The Willamette Valley grows most of the world's grass seed, and from late May the fields release it. Windows open on a warm evening means a fine yellow film on every surface by morning.
Keep windows closed between 10 am and 4 pm when counts peak, and run the HVAC fan with a fresh MERV 13 filter. Wipe sills with a damp microfibre rather than a dry duster, which just lifts pollen back into the air.
Entryways matter most. A washable mat inside and out, shoes off, and a weekly hot wash of the mats cuts what travels through the house by half.
For recurring clients I add a sill-and-track pass in June at no charge. It's the single most noticeable thing I can do that month.