Now that the weather is getting cold and I'm keeping the windows closed, I starting thinking more about the air quality in my home. I wanted something more natural than those air purifier machines (something cheaper too). I read about how houseplants can help clean the air as well as add some wonderful nature to your living space.

You may not even think that the air in your home or office needs any cleaning, but it is a very common problem due to modern building and decorating materials. Synthetic materials in counter-tops, carpeting, paint, adhesives, fabrics and wallpaper tend to slowly give off fumes, known as "off-gassing". During the seasons when your windows are closed, these chemical vapours can accumulate, leading to eye and lung irritation, as well as other allergic reactions. Houseplants are an easy way to help reduce this problem.

Plants act as natural air filters, because of constant intake of air through the leaves. All manner of chemicals and compounds then move through the plant and end up exiting through the roots. Bacteria and other microbes in the soil then digest or otherwise break these toxins down.

It sounds ideal, but how effective are houseplants at really cleaning the air? A 2-year study done by NASA has the answers. Their interest in the concept is to find ways to keep the air in future space stations clean naturally. Common houseplants were enclosed in glass and exposed to measured amounts of various air pollutants, such as benzene and formaldehyde.

They found that some plants were much better at filtering pollutants from the air than others. The top ten air-cleaning houseplants are:

• Areca Palm
• Peace Lily
• English Ivy
• Cornplant
• Weeping Fig
• Rubber Plant
• Dwarf Date Palm
• Boston Fern
• Chrysanthemum
• Gerbera Daisy

To a lesser extent, also Dumb Cane, Spider Plant, Pothos, Philodendron, various Ficus species and Dracaena species.

You'll need approximately 1 plant for every 10 sq yards (with average 9 foot ceilings) . So a typical living room (20 sq yards or more) would need 2 or 3 plants to help keep the air clean. Make sure that potentially toxic plants (like Dumb Cane) are out of reach of children or pets.

So if you have a corner that gets a reasonable amount of light, you might want to think about getting an all-natural air filter in a pot. Plants won't clean things like cigarette smoke, dust or pet dander, though. You will still have to do a little bit of housecleaning for that.