Effects of Green Network Management of Urban Street Trees on Airborne Particulate Matter (PM2.5) Concentration

Abstract

Street trees are crucial for air pollutant reduction in urban areas. Herein, we used computational fluid dynamics (CFD) simulation to identify changes in airborne particulate matter (PM2.5) concentration based on wind characteristics (direction and velocity) and the green network of street trees. The green network was assessed based on composition of the green area of street trees in the central reserve area and between the motor and pedestrian roads. The PM2.5 concentration varied according to the presence or absence of major reserve planting and the planting structure of the street trees, but not according to the wind direction or velocity. The concentration was lower when the wind direction was 45° (than when the wind direction was 0°), whereas it showed a more significant decrease as the wind velocity increased. Despite variation at each measurement site, the PM2.5 reduction was generally higher when the central reserve and street trees had a multi-planting structure. Hence, to ensure an effective reduction in the PM2.5 concentration on motor roads and reduce its negative impact on pedestrians, both arbors and shrubs should be planted in the central reserve area. The study results will serve as reference for managing the green area network and linear green infrastructure in terms of improving the atmospheric environment.

The Green Heart Project: Objectives, Design, and Methods

“…We planted roadside trees in a multi-planting structure with both arbors and shrubs to enhance pollutant dispersal. 54 Design parameters for roadside barriers were optimized to maximize pollution capture and dispersion with large trees in the back and smaller trees or shrubs in front. For each area, we targeted a wide distribution of species; considering sun exposure, soil type, disease, hydrology, community preference, aesthetics, and plant availability and suitability of the space for planting trees.…”

Computational Fluid Dynamics Models to Estimate Pedestrian Exposure to Traffic-Related Air Pollution: A Review

“…The calibration of these sensors should be performed for each measurement and ideally compared with data from monitoring stations. [17][18][19][20][21][22][23][24][25][26] Monitoring stations…”

Revisiting Urban Street Planning and Design Factors to Promote Walking as a Physical Activity for Middle-Class Individuals with Metabolic Syndrome in Cairo, Egypt

“…In addition, promoting walking can lower obesity rates and enhance academic performance [43]. It can also help older adults maintain physical function and independence to decrease the risk of falls [24] and improve the quality of life through urban trees [44] and healthy lifestyles by incorporating nature into healthcare strategies [45].…”

“…These ideas are consistent with innovative growth principles emphasizing the importance of healthy streets and environmental performance measures. The results conducted by Yu et al [96] and Jeong et al [44] suggested green networks for reducing air pollution, while Velázquez et al [97] recommended controlling extreme climatic conditions by incorporating vegetation areas with trees to minimize sun exposure. Kent et al [12] considered the interaction of urban form-related walkability and health interaction, while Shartova et al [17] proposed expanding green infrastructure and urban form implementation.…”

“…Taking measures to reduce air pollution for low-income individuals who walk outdoors [96], such as managing green networks through urban street trees [44]. 10.…”