateful for the data point.

 

[Poindexter]

I also note that sometimes wood has some mold on it from when it was still wet. I don't know if that can still spread spores that you are bringing into the house.

It can and it is cold hearted. Spruce is not so bad, my wife is sensitive to spores. Birch is much worse, for my wife in my house. I expect a lot if individual variability here.

I keep my indoor cordwood in the garage, with a firedoor to the living spaces. I can trot out there on work mornings in underwear and flip-flops to keep the woodstove running, and load the rack in the garage about once per week. If my wife's allergies get much worse I would look very seriously at putting in solar panels where my wood stacks are.

This is a valid point. Besides minimizing our impact on the planet by running an up to date woodstove, each of us needs to consider the impact of the woodstove on the people in our household.

 

[Poindexter]

The very best news. My observations of the summer 2022 wildfire season showed a metric crap ton of PM10 floating around. My data suggest that the lion's share of my local friends and neighbors are burning dry wood in the winter months- because PM2.5 is the controlling variable for AQI in the winter months; while both PM10 and PM2.5 can be the controlling variable in summer wildfire season- with live trees on fire.

 

[EbS-P]

I have not seen much research. This makes the rounds regularly, but there was some (or a lot) of skepticism As to how the data was collected. https://amp.theguardian.com/environ...iple-harmful-indoor-air-pollution-study-finds

I have been monitoring (but not logging) my indoor AQ. I can’t say it’s any worse when burning but does get worse the 15 minutes after a reload. A stove is heaps better than a fireplace. Blowing out 10 candles is worse than a reload. I Run air purifiers year round. And merv 11 in my hvac. Fire pits exposure is way way worse than wood stove.

I’m curious and will do some digging this weekend to see what I find.

 

[EbS-P]

First paper to come up did not read through it yet.

Edit… here is the author. Has most of the IAQ puds that came up in my quick search

IDS Core Faculty

The faculty of the International Development Studies program at the University of Montana.

cas.umt.edu

 

[mikey]

I have a 602 not a 602 dhh

 

[stoveliker]

My reading of that paper is that there were no clear improvements in the perception of the asthma severity (the quality of life) for those with filters installed. Some flow measurement did improve.

My problem with this study is that they compared pre-EPA stove households with EPA-stove households, air-filter households (and placebo's).
This does not make a lot of sense imo if draft etc. is not specified. I can have the most modern and clean stove, if my chimney is not up to par, I'll have smoke roll-out and I'll have PM2.5 issues in the home. But having an old smoke dragon on a 30 ft chimney straight up I would have zero smoke roll-out and all PM2.5 (possibly a lot), goes outside.

It is important that any PM2.5 particle that is produced actually goes thru the system in the stove that is meant to combust those (cat or tube). So draft is important.

This is a study by medical folks, that should first have talked to engineers. I applaud research like this (having had severe excercise and pollen allergy induced asthma as a kid myself), but without a proper characterization of, and correction for, the properties of the install itself, the results are not teaching us much, imo.

 

[ericm979]

I only get smoke in the house if I open the stove while it's burning but not yet down to coals. I only do that if a split has rolled up against the doors. It happens a few times a season.

As for dirt and stuff from firewood, I carry mine into the house in plastic bins with lids. I remember I knock the splits together to dislodge insects and dirt before loading into the bins. So there's little dirt from the splits that ends up in the house. The hearth is large tiles so it's easy to sweep up anything that drops.

For ashes I use a dedicated ash can with a tight fitting lid with a bail that locks it on. When I load it up there are coals in there and in our fire prone environment I do not want to chance the can getting knocked over and igniting a fire. A small handheld vacuum works well for vacuuming up ashes that fall on the hearth when I'm loading the can. Yes you need to make sure they're ashes and not coals or you can set the vacuum on fire.

 

[Poindexter]

I have not seen much research. This makes the rounds regularly, but there was some (or a lot) of skepticism As to how the data was collected. https://amp.theguardian.com/environ...iple-harmful-indoor-air-pollution-study-finds

I’m curious and will do some digging this weekend to see what I find.

This article in the guardian was impetus for me to bring a particle counter and an air filter system from my woodshop into my house. There are 3 basic ways to get woodsmoke into your house.

1. smoke rollout with the loading door open
2. leaky chimney pipe or other unsafe condition about the install
3. outdoor forest fire smoke coming in through the HVAC

1. My wife and I watch a LOT of BBC channel 4 when we have time to watch television, and my first guess at the Guardian data is they were looking at mostly small, decades old homes with excruciatingly small woodburners retrofitted into masonry fireplaces. I think I could probably learn to run one of those little burners without smoking up the living room, but there would be a learning curve for sure.

2. Get it fixed

3. This is a different problem. I suppose in big cities vehicle exhaust and etcetera, actually Beijing. Here the problem is to make the air in the home cleaner than the outdoor air, but maintain healthy air turnovers inside the home as well.

Looking forward to @EbS-P 's findings.