High Most individuals with any sensitivity to these pollens and molds will experience symptoms. Moderate Many individuals sensitive to these pollens and molds will experience symptoms. Lower recorded daily pollen counts following higher seasonal pollination patterns may not provide any relief to allergy sufferers who have been repeatedly exposed to pollens during the season. Pollens are transmitted from plant to plant in several ways. Depending on the size and the weight of the pollen, they may be carried via the wind, sometimes requiring certain environmental conditions such as humidity or temperature for transmission.
Insects also carry pollens from plant to plant.
Contrary to popular belief, it's not the pollen from flowers that is the major source of most people's allergies. In addition, when it's pollination season, plants release into the air extremely large numbers of pollen ovules, which become the primary source of allergen irritants. The most potent allergenic pollens come from the grass family, ragweeds, and birch and oak trees. Depending on what area of the country you live in, pollination dates will vary from region to region for the same plant species. In addition, different plant species have different cycles.