The best way to find out if you need to improve your indoor air is to have your air tested by a professional. Any number of noticeable symptoms may also be trying to tell you it’s time to clean your air ducts. Skin irritations, watery eyes, coughing, congestion, and obvious particles in the air can all be signs of dirty ducts.  Keeping a schedule of your air duct cleaning is also a good way to stay on top of air quality – you can’t see the dirt in your ducts, so it can be an “out of sight – out of mind” problem.