Field study on the reducing effect of small-scale public green space on atmospheric particle matter concentrations

Abstract

A field study was conducted in small-scale urban green spaces in Zhengzhou to monitor PM_2.5 and PM₁₀ concentrations along with temperature, humidity, and wind speed. Data analysis using SPSS revealed that PM_2.5 showed a fluctuating decline throughout the day, while PM₁₀ steadily decreased. No significant spatial differences were found in PM_2.5, PM₁₀, temperature, or humidity between the interiors and exteriors of the green spaces, but wind speed varied significantly. The reduction in PM_2.5 and PM₁₀ concentrations was influenced by distance from pollution sources and canopy density, with greater distances and sparser canopies leading to lower concentrations. However, the reduction rates remained below 5%, indicating a weak effect. Meteorological factors played a key role: PM_2.5 was negatively correlated with temperature and positively with humidity, while its correlation with wind speed was not significant. PM₁₀ was positively associated with humidity and negatively with both temperature and wind speed. A regression model estimated that a 1°C increase in temperature could decrease PM_2.5 by 0.502 μg/m³ and PM₁₀ by 3.586 μg/m³. Based on these findings, an optimized strategy for small-scale green space design is proposed to improve air quality while meeting urban functional needs.