Seeing a lot of posts about fires and smoke in the east and for anyone who owns or rents a house and doesn't have an air purifier try and look for a MPR 2200/MERV 13 furnace filter and run the furnace fan as much as you can, it can help the air quality in your house.
if you live somewhere that you don't have access to a furnace or can otherwise change the filters you can buy a 20x20 merv 13 filter and strap it to the back of a box fan as a low budget but highly effective air purifier! you could even go all out and make a megafilter by taping multiple 20x20 filters into a cube shape and duct taping that to the box fan. i've been doing this every summer when the smoke wafts up to my neck of the woods and it works very well.
basic box fan filter instructions
corsi cube box fan filter instructions