5.1 To produce an air quality map, in oder to define the zones of different air quality in the study areas based on lichens community
5.2 To determine the concentration of nitrogen dioxide in Chiang Mai City by using passive sampling technique
5.3 To indicate the relationships between lichen indexes and concentration of nitrogen dioxide in ambient air by using passive sampling technique
5.4 To study the distribution of some selected lichen species in urban and suburban areas of Chiang Mai