地衣作为空气污染的指示生物。

Naturwissenschaften. 1976 Aug;63(8):364-7. doi: 10.1007/BF00607929.

Field and laboratory studies have demonstrated that lichens are extremely sensitive to sulfur dioxide and that lichens are fairly sensitive to hydrogen fluoride and heavy metals. Further studies are necessary to assess lichens' relative sensitivity to oxidant air pollutants.

野外和实验室研究表明，地衣对二氧化硫极为敏感，且对氟化氢和重金属也相当敏感。有必要开展进一步研究，以评估地衣对氧化性空气污染物的相对敏感性。