Here's another good article from the science magazine Nature: Cities offer hope for cleaner world. The article surveys the pollution reduction programs that have been implemented in several cities and discussed at a recent conference of city governments.
Representatives of more than 20 world cities have gathered in London to trade ideas on how to address climate change. The summit is the first to bring together city leaders, rather than national governments, to discuss attempts at reducing greenhouse emissions....We should expect cities governments to be more effective at pollution reduction than national governments because..."cities have control of transport, managing waste and future planning..."
Cities are also the place where most of the world's people live. This year, the proportion of the world population living in urban areas passed 50% for the first time. And because of their dense transport and power systems, cities account for 75% of the world's energy use.The solutions covered at this conference apply to cities ranging from London and New York to Curitiba, Brazil. With such variety, I expect that Pittsburgh could find some solutions that are applicable here.