**Sin-Yee Yoo , Taehee Kim , Suhan Ham, Sumin Choi and Chan-Ryul Park \***

Urban Forests Research Center, National Institute of Forest Science, 57, Hoegiro, Dongdaemun-gu, Seoul 02455, Korea; dbtlsdl94@korea.kr (S.-Y.Y.); kth9064@korea.kr (T.K.); hamsu2498@si.re.kr (S.H.); ciromi@korea.kr (S.C.)

**\*** Correspondence: maeulsoop@korea.kr; Tel.: +82-2-961-2612

Received: 5 July 2020; Accepted: 12 September 2020; Published: 16 September 2020

**Abstract:** The utilization of urban green areas has increased, but it is unclear whether urban green areas can decrease the concentration of particulate matter at an industrial complex city in Korea. We measured the extent of particulate matter (PM) reduction at a buffer green area in the Sihwa Industrial Complex. PM was measured at the industrial complex, the urban green area, and a nearby residential area from April to October 2019. PM reduction rates were highest at the urban green area in August and October, which is related to increased atmospheric mixing height and the active west wind blowing from the industrial complex to the residential area. Reduction rates of PM<sup>10</sup> and PM2.5 at the urban green area showed the lowest values, namely 14.4% and 25.3%, respectively. The air temperature, wind speed, and humidity could affect the PM reduction rate by influencing the movement and dispersion of PM at the micro-spatiotemporal scale. These results indicated that PM concentration could be reduced by the structural change of a forest layer at a micro scale in urban green areas.

**Keywords:** urban green area; Sihwa Industrial Complex; air pollutants; PM reduction; atmospheric mixing height; wind speed
