These Dyson air purifiers are $120 off—just in time for allergy season

When it comes to air purifiers, there are a lot of misconceptions about their effectiveness and whether or not they are worth the money. Science shows they can be effective and worth the investment. You just need to choose carefully.

One of the leading companies in this space is Dyson, which employs more than 350 engineers, chemists, and research scientists who have spent nearly three decades dedicated to air science. The brand’s purification technology is currently in its sixth generation. And two of its signature air purifiers—the Pure Cool fan tower and the Pure Hot + Cool purifying fan—are on sale through May 1.

According to Dyson, both models eliminate 99.97% of particles as small as 0.3 microns (which is 233 times smaller than the width of a human hair, for scale). They achieve this by using fully sealed HEPA filters and three intelligent sensors that track, in real time, the levels of pollution in your home. (You can use the Dyson Link app, which connects to the devices, to follow along.)  These sensors detect particulates (such as dander and dust) and gases (such as nitrogen dioxide and industrial emissions), while also monitoring temperature and humidity. Whenever your purifier detects a certain level of pollutants, it will activate and purify the air.

Air purifiers with sealed HEPA filters provide added protection from bacteria, viruses, smoke, dust, and pollen—while also keeping the air clean of everyday pollutants found in homes, such as dander from pets, fumes from gas stoves, and volatile organic compounds (VOCs). Dyson’s purifiers are certified by the Asthma and Allergy Foundation of America.

Through May 1, you can save up to $120 on both the Dyson Pure Cool and Pure Hot + Cool models.