This is such a refreshing idea. There is already too much pollution, so why not use the pollution to create art? Instead of spray paint, artist Paul ‘Moose’ Curtis uses stencils and a power washer to CLEAN his canvases. I love the idea of taking away what is unnecessary to create something completely new. His most recent canvas was the 140 foot wall inside the Broadway tunnel in San Francisco. The artwork was made up of varieties of indigenous plants that would be found in the area of the tunnel.