基于ENVI-met的城市道路绿地植物配置对PM2.5的影响研究

随着城市化的快速发展,大气污染尤其细颗粒物(PM_(2.5))已成为制约城市环境的重要因素,相关研究表明,在众多的PM_(2.5)来源中道路交通是在其中的重要来源之一,而道路绿地植物群落能够消减来自道路的PM_(2.5)。运用场地观测和ENVI-met模拟相结合的方法探讨城市道路绿地植物群落对PM_(2.5)的影响,分析仅有乔木(i)、乔木+树篱(ii)、乔木+树篱+灌木(iii)3种模式下的植物群落配置对PM_(2.5)的影响,揭示绿地植物群落的长度、宽度、高度和LAI对PM_(2.5)的影响。结果表明:(1)场地观测中的道路绿地植物群落的3种配置模式对PM_(2.5)的消减率分别是iii(14.2%)ii(12.9%)i(9.2%)。(2)绿地中植物的种类、绿地宽度、绿地植物的叶面指数等要素对消减作用起正面作用,高度和长度起负面作用。(3)绿地的长度的一定量的减少可以在绿地后方形成一个宽度约为绿地长度80%的、随着与绿地的距离的增加而宽度递减的较绿地长度更长环境PM_(2.5)浓度更低的低谷区,但其他没有绿地的空间的PM_(2.5)浓度会加重。(4)绿地高度的增加会迫使PM_(2.5)向更高的空间运动。

Influence of vegetation arrangement on PM2.5 in urban roadside based on ENVI-met

With the rapid development of urbanization, air pollution, especially fine particulate matter (PM_2.5), has become an important factor restricting urban environment. Relevant studies have shown that road traffic is one of the important sources of PM_2.5 among many sources, and plant communities in road greenbelt could reduce PM_2.5. In this study, a combination of site observation and ENVI-met simulation was used to investigate the influence of plant communities in urban road greenbelt on PM_2.5. We also analyzed the influence of plant community configuration on PM_2.5 in three modes including tree (i), tree+hedge (ii), and tree+hedge+shrub (iii), so as to reveal the influence of length, width, height and LAI on PM_2.5. The results showed that (1) in field observation, the reduction rate of PM_2.5 in the three configuration modes of plant community of road greenbelt was iii (14.2%) >ii (12.9%) > i (9.2%). (2) The increase of plant species, greenbelt width, and leaf area index played a positive role in PM_2.5 reduction, while the increase of height and length played a negative role. (3) A certain amount of reduction in the length of the green space formed a region behind the green space that had a lower PM_2.5 concentration than the longer length environment. The width of this area was about 80% of the length of the green space and decreased as the distance from the green space increased. However, the PM_2.5 concentration of other spaces without green space would increase. (4) The increase in green space height would force PM_2.5 to higher space.