Editors' Pick: Originally published Dec. 28.

Air purifiers are said to relieve allergy symptoms, fight pollution, eradicate airborne pollutants, remove unwanted smells, and eliminate germs. It's easy to be skeptical: how could one device have all of these benefits? The term itself -- "air purifier" -- is vague. What exactly does an air purifier do?

The answer depends on the type of machine. Different air purifiers are designed for different priorities. They can, in fact, provide all of the benefits listed above -- but only if you choose the right one. So if you're considering purchasing an air purifier, make sure your intended model is designed to meet your goals.

Luckily, many of today's models are multi-use units with functionality in several areas. To help you breathe more freely, we identified the best new air purifiers and their areas of top performance.

RabbitAir BioGS 2.0 HEPA Air Purifier

The BioGS 2.0 won international product design awards when it premiered in 2014. It remains a frontrunner in the marketplace a year later.

It combines a three-filter system with an additional ionization option to keep common household air pollution at bay. Large particles are caught in its pre-filter, the HEPA filter removes the bulk of pet dander, bacteria, and dust particles, while the charcoal filter deodorizes. Its coverage area is up to 625 square feet.

The BioGS is as easy on the eyes and ears as it is on the lungs. Nearly two feet high, it's a sizable unit, but its modern white finish and minimalist curves earn it points in the style department. When the unit is not being configured, its indicator lights fade out, so you won't be bothered by unwanted brightness. The five-speed motor is hardly audible in its lowest settings, and has been lauded as a good provider of white noise.

It's also Energy Star Certified and has an integrated auto-shutdown feature, should curious hands tamper with the front panel. Talk about a breath of fresh air.

Image placeholder title

Buy the BioGS 2.0 now

Rowenta Intense Pure Air

Like the BioGS, this smart air purifier also has a multi-filter system that includes a pre-filter, HEPA filter and active carbon filter. However, the Rowenta Intense Pure Air adds another filter that might be of interest to consumers concerned about formaldehyde.

Formaldehyde is a cancer-causing chemical that's given off by many building supplies, cleaning fluids and consumer products. The Rowenta Intense Pure Air has a special filter that uses "Nano Captur" technology to eradicate the chemical. The filter turns brown as it destroys formaldehyde, so you not only know that it's working, but you know when it's time to change it as well.

Another feature that separates this filter from others is its pollution sensor. The machine will automatically detect the presence of harmful chemicals in the air and adjust its filtration speed to optimize air quality.

The bedroom size purifies up to 400 square feet. For a larger area, you can purchase the Rowenta Intense Pure Air model that covers up to 835 square feet.

Image placeholder title

Buy the Rowenta Intense Pure Air now

RXAIR Plus UV Air Purifier with TiO2

This updated machine earned a spot on our list for its excellence in germ eradication. The powerful tower kills more than 99% of airborne bacteria and viruses; its manufacturer touts that RXAIR machines are used in over 400 hospitals. It's an industrial-quality purifier strong enough for the medical profession, schools, nurseries, and meeting places, and a good addition to any home with an immunocompromised inhabitant.

The RXAIR Plus utilizes high-intensity ultraviolet light (UV-C) to kill airborne bacteria and viruses. Since it doesn't use any filters, there are no ongoing ownership costs beyond operational electricity.

It also boasts proprietary titanium dioxide (TiO2) technology designed to eradicate volatile organic compounds (VOCs), a form of air pollution particularly irritating to those with respiratory illnesses and chemical sensitivities.

This 32-inch-high unit provides 800 square feet of sanitization coverage. Its adjustable fan gives a degree of control over air circulation and noise.

A major caveat: while UV-C light sets the standard for anti-viral and antibacterial air cleansing, and this model battles potentially dangerous VOCs as well, it does not offer other benefits often sought after in air purifiers, such as large particulate filtering.

Image placeholder title

Buy the RXAIR Plus now

InvisiClean 4-in-1 Air Purifier

The InvisiClean 4-in-1 Air Purifier is a competitively priced powerhouse with a full array of air cleaning potential. It's a quadruple threat against dust, allergens, and germs, and is especially efficient at removing unpleasant smells.

It has a four-level cleaning system, which pulls contaminated air through a HEPA filter, blasts it with UV-C light, ionizes it and removes odors. Both the UV light and the ionizer can be turned on and off independently.

Adding to the customizability of InvisiClean 4-in-1 Air Purifier, there's also time feature that allows it to be programmed to turn off between 1-8 hours after activation. The model is sleek and modern looking and rated to clean the air in a medium-sized room.

Image placeholder title

Buy the InvisiClean 4-in-1 Air Purifier now

HAYATA Car Air Purifier

Anyone spending a lot of time in an unventilated automobile is likely to see the appeal of an in-car air purifier. This capable Hayata Car Air Purifier console includes a true HEPA and charcoal filter and a 12V car adapter to keep the commute free of allergens, smells, and pathogens.

The Hayata is a tidy multifunctional unit, measuring about 8" x 6" x 2". In average-sized cars, it can circulate entirely clean air every 15 minutes or so. It also has a filter replacement notification light and a sensor that indicates current air quality. This air quality sensor also enables its smart mode, which automatically adjusts the fan speed to match its environment.

It can be secured to the back of a headrest, underneath a seat, or on the dashboard with Velcro (included). If you want an air purifier you can take anywhere, you can also use the Hayata in smaller rooms with the help of a universal power adapter (sold separately).

It does contribute to cabin sounds - with a running noise of 52 decibels, it's about as loud as an electric toothbrush. You don't need to worry about it draining your battery, though. It has an automatic shutoff for when the car is not running.

Buy the Hayata Car Air Purifier now

Image placeholder title

-- Written by Michael Franco

Disclosure: TheStreet has advertisers and partnerships; we may get a share of the revenue from your purchase.