Air purifiers play many roles. They are the tool of choice for removing harmful particles from the air, including everything from air pollution to pet dander.

But for as many as 21 million Americans with a condition known as “multiple chemical sensitivity,” particles are just part of the problem in the air. For you or someone you know, even a whiff of perfume or a hint of lemon in the dishwashing soap can start the sneezing and scratching and wondering what’s wrong.

Even the best air purifier particle filter (such as the IQAir HealthPro Plus) can’t help unless it is teamed with a separate carbon-based chemical filter (the HealthPro Plusis).

Millions of Americans experience contact dermatitis in reaction to cosmetics, and the National Institutes of Health publisheda study that implicates hair dyes, gels/soaps and moisturizersas the worst offenders, along with perfumes. These products release odors and chemicals into the air, and that’s where an air purifier can help. A typical perfume can contain up to 300 components.

Fragrances in the air can also affect pets’ allergies. And the high-performance air purifiers that protect humans also protect pets. The increasing use of scents in pet products may be one reason why feline allergic airway disease has been increasing. Veterinarians advise against heavily scented shampoos or sprays for pets. Remember, it’s hard for our pets to report their symptoms or emotions.

But those Americans suffering from multiple chemical sensitivitycanreport their symptoms, including burning, stinging eyes, wheezing, headaches, runny noses, skin rashes and other complaints. Extremely low levels of common irritants that go unnoticed by others can cause severe symptoms for an MCS sufferer.

Those with MCS will find some relief at home with the right air purifier.The best overall strategy is to “rid your home as far as is reasonable possible of all pollutants,” according to www.multiplechemicalsensitivity.org. At work, avoid smoking, perfumes and request a workstation or office a safe distance from photocopiers, fax machines and printers.

Air purifiers, of course, cannot protect you when you travel, but at least your living space can be a relatively safe haven with a little effort. Pets and humans alike who have allergies will benefit from a home chemical cleanup. Close inspection of all products such as paints, cleaners and solvents, perfumes and cosmetics and even furniture, carpet and clothing is required. Remember, the MCS patient improves when the triggers are removed. So if you or someone you love suffers from MCS or other chemical sensitivities, the right air purifier teamed with the elimination of fragrances and other chemicals around the house might just give you the help you need.