Frying would require some sort of oil or fat and it’s hard to tell but the pan looks clean. Anything with oil will dramatically bump up those numbers. It’s intuitive just cleaning your kitchen, grease being cooked travels.
My one wish is the west adopted Chinese style kitchens. Even in new condo builds the kitchen will be isolated in a room you can close off, with an exterior wall and powerful exhaust vents. I always found it perplexing how ok folks are with what feels like cooking food in their bedroom.
Because I want to feel connected with my family or my guests while I'm cooking. I spend a lot of the day in the kitchen preparing multiple meals for a family, I don't want to be closed off.
A concept of a door is such that if you want to be closed off you can be and if you don't want to be you also have that choice. Having a door to the kitchen is strictly better than having no door. Personally I'd pick a glass sliding door too.
The air quality depends on exactly what you are cooking. Close the door if your cooking involves high heat, open it otherwise. And incidentally I don't understand why the author would do testing while frying an egg. Frying an egg does not involve high heat. High heat means getting close to or past the smoke point of your oil. I would not close the door when frying an egg.
I've tested with oil. You don't see a large spike unless something is blackened or the oil
smokes
Biggest generator of pwm during cooking is when things actually burn. Which can be just a very tiny portion of the food, like one black speck that came off and heated extra. This produces more pwm than the mass of oil and food.
You’re right but I also think as you hint, that it’s very hard to cook without causing this to happen. I would add that when frying, even if you are below smoke point, just the act of cooking food in that oil atomizes the oil enough that it lowers air quality.
Have you ever wiped the top of the cabinets in your kitchen? Mine always get coated in grease. It is almost like the oil is being atomized like perfume. Hood works great with smoke testing but this still happens. Inside of the hood is also extremely gross to the point where the oil condenses and drips if I forget to clean it for a while.
Even in nicer houses in the US, they’ll have a range hood but no intake air! And then I’ll hear neighbors complaining about it not working well because nobody tells you that if you don’t have make-up air, you also need to open a window for it to work well.
I think that's because people don't cook as much as they used to. And when they do it's rarely proper cooking and more assembly of prepared stuff, often just reheating.
In France too, most kitchen are optimized for looks with an island and fully opened to the living room. If you use noisy equipment, it makes both places uncomfortable.
But I think that's the point, it doesn't happen that often.
There are not a whole lot of people who actually cook anymore and those who do deal with the annoyance or have their house choice influenced by that requirement.
I think complex home cooking is a vestige of the time when there were middle class housewives with a lot of time to actually do that. Nowadays with both parents working, cooking has been relegated to an activity that has to be fast, easy and efficient; which is why those multifunction cooking appliances are so popular. You never get something great out of it but it works decently enough to have the person responsible take care of some other errands simultaneously.
I have plenty of million dollar plus houses around me selling without any exhaust at all, just a cooktop on an island in the middle of the kitchen, and most of the times it is a gas cooktop! And in 80% of the houses, it's just a shitty microwave exhaust above the range.
So right off the bat, you're down $20k at least to remodel the kitchen so it has proper ventilation, assuming you cook.
Forget the health effects and whatnot, but are people not bothered by cooking smells pervading the house?
I wonder what the difference between PM2.5 from cooking oil or fat vs PM2.5 from combustion engines is on the lungs.
My instinct is that it should be less toxic from vegetable oil, if it's just vaporised... past the smoke point maybe the chemistry changes enough to make it more toxic. The body has mechanisms to remove foreign matter from the lungs, but how easily and how much it clogs up your lymph nodes seems to depend on what it's made of.
My current kitchen has a quite good vent that exhausts outside. Several years ago when I was testing a weather station with a particulate sensor before deploying it, it would pick up large spikes when I cooked, even though it was across the house and behind several doors. For air quality specifically, I very much doubt that realistic levels of separation between the kitchen and the rest of the house make much difference.
You can doubt it but it’s a fairly simple idea. Most homes don’t have makeup air systems. You have adequate ventilation you need makeup air. A good compromise is having an area that does not allow odors and smoke to move around easily. Hence separation. Now of course an adequate hood is the best but only the 1% of homes have that.
If you had all the windows closed and you don’t have makeup air, then running the exhaust will suck air in through any available gaps, which can potentially worsen air quality.
Try measuring PM2.5 in that room and log it as you turn on the fan for a while without cooking anything.
