What are we thinking about Air Purifiers/Filters these days?

[Josh]

Hey all.

Air Purifers on amazon and stuff are full of high rating reviews, and I used them back in 2019/2020 for a year and I think it helped me. I'm sure my skin was just better back then on my face, where as it's been worse in the last few years? Could be just a coincidence.

Winter now so window are not open as much in the rooms in my house I work/sleep in and I've noticed there is some mold formation on the windows and I think sometimes it doesn't smell great if the room has been closed with no windows and I come back into it after a while.

So I'm thinking of getting an air purifier or filter. I know there's that thread where Haidut explains the downfalls of them, but how true is this? I've never seen bad comments on them before.

I'd assume they'd be fine as long as one is changing the filter.

I'd probably get one of them highly reviewed ones on Amazon from Levoit or something. Unless someone has a better suggestion on one thats not expensive. it's only going to be in small to medium sized rooms.

Thanks

 

[supercoolguy]

from Levoit

Mine works great. They have different filters options that fit my "Pet" model.

Now Its about $10 cheaper than when I bought.

Amazon product ASIN B08131HFSGView: https://www.amazon.com/LEVOIT-Filtration-Eliminators-Core-P350/dp/B08131HFSG?ref_=ast_sto_dp&th=1&psc=1

 

[liam183]

Buy a box fan and duct tape some filters onto the intake side. Seriously.
That and keep your windows open when possible.

 

[golder]

Buy a box fan and duct tape some filters onto the intake side. Seriously.
That and keep your windows open when possible.

This is a good idea, does it actually work well? Have you got a picture of yours by any chance, I’m keen to assemble this myself!

 

[liam183]

This is a good idea, does it actually work well? Have you got a picture of yours by any chance, I’m keen to assemble this myself!

It all comes down to the quality of filter, which is entirely up to your discretion. I think for a household, MERV 13 is more than enough, with a carbon-based prefilter beforehand to 1) extend the life of the merv filter and 2) reduce odors.
No pics at the moment as I'm experimenting with another air purifier until I order more filters for the box fan. There are guides online on how to do this, though, so Im sure you could find some pics

 

[ecstatichamster]

you must clean the filters very frequently or you blow around endotoxin into the air.

 

[liam183]

you must clean the filters very frequently or you blow around endotoxin into the air.

This is why I'm a big fan of a carbon based filter as a pre-filter. You can vacuum it off and reuse it without really compromising the filter's effectiveness, whereas a paper filter will be damaged by the high speed air.

 

[Josh]

you must clean the filters very frequently or you blow around endotoxin into the air.

How often would you say? I've seen some air filters from Philips for example that state that their filters specifically can last up to a year and they will give a notification when this needs to be done.

 

[liam183]

How often would you say? I've seen some air filters from Philips for example that state that their filters specifically can last up to a year and they will give a notification when this needs to be done.

I like to vacuum the prefilter once every week or two and replace the paper filter every 3 months or so. I definitely wouldn't go past 6 months

 

[Mossy]

I like to vacuum the prefilter once every week or two and replace the paper filter every 3 months or so. I definitely wouldn't go past 6 months

This is why I'm a big fan of a carbon based filter as a pre-filter.

Good info. Thanks. I have a carbon filter in an air purifier which I never vacuum.

 

[liam183]

Good info. Thanks. I have a carbon filter in an air purifier which I never vacuum.

Have you looked at it?? Mine gets disgusting within a couple weeks lol

 

[Mossy]

Have you looked at it?? Mine gets disgusting within a couple weeks lol

I just looked at mine. It's not too bad. But I don't run it 24/7; and I just changed it a few weeks back. Even so, I'll be more conscious about it.

 

[matty]

As someone who sells air purifiers and consults with folks on various air filtration configurations, the comment on HEPA filters causing an increase in airborne endotoxin is particularly interesting. I read Haidut's old post on this subject, and have read most of the study that he refers to. It seems that the force of air moving through the HEPA filter is causing the bacteria to break apart, and be released at sub-micron sizes too small for a typical True HEPA (H13) filter to capture.

I'm not sure that there's a perfect solution, but as others have pointed out, it seems running all air purifiers at the lowest setting is a good start. Other than that I wonder if there are two other potential solutions...

The first would be to use an H14 HEPA filter, which captures even smaller particulates: 99.99% efficient down to 0.3 microns in size. Or perhaps even better would be to utilize ULPA filters, which are a step up from HEPA and are 99.9999% efficient down to 0.1 microns. This may prevent the smaller DNA fragments from releasing back into the environment after the pressure from the air movement breaks apart the bacteria. Here is a really good unit that allows for an upgrade to Super-HEPA (H14) or even the UPLA filters: Airpura R700 Air Purifier - Honest Air Purifiers

The other factor is whether the bacteria are alive or dead. Endotoxin is released when bacteria grow/reproduce and when they are killed and disintegrate. If gram-negative bacteria are trapped in the HEPA filter and allowed to live in the filter media, that means they can continue to shed their outer membrane. If they are dead, yes endotoxin will be released, but perhaps less so than if they are alive and continue to reproduce and grow and shed endotoxin.

This is where UV could be used to at least kill the bacteria and prevent further growth and shedding. Something like this model might work as it utilizes UV light to kill pathogens caught in the filter, while also allowing for a configuration with Super-HEPA or ULPA filters -- so both potential solutions are being used at the same time: Airpura UV700 Air Purifier - Honest Air Purifiers

I also found this study which says the opposite concerning HEPA filtration and endotoxin. I still have to read the study in its entirety to see how they came to their conclusion, but it appears that their testing shows a reduction in endotoxin using air purifiers... Reduction in Indoor Airborne Endotoxin Concentration by the Use of Air Purifier and Its Relationship with Respiratory Health: A Randomized Crossover Intervention Study

A very interesting subject. I'm going to look into this further and see what I can find...

 

[Mossy]

This is where UV could be used to at least kill the bacteria and prevent further growth and shedding.

I had seen this UV option on other units before I decided on mine, which doesn't have it. Maybe in the future this feature would be worth looking for; as well as the ULPA. Thanks for the info.