Indoor Air Quality in Homes
What Do I Do If I Have an IAQ Problem in My Home?
EPA's indoor air program is a non-regulatory program, so while we can provide information and resources, we can not visit or inspect your home. If you suspect you have an IAQ problem in your home, but you don't know what is causing it, start by looking at The Inside Story: A Guide to Indoor Air Quality
If your problem appears to be structural, you may be able to get help from your city building inspector (in most cities this is part of the Building Department- see the blue government section in the front of your phone book).
Otherwise, you may need to hire a consultant. If you can first narrow down possible sources of the problem, you can focus your consultant search. For instance, if the problem is in the ventilation system, you can hire a ventilation specialist. If it's a plumbing problem, you should start with a plumber. If you cannot tell the source of the problem, or previous specialists are stumped, you may want to hire an IAQ consultant. But you should always call several to compare costs, qualifications, and experience. Sampling may be necessary, but it's pricey and you should be wary of a consultant who proposes sampling without also conducting a thorough investigation, asking a lot of questions and doing a complete visual inspection of your home.
For more on choosing an IAQ consultant, see page one of
http://www.health.state.mn.us/divs/eh/indoorair/contractors.pdf 
Publications:
Resources:
The Tenants Union ( http://www.tenantsunion.org/) Information about tenants rights in Washington.
Community Alliance of Tenants ( http://www.aracnet.com/~cat/) Information about tenants rights in Oregon.