A diagram showing concentrations of methane collected on a cross-country trip in 2010.
Ah, summertime — the perfect excuse to set up a gas chromatograph in a rented camper and drive across the country sampling methane.
Or at least that's what a team of researchers did in the summer of 2010. The scientists drove across the southern United States and measured levels of methane in the atmosphere along the many roads and highways upon which they traveled.
In many areas, they found higher concentrations of methane than had previously been measured. That's a cause for concern because, among other reasons, methane traps more heat than carbon dioxide, making it a more potent greenhouse gas and thus of concern for global warming, according to a study detailing the trip’s findings and published recently in the journal Atmospheric Environment. (Although methane may be a more potent heat-trapper, carbon dioxide is still the main greenhouse gas of concern because there is much more of it in the atmosphere.)
For the rest of the story: http://www.livescience.com/32074-methane-cross-country-drive.html