Carbon monoxide, stovetop smoking, and recirculating range hoods

[Hassouni]

I've just settled on and will soon be moving into a condo with a gas stove, with a microwave mounted recirculating fan above it. As I understand it, unvented gas stoves can emit CO into the air. Is there ANY recirculating system that can filter/trap CO? I'm not sure I'll be able to install a vented system....and apart from general usage CO emission, I'm also interested in stovetop wok smoking, as I don't think I'll be bringing my WSM. That must also produce CO, so does everybody who does the stovetop wok smoke have a vented hood or a kitchen with a window (mine is not by a window)?

[dcarch]

"---unvented gas stoves can emit CO into the air.---"

Not really true. CO is generated if you are running out of oxygen in the space.

So make sure you have fresh air (open window) to replenish oxygen consumed and get a good CO detector.

dcarch

[KennethT]

Right - and as far as stovetop smoking goes - I have the same situation (I actually never use my vent since it just blows air back around - the filters are there to trap grease more than anything but they're not that effective) - I have good results using a Cameron Stovetop smoker - it's inexpensive, works pretty well and doesn't release tons of smoke into the kitchen as it's pretty well sealed. It's good for short smoking jobs - not necessarily long ones though.

[Edward J]

"---unvented gas stoves can emit CO into the air.---"

Not really true. CO is generated if you are running out of oxygen in the space.

So make sure you have fresh air (open window) to replenish oxygen consumed and get a good CO detector.

dcarch

O.K. ...............

But-tum, uh... we're burning a fossil fuel here. By burning a fuel we are producing heat, light, and spent gasses.

So what kind of gas does burning natural gas produce?

[Hassouni]

"---unvented gas stoves can emit CO into the air.---"

Not really true. CO is generated if you are running out of oxygen in the space.

So make sure you have fresh air (open window) to replenish oxygen consumed and get a good CO detector.

dcarch

Sorry, I should have said "gas stoves CAN emit CO (I've seen many many references to it), and if it's not vented, then that's not good"

[Hassouni]

"---unvented gas stoves can emit CO into the air.---"

Not really true. CO is generated if you are running out of oxygen in the space.

So make sure you have fresh air (open window) to replenish oxygen consumed and get a good CO detector.

dcarch

O.K. ...............

But-tum, uh... we're burning a fossil fuel here. By burning a fuel we are producing heat, light, and spent gasses.

So what kind of gas does burning natural gas produce?

Theoretically if it's complete combustion, natural gas burns very clean - it's when combustion is incomplete (for whatever reason) that carbon monoxide and other nasties are produced

[Panaderia Canadiense]

Even with fairly complete combustion, CO₂, CO, SO₂, NO₂, and soot are produced, just in very very small quantities. In the case of a kitchen stove without an outside-venting hood, this would only be problematic if the kitchen itself is also poorly ventilated. In general, leaving the kitchen window open a crack for air exchange is more than sufficient to allow the very small quantities of gas combustion byproducts to dissipate.

[JAZ]

NPR's All Things Considered ran this story on "kitchen pollution" a few days ago, and while it's not terribly helpful for your situation (their main fix is to buy a better exhaust fan), it is interesting in what it doesn't mention, which is carbon monoxide.

Cooking on a gas stove releases some of the same pollutants that you find outdoors in smog. Logue looked at homes in Southern California that cook at least once a week, and found more than half of them were above the outdoor health limit for a pollutant called nitrogen dioxide.

They do have a few tips if you can't buy a new fan that vents outside. I'm not sure how much of a difference they'd make, but they're easy enough to do.

[rotuts]

A few years ago I was able to add new insulation, new windows, siding, roof etc to my house. It was a big project and done fairly well.

the Electric company had rebates for 'blow in' wall insulation, which this house, built 1950 in New England did not have. go figure. Heating Oil was very cheap etc back then.

at the completion of the project, the Electric Company sent an Auditor of sorts to do some efficiency tests on the house. they had this nifty IR camera and looked at the wall, the widows sides ( a common place to loose a lot of energy -- then the window casings meet the walls ) etc.

they then attached some sort of rubber diaphragm with a fan in it to the front door with all windows, other doors etc sealed to test the 'vacuum' the fan might create which gave a reading on how 'tight' the house was.

it was pretty tight. not in any way like those really tight houses you find in Europe, but tight for New England.

having noticed I had a gas oven/cook top with the non-venting microwave over it, they suggested opening a nearby window a crack for baking to make sure the gas properly combusted.

they also said for cook top use if not for long it was less of a big deal.

so baking for a few hours is different than making scrambled eggs.

a little fresh air goes a long way. YMMV

Edited September 7, 2013 by rotuts (log)

[dcarch]

Nothing is ever 100%. Yes, there will be a tiny tiny tiny amount of CO, I am sure, but it will be so so so tiny, that it is of no concern medically speaking. If your CO detector can't detect it you probably are OK , for the limited cooking time you subject yourself to in 24 hours.

