>Get a standard box fan, get a furnace filter that has HEPA ratings, duct tape the furnace filter to the back of the fan. Please be very careful with this. Thi

>Get a standard box fan, get a furnace filter that has HEPA ratings, duct tape the furnace filter to the back of the fan. Please be very careful with this. This significantly strains the motor of your average cheap box fan, and hot motors tend to die faster and can get hot enough to melt plastic and start fires. I'd really recommend an actual air purifier instead, especially if it will run while you're asleep or not at home.