Have you been into a western home? The stove may not have a hood, if it does have one it’s usually inadequate. The kitchen will be in an open space so anything you cook travels everywhere. The number of homes without range hoods is wild to me. Hence cooking in your bedroom, you cook and the whole house smells.
> one wish is the west adopted Chinese style kitchens
This works if there is a designated member of the household (whether family or employee) who prepares food away from everyone else.
It doesn't for a social setting. Fortunately, the only thing you need to reach the health benefits of the former in an open kitchen is a good vent. If you have a multi-story home, the motor doesn't even have to be in the kitchen, allowing for quiet designs.
Sure but most homes in America don’t have a good vent and often with new builds, to have a good vent you need makeup air and you then introduce a lot of annoying issues.
The socializing part feels like an edge case but I guess it depends if you are cooking to entertain or cooking for your daily food. The daily food only a small portion of the cooking requires closing up the kitchen.
Hey, the author here! Thanks for your suggestion. I did use oil here, but not alot. I should measure it next time. I'm trying to figure out how to synthetically generate uniform particles for testing some DIY filters I'm making, and just frying stuff in more and more oil seems like a good bet.
After being in a number of Chinese condo apartments I realize how awesome it was. Most had sliding glass doors so you could open it up if you want but if you were cooking something heavy, you could close the doors or internal windows, open that window or balcony door outside and let the cooking commence.
At least in America, most places will have big enough kitchens that can isolate grease to the area around the stove. Good design will put the stove far enough from living and dining areas.
Good design probably exists in the minority then? I live in America and venting requirements are terrible and open concepts lend to lots of smells across a house with central air.
Two things, no oil as others have suggested but also frying eggs does not require a very high temperature, around 150 Celsius and your eggs don’t look particularly browned (which is how I prefer them too) so you aren’t exercising the Maillard reaction, which generates the PM2.5. Try again with browning a fatty cut of beef or pork steak in oil which require higher temperatures where lots of browning is occurring and you are also closer to the smoke point of the oil.
I used oil but not a lot. I didn't know about the Maillard reaction, and this is good info. Thank you, and I'll do this for next time. I want to figure out an easy way to make PM2.5 to test my air purifier.
I have an air purifier in my bedroom. It measures PM1, PM2.5 and PM10 as well as TVOC (Total volatile organic components) and adjusts it's air intake according to the air quality. Usually it runs at very low speed and is inaudible, even at night.
When I start cooking downstairs, within a minute or so I hear the purifier upstairs ramp up to full speed.
Indeed, and I prefer short period of increased air pollution + ventilation and air filters, to nonstick pan and eating PFAS which is unavoidable (and unmeasurable at home).
Afaik the nonstick pans are not emitting pollution in that sense, the food does not get contaminated, even if the surface peels off that is supposed to be benign. The problem is the production process, having already contaminated the drinking water of the whole world with PFAS - and that's the route where we get contaminated for real as well.
But who knows, maybe those pans are even more dangerous than currently known.
If it's Teflon / PTFE, as long as you don't let it smoke you should be fine. The polymer chain is too large to enter your cells, so your body just expels them intact.
That's not to say you should go out and buy everything coated in PTFE. It generates tons of pollution when it's synthesized. I'm just saying there's no need to rush to throw away the ones you may already have at home - that might be counter-productive as you're now generating waste unnecessarily.
Not sure about yours, but many extractor (vent) fans will just suck the air over a very loose filter and throw it back into the room. Many in the US are part of the over stove microwave and rarely vent at more than 250cfm (~7 m3/min) where specific vent fans that go outside can move upwards of 700-800cfm (20m3/min).
My favorite method of frying an egg is in a wok with oil. It gets amazingly crispy, rather than floppy, which is how it usually turns out in a conventional nonstick pan.
But it pretty consistently sets off the Coway air purifier in my kitchen when I do it...so I would assume frying with oil to the point of smoking does adversely affect air quality.
Sure, although it's interesting to see how long those pollutants linger, based on how long it takes my air purifier to return to "normal" quality. The egg fry will make it angry for about five minutes, maybe. By contrast, every time I fry up some bacon, the indicator will stay in the red zone for 15-20 minutes.
> Something weird though is that turning on my extractor fan didn’t really do much.
