Mitigating particulate matter exposure at bus stations using green infrastructure

Abstract

With the rapid urbanization, traffic volume and road density have significantly increased. Urban residents are encountering high exposure risks to roadside particulate matters emitted from traffic (e.g., PM2.5), especially at bus stations where vulnerable passenger groups like children are at higher risks. Using green infrastructure such as green hedge is an effective strategy to mitigate exposure risks to PM2.5. However, rare studies have explored the effectiveness of such strategy at bus stations. This study investigated the influence of different green hedge heights (0.5, 1.0, and 1.5 m) on PM2.5 deposition and passengers’ health risk at bus stations, under different incoming wind directions. Field surveys were conducted to analyze the passengers’ demographics and waiting time. Based on the simulation method, it can be found that green hedges at the heights between 1.0 m and 1.5 m proved more effective in blocking PM2.5 compared with that of 0.5 m. Without green hedges, passengers faced average daily exposure risks between 10–6 and 10–4. After using green hedges, risks were largely decreased by approximately 62 %, reaching the safety threshold below 10–6. Improvement strategies including control of passengers’ locations, optimaztion of entrance and exit of bus station, and integration of green hedges and belts were further proposed. This study can provide valuable insights into effective roadside greening initiatives for creating a healthy urban environment.