In the US, grab a basic 20" box fan and toss on a 20x20x1 furnace filter like this one: https://www.homedepot.com/p/Honeywell-20-in-x-20-in-x-1-in-Allergen-Plu

In the US, grab a basic 20" box fan and toss on a 20x20x1 furnace filter like this one: https://www.homedepot.com/p/Honeywell-20-in-x-20-in-x-1-in-Allergen-Plus-Pleated-FPR-7-Air-Filter-90701-012020/203145810 https://www.homedepot.com/p/Honeywell-20-in-x-20-in-x-1-in-A... For extra flow, set up a triangle with the fan on one side and 2 of these filters on the intake end as the other two sides, and duct tape some cardboard to seal the top and bottom.