We're a red state (in carbon emissions)

Take a look.

Greater Boston is among the reddest parts of the United States in this map, which measures carbon usage nationwide. The map measuring atmospheric pollution levels, from Purdue University's Vulcan Project and featured in the Globe's Sunday Ideas section, shows how vehicle traffic along interstates makes even sparsely populated areas carbon heavy.

Read on from Globe contributor Matthew Battles for the sometimes surprising data about where -- and how -- America pumps out its CO2:

"Southern California is infamous for its smog and air pollution, but how much CO2 do all those cars produce? It turns out nobody really knows. Despite its importance to the climate, CO2 has few if any health risks, so it’s not routinely measured by the dense network of instruments that gauge toxic emissions. To produce this map, researchers started with existing estimates and improved them with measurements of pollutants known to be emitted alongside CO2. Either way, the Los Angeles area emerges as one of the top CO2 sources in the country, chiefly because of the vast amount of time people spend in their cars here.

"When you rank America’s counties by their carbon emissions, San Juan Co. N.M. – a mostly empty stretch of desert with just 100,000 people – comes in sixth, above heavily populated places like Boston and even New York City. It turns out that San Juan County hosts two generating plants fired by coal, the dirtiest form of electrical production in use today. San Juan County, which also has unusually high levels of ozone, shows how a single decision such as how to fuel a power plant can equal the impact of tens or hundreds of thousands of gas-guzzling daily commutes. The lesson wasn’t lost on neighboring Texas, where a surprising coalition of traditional environmentalists, ranchers, and business interests came together last year to block the fast-tracking of 11 proposed coal-fired generating plants.

"Although emissions in the Great Plains and western states seem low, the traces of long-distance trucking and automobile traffic make their appearance in these sparsely populated places; the skeleton of the interstate highway system is clearly visible here as green veins of higher emissions spreading across the middle of the continent.

"Purdue researchers were surprised to discover higher-than-expected emissions levels in the Southeast, likely due to the increasing population of the Sun Belt, long commutes, and the region's heavy use of air conditioning. According Kevin Gurney, assistant professor of atmospheric science at Purdue and the project leader, this part of the map also overturns the prevailing assumption that industry follows population centers: in the Southeast, smaller factories and plants are distributed more evenly across the landscape. Cities, meanwhile, prove less damaging than their large populations might suggest, partly thanks to shorter commutes and efficient mass transit. Of course, urban dwellers also rely on heavy-emitting industry and power generation that has been pushed elsewhere.''

In the animated version of this map,also viewable here on YouTube, the Northeast strobes vividly, its carbon dioxide levels winking on and off as day turns into night. The animation also shows carbon dioxide leaving the continental United States on prevailing winds: one plume gyrates into the Pacific from Southern California, and a great roiling flood piles up over the East Coast and pours out over the North Atlantic to become part of the global atmosphere. According to Gurney, the YouTube animation had received over 170,000 hits as of April 23. One surprising result of making the project available on the web: new data streaming in from researchers and local officials around the world. Where previous climate modeling sought to simplify conditions and keep data sets manageably small, Vulcan is designed as “open-source science” to accommodate an ever-increasing body of information. Gurney's next project, called Hestia, will do for the globe what Vulcan has done for the continental United States, giving vivid displays of hourly carbon dioxide levels around the planet.

For more CO2 maps from the Vulcan Project, click here. Let us know your conclusions.