world gone mad

A few weeks ago there was an article in the New York Times (available through TimesSelect here) citing a study suggesting that children who grow up within a third of a mile of a highway may be sustaining permanent respiratory problems. I grew up in Morningside Heights, about a quarter mile from the West Side Highway, and am currently raising a child less than a quarter mile from the BQE. So this got me to thinking.

I looked at air purifiers. I talked to a few people about them, and got a recommendation for this one.
It's certainly good if you are a smoker or allergic to pet dander. But I recalled my doctor's advice when I asked if I should get one of the then-popular face masks for city cycling: you can't filter the most damaging stuff. "The most damaging stuff" is carbon monoxide and assorted other molecules that industry and autos put into the air, and cities have quite a bit. It was time to do my homework.

The results are almost too good to be true - none other than NASA found (in a one-year study) that houseplants are extremely effective at improving indoor air quality. The full PDF of the report is available here. The basics I got from 9th grade biology: plants convert CO2 to O2 and glucose, which makes them really handy to have around for animals who do virtually the opposite (remember photosynthesis? the Krebs Cycle? Those were good times.).

It gets better. Plants are actually very good at removing not only carbon dioxide but it's more dangerous cousin carbon monoxide as well as formaldehyde, benzine, and a host of other bad guys. Activated carbon in the soil can enhance this effect.

Frugual Living has a good practical guide to using house plants for air scrubbing, with a list of the plants that are best at it. They put the number of plants you want at about 1 per 100 sq ft of your home.

Note for those in the hotter climates: the down side of adding a lot of house plants is that you are also effectively increasing the humidity of your home - all that water you put in your plants they put right back in the air. This study from the University of Florida correctly notes that houseplants in an air conditioned environment have an associated cost, as air conditioners need to dry the air in order to cool it. This actually creates a vicious cycle if you have especially thirsty plants (like bonsai trees) that simply will not tolerate dry conditions.

But up here in the northeast, this is still all great news. My windows are open most of the summer, and the apartment is at it's most isolated (in terms of airflow) in the winter, when the radiators dry out the air so much that we have several humidifiers going 24/7. The idea that a fairly inexpensive and attractive addition to the house can both increase the humidity and clean the air is great news.

I'm looking for a good way to measure both the air quality and the progress of my foliage. I may order one of these and see how it does.