Sometimes we need to bring our own air filters. #BYOHEPA
These portable solutions will not clean entire spaces well enough to drop other precautions like masking. The physics of air movement make it difficult to recommend reliance on a personal air filter for safety, as blowing clean air can bring some contaminated air with it. Consider it an additional layer of protection in addition to a well fitting respirator and proper ventilation whenever possible, especially where appropriately sized HEPA filters are not in use. Consider adding eye protection if blowing air directly at your face.
Travel DIY air filter
In the spirit of the Corsi-Rosenthal Box, @SharonBurnabyBC came up with a winning combination of a small, rechargeable battery operated fan, and round HEPA filter of similar size. Important to this combination of parts is access to the power button and recharging port once the filter is attached, as many fans place the on/off button and USB port in the back, where it would be inaccessible once taped to the filter. The two HEPA filter options listed below have been tested and fit with this fan.
A 1cm “shroud” covering the perimeter of the face of this fan is suggested.
I made a portable, rechargeable air filter using the principles of a Corsi Rosental. Materials Used: Rechargeable fan, HEPA filter (intended as a replacement filter for a $550+ air filter), cardboard, duct tape. pic.twitter.com/7LwJBrxrYc
— SharonBC,Canada (@SharonBurnabyBC) July 10, 2022

Parts list:
USB Rechargeable mini fan (This mini portable fan can last 9 to 42.5 hours with fan only – The working hours based on different speed) (original tested item sold out)
True HEPA filter (US) (closed bottom)
True HEPA filter (Canada) (this one has an open bottom, so cut a piece of cardboard or foam board to cover the opening)
Tape
Optional: Powerbank for adding run time if needed.
Optional: Mesh drawstring bag for ease of carrying and lower profile. Can be run right within the bag, this one is tested to fit with the US filter.
Wynd
The Wynd is a powerful portable HEPA filter, at around $130 range. It moves a lot of air but is louder than the DIY portable filter. It fits in mesh water bottle pockets on backpacks, and air flow is adjustable.

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