Below is a list of prime pollens and when they are prevelant in the enviornment.

April through the end of May: tree pollen May through the end of June: grass pollen Mid-August through the first frost: weed pollen, including ragweed pollen Mid-October through mid-November (the rainy part of the fall): mold spores All year round: dust mite, cockroach, feather, animal dander.