When you sign a lease committing yourself to a unit in an apartment complex or building, you're agreeing to live in close quarters with strangers. You're also making the assumption that your building will be properly managed and maintained. That includes such factors as air quality and adequate pest control. As a tenant, you have rights, of course, but some of the most serious threats to your health -- such as carbon monoxide -- are ones you can't even see or smell. Particularly scary is the p.