Every time Los Angeles exhales, odd-looking gadgets anchored in the mountains above the city trace the invisible puffs of carbon dioxide, methane and other greenhouse gases that waft skyward. Halfway around the globe, similar contraptions atop the Eiffel Tower and elsewhere around Paris keep a pulse on emissions from smokestacks and automobile tailpipes. And there is talk of outfitting Sao Paulo, Brazil, with sensors that sniff the byproducts of burning fossil fuels.
It’s part of a budding effort to track the carbon footprints of megacities, urban hubs with over 10 million people, which are increasingly responsible for human-caused global warming.
Read more: http://www.laboratoryequipment.com/news/2013/05/project-will-track-city-carbon-footprints