To help fight air pollution while recycling, designers Mario Caceres and Cristian Canonico have designed a set of beautiful air-filtering trees for the SHIFTboston urban intervention contest. Called TREEPODS, they would help filter the C02 and would be powered by the sun and children playing on seesaws. This would use the humidity swing process developed by Columbia University which captures C02 and releases oxygen. Constructed entirely out of recycled plastic bottles, the treepods would also provide shade, lovely lighting, and shelter for birds. For more information: Inhabitat and dvice.