Clean an engine cylinder air filter
What is the filter on? Car, lawn mower, etc.?
If a car, the auto parts stores have replacement filters, they will help you look up what your car needs.
It's probably better to replace it, but a leaf blower will blow dust out of the filter.
replace if you can. If that isn’t an option pull the filter and vacuum it with a shop vac. We had to do that when we lived in California and wildfires came close to us. It was raining ash like snow and it was the best solution till the air cleared enough that replacing it was good idea.