Dust mites live in bedding, upholstered furniture and carpeting; mold grows in damp places such as bathrooms and basements; and pets ??? well, if you have a dog or a cat, you should at least keep the animal out of rooms where you spend a lot of time, such as your bedroom.??? Cockroaches. ???They are a major allergen,??? Lehach says, and are widely prevalent in urban settings ??? both housing and s