There's a fascinating new study reported in New Scientist that washing your hair less is better for the environment. According to the article:

Lakshmi Pandrangi and Glenn Morrison from the University of Missouri in Rolla exposed eight washed and eight unwashed hair samples to ozone for 24 hours. They found that, on average, unwashed hair absorbs around seven times as much ozone as freshly washed hair (Atmospheric Environment, DOI: 10.1016/j.atmosenv.2008.02.009). 'Ozone is probably reacting with components of hair oil,' says Morrison.

They don't cover this aspect of it (and please keep in mind, I am not some fancy university scientist but a mere  blogger, as if you didn't know that), but I would venture to say that the less often you dump chemical compounds found in beauty products like shampoo down the drain, that makes an environmental impact as well. Right? Maybe?

No news on whether you should stop washing your face twice a day, but if you do want to err on the green side, cleanse with face wash that boasts environmentally friendly ingredients. This public service announcement will now end.