Several researchers and practitioners, working together and in parallel, have come up with a design for an in-room air purifier which can remove a significant amount of COVID-19 virus from the air.
The design involves making a ‘box’ out of four 20″ MERV-13 filters (the ‘sides’ of the box), a 20″ box fan (the ‘top’ of the box), and a cardboard (the ‘bottom’ of the box’). Air flows in through the filter sides, removing particulates of the sizes that can transport COVID-19 particles, and then flows out through the fan at the top.
These devices can be built from parts that cost less than $200 USD, without any special tools.