设施塑料大棚风洞试验及风压分布规律

风洞试验是研究建筑结构表面风压分布规律的最重要且有效的技术手段.利用NH-2型风洞研究设施塑料大棚表面风压分布规律,风洞为串置双试验段闭口回流风洞,风速连续可调,最高风速为90 m/s.试验模型的几何缩尺比为1:6,模型表面共布置192个测点,其中端面布置3排测压点,共63个测点,模型固定在风洞转盘上,试验风向角从0°到180°,间隔15°,共13个风向角.测量和分析不同风向角下设施大棚表面的风压系数和分布规律,并推导出了设施大棚各区域发生风灾的临界风速.结果表明:设施大棚迎风面以风压力为主,迎风边缘等值线密集,风力梯度大;背风面则受风吸力影响,风力变化平缓.在不同风向角下,设施大棚各迎风区域风压系数均由正压向负压过渡,在此过程中出现了零压区;而一直背风的区域风压系数均为负值.在45°风向角下,大棚顶端迎风边缘最高点处的负压达到最大.根据公式推导出各区域的临界风速,设施大棚顶部两侧区域受风吸力影响最大,最小临界风速为14.5 m/s,研究为设施大棚的风灾防御提供科学依据.     

基于“风感”的紧凑型城市开放空间风环境实测和CFD模拟比对研究

城市开放空间的风场不仅影响微环境的"风感"舒适度还影响宏观尺度的城市气候。从景感生态学的角度出发,首先阐述"风感"的定义,总结了街道峡谷空间风场的基本规律和特点。运用Kestrel NK4500手持气象站对城市开放空间的风环境进行实测,采用CFD(Computational Fluid Dynamics)模拟软件Fluent 14.0对不含绿地的同一空间进行风环境模拟,通过两者的数据比对来研究紧凑型城市开放空间内绿地对行人高度风场的实际干扰程度。结果发现,紧凑型城市开放空间的"风感"受建筑和绿地空间布局的共同影响。当建筑高于绿地时,风场受建筑的控制;当林带高于建筑时,林带对风环境的影响程度受其疏密度影响。疏密度较高的常绿林带对风向和风速影响很大,而疏密度较低的林带会影响风速,对风向影响不大。影响风速的主要因素是空间围合所形成的空气域,相比实体、多孔介质,空气域对风的阻力要小的多。如铺装、草坪上方的通风廊道是影响行人高度层通风、导风的关键因素。紧凑型空间内的绿地在行人高度应保持通畅以保证通风,并通过建立平面和竖向上的通风、导风廊道体系,促进空气循环。     

河西绿洲边缘积沙带的稳定性及其生态效应

甘肃河西沙区经过60多年的防沙治沙,在绿洲边缘尤其是上风向形成了一条积沙带。积沙带作为绿洲边缘造林固沙和沙障固沙过程中的副产物,其稳定性如何?又具有什么样的生态效应呢?本文分析了甘肃河西沙区绿洲边缘积沙带上21个样点风速、风向等观测资料。结果表明:1)河西沙区绿洲边缘积沙带均处于稳定状态。2)积沙带具有显著的防风作用,且防御风的作用随风速的增大而增强,当风速≥2 m·s-1时,积沙带下风向防风距离大于积沙带高度的20倍。风速越大,则沙丘下风向降低风速越明显。3)高度是表征积沙带防风功能的一个重要指标,而当风速≥8 m·s-1时,积沙带顶部风速小于上风向空旷风速。4)气流到达积沙带迎风坡时,通过沿坡面抬升和向两翼分流2种方式释放能量并降低流速。风向偏转会降低迎风坡主风方向的风速。     

