Chemical composition and physiological responses of lichens are widely used as indicators for assessing environmental alteration in several land uses. Therefore, the objective of this study was to utilize ion content sand photosynthetic parameters inthe lichen Parmotrema tinctorum to evaluate air quality in industrial,agricultural and natural areas in Thailand. The lichen samples were collected in a relatively unpolluted area, and then transplanted at one natural site in the Khao Yai National Park, one agricultural site and three industrial sites in Map Ta Phut. 0uring the exposure period of 8 months (October 2013 to June 2014), the transplanted lichens were periodically collected 4 times for analysis of ion contents including Cl-, NO3 -, SO4 2- and PO4 3-, as well as for measurement of photosynthetic parameters including net photosynthesis, chlorophyll fluorescence (Fv/Fm), total chlorophyll (a+b) content and the degradation of chlorophyll a, which was estimated by O0435/O0415 ratio. The mean concentrations of all ions had increasing trends at sites closer to the industry. The monitoring site that was located downwind of the industrial core center for a longer period of time had higher ion concentrations. All photosynthetic parameters were conspicuously lower at the closest sites to the industry, and had negative correlations with the accumulated ion contents. This study clearly confirmed that lichen can be used as a bioaccumulator of inorganic pollutants and a bioindicator of atmospheric purity, whic his appropriate for developing countries where air quality monitoring instruments are insufficient.