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Comment by legulere | Hacker News Reader

I have a sensor built into an air purifier and have observed the same. Anything textile-related is bad like shaking out your blanket, which makes carpets seem horrible to me. But frying stuff really is the worst. You can go in the hundreds of micrograms, even with induction.

A positive thing I have also learned is that opening the windows works best to get PM levels to a background level. Luckily it is only in the area of 5-20ug pm2.5 here

For CO2 i have been recommended this one: https://clientmedia.trade-server.net/1768_tfadost/media/8/00... which seems to measure CO2 directly.

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PM2.5 particulates are also a big problem with woodworking and other manufacturing processes. There, having proper particulate capture (via properly designed hoods, ducting, etc.) and adequate airflow and duct design (to not restrict airflow) is critical.

For kitchen use, the lessons are largely similar: you need a fume hood that's properly designed and installed, with adequate airflow (often rated in CFM in the USA) to hold and exhaust the particulates. The particular heat source used of gas, electric, or induction, doesn't matter so much because it's the heated food, cooking oil, etc. that's throwing off the particulate matter.

The food is part of it, but the heat source must have some involvement. Combustion of gas produces byproducts, no way around it, and studies of camping stoves have shown the cleanliness of burn is wildly variable depending heavily on basic parameters like the shape of your cookware and the distance from the flame.

(For camp stoves, the chief question is carbon monoxide production- if a stove produces low enough levels of carbon monoxide, it's safe-ish to use inside a small tent high on a mountain in a blizzard where you can't cook outside. Climbers have died of CO poisoning cooking in tents, so it is a real possibility)

Do you recommend the air purifier that you have? And would you mind sharing which one has a built-in sensor? I'd like to try measuring my laundry room.

Most purifiers on the market with built-in sensors are unreliable to measure. They usually go for cheap IR sensors without flow control. Your results will vary wildly depending on conditions (temperature and humidity affect measurements a lot). I personally like Xiaomi purifiers for their affordability and noise level.

If you're concerned about measuring pm2.5 in your space, you should consider buying a good entry level monitor like the laser egg or air visual (acquired by iqair not so long ago).

Don't hesitate to ask more questions, air quality had been my main business for the past 4 years.

Are there air quality meters available at affordable prices (say, <= $100) that can easily be integrated with home automation systems? (like, have an api, or that connect to cloud services so that I can capture the traffic?) Also, any recommendations on outdoor sensors? There have been a few crowd sourced efforts over thale last few years, but I've not been very impressed by them.

I don't know of any cheap outdoor sensors, they are more tricky than indoor as wind (air flow in the sensor), temperature, humidity and dust become more of a prominent problem. For a cheap sensor, laser egg publishes API endpoints to get latest data. You can also fairly easily add a plantower to an arduino/raspi kind of setup. Pantower is a sensor that will give you reliable output OOTB, can be improved but good enough.

We have a Coway AP-1008DH, and it's interesting to see how quickly it comes on when cooking. Probably cheap sensors, but it appears to be a good device overall.

I see that Air Visual ship to Australia; could this be a good way to assess the pollution levels at the school we're considering moving our son to (see my other response in this thread), or could there be cheaper options? Thanks!

We do work with a lot of schools here in SEA. not in Australia yet but AFAIK the market is probably not ready yet.

They are expensive, and it doesn't have a built in sensor, but I have an IQAir healthpro compact and have confirmed with my own particle detector that it filters out > 99% of PM0.1 particles, and 100% of PM2.5 particles.

If you don't care what it looks like, you can easily build your own air purifier for much cheaper. All it is is a blower fan which forces air through 2 or 3 filters, with the last being a HEPA filter. You can get all the requisite pieces for about $100.

We use IQAir machines, too, but buy third party filters from HEPAAirDirect.com as they're cheaper than the originals, and seem very well made. And their pre-filter comes with a removable coarse dust filter.

For the DIY route, these guys in Beijing sell a kit: https://smartairfilters.com/cn/en/

IQAir is just a fan, but it isn't just a HEPA filter. IIRC, the bottom filter is a large particle filter (for dust and hair), the middle filter is a carbon filter (for smoke and paint) and the third is a micro particle filter (<2.5pm). HEPA is a loose industry standard and not everybody meets those requirements anyway.

But yeah, you can easily just put a few dryer sheets on the back of your fan if all you're worried about is large dust and hair particles. The only reason to buy IQAir is if you're paranoid or severely allergic/have health problems.

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