Tonight, an estimated 5,000 people will be sleeping rough on Toronto's city streets. To address this stark statistic and an ongoing issue, two Canadian artists Patricio Davila and Dave Colangelo have initiated In The Air, Tonight, a public data visualisation project that monitors twitter for conversations about #homelessness.

This undertaking involves two huge outdoor LED displays, mounted to the side of the Ryerson School of Image Arts building and Ryerson Image Center in Toronto. The installation monitors Twitter activity, and each time someone tweets about #homelessness, a pulse of light is sent across the LED facade. Accompanied by a microsite, which aggregates all these twitter conversations into one place, the civically minded project has aspirations to address some of the stigmas and misconceptions surrounding homelessness by making the conversations surrounding the issue public facing.

We've seen participatory projects like this in the past. Take for example NOX which let members of the public control whether the encasing LED display was switched on or off. Both reply on the public's involvement, however, what is special about In The Air, Tonight is that it addresses a real problem and social epidemic, connecting the online and offline worlds in a constructive and socially conscious way.