珠江三角洲地面风场的特征及其城市群风道的构建

利用珠三角20个观测站1964—1983年的风数据分析了珠三角城市群地面风场风向、风速分布与季节变化特征,并基于经验正交函数(EOF)进行了地面风场的空间分类。呈缺口盆地地形的珠三角风速较低,为3—2 m/s,整个区域风速南高北低;以伶仃洋为界,西岸高于东岸;西南部潭江谷地夏季多南风,冬季为北风,东岸东江谷底全年多东风,北江与西江河谷冬季盛行北风,夏季为东南风。综合风向与风速,结合地形,可将珠三角地面风场由南向北依次划分为较高风速区、中风速区和低风速区三类。根据空间尺度以及在区域中发挥的作用,珠三角城市群应构建多级风道,且风道还有常年与季节之别:伶仃洋(伶仃洋—虎门—狮子洋—广州水道)、西江(磨刀门—九江—三水)、潭江河谷应属于一级常年风道;北江(清远—三水)和东江(博罗—狮子洋)为一级季节风道。广州—三水段、黄埔—东莞段、中山—江门段以及伶仃洋段是影响整个珠三角大气环境质量风道的枢纽地段。城市群规划中对枢纽段超高建筑群进行风环境影响的评价,对枢纽段河道宽度、建筑物高度与密度的控制,将有助于提高珠三角城市群的空气质量,并防范下垫面粗糙度改变引起峡谷风的新风险。     

科尔沁沙地流动沙丘掘穴蚁蚁丘分布及影响因素

以科尔沁沙地典型流动沙丘作为研究对象,通过样方法调查分析了不同地形上掘穴蚁的蚁丘密度、直径、盖度及其与土壤环境的关系,讨论了不同地形和土壤环境对掘穴蚁筑丘活动的影响,并探讨了蚁丘的空间分布格局.结果表明：受到地形变化影响的土壤环境和地形共同影响掘蚁穴的筑巢活动,蚁丘密度表现为丘顶>背风坡>迎风坡;蚁丘直径和盖度均表现为丘顶>迎风坡>背风坡,并且亦均受到蚁丘密度的制约.蚁丘的空间格局表现为随机分布型.地形及土壤环境的共同作用决定了掘穴蚁的筑巢行为.     

海岸梯度上黑松针叶化学计量特征的变化规律

风对树木形态、生理和生长的影响一直是生态学研究的热点和难点问题,目前主要采用模拟风速或机械刺激的方式来研究树木对风胁迫的响应与适应变化,无法准确反映出树木在风环境下的长期适应机制。揭示自然环境下树木对风胁迫的长期适应机制,测定了海岸梯度上迎风面和背风面60年生黑松林(Pinus thunbergii)针叶有机碳、氮、磷、钾、钙、钠、镁元素含量,并分析元素含量及其化学计量特征的变化规律。结果表明:黑松林迎风面针叶有机碳含量随离海岸距离的减小显著降低(P0.05);而氮、磷、钾、钙、钠、镁含量则显著增加(P0.05);氮磷比保持相对稳定。黑松林背风面针叶除钙和钠含量随离海岸距离的减小逐渐增加外,其他元素含量变化规律均不明显;距海岸500 m内黑松针叶化学计量特征差异显著(P0.05),其后趋于相对稳定。黑松林迎风面针叶化学计量特征普遍存在相关关系,背风面仅针叶氮和磷、钙和钠间存在相关关系,且与迎风面存在共同的SMA斜率和截距。研究表明,海岸梯度上风胁迫会显著改变黑松针叶化学元素含量,但其比值相对稳定;随海岸距离减少,风胁迫增加,针叶碳同化能力受到明显影响,黑松通过针叶氮、磷、钾、钙、钠、镁含量的增加来提高耐风胁迫的能力,这可能是自然环境下黑松对长期风胁迫的一种适应策略。     

海岸梯度上黑松针叶形态与解剖结构性状的变化规律

风对树木形态、生理和生长的影响一直是生态学研究的热点和难点问题,目前主要采用模拟风速或机械刺激的方式来研究树木对风胁迫的响应与适应变化,无法准确反映出树木在风环境下的长期适应机制。本文以海岸60年生黑松林（Pinus thunbergii）为对象,分析了海岸距离梯度上黑松迎风面和背风面针叶长度、宽度、面积、比叶面积、角质层厚度、表皮厚度等形态和解剖结构特征的变化规律。结果表明：黑松迎风面针叶长度、宽度、周长、面积、厚度和比叶面积随着离海岸距离的减小逐渐减小（P<0.05）;而表皮厚度、角质层厚度和导管孔径则随着离海岸距离的减小逐渐增加（P<0.05）;背风面各指标均无明显变化规律。黑松迎风面与背风面针叶性状（比叶面积除外）主要在海岸500 m内存在显著差异（P<0.05）。可以看出,随着海风胁迫的增加,黑松通过降低针叶长、宽等形态指标,有效减少了风胁迫下黑松的受力面积,是一种躲避策略;而增加针叶表皮、角质层厚度和导管孔径等解剖结构指标,则增强了针叶坚韧性和保证针叶的水分供应,是一种忍受策略,这些策略有利于该树种在大风环境中得以更好的生存。     

