The World Health Organization recently linked air pollution to millions of premature deaths around the world. Most of the pollution comes from burning fossil fuels for electricity and transportation that has blanketed some cities with a haze. But not all air pollution is so visible. An infrared camera is being used in London to see the dirty air particles that people can’t. As we hear from VOA’s Deborah Block, the results could help people avoid places where the air is the filthiest.