Nitrogen dioxide monitoring by using passive sampling technique
7.2.1 The areas in urban and suburban areas in Chiang Mai Province will be selected for nitrogen dioxide monitoring. The sampling sites will be selected, based on human activities.
7.2.2 Nitrogen dioxide level in ambient air in each sampling site will be monitored by using passive sampling technique. The sampling tubes will be exposed in the study areas for some period. The tubes will be collected and air sample will be analyzed using spectrophotometry. Sampling will be done twice, in rainy season and dry season.
7.2.3 The correlation between nitrogen dioxide concentration and lichen diversity in each area will be analyzed by using statistical method i.e. Pearson’s correlation.