广州市主城区城市地形类型与风环境评价

对城市地形组合类型及其地形对风场影响的研究,有助于城市风场机理的认识与生态环境的优化。以高层建筑密集的广州市主城区为例,在确定城市宏观地形类型的基础上,基于最小成本路径（LCP）辨识了风道,并对风环境质量进行评价。主要结论有：（1）将城市地形简要概括划分为4个一级地形、11个二级地形类型。（2）以LCP路径与盛行风交角不超过22.5°的标准,筛选确定通风路径作为风道。根据LCP格网的密度与频次,结合不同风向下风速与风频,评价分析了风环境类型与空间分布。（3）根据自然与城市地形的配置,北风风环境质量远高于西北风和东风;东风由于风频与风速最低,因此通风条件较差。（4）珠江航道在三种风向下都是尺度最宽贯穿城市最好的风道;区域性的风道与风环境较好的地段集中在与主风向平行的主干道上,但以近似南北走向的居多;由于广州城市地形高度以珠江新城峰林为中心向外递减,以低地地形为主的主城区外围通风优于中心区域,特别是珠江新城峰林与网络状台地为主的老城区,通风环境较差。基于LCP的评价结果需要同其他方法相互验证,才能使其不断完善优化。     

热带人工橡胶林林冠截留雾水的边缘效应研究

利用 2 0 0 1年 1 1月～ 2 0 0 2年 1 0月的林缘和林内雾水截留及相关环境因子观测资料 ,对西双版纳热带人工橡胶林林冠截留雾水的边缘效应进行了研究。西双版纳热带人工橡胶林内的雾日数及雾日频率呈现明显的季节变化 ,全年雾日数可达 1 72 d,其中雾季 (1 1～翌年 2月份 )的雾日数及雾日频率最多 (高 ) ,月均雾日数可达 2 3d(76 .7% )。由林缘至林内 ,年雾水截留量在迎风面和背风面均呈现指数形式急剧减小 ,二者均是在林缘最边行外测的林冠下 (0 m处 )达到最大 ,分别为 4 1 .1 mm和 2 4 .3mm。迎风面和背风面林缘 0 m处的雾水截留量分别是林内雾水截留量 (1 6 .2 mm )的 2 .5倍和 1 .5倍。迎风面雾水截留在林内约 2 5 m处趋于稳定 ,而背风面在林内约 1 5 m处趋于稳定。林缘处的雾水截留量与日 0 :0 0～ 1 0 :0 0平均风速呈显著的正相关(P<0 .0 1 )。风速大 ,则雾水截留的边缘效应向林内越深入 ,且空间变异性减小。相对于迎风面林缘 0 m处的雾水截留而言 ,大的风速将削弱林内和林缘雾水截留量的差别 ,从而导致更多的雾水进入森林     

基于城市微气候模拟软件的城市道路绿化带对PM2.5消减作用的研究

随着经济的快速发展及机动车保有量的持续增长,车辆造成的道路污染问题日益严重。广州作为中国重要的经济发展城市,交通源排放问题高度集中,机动车排放是城市PM2.5的主要来源之一,开展减缓城市道路污染危害的研究具有重要意义。本研究为调查绿化带对广州城市道路PM2.5的影响,运用实测与城市微气候模拟软件（ENVI-met）模拟结合的研究方法,实测并分析城市道路空间PM2.5的浓度分布及其影响因素,使用实测数据对模拟软件进行验证分析,模拟研究理想道路模型下不同高宽比、风向等因素及绿化带植配类型对PM2.5的消减作用。研究表明：（1）城市道路空间PM2.5浓度分布受污染源、街道高宽比、风速风向、绿化带等综合影响,自然消减情况下,其主要受风速风向和高宽比双因素影响;（2）通常街道高宽比越大,越有利于道路空间PM2.5的扩散;（3）城市道路空间PM2.5自然沉降最小距离为12 m,0-12 m范围内应保持无障碍物的开敞环境,PM2.5消减的关键范围是12-24 m,此范围内可以利用生态手段沉降颗粒物;（4） PM2.5消减率受绿化带和风向的双控制,应根据主导风向选择绿化带植配方式。在主导风平行面和垂直迎风面绿化带对PM2.5有正消减效应,建议植配类型为"乔-乔+灌+草";在主导风垂直背风面绿化带对PM2.5呈负消减效应,植配类型为"乔-灌"绿化带消减率接近于自然消减率,而植配类型为"乔-灌+草"和"乔-乔+灌+草"的绿化带加重了颗粒物在该区域的积聚。     

