The fall pollen season has begun, much to the dismay of the more than 36 million Americans who suffer from seasonal allergies. There's nowhere to hide until the first frost ends the growing season.

Ragweed, which is the most common outdoor allergen in the fall, is most prevalent throughout the Northeast, South and Midwest, and commonly found in fields and along roadsides. Allergy sufferers in urban areas can also feel the impact because ragweed grows in abundance in vacant lots. Each ragweed plant produces one billion pollen grains per average season, and the wind can carry those grains up to 400 miles due to their lightweight texture.