Lichen is a bioindicator which lacks roots and therefore gets nutrients directly fromprecipitation, atmospheric gases and dry deposition of airborne particles. A survey of lichens, in four Metro Manila sites and two sites near and around coal fired power plants, found the lichen Pyxine cocoes (Sw.) Nyl. (Physciaceae) as being abundant and ubiquitous in all the six study sites. X-ray fluorescence spectrometry of samples of the species yielded wide data ranges for several air pollution-related elements (such as S, Pb, Zn, Cu, Co and Br) in the sites, indicating that this lichen species could be used to differentiate levels of the cited elements in polluted and non-polluted sites.

Key words: atmospheric pollution, biomonitor, Pyxine cocoes (Sw.) Nyl., Physciaceae, lichens, X-ray flourescence, XRF, coal-fired thermal power plant, Batangas, Mauban, Metro Manila, Southern Luzon, Philippines