北方城市绿地对大气颗粒物浓度的削减作用对比研究OA北大核心CHSSCDCSTPCD

Although urban green space can make the air cleaner,the lack of a system to classify green space makes it difficult to improve air quality from the perspective of optimizing vegetation structure in practice.A classification system of green space that incorporates vegetation structure and species composition was constructed to explore the differences in reducing PM concentration among green spaces of different structures in northern cities.Based on the system,five common types of vegetation structure green spaces were selected in each of the three cities of Beijing,Xi'an,and Baoji.The effects of different background environments,vegetation structure,plant diversity,meteorological factors,and time factors on the concentrations of atmospheric particulate matter(PM2.5 and PM10)were explored by combining interpretation satellite imagery and field measurements.The results are as follows:(1)Urban green space rate has a significant impact on the concentration of atmospheric particulate matter:the background environment with higher green space rate has lower concentration of particulate matter,which means the PM concentration in different background environments ascends in this order:green background,gray-green background,and gray background.(2)Vegetation structure and plant diversity significantly affect the dust-retention capacity of green spaces.As for various vegetation structures,the dust-retention capacity of the semi-open green space in northern cities marks the top,followed by semi-closed green space and closed green space,with the open green space at the bottom.When plant species diversity increases,the particulate matter concentration in the green space increases.(3)The concentration of atmospheric particulate matter in green spaces is significantly influenced by meteorological factors,decreasing with higher temperature and wind speed,and increasing with higher humidity.(4)There are obviously seasonal and daily changes in the concentration of atmospheric particulate matter in green spaces in northern cities.In the same year,the atmospheric particulate matter concentration is lowest in summer and highest in winter.The concentration of particulate matter is the lowest in the morning in one day.The results are expected to be used as the theoretical basis for future planning and design of green space concerned about atmospheric particulate matter reduction under different background environments.