Pollen are small, round-shaped male cells of various flowering trees, grasses and weed plants. The average pollen particle is under 50 microns in size and is less than the width of an average human hair. Pollen can travel as far as 400 miles and up to two miles high in the air. Plants have pollination cycles which are consistent from year to year, though weather conditions can affect the amount of pollen in the air at any one time. Pollination season occurs earliest in the south and starts progressively later in more northern regions. Trees pollinate earliest, followed by grasses. Weeds pollinate last. Pollen vanishes after the first hard frost. Source: AAAAI.
Molds are parasitic, microscopic fungi without stems, roots or leaves. As many as 250,000 spores can fit on one pin head. These small spores float in the air like pollen. They are found outdoors and indoors and their levels peak in the late summer and fall months. Outdoor molds commonly grow in moist, shady areas such as in soil, decaying vegetation, leaves and rotten wood. Cladosporium and Alternaria are common outdoor molds. Indoor molds are found in dark, warm, humid areas inside the home including basements, cellars, attics and bathrooms. Mucor, Aspergillus and Penicillium are common indoor molds. Source: AAAAI.