I'm trying to put together my Christmas list (per the request of my family) and I came across this book: How to Grow Fresh Air. It's all about the 50 best houseplants to remove indoor pollution.
I know lots of you are choosing potted plants to use as sustainable centerpieces. This book might give you some good options for plants to choose. It could also be fun to attach a little tag explaining why you chose the plant you did. It might inspire some of your guests to think about the potential toxins within their own homes.
P.S. The plant featured above is a Boston Fern, which is apparently one of the most efficient plants for removing formaldehyde, the most common indoor pollutant.