From rapid urbanization in China to dung-fired stoves in New Delhi, air pollution claimed 7 million lives around the world in 2012, according to the World Health Organization. Globally, one out of every eight deaths is tied to dirty air - which makes air pollution the world's single biggest environmental health risk. And, in areas with very bad air pollution, people live an average of 5 fewer years than those in other areas. Not only in Chinese megacities or indian agricultural areas, people are trying hard to keep air pollution at bay. In Portland, Oregon, a local initiative called Neighbors for Clean Air is using Big Data to make bad air visible. The group is part of an experiment in initiated by Intel Labs, that uses 17 common, low-cost sensors, each weighing less than a pound to gather air quality data. This data feeds to websites that analyze and present comprehensible visualizations of the data. The sensors itself are built using an Arduino controller. They measure carbon and nitrogen dioxide emissions, temperature and humidity. By making the air pollution problem visible, the experiment not only made people recognize the importance of technology in understanding air quality, but Neighbors for Clean Air could forego an agreement with a local metal foundry to cut emissions. If you want to have a look at your own air pollution, go to Air Quality Egg - perhaps one of the several hundred eggs worldwide has been installed in your neighborhood.