How good are air ionizers at alleviating indoor pet allergies?

Do air ionizers work? or air purifiers?

• my friend has asthma, and her dog produces quite a bit of dander and it gets my friends asthma pretty bad, but she wouldn't give up her dog for anything. i'm looking into buying her an air ionizer or air purifier for a present. do they work? what's the difference between the ionizers or the purifiers? and can they be bad for you? what do you recommend? thanks so much x

• Answer:

  Ionizers don't do much of anything other than charging the dander and making it stick to things like the carpet and bedding. The ozone they produce is not healthy. Electrostatic filters work on a similar principle, but they include filters that catch the particles and they do not produce ozone. One of the best ways to reduce dander is to get rid of carpeting. Otherwise, the next best thing is to get an upright vacuum that has HEPA filtration. The Eureka Boss upright is a inexpensive HEPA vacuum. The filtering capacity only works if the vacuum bags have pores of 0.2 microns or less - these are not standard bags, but they area avialable online.