Natural Filters: The Impact of Urban Plants on Air Quality

Plants are among the first solutions considered in the fight against air pollution. As natural and effective agents, they play a vital role. However, success depends on selecting the right species and placing them in suitable climates and locations. When properly chosen, plants can significantly improve air quality and support sustainable urban environments. This study focuses on the concept of "natural filtration," particularly "the role of trees," using the city of Trabzon as the study area. Two sites were selected: one with dense urban vegetation and the other with sparse vegetation. Emission measurements were conducted and analyzed statistically. Results revealed that broad and oval-leaved plants had greater potential to enhance micro air quality. Among all species, Rhododendron cynthia had the most consistent positive effect across all seasons. In spring, the park’s average air quality was 95.48 µg/m³, with R. cynthia recording 357.44 µg/m³. In summer, the average was 106.87 µg/m³, while this species measured 310.37 µg/m³. Autumn showed 124.74 µg/m³ overall, and Rhodendron cynthia had 201.43 µg/m³. In winter, it had the lowest CO emission at 1.03 µg/m³, while the average was 107.96 µg/m³. These findings emphasize the species’ strong potential to improve air quality. Furthermore, 80% of the species with the highest air quality contribution were trees, suggesting they should be prioritized in landscape planning. ANOVA results showed that broad and oval-leaved trees had a significant positive impact, while the difference between deciduous and evergreen species was not significant. In conclusion, urban plants' effectiveness in improving air quality depends on species, leaf shape, and growth form. These findings serve as a guide for environmentally sustainable and informed landscape planning.