Correlation between Urban Forest and Satellite-borne Imagery-based Ambient Particulate Matter across Seoul, South Korea

Abstract

In South Korea, Particulate matter (PM) has become one of the major threats to public health and safety across the country. Urban forests have been considered as a possible contributor to mitigate the air pollutants in urban areas. However, there is lack of research on investigating the role of urban forests on mitigating PM. This study investigated on the relationship between urban forests and PM concentrations in Seoul, South Korea, by using urban forest data, PM measurements, satellite imagery, and meteorological data. The correlation between the size of urban forests and PM measurements within three concentric buffers of 1 km, 500 m, and 300 m in radius were analyzed. Overall PM10 and PM2.5 concentrations varied significantly with different seasons during the 2-year study period. Overall PM10 and PM2.5 concentrations tended to be reduced as the urban forest size increased. This tendency became less noticeable as smaller urban forest patches were predominant over larger patches in the buffers. Season-specific models were developed by using 30m-resolution satellite imageries of Landsat 8 and meteorological parameters for estimating PM concentrations. No noticeable correlations were found between the modeled PM concentrations and the Urban forest size showing the ualves of Pearson’s coefficient r of 0.08 to 0.23 for PM10 and -0.16 to 0.04 for PM2.5. In this study, the variations in PM measurements with the presence of high urban forests within buffers were investigated. Overall PM10 and PM2.5 concentrations were lower along the domains encompassing higher urban forests in elevation.