91–100 of 355 posts
Can we talk about Molekule? Their team and some SF tech community folks have been plugging it all over Twitter during this tragic wildfire crisis. But it seems like snake oil to me. It’s $800. Certainly for smoke particles it can’t possibly offer any more protection than a standard HEPA filter. But even for its claimed ability to nuke VOCs, the claim seems ridiculous. While particles can deterioriate under prolonged…
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.
Is there an advantage to attaching the filter to the front of the fan so air is blown through it (as shown in the video) versus taping it to the back of the fan so air is sucked through it? Just curious if that would make any difference. It might be easier to get the filter to stay if it's getting sucked to the fan.
I can think/guess two reasons: 1) If the filter is at the back, since the air is pulled through it, the dirty side is outside where people and kids can touch it as it builds up. If the filter is in the front, the dirty side is inside (towards the fan blade) while the clean side is outside. 2) If the filter is at the back, due to air's resistance it is possible, due to nooks/gaps in the fan, that the some of the air m…
I'm curious... doesn't #2 cut both ways? i.e. if you can seal the front, you can seal the back?
I worry about the long term effects of being “too clean”, that is, I think there’s something to hygiene theory of disease. The body needs small stressors and perturbations in order to thrive.
I built my own air purifier in 2016, living in London, I was living in a basement and was having breathing problems due to mould. My landlady was gaslighting me at the time, so I built the air purifier. It worked for a while but mould spores cling to the paper filter and eventually grow into the filter material. I think Dyson uses glass fiber filter to stop this problem. My filter helped a lot, but eventually I had s…
Generally there are two classes of objects that you want to filter for. Particulates and VOC (Volatile Organic Compounds). Think of particulates as specs of dust with varying size and VOC's as random chemical compounds such as spray paint, smoke, oders. The general go-to clean room/industrial filter stack is Prefilter(F5 Bag)->HEPA->Activated Carbon. The pre-filter catches all the big particulates to prevents cloggin…
The purifiers I use have the activated charcoal before the HEPA. Probably doesn't matter that much though I sometimes findd a small amount of dust leakage from the pre-filter screen on the carbon filter which would just clog the HEPA.
Generally there are two classes of objects that you want to filter for. Particulates and VOC (Volatile Organic Compounds). Think of particulates as specs of dust with varying size and VOC's as random chemical compounds such as spray paint, smoke, oders. The general go-to clean room/industrial filter stack is Prefilter(F5 Bag)->HEPA->Activated Carbon. The pre-filter catches all the big particulates to prevents cloggin…
> “The general go-to clean room/industrial filter stack is Prefilter(F5 Bag)->HEPA->Activated Carbon.” yup, i bought a blueair 211+ ( https://www.blueair.com/us/blue/blue-pure-211/1695.html ), that has exactly those filter elements in a nice (if bigger than expected) package. this model was recommended by both consumer reports and the wirecutter (until recently, cynically thinking they didn’t pay wirecutter’s “endors…
Nifty idea, but I'm not sure I agree with the technique used to prove effectiveness: https://www.youtube.com/watch?v=kH5APw_SLUU The narrator puts a particle counter in front of the fan and notes the 90% reduction. So far so good. The problem is extrapolating this result to the entire room. Yes, maybe you'd get close to 90% if the device were allowed to run a few days. On the other hand, it could leave the situation…