Does your extractor fan vent to the outside, or just recirculate through a filter? In my experience, people often overestimate how much protection ventilation provides. It mostly dilutes contaminants rather than removing or isolating them. For example, with moderately hazardous compounds, a fume hood works fine under normal use, but in the event of a spill it can’t bring levels back down quickly enough to protect the operator. In that kind of situation, an isolator makes far more sense or adding PPE, though that can be burdensome.
What really surprised me is how high the values get from just a single pan. It makes me wonder what it’s like in a commercial kitchen with multiple pans at higher temperatures, especially if the extractor fan fails and there’s no time to shut down operations to fix it.
>In my experience, people often overestimate how much protection ventilation provides.
Do you have references to back this up that I could read? Assuming the same fan size, ventilation would act like a perfect filter and remove everything out of the room that the fan pushes, whereas a filter will allow some particles to pass and recirculate. Especially useless if it is those metal fiber filters that are in a range hood that just remove some grease.
Yes, ventilating out > recirculating no question! I just wanted to raise awareness that ventilation is not instantaneous. It takes time to bring things back to safe levels in case of spikes.
A quick search brings up the CDC guidance, where they discuss air changes per hour for a room. This will be for HVAC units, which operate on a completely different magnitude of airflow compared to a kitchen extractor fan.
This also matches my experience in industrial applications, you only need a single failure point such as a spill or a large enough leak and ventilation alone is no longer enough to keep people safe. This is why it's worth considering a glove box/isolator. You could make the argument that a glove box can also leak and I'm starting to sound like a safety engineer. Anyway at home either will be fine with outside ventilation being superior if done right.
Low PM count in his bedroom? Good for him, but try right after making your bed. Nobody is so perfectly defoliated that they don't have dust in their bedroom.
Also, cooking of all kinds spikes PM levels in my experience. Maybe eggs in a 100% clean non-stick pan are an exception, but I doubt it if you can smell it.
I have a Winix air purifier from Costco in my bedroom, and it has a small air quality indicator light (blue -> yellow -> red) though I'm too lazy to look up what it's measuring.
Surprisingly, making the bed, shaking out the sheets, or vacuuming doesn't make it change color.
But farting in the room makes it red for minutes.
An ever amusing phenomenon that makes my girlfriend and I chuckle on a weekly basis.
Winix air quality sensors (at least the ones I have) measure volatile organic compounds (VOCs), which is a little ironic since HEPA purifiers do little to remove VOCs from the air.
Some other air purifiers like Coways measure particle pollution.
No, gas combustion doesn't generate any significant amount of particles.
It produces CO2, NO2 and some CO. But it's not going to show anything on a PM2.5 meter.
The particles when frying come from the oil turning into smoke, as well as just aerosolization even well below the smoke point. These are what send PM2.5 levels skyrocketing.
When I sear a steak in cast iron, my PM2.5 levels go from their baseline of ~2 ug/m^3 to ~200–400. And course you can smell it in the air.
Gas combustion absolutely contributes to poorer air quality but I would argue that actually cooking (not what’s happening in this test) is much worse. Heating oil and cooking proteins will quickly fill a house. If you can smell it, the air quality has been reduced.
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My one wish is the west adopted Chinese style kitchens. Even in new condo builds the kitchen will be isolated in a room you can close off, with an exterior wall and powerful exhaust vents. I always found it perplexing how ok folks are with what feels like cooking food in their bedroom.
The air quality depends on exactly what you are cooking. Close the door if your cooking involves high heat, open it otherwise. And incidentally I don't understand why the author would do testing while frying an egg. Frying an egg does not involve high heat. High heat means getting close to or past the smoke point of your oil. I would not close the door when frying an egg.
Biggest generator of pwm during cooking is when things actually burn. Which can be just a very tiny portion of the food, like one black speck that came off and heated extra. This produces more pwm than the mass of oil and food.
In France too, most kitchen are optimized for looks with an island and fully opened to the living room. If you use noisy equipment, it makes both places uncomfortable. But I think that's the point, it doesn't happen that often.
There are not a whole lot of people who actually cook anymore and those who do deal with the annoyance or have their house choice influenced by that requirement.
I think complex home cooking is a vestige of the time when there were middle class housewives with a lot of time to actually do that. Nowadays with both parents working, cooking has been relegated to an activity that has to be fast, easy and efficient; which is why those multifunction cooking appliances are so popular. You never get something great out of it but it works decently enough to have the person responsible take care of some other errands simultaneously.
So right off the bat, you're down $20k at least to remodel the kitchen so it has proper ventilation, assuming you cook.
