I recently posted a description of a powerful cooling fan I set up for my MacBook Pro that I'm thinking of adding a filter to. I wonder if the inline duct fan I got is strong enough for HEPA filters. It's a lot stronger than a box fan. It runs off of AC and has a speed adjustment control. The TD-500/150-160 moves 550 m^3/hour at 2480 rpm.

https://www.solerpalau.com/nl-nl/ronde-buisventilator-td-sil...

https://statics.solerpalau.com/media/import/documentation/NL...

Here are some centrifugaal high pressure tube fans, but I don't know how noisy they are compared to the S&P "TD-SILENT" silent series (with noisy sounding names like "Cyclone").

https://www.ventilatieshop.com/buisventilatoren/hogedruk-bui...

https://news.ycombinator.com/item?id=28736187

The overheating problem on my MBP was so bad and so pathetically common, that I had to take drastic and expensive measures, which work pretty well.
I tried various laptop cooling stands, and they were cheap and plastic and had shitty fans that hardly pushed any air, and didn't help.

So I got a solid aluminum laptop stand without a fan, which conducts heat much better than plastic, and I bought four sets of stick-on heat sinks (some large and some small), and stuck them all over the back of the aluminum laptop stand on the surface that touches the bottom of the laptop.

Then I bought a very powerful and quiet inline ventilation fan (the kind you use to pump air out of the bathroom), and analog speed dial (make sure you get an AC speed control for an AC fan, or a DC control if you get a DC fan) and some big wide round air tubing, and I set the fan in the opposite corner of the room (or outside the room with the door open) where the noise it generates is harder to hear, and ran the tube up to the cooling-fin encrusted back of the laptop stand, where it quietly blows lots of air on the back, and cools the stand and laptop quite effectively.

I usually run it at the lowest quietest setting "1", but can turn it up to "10" to cool it down quicker when it's overheating.

If anyone's interested I can provide links to the actual products I bought. Desktop and laptop fans were just not powerful enough, and very loud and clumsy, and it sucks to have the fan itself right next to you instead of in the next room. But the inline room ventilation fans are much more powerful and quieter and adjustable, but more expensive, and the flexible air tube lets you position the fan far away from the computer.

I was losing so many hours of work due to overheating that it was well worth investing in all the equipment to really cool it down.

Here are the small and large adhesive heat sinks, which are sold for 3d printers (I got two packs of each size: 16 eur total for 40 small ones, 16 eur total for 8 big ones):

CTRICALVER Aluminium Heatsink, Black Heatsink, Thermal Adhesive Pad Cooler, for 3D Printer, Pack of 10 (20pcs)

CTRICALVER Thermal conductivity of the radiator, heat conduction measures L40 mm x W40 mm x H11 mm, pack of 4

The fan was 185 eur, and the AC speed control was 35 eur or so, and I wired it myself with a switched plug for a couple euros. There are many models of fan, some AC and some DC, that move various amounts of air per minute, with fixed or three or variable speeds, that make different amounts of noise, but I shopped around and am pretty happy with the mid-range one I got. (S&P is a European brand so YYMV.)

Soler & Palau TD-500/150-160 Silent 580/430m3 Air Conditioning Fan + REB-1N AC speed control

The aluminum stand was 36 eur:

NULAXY Laptop Ständer, Einstellbar Notebook Ständer, Ausblendbar laptopständer Kompatibel für alle 11-17 inches Notebooks: MacBook Pro/Air, Dell

The next step I'm planning is making an air filteration system by taping together some filters like this DIY box fan air purifier, but using the powerful inline fan instead of a weak box fan:

https://tombuildsstuff.blogspot.com/2013/06/better-box-fan-a...

I haven't decided what kind of filters to use yet: cheap high flow central air conditioner filters, or more expensive HEPA filters, that restrict the air flow more. The fan is quite powerful so I'm pretty sure it can handle the HEPA filters, but I haven't tried yet. Maybe that's overkill. But after wasting so many hours on overheating, overkill is kind of the point.