The gas jet from your stove is designed based on Venturi principle of aerodynamics. It draws air and mixes air to give you complete combustion. However, if you blue flame is yellowish, you should have a qualified plumber to adjust the air intake of the flame system to the burner.

dcarch

[Hassouni]

Even with fairly complete combustion, CO₂, CO, SO₂, NO₂, and soot are produced, just in very very small quantities. In the case of a kitchen stove without an outside-venting hood, this would only be problematic if the kitchen itself is also poorly ventilated. In general, leaving the kitchen window open a crack for air exchange is more than sufficient to allow the very small quantities of gas combustion byproducts to dissipate.

Kitchen is nowhere near a window, I'm afraid...

[Panaderia Canadiense]

Do you have any way at all to circulate fresh air into the kitchen (and I though building codes in most countries required a kitchen window, even if it's a tiny one?)

[dcarch]

You know when you are cooking something you can smell it in the whole house?

Because air molecules can move around by "Brownian Motion" and natural convection current due to temperature differential and even out eventually. Have you ever burnt something and the whole house is filled with smoke? If your kitchen is connected to other rooms with good circulation, you are probably OK. Again, a CO detector is good to have.

dcarch

[Hassouni]

Do you have any way at all to circulate fresh air into the kitchen (and I though building codes in most countries required a kitchen window, even if it's a tiny one?)

You know when you are cooking something you can smell it in the whole house?

Because air molecules can move around by "Brownian Motion" and natural convection current due to temperature differential and even out eventually. Have you ever burnt something and the whole house is filled with smoke? If your kitchen is connected to other rooms with good circulation, you are probably OK. Again, a CO detector is good to have.

dcarch

I haven't "burnt" something per se, but in the family house I've seared a lot of steaks and done a lot of high intensity stir fries, I know all too well how smoke and cooking smells get EVERYWHERE - and that's in a kitchen with a big wide door to the deck and an overhead fan.

As for the new place, it's an open plan living space, so living room/dining room/kitchen are all part of the same space. The living room has windows near the floor (all glass wall). I don't see what'll keep the smoke/smells from getting all over the living room...

[Smithy]

Unless the recirculating fan is much, much better than mine is at capturing and filtering soot, I think you *will* have smoke getting everywhere, and you'll be wishing you'd brought the WSM. I think the smoke is more likely to be discouraging than the CO. Get a CO detector and set it up in the kitchen area to keep yourself safe - that is, for your peace of mind. If the stove operates properly and the condo isn't too tight, you'll probably never set it off.

Oh, and make sure it alarms in a range you can hear. My husband can't hear any of those pitches, so *I'm* the resident smoke and CO alarm.

Edited for clarity and hearing note.

Edited September 13, 2013 by Smithy (log)

[Hassouni]

Well, forget "smoking" per se, I'm just wondering how I'm going to make my repertoire of stir fries...

[dcarch]

As for the new place, it's an open plan living space, so living room/dining room/kitchen are all part of the same space. The living room has windows near the floor (all glass wall). I don't see what'll keep the smoke/smells from getting all over the living room...

Smoke is not "air" Smoke is particles in air.

An electrostatic air cleaner can trap very tiny particles in air.

Smell is air, only activated charcoal can trap the smell.

They do make electrostatic air filters with an activated charcoal filter.

dcarch

[Smithy]

As for the new place, it's an open plan living space, so living room/dining room/kitchen are all part of the same space. The living room has windows near the floor (all glass wall). I don't see what'll keep the smoke/smells from getting all over the living room...

They do make electrostatic air filters with an activated charcoal filter.

dcarch

For home use? This I didn't know. How big, how expensive, how easy to find and install? Please tell more!

[dcarch]

As for the new place, it's an open plan living space, so living room/dining room/kitchen are all part of the same space. The living room has windows near the floor (all glass wall). I don't see what'll keep the smoke/smells from getting all over the living room...

They do make electrostatic air filters with an activated charcoal filter.

dcarch

For home use? This I didn't know. How big, how expensive, how easy to find and install? Please tell more!

