So far, the month of March has been usually warm, following an equally warm winter. That has helped consumers in colder climates save on energy bills. But here’s the bad news: an apparent early departure of winter has heralded the early arrival of itchy eyes, sneezing and stuffy noses. That’s because many plants and trees (ash, birch, maple and cedar, to name but a few) are pollinating weeks ahead of schedule as a result of the unusually warm temperatures, and producing more pollen than usual where rainfall amounts have been elevated as well. In fact, it’s rainfall and daylight, rather than temperature, that has the greatest effect on tree pollen production. If you live in the Northeast or Midwest, where tree pollen season usually starts in April, you are probably especially aware of the early allergy-season start this year. If you don’t already own an air purifier, now is a good time to get one. In fact, an air purifier is one of your best defenses against seasonal allergies, at least when you are indoors.

About one in four Americans suffer from allergies of three basic types: inhalation, food and contact allergies. There are two basic types of inhalation allergies: seasonal (that’s the kind caused by pollen), and perennial allergies caused by indoor allergens: house dust mites, mold spores and pet dander. Allergies result when the body’s immune system incorrectly responds to any of these otherwise harmless substances, airborne pollen included.

An air purifier can help protect you against both types of inhalation allergies. Medical experts – including The American Lung Association, and websites such as WebMD, among others – agree an air purifier can help reduce or eliminate seasonal allergies, at least so long as you are indoors, by reducing or eliminating pollen and other airborne allergens before they reach your airways or lungs. But your air purifier can’t protect you when you’re outdoors, so it’s also important to keep tabs on the local levels of various allergens. The National Allergy Bureau maintains awebsitethat enables you to track the local levels of allergens where you live.

So how bad are allergies so far this spring? One allergist in New York City told ABC News the winter there was so mild the fall allergy season never even really ended. “We didn’t really have a nice deep freeze this winter, so a lot of what would have been killed in the fall didn’t die,” she said. Of course, it’s worth keeping in mind that last spring many allergists saidthatspring of 2011 was one of the worst allergy seasons ever, the result ofso muchrain. But this year the increase in pollen is attributable totemperature, notrain. In fact, January of 2012 was almost 6 degrees higher nationwide than in a normal year, and that trend seems to be holding in the first half of March. Meanwhile, don’t count on the early start of allergy season resulting in an early end to the season. In fact, this spring season of allergies is also likely to last longer than usual, too, experts say.