Throw open the windows in your home or office to improve the indoor air quality. Remember that the air outside is likely to be much cleaner than the air inside, even in the city. To purify air—and make your space look nice—add plants, which are natural air purifiers that can absorb formaldehyde, benzene, and other chemicals that aren't great to breathe.

Plants won't filter everything, but every little bit helps. To be most effective, use a lot (a NASA study recommends 15 to 18 good-sized houseplants in six- to eight-inch-diameter containers to improve air quality in an average 1,800-square-foot-house), and don't forget to water them.

The plants that filter out the most unwanted chemicals are:

  • Boston fern
  • Areca palm

A few other great bets and the gases they absorb:

  • Aloe vera (formaldehyde)
  • Ficus (formaldehyde)
  • Spider plant (carbon monoxide)
  • English ivy (benzene, formaldehyde)
  • Bamboo palm (formaldehyde, benzene, and trichloroethylene)
  • Rubber plant (formaldehyde)
  • Peace lily (alcohols, acetone, formaldehyde, benzene, trichloroethylene)

For more info on plants, see "How to Grow Fresh Air: 50 House Plants that Purify Your Home or Office," by B.C. Wolverton.

Find more tips like these in "Planet Home: Conscious Choices for Cleaning & Greening the World You Care About Most."