'Nowcasting' Pollution on the Streets of London

The London Air Quality Network at King's College London offers a "nowcast" on its website of pollution levels across the city, updated by the hour using reports from air monitoring stations across the area. The real-time (or almost real-time) visualization is impressively specific, allowing any Londoner to zoom into a view of Ozone, Nitrogen Dioxide and particle pollution levels practically down to the block.

What's more telling about these maps though, whether you live in London or not, is the way they they visually highlight the predominant source of the problem: "Much of the pollution in London," the researchers write, "is associated with traffic."