How do air filters work?

How do filters remove particles from the air and reduce exposure - especially the small ones? As this Risk Bites primer shows as it dives into the science of aerosol particle capture, it may not be how you think!

Air filters are an important tool for protecting health, improving air quality, and reducing air pollution by removing potentially harmful particles from the air you breathe. But how they work isn't that intuitive -- especially at small particle sizes.

This introduction to the aerosol science of filtration is relevant to workplace safety and public health, and is suitable for K-12 as well as college and professional audiences interested in how filters work.

It specifically addresses collection mechanisms of diffusion and impaction, and explains how filters efficiently collect very small and very large particles, but not necessarily those that are between 200 - 300 nanometers in diameter.

#filter #risk #dust #exposure

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Professor Andrew Maynard is a scientist, author, and leading expert on risk and the ethical and socially responsible development and use of new technologies. He is an elected Fellow of the American Association for the Advancement of Science, serves as co-chair of the Institute for the Advancement of Nutrition and Food Science (IAFNS) Board of Trustees, is a member of the Canadian Institute for Advanced Research President’s Research Council, has served on a number of National Academies of Sciences committees, and has testified before congressional committees on several occasions.

As well as producing Risk Bites, Andrew’s work has appeared in publications ranging from The Washington Post and Scientific American, to Slate, Salon, and OneZero. He co-hosts the podcasts Mission: Interplanetary and Future Rising, and is the author of the books Films from the Future: The Technology and Morality of Sci-Fi Movies, and Future Rising: A Journey from the Past to the Edge of Tomorrow.

Andrew received his PhD in aerosol dynamics from the University of Cambridge in 1993, and is currently a professor in the Arizona State University School for the Future of Innovation in Society, and an Associate Dean in the ASU College of Global Futures.

[moochify]

*The two units I purchased work great. **Fastly.Cool** and air purifier perfectly this machine The filters are definitely collecting dust! I contacted Levoit directly for a minor issue, and received exceptional customer service!*

[gigglysamentz]

It reminds me of the counter-intuitive way that size-exclusion chromatography works.
It's sometimes called "gel filtration" but I find that more confusing.
Basically if you pass a solution of different proteins through a size exclusion column, the big ones come out first and the smaller ones come out last.
This is because the smaller ones takes the long narrow winding paths through the porous beads, but the bigger ones don't.

[FusionDeveloper]

Thanks for the video.
I hope it helps educate people.

[demonsrexis]

A well made definitive video clip, keep it up.

[Freelancer.academy]

Hi, thanks for your useful information. I have a request, may I have permission to translate your video in Persian(Farsi) or subtitle it??

[hvacmensch]

impingement + Brownian motion are the mechanisms for air cleaning with pleated air filters. There are other methods as well.

[cotinis]

Really nice non-technical explanation of particle filtration by interception, impaction, and diffusion (Brownian motion). Might be neat to do an extended version with a bit more physics as well as cover other mechanisms, such as sedimentation and electrostatic precipitation.

[bensheapard]

More videos please!! I subscribed after watching your battery video.

[FusionDeveloper]

The nice thing about physics, is that physics can't lie.

[hehe]

Great video, the demonstration and wording were very helpful for me to understand. Based on your knowledge of air filters, in your opinion what air filters do you know of that do a great job in removing medium size particles?

[tomaslaurenfilm]

Why does not air filters eliminate odors? Aren't odors small enough to have the Brownian motion?

[Nonume]

Is this the same for 0, 22 micras water filters? I've always wondered how can a 0, 22 micrometer filter could be a sterilizing filter if there are bacteria smaller than 0, 22!

[khadijakinawy]

can you please send the words that you said?

[nwt]

Is this video stolen?
Because there is a same video uploaded 2 years before this vid

[Skeptik]

Interesting! The big question: Can we consider cheap imported cloth masks an effective filter (capture) an airborne agent measuring 5 millionths of an inch (C-19)? I think not. Experts - educate me. Cheers

[johnmccallister]

"If you confess that Jesus is Lord and believe that God raised Him from death, you will be saved." -- Romans 10:9
“Whoever calls upon the name of the Lord shall be saved.” -- Romans 10:13

[mregamesanime]

Haha no wonder i can't crank my bike cuz my airl filter covered with rugby and my exhaust well yeah the big rock stuck inside it pretty much.

[EM]

horrible choice of music. but man you draw well

[angelacoppola]

I'm sitting in front of my air filter with an N95 because the air quality is over 300 AQI. I could do without the cutesy music - handclaps and "oh-oh-ooh-oh-oh". It feels like the end of the world here in California.

[kimienick]

Its same on LUNG CASES, when your lung cannot flow the air you will get less OXYGEN, same on engine too... Your engines CANNOT due not have enough enter inside, even have the PERFORMANCE will drop half... Human also... When your oxygen not enough all drop low.... THAT HOW AIR FILTER WORK!!!