It was your cocoon for the cold season ? but your airtight home could be harming your family's health. By shutting the windows all winter, you also shut off ventilation and air circulation. That means you kept the house warm, but allowed irritating and sometimes toxic particles to build up.

The lack of ventilation in homes is one major cause of indoor air pollution, experts say. According to the Environmental Protection Agency (EPA), indoor air pollution is two to five times worse than outdoor air pollution. And the at-home version can cause or aggravate asthma and allergies, which are on the rise in the United States.

You can't fix outdoor pollution (at least, not on your own). But you can detox your home. Start now by following the easy steps in our room-by-room guide.