Bio-Monitoring of Air Quality Using Leaf Characteristics

An evaluation of eight roadside ornamental trees was conducted for the purpose of evaluating their potential as bio-indicators of air quality. Tree leaves were analyzed to determine leaf area, stomatal density, and stomatal pore size. Leaf samples were collected from two sites: Ludhiana city (polluted site) and the university campus (control site). The mean stomatal density of selected tree species ranged from 200–412 mm⁻². In selected trees, mean stomatal density ranged between 246.88–351.56 mm⁻² (control > polluted). Among selected tree species, the mean stomatal length ranged from 8.61–14.40 μm. The location-wise order of mean stomatal length in selected trees ranged between 9.88–11.66 μm (control > polluted). The mean stomatal width of selected tree species ranged from 4.03–1.39 μm The mean stomatal width of selected trees ranged between 2.47–2.87 μm (control > polluted). Polluted sites showed reduced stomatal density, length, and width. In light of these findings, it can be concluded that tree stomatal characteristics can provide practical information about air quality.