In December 2013 when Sarah Jovan and Geoffrey Donovan, two scientists with the U.S. Forest Service’s Pacific Northwest Research Station in Portland, Oregon, crisscrossed the northwest area of their city they had no idea they were onto something big. Armed with a ladder and collection equipment, the two spent most of that gray and rainy month carefully plucking hundreds of moss samples off the trunks of the city’s hardwood trees.
They were in relatively uncharted scientific territory, though their research focus seemed straightforward enough: determine if moss, in particular, the ubiquitous Lyell’s orthotrichum moss which grows abundantly across much of the city, could help measure urban air pollution.
