Artificial trees, smog-free towers, and other air-purifying urban structures

The mayor (centre) of Toulouse, France unveiling the city's pollution-absorbing artificial tree in September. Photos: AFP

The French city of Toulouse is currently trialing a new addition to its urban landscape. An artificial tree can suck up pollution and release clean air – and could soon be coming to other city centres. But this isn't the first air-purifying concept out there. In fact, there's no shortage of ideas for eliminating fine particles, from green walls to advertising billboards.

Since mid-September in the southwestern French city of Toulouse, a start-up has been trialing a new generation of air purifier that can help tackle pollution. This futuristic structure actually features microalgae that feed on carbon dioxide – like plants – and release oxygen.