Ah, spring — birds chirping, flowers blooming, sun shining ... and sneezing, wheezing, coughing and itching. The culprit: pollen.
According to pollen.com, pollen is a plant's only form of reproduction and it's produced in mass quantities. It is carried in the air and can land in a person's eyes, nose, lungs and on the skin.
Pollen is produced by trees, grass and weeds and spreads by wind.