I sugges Amaircare. I did some research on air purifier and found that a lot of air purifiers are not 100% HEPA. Even popular brands like sharp or Philips do not have 100% HEPA. IQ Air is the best as it's used by hospital during SARS. But it's very expensive. I found that there's another brand called Amaircare which is as good as IQ Air but 1/3 the price.