Assessment of air pollution tolerance index (APTI) for some ornamental woody species in green space of humid temperate region (Rasht, Iran)

Abstract

The green space of parks with its vegetation population of trees and shrubs plays a key role in air purification and the absorption of air pollutions, thereby contributing to the alleviation of environmental pollutions. The present factorial experiment was carried out in urban parks with 18 treatments. The leaf samples of 18 ornamental species were collected in two sites [(1) the margin and (2) the downtown] of Rasht city in north of Iran. Then, they were subjected to the measurement of leaf relative water content, total chlorophyll content, leaf extract pH, and ascorbic acid content to evaluate their air pollution tolerance index (APTI). The tolerance of the species was assessed by two methods: the comparison of their APTI with the average APTI of all species and the use of a constant APTI as a standard. The results showed that the species differed in their tolerance in different sites. Among the studied 18 species, Yucca filamentosa and Berberis thunbergii were identified as air pollution-tolerant species, so they are recommended for the use in parks. Yucca had an APTI of 78.24 and Berberis had an APTI of 67.56. The lowest APTI was obtained from Fraxinus excesio and Ligustrum texanum.