As March marches on and warmer weather attempts to filter into the United States, plants are reproducing like crazy and making millions of people miserable in the process.

Pollen, you may remember from elementary school, can be transferred from one plant to another through wind, on an insect, or on the fur of an animal. It's when pollen spreads away from its source through wind that it begins to cause problems for allergy sufferers the world over.

As temperatures begin to warm up and the seasons change, plants will start the reproductive process and the yellow allergens of doom explode seemingly overnight. The culprits vary by location and time of year. According to pollen.com, today's sources of misery in Mobile, Alabama (where yours truly is sneezing it up) are oak, fir, and grasses. In Dallas, the major producers today are oak, hackberry, and maple.

If you've never seen what a grain of pollen looks like under a microscope, it's essentially a wrecking ball covered in spikes. The barbs allow the grains to stick to things easier, and in the case of allergy sufferers, that includes the inside of your face.

When the pollen enters through your nose or mouth, its presence triggers your immune system to release histamine in an attempt to fight it off. Histamine causes "increased vascular permeability," meaning that your nose will start running, you'll start sneezing and coughing, and your eyes will start watering up. Drugs aptly called antihistamines serve to prevent histamine from screwing with you so much and help to relieve some of the symptoms of seasonal allergies.

Scientists are able to come up with a "pollen count" to help the public get an idea of how much pollen is in the air on any particular day. According to Wunderground, the pollen count "is expressed in grains of pollen per square meter of air collected over 24 hours." They then condense the number into an index ranging from 0 (very little pollen) to 12 (clouds of pollen).

As shown by the popular allergy website pollen.com, pollen levels across most of the United States will be pretty high for the next couple of days as warm air (briefly) takes hold.

Numerous sites have tips for allergy sufferers, but they're more obvious than helpful. Limit your time outside on high pollen days, cover your face as much as possible, make someone else mow the lawn, don't stick your face in a flower. Pretty sound advice.

From one allergy sufferer to another, we'll get through this. Godspeed.

[Images via AP / Dartmouth / pollen.com]