Understanding the Pollen Count

Because of the unusually warm winter, allergy season is hitting early and hard this year, and you'll surely hear a lot of buzz about the pollen count. But what does this number mean, and how is it obtained? Before we explore these questions, let's take a closer look at pollen itself. When weather conditions are favorable, seed plants begin to produce a fine powder known as pollen, which consists of microscopic pollen grains. Pollen grains carry male gametes, and they are transferred to female plants in the process of pollination.

Entomophilous ("insect-loving") plants typically have bright flowers and produce heavy, protein-rich pollen that is transferred by pollinating insects like bees; this type of pollen poses no threat to allergy sufferers because it is too heavy to travel through the air. Anemophilous ("wind-loving") plants produce great quantities of lightweight pollen for wind dispersal, and this invisible, airborne pollen is to blame for allergies.

Allergy to pollen is known as hay fever, seasonal allergic rhinitis, or pollinosis. Various trees, grasses, and weeds produce the springtime pollen that irritates allergy sufferers. Ragweed is the most prolific producer of pollen; it is estimated to cause about 75% of pollen allergies.

Common symptoms of hay fever include: sneezing fits; a stuffy, watery nose; swollen, itchy eyes, nose, throat, or mouth; headaches; sore throat; insomnia; and difficulty breathing. If experienced year after year, these symptoms can worsen and lead to chronic sinusitis or asthma.

The amount of pollen in the air determines whether hay fever symptoms will develop. A pollen count tells us how much pollen collects in a certain amount of air over a certain amount of time; it is usually expressed in grains of pollen per cubic meter over a 24-hour period. Pollen grains are collected using air-sampling devices that trap them on a sticky surface. Then an expert counts the pollen grains using a microscope. The counting process can take several hours when the pollen count is high.

Similar to a weather forecast, a pollen forecast is a prediction of future pollen levels and helps allergy sufferers plan their outdoor activities and medication regimens. Specific for geographical regions, pollen forecasts take into account pollen counts, temperatures, precipitation, weather forecasts, and other natural events. You can view the four-day pollen count forecast for your city by entering your zip code in the box below.