Pollen is able to float in air due to its small size and low density. Pollen grains are typically between 10 and 100 micrometers in diameter, and their density is typically around 1,000 kilograms per cubic meter. This means that pollen grains are about the same density as air, which allows them to remain suspended in air for long periods of time. Additionally, the shape of pollen grains, which is often spherical or oval, also helps them to remain airborne.

The ability of pollen to float in air is important for the reproduction of plants. Pollen grains are produced by male flowers, and they are transferred to female flowers by wind, insects, or other animals. When a pollen grain lands on a female flower, it germinates and produces a pollen tube, which grows down the style of the flower to the ovary. The pollen tube contains sperm cells, which fertilize the eggs in the ovary, resulting in the production of seeds.