Estimates of air pollutant removal by urban park trees in heavily polluted city of Mashhad, Iran, the associated economic value and the impact on air quality improvement are the main contributors of this study. The economic value of Mellat Park is substantial with a benefit-cost ratio at 0.6; however, the design of Mellat Park has not been adopted in accordance with air quality condition. While carbon emissions is not substantial, a significant part of Mellat Park’s value (53.5 %) arises from carbon sequestration. Regarding PM2.5, the most harmful air pollutant, there was a decline in air quality. The economic analysis of the park’s three most frequent and three most valuable species highlights the inconsistency between the tree species and the environmental demands. If Acer rubrum (the most valuable species) or Paulownia (the second most valuable species) had been planted rather than Platanus orientalis (the most common species), the park’s tree value would have seen 2.7 times increase and a 41.8 % boost. Local scale design considering the link between air pollution and vegetation configuration -including landscape for vegetation and superior plant species - can maximize value of the park’s trees on removal rates and air quality improvement.

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