If you're lucky enough to live in an area that doesn't experience heavy pollen ... you might ignore this.
Otherwise, you might want to pause your outdoor painting and deck staining until the heavy pollen stops falling.
Here in the southeast, we've been so warm all winter that we're ahead of the normal spring season by about three weeks.
This would normally be a great time to precede the pollen with a fresh coat of exterior paint or stain. But with our world covered outside with that yellow dusting of nature's rejuvenator, it is exactly the wrong time to apply outdoor coatings.
The risk you accept if you choose to proceed is a grainy looking coat of paint or stain ... essentially pollen grains encapsulated in the surface of your new coating. Unsightly at least and potential for early failure at worst.
So if you must paint, take it indoors for a few more weeks. When that yellow cloud subsides you'll produce a much more long-lasting protection for your home or deck.
NOTE: You should always clean with combined detergent and mildew killing agent, rinse thoroughly, and allow the surface to air-dry before painting or staining any exterior surfaces ... regardless of the season. I like to use deck wash a day or two before entertaining. If you apply either before a thunderstorm, nature will add a "natural rinse" when it showers ... saving water.