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Comment by AdmiralAsshat | Hacker News Reader

I've got a Coway Air Purifier in my 1-bedroom apartment, near the separator between the kitchen and the dining room. We have a gas stove.

It's been amazing to see how much what I considered "light" stovetop cooking will set it off and make it spend the next 20 minutes on max settings trying to decontaminate the air. Pan-frying and stir-frying are expected triggers, but even the evaporated vapor from a pot of simmering soup can make it momentarily angry.

Meat fat seems the worst offender. Nothing angers it quite like trying to brown/sear meat does. God help us when I cook bacon in the cast-iron skillet. Even if there's no smoke (I keep the heat at medium low to prevent the bacon from burning), the AP might continue to run for up to an hour after I've turned the damn stove off!

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> but even the evaporated vapor from a pot of simmering soup can make it momentarily angry

Yeap. Not sure what type of sensor it has, but it will react to water vapor. Our master bedroom is right next to the bathroom so showering will cause it to work at its highest setting.

Not that it's a problem per-se. Just that it doesn't really "know" what's in the air. So while your cooking may indeed be spewing pollutants everywhere, the fact that the filter is working harder doesn't mean the air is bad.

That said, humidity needs to be controlled too.

What is interesting is, cooking downstairs will set it off. I have two humidity sensors, and they can't see any difference. Still the filter will start to work and I can't claim it's because of water vapor. It some other type of particulate, harmful or not. It's getting filtered anyway.

To be nit-picky, little to none of that has to do with your gas stove. Our Coway kicks on if I take a shower (water vapor). It also kicks on for all of the cooking scenarios you list. There is no gas line running to our house.

> but even the evaporated vapor from a pot of simmering soup can make it momentarily angry.

It sounds like it can't tell the difference between water vapor and harmful pollutants. Not that it needs to for it to do its job, but the machine may not be a good indicator of actual pollution levels.

We have a Sharp air purifier and it's fun watching it go off whenever we empty the diaper bin

But looking at it purely from a technical standpoint but the Sharp and Coway and other actively monitoring filters are kicking into action because of an increased particle count in the air. Whereas the article is about NO2 gas emissions trapped indoors.

I am not sure these HEPA filters are fine enough to actually filter NO2, SO2, CO, etc, are they?

HEPA cannot filter molecules.

Activated Carbon filters can capture VOCs and gases, but you need a ton of carbon, and you need to replace the carbon when it's "full" (since recharging it in your home kind of defeats the purpose)

It's a great little unit. Mine does the same thing (notably when searing steak in the cast iron) despite being on different floors.

I've been wondering whether to put in a heat recovery ventilation system. I imagine that if the air purifier could trigger the ventilator to bring in fresh air, it would cut the time needed to clean the air to a fraction.

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