Carbon and PM2.5 reduction and design guidelines for street trees in Korea

Abstract

An increasing concentration of air pollutants, which negatively affect human health and living environment, present a serious environmental concern around the world. Street trees can help reduce carbon (C) and PM2.5 in cities that lack sufficient greenspace. This study quantified C uptake and PM2.5 deposition on street trees in the Republic of Korea and suggested sustainable design guidelines to enhance the effects of C and PM2.5 reduction. The mean C uptake and the PM2.5 deposition on street trees per unit area were 0.6 ± 0.1 t/ha/y and 2.0 ± 0.3 kg/ha/y, respectively. The major determining factors of the levels of C uptake and PM2.5 deposition on street trees were the species, density, size, and layering structure of the planted trees. Street trees in the Republic of Korea annually offset C and PM2.5 emissions from vehicles by 1.4% and 180%, respectively. Based on these results, design guidelines are suggested that can contribute to sharing the value and the importance of planting street trees for the reduction of C and PM2.5 levels in greenspaces.