Forget the health effects and whatnot, but are people not bothered by cooking smells pervading the house?
- Most days when cooking PM2.5 doesn't exceed 5ppm.
- I accidentally burned some vegetable oil this week, and PM2.5 shot up to around 70ppm.
- I fried up pancetta a little too hot a few months ago, rendering the fat entirely, and both PM2.5 and PM10 went up to >999ppm.
Deleted Comment
My instinct is that it should be less toxic from vegetable oil, if it's just vaporised... past the smoke point maybe the chemistry changes enough to make it more toxic. The body has mechanisms to remove foreign matter from the lungs, but how easily and how much it clogs up your lymph nodes seems to depend on what it's made of.
Try measuring PM2.5 in that room and log it as you turn on the fan for a while without cooking anything.
Aside from studio apartments, where space is at a huge premium, I'm having a hard time understanding what you mean by this. Can you elaborate?
This works if there is a designated member of the household (whether family or employee) who prepares food away from everyone else.
It doesn't for a social setting. Fortunately, the only thing you need to reach the health benefits of the former in an open kitchen is a good vent. If you have a multi-story home, the motor doesn't even have to be in the kitchen, allowing for quiet designs.
The socializing part feels like an edge case but I guess it depends if you are cooking to entertain or cooking for your daily food. The daily food only a small portion of the cooking requires closing up the kitchen.
Try cooking with oil and you'll see PM levels go to enormous heights.
When I start cooking downstairs, within a minute or so I hear the purifier upstairs ramp up to full speed.
But who knows, maybe those pans are even more dangerous than currently known.
That's not to say you should go out and buy everything coated in PTFE. It generates tons of pollution when it's synthesized. I'm just saying there's no need to rush to throw away the ones you may already have at home - that might be counter-productive as you're now generating waste unnecessarily.
But it pretty consistently sets off the Coway air purifier in my kitchen when I do it...so I would assume frying with oil to the point of smoking does adversely affect air quality.
.... That should be obvious though, right?
Does your extractor fan vent to the outside, or just recirculate through a filter? In my experience, people often overestimate how much protection ventilation provides. It mostly dilutes contaminants rather than removing or isolating them. For example, with moderately hazardous compounds, a fume hood works fine under normal use, but in the event of a spill it can’t bring levels back down quickly enough to protect the operator. In that kind of situation, an isolator makes far more sense or adding PPE, though that can be burdensome.
What really surprised me is how high the values get from just a single pan. It makes me wonder what it’s like in a commercial kitchen with multiple pans at higher temperatures, especially if the extractor fan fails and there’s no time to shut down operations to fix it.
Do you have references to back this up that I could read? Assuming the same fan size, ventilation would act like a perfect filter and remove everything out of the room that the fan pushes, whereas a filter will allow some particles to pass and recirculate. Especially useless if it is those metal fiber filters that are in a range hood that just remove some grease.
A quick search brings up the CDC guidance, where they discuss air changes per hour for a room. This will be for HVAC units, which operate on a completely different magnitude of airflow compared to a kitchen extractor fan.
https://www.cdc.gov/infection-control/hcp/environmental-cont...
This also matches my experience in industrial applications, you only need a single failure point such as a spill or a large enough leak and ventilation alone is no longer enough to keep people safe. This is why it's worth considering a glove box/isolator. You could make the argument that a glove box can also leak and I'm starting to sound like a safety engineer. Anyway at home either will be fine with outside ventilation being superior if done right.
Deleted Comment
Also, cooking of all kinds spikes PM levels in my experience. Maybe eggs in a 100% clean non-stick pan are an exception, but I doubt it if you can smell it.
Surprisingly, making the bed, shaking out the sheets, or vacuuming doesn't make it change color.
But farting in the room makes it red for minutes.
An ever amusing phenomenon that makes my girlfriend and I chuckle on a weekly basis.
Some other air purifiers like Coways measure particle pollution.
Were they talking about gas hobs? Surely that's much worse than the electric/induction one you appear to be using.
It produces CO2, NO2 and some CO. But it's not going to show anything on a PM2.5 meter.
The particles when frying come from the oil turning into smoke, as well as just aerosolization even well below the smoke point. These are what send PM2.5 levels skyrocketing.
When I sear a steak in cast iron, my PM2.5 levels go from their baseline of ~2 ug/m^3 to ~200–400. And course you can smell it in the air.