北京市道路绿地对PM2.5浓度分布与消减作用的影响

The Effects of Road Green Space on Concentration Distributionand Subduction of PM2.5 in Beijing City

摘要:

摘要：选择北京市典型道路绿地类型为试验监测点，对0，6，16，26，36 m不同绿带宽度下PM2.5浓度分布、消减能力及与气象因子的关系进行了研究。结果表明：道路绿地空气中PM2.5浓度的日变化均呈现双峰单谷型特征，即早晚高、白天低，最低值出现在午后14∶00左右，最高值出现在晚高峰20∶00左右；0，6，16，26，36 m绿带宽度下PM2.5浓度平均值分别为46.64，44.35，42.91，40.96 μg·m-3和41.97 μg·m-3，以26 m绿带宽度最低，0 m最高；无污染或轻度污染（PM2.5＜115 μg·m-3)天气条件下，绿地对PM2.5消减作用十分明显，26 m的绿带处消减作用最强，最高可达28.0%；中度污染及以上（PM2.5＞115 μg·m-3)天气条件下绿地对PM2.5消减作用不明显；PM2.5浓度与气象因子中的温度、风速成负相关关系，与相对湿度成正相关关系。

Abstract:

Abstract:Through selecting typical road green space as experimental monitoring points, PM2.5 concentration distribution, subduction and its relationship with meteorological factors were studied under different greenbelt widths of 0, 6, 16, 26 m and 36 m. The results showed that diurnal variation characteristics of PM2.5 concentration in road green spaces was described by the double peak and single valley curve, which were high in morning and night and low in daylight, and the highest values in 20∶00 and the lowest values in 14∶00. The average values of PM2.5concentration in different greenbelt widths of 0, 6, 16, 26 m and 36 m were 46.64, 44.35, 42.91, 40.96 μg·m-3 and 41.97 μg·m-3 respectively, which the lowest concentration occurred in 26 m and the highest in 0 m. Under the weather condition of non pollution or slight pollution (PM2.5＜115 μg·m-3), the subduction effect of green spaces on PM2.5 concentration was very obvious and greenbelt width of 26 m had the best subduction effect by 28.0%. Under the weather condition of moderate pollution (PM2.5＞115 μg·m-3), however, the subduction effect was limited. The wind speed, air temperature and humidity are all influencing factors on PM2.5 concentration variation. There existed negative correlation between PM2.5 concentration and air temperature, wind speed, and positive correlation between PM2.5 concentration and air humidity.