There are many makers. I had bought one from Sears long time ago. If you have allergies, get your doctor to write a prescription and deduct it as medical expense.

It filter out all the pollen and tiny dust particles. It even filters out tobacco smoke.

You can pull out the electrostatic filter and wash in the dish washer. scary to see what gets filter out from your "clean" air.

dcarch

[Hassouni]

Man, after making mapo tofu and stir fried yu choy tonight, I need some solution. Recirculating SUCKS (or rather I wish it did). Flat was smoky to the point I had to open the front door, and the stove heated up the entire place so much that I had to go to the patio to cool off. This is fine in nice weather, but I dread this come winter.

How quickly will a good filter rid me of the smoke? Not much I can do about the heat, I'm guessing

[Smithy]

Man, after making mapo tofu and stir fried yu choy tonight, I need some solution. Recirculating SUCKS (or rather I wish it did). Flat was smoky to the point I had to open the front door, and the stove heated up the entire place so much that I had to go to the patio to cool off. This is fine in nice weather, but I dread this come winter.

How quickly will a good filter rid me of the smoke? Not much I can do about the heat, I'm guessing

I feel your pain. Since I read your post this morning I've gone looking online for electrostatic air filters and cleaners, and made the following discoveries:

1. Consumer Reports did a survey on them that's available online. As usual, they give a decent background on terminology, styles (floor-mounted, in-duct, etc) and the pros and cons of each. I didn't go into enough detail to see which they recommend, and why, but there's the usual table. That article should give you some background to start your search.

2. Home Depot and similar household-supply places offer a broad selection of filters that may do the trick. A Google search brought them right up.

3. These things range from large floor models on rollers to smallish models that might sit on the counter and collect the smoke from next to the stove. Some are listed as being good for an entire house; of course that will depend on how well air circulates through the house, but you may be able to find something that sits innocuously in the open living space and does the trick.

I won't be Investigating With Intent To Buy for myself any time soon, I fear, due to other demands on time and money, but I'll probably be looking into it at some point. I'll be looking at these parameters: high air volume, easy cleaning, portability, quietness, efficiency of removal, cost, and satisfaction guarantee in case I have to try more than one. (No doubt I'll be wanting what my father would have called a champagne model on a beer budget. ) I'll probably look for a smallish filter that I can hoist onto the counter and set next to the cooking space, to maximize capture efficiency, instead of a larger model that has to collect air after it's dispersed through our entire open area. The farther from the stove your collection system is, the more chance the smoke and grease has to disperse. I may even look to see whether an in-duct filter can be put into my microwave-range hood system, but I doubt that will be possible. The in-duct systems I saw were designed for restaurants and they vented outside. Very impressive, but not in my budget or space!

Good luck. I hope someone else has more specific information for you. Please let us - me, at least - know what you find and how it works out.

[Hassouni]

My budget has become unexpectedly constrained so I won't be moving on these any time in the immediate future, but I'll do some research and when I do purchase something I'll be sure to report back. The good news is that the next day, the flat doesn't smell of cooking, but again, let's see what happens when it gets really cold out and opening the door is a nuisance...

[jsager01]

Man, after making mapo tofu and stir fried yu choy tonight, I need some solution. Recirculating SUCKS (or rather I wish it did). Flat was smoky to the point I had to open the front door, and the stove heated up the entire place so much that I had to go to the patio to cool off. This is fine in nice weather, but I dread this come winter.

How quickly will a good filter rid me of the smoke? Not much I can do about the heat, I'm guessing

can you set up a gas stove, much like a barbecue, in your patio? and do most of your stir fry and other highly aromatic cooking out there? If so, this will be IMO the cheapest and easiest solution.

If you are into hardcore stir fry, especially when you do as much or more flipping as stirring, then your biggest problem is the vaporised oil that will spread and coat every exposed surface, including whatever electronics you may have in the living room.

With a window-less kitchen and an open design into other rooms, your only other easy solution is to tone down your stir fry and other aromatic cooking. Sorry if i am being negative.

[Hassouni]

I could theoretically get a high powered gas burner for the patio, It'll just be a vicious nuisance when the weather gets really cold or brutally hot

[RobertCollins]

Before I threw in the towel, I'd get a couple HVAC companies to give me a design build bid. I say a couple because different contractors, like other people, see the same task differently and often one will figure out something that another would never thought about.

Also you might think about replacing ALL your condo's Smoke detectors with the new combo smoke/CO units. Make sure everybody there understands the real rules of CO detection; if a CO detector goes off, get everyone and you out of the building NOW and call 911.

Luck to you.