PS 48-240 - Dynamics of particulate matter concentration in broad-leaved forests located in urban forest of Seoul, Korea

Abstract: Urban Forest(UF) is very important natural or semi-natural infrastructure existing in urban areas by mitigating and adapting urban climate in the era of climate crisis by providing various ecosystem services such as heat island effects and air pollution reduction. Especially in Korea, more than 90% of the population lives in cities, so the use of UF is increasing. Recently, the PM reduction function of UF is attracting attention as the heat island phenomenon and PM damage have occurred in various parts of the urban areas. The dynamic characteristics of PM in UF is believed to appear differently depending on the composition and structure of the forest. This study attempt to find out the PM reduction effect of UF through the dynamic PM concentration in UF located in Seoul, where PM problems are serious. PM concentrations (PM₁₀, PM_2.5) and meteorological data (temperature, humidity, wind direction, wind speed) were measured and analyzed for 24 hours in a row in a broad-leaved forest(BF) in an UF located in Seoul. The characteristics of pollutants around UFs were analyzed through wind-rose analysis on measurement points.

To analyze the characteristics of PM dynamics according to height in BF, PM concentrations for vertical positions were measured. PM₁₀ and PM_2.5 were measured at four different vertical position(0.5m from the forest floor: floor, 1.5m: lower, 4m: middle, 6m: top). In addition, PM₁₀ and PM_2.5 concentrations were analyzed based on the Ministry of Environment in Korea (Good: 0-30㎍/㎥, 0-15㎍/㎥; normal: 31-80㎍/㎥, 16-35㎍/㎥; bad: 81-150㎍/㎥, 36-75㎍/㎥; very bad: 151-㎍/㎥, 76-15㎍/㎥). As a result of the analysis by dividing into 'good' and 'normal, bad, very bad', in the 'good' period when the PM concentration was low, PM₁₀ was found to be 15.6㎍/㎥, 14.08㎍/㎥, 14.66㎍/㎥, 14.53㎍/㎥ (in order of top, middle, lower, and floor), and PM_2.5 was analyzed as 8.31㎍/㎥, 7.94㎍/㎥, 8.77㎍/㎥, 8.71㎍/㎥. In the 'normal, bad, very bad' periods with relatively high concentrations, PM₁₀ was 49.1㎍/㎥, 16.14㎍/㎥, 47.38㎍/㎥, 47.27㎍/㎥, and PM_2.5 was 32.34㎍/㎥, 30.14㎍/㎥, 32.17㎍/㎥, and 32.11㎍/㎥. PM from outside the forest moves to the inside of forest, is absorbed and adsorbed by the canopy, and deposited in the floor layer. The canopy layer of BF is thought to functions as a filter. However, it is thought that the seasonal PM reduction dynamics will vary depending on the presence of leaves of BF. This study can be applied to ecological implementation and management to enhance the role of UF.