As bad as the air quality may be outside your home, it can be even worse inside. The federal EPA estimates that indoor pollutant levels may be as much as two to five times higher than outdoors, which can pose a risk to your health and comfort. While there are a number of ways you can help to clean your indoor air, one of the easiest and most effective is by placing any or all of the following houseplants in your home, and letting nature do the work for you: