We're all familiar with moss, the fuzzy green stuff that grows on top of statues, along trees and sometimes in the cracks of asphalt. Moss brings a bit of character to its surroundings. It also may be an easy, low-cost way to monitor pollution in cities.
A study conducted by Japanese scientists and published in Landscape and Urban Planning analyzed moss in Tokyo's Hachioji City to see what it could tell them about four different aspects of pollution: the severity of nitrogen pollution, the degree of pollution from nitrogen oxides, atmospheric purity and drought stress that accompanies urbanization. While they were unable to use moss to determine air purity, researchers found that the stable isotopes in moss can reveal the degree of nitrogen pollution in the air and indicate drought levels in cities, a sign of the heat island effect.
In addition to its isotopes, the scientists considered changes in mosses' shapes, densities and prevalence in an area.
"This method is very cost effective and important for getting information about atmospheric conditions," Yoshitaka Oishi, an associate professor at Fukui Prefectural University and one of the authors of the study, explained to the Guardian.
"Mosses are a common plant in all cities so we can use this method in many countries ... they have a big potential to be bioindicators."
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