All of this sounds difficult and expensive. But there is another possible solution that is simple and inexpensive. NASA (the National Aeronautics and Space Administration) was trying to find ways to clean the air in space stations. One scientist with NASA discovered that houseplants actually remove pollutants from the air. Certain plants seem to do this better than others. Spider plants, for example, appear to do the best job. Even defoliated plants (without leaves) worked well! In another study, scientists found that the chemical interaction among soil, roots, and leaves works to remove pollutants.