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Build a do-it-yourself home air purifier for about $25

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Re: Build a do-it-yourself home air purifier for about $25

#71

Post by ed_balls »

mannykannot wrote: post #58
ggregoire wrote: post #53

Might be a stupid question but does this work for external air pollution? I live at the 20th floor in a city with terrible air quality and we open the windows once or twice a day.

I imagine it would help with particulate matter (such as smoke, whether visible or not), but I do not think it would have any effect on gases such as ozone, sulfur dioxide or nitrous oxide.

That's correct. HEPA filters anything bigger than 2,5 μm e.g. https://en.wikipedia.org/wiki/Benzopyrene and NO2, SO2 etc. are 1000x smaller.

Re: Build a do-it-yourself home air purifier for about $25

#73

Post by [deleted] »

Dave_Rosenthal wrote: post #60

I spent the weekend researching, implementing, etc. air filtration as one of those affected by the CA fires. It was worth it! The first step for me was getting a device to measure particles in the air. The air quality index (AQI) is an aggregate score that is made up of contributions from several harmful components. Of these, the quantity (weight/volume) of small particles ( Directly measuring PM2.5 is very hard, req…

[deleted]

Re: Build a do-it-yourself home air purifier for about $25

#74

Post by ed_balls »

blattimwind wrote: post #70
ed_balls wrote: post #52

I wonder if you'd put cotton wool, how effective it would be. Here is my set up: - I bought XIAOMI Mi Air Purifier 2 straight from China for $137.00 and spent 1 euro on a EU plug. It's so quiet that I can sleep next to it, looks nice and it's quite compact, so doesn't take up much space. It has a particle detector to adjust the fan speed. The app is useless, so a cheaper version without WiFi and bluetooth would be gr…

> I wonder if you'd put cotton wool, how effective it would be. Not very. Wet wool is better, but only as long as its wet and clean. > XIAOMI Mi Air Purifier 2 straight from China Interesting question. Does the removal of particulates offset the health impact of its cheap plastics?

> health impact of its cheap plastics

Do you mean the health impact of when the device is thrown away?

Re: Build a do-it-yourself home air purifier for about $25

#75

Post by blattimwind »

zzzcpan wrote: post #50
peepopeep wrote: post #22

I was looking up air quality monitors but can't seem to find any on amazon with a calibration certificate that will accurately measure 0.3 micro particles. Am I the only one who thinks this is a great opportunity for a smart product with an app that has the features of a professional air quality monitor and simple UI / UX? If such product exists, does anyone know where I can find it?

Why do you need an accurate measurement for consumer air quality monitoring? I believe even a DIY arduino project with cheap optical dust sensor, like PPD42NS or GP2Y1010AU0F, would be enough.

Why use a measurement device at all? Your nose is quite good enough, as long as it's neither clogged nor "calibrated" to city air. Putting a dust mask with a P3+carbon filter on for an hour or so tends to fix the latter.

Re: Build a do-it-yourself home air purifier for about $25

#76

Post by evolve2k »

ed_balls wrote: post #74
blattimwind wrote: post #70

Earlier quoted context omitted.

> I wonder if you'd put cotton wool, how effective it would be. Not very. Wet wool is better, but only as long as its wet and clean. > XIAOMI Mi Air Purifier 2 straight from China Interesting question. Does the removal of particulates offset the health impact of its cheap plastics?

> health impact of its cheap plastics Do you mean the health impact of when the device is thrown away?

I think they mean of small plastic particles coming off the cheap device and polluting the air.

Re: Build a do-it-yourself home air purifier for about $25

#77

Post by ar_turnbull »

gregwebs wrote: post #72

I have been quite happy with the top pick from this review: https://thewirecutter.com/reviews/best-air-purifier/ Although the price of that purifier is now $40 more then when I bought it, so it may make more sense to look at their other picks.

I have the same one and think it’s great. Bought it when the wildfires in British Columbia blew over and turned Calgary into an apocalyptic wasteland.

Air quality was bad and I’m still not sure what kind of filtering my condo building has.

Re: Build a do-it-yourself home air purifier for about $25

#78

Post by pwarner »

mikenew wrote: post #41
pwarner wrote: post #34

I've been running a 3M Filtrete MPR 2800 in my furnace filter. https://www.purpleair.com/ confirms it works. There house averages maybe 60 PM 2.5 vs 200 outside. Don't know how good it is for furnace, but it hardly runs otherwise in Northern CA.

Do you have two air sensors, or do you just have one indoors and compare it with weather data?

I am relying on 2 purple air sensors 10 miles away in opposite directions for an outside estimate. They are usually within 10%, and we are in the same valley, so should be close. I also see when I stop the furnace fan, levels spike. Then drops when I turn on again...

Re: Build a do-it-yourself home air purifier for about $25

#79

Post by pwarner »

peepopeep wrote: post #39
pwarner wrote: post #31

Earlier quoted context omitted.

https://www.purpleair.com/ seems to work great for me!

Can the sensor be used indoors or does it have to be their "indoor sensor"? The products look interesting but the site does not inspire confidence.

Their site is simple but it works great. I "installed" my outdoor sensor by laying it on my desk inside and plugging it in. Will move outside when fires end.

Re: Build a do-it-yourself home air purifier for about $25

#80

Post by koolba »

LeoPanthera wrote: post #57

Huh! I independently "invented" this myself a couple of days ago when the Camp Fire blanketed the bay area in smoke. I got a 20x20 filter and some duct tape from Home Depot and a box fan from Target. (After discovering that Home Depot only sells fans in the summer.) I don't think I was the only one, though. HD was doing a brisk trade in 20x20 filters, and I think I bought the last box fan at any Target in the entire…

That’s looks as professional as anything I’ve put together!

Is that the spot of use as well? I’d imagine the vicinity of the wall would limit the airflow.

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