Remember that if you open your windows, even briefly, during our clement spring days, it takes 24-36 hours of HVAC circulation to filter the air back to “indoor quality.”
To reduce the tracking in of pollen on dog feet, have them dip their paws in a pan of water and dry them off as they return from their “potty sorties.”
During the spring the yellow green carpet of pollen is primarily from the pine and oak trees. The pine pollen is very large and easily seen, but it is the tiny oak pollen that stays airborne longer that causes most of the allergic misery.
If you open the windows in your home, keep in mind that it takes about 24 hours for the central air conditioning filtration to remove the pollen and mold that came into the house once you close the windows.