科尔沁沙地人工杨树林生态服务效能评价

采用定位观测法,系统评价了杨树(Populus simonii)林的防风、抗蚀和滞尘等生态服务效能及其间接价值,同时定量探讨了风速减弱系数与实测林地叶面积指数的关系。结果表明,在研究区主害风(西北风)天气下,林地迎风区6H(H为平均树高)、3H、林地中央、林地背风区林缘、6和8H处2m高度的日平均风速与对照点(流动沙丘)相比均有不同程度减弱,风速减弱系数在18．3％～66．2％之间。林地背风区6H处0．25、0．5、1和2 m 4个高度的月平均风速减弱系数与林地叶面积指数呈显著非线性相关,其间存在良好的三次曲线关系(P<0．0001,R²=0．43～0．94,n=80)。在主害风天气下,林地各观测点的地表日风蚀量与对照点相比大幅度降低,平均降幅85．2％～99．9％。在观测期内,林地中央的日平均降尘量为13.2 kg·hm^-2,而林地迎风区6H处的日平均降尘量为9．9 kg·hm^-2,林地的日滞尘能力约为3．3kg·hm^-2。       

Presence of shrubs influences the spatial pattern of soil seed banks in desert herbaceous vegetation

Question: Do shrubs influence the spatial pattern of soil seed banks in herbaceous vegetation and are these effects influenced by wind direction, sampling position (windward vs leeward sides of the shrub) and distance from the shrub? Location: Horqin desert in eastern Inner Mongolia, China. Methods: A pioneer shrub, Artemisia halodendron, occurring in a mobile sandy habitat was used as a case study. Species composition and abundance of the seed bank and established herbaceous vegetation around six target shrubs were sampled along transects aligned to the four main wind directions and at 0.5, 1, 2, 3, 4.5 and 6 m from the shrub base on both windward and leeward sides of a transect. Results: The presence of shrubs significantly modified the spatial pattern of seed deposition, but effects varied with wind direction, sampling position and distance from the shrub. More seeds were deposited on the leeward side than on the windward sides in all four transects, especially on transects with the most prevailing wind directions. Shrubs also caused a marked variation in seed deposition across sampling locations; this effect was more pronounced on the leeward side of transects with the most prevailing wind directions, suggesting the mean range of the shrub's influence is within ca. 2 m. Conclusions: The study shows clear evidence of shrubs as a source of spatial heterogeneity in seed availability in the herbaceous layer. Shrub presence effects were strongly influenced by complex interactions between wind direction, sampling position, and distance from the shrub.     

Is microclimate important for Orthoptera in open landscapes?

Orthoptera were monitored on field edge public footpaths on the east (leeward) and west (windward) side of hedgerows in Chelmsford, UK, in 2006. A total of 6 species were recorded from footpaths on the leeward side of hedgerows probably due to the shelter from the prevailing westerly winds provided by the trees and shrubs. On the windward side of hedgerows species richness and abundance of Orthoptera were reduced (only 4 species were recorded). It is suggested that shelter from the wind and the exposure to early morning sunlight for Orthoptera on the east side of hedgerows are important factors governing their occurrence on farmland. Many replicates had Environmental Stewardship (ES) scheme field margins adjacent but they did not affect Orthoptera species richness or abundance.     

The architecture of Picea sitchensis structural root systems on horizontal and sloping terrain

The coarse root systems of 24 Sitka spruce (Picea sitchensis (Bong.) Carr.) trees, from a 40-year-old plantation in west Scotland, were extracted, digitised in three dimensions, and root topology was recorded. Roots were from trees grown on a steep (ca. 30°) north-facing slope, and from an adjacent horizontal area with similar gleyed mineral soil. The prevailing wind was across-slope from the west. Analysis of below-ground parts of the trees in comparison with those above-ground revealed a positive linear relationship between coarse root volume and stem volume. Most non-directional characteristics of the root systems were similar between trees on the slope and on flat terrain. Allocation of root mass around trees was examined in relation to the slope and the prevailing wind direction. Trees on the horizontal area had more root mass in leeward sectors than other sectors, but trees on the slopes had more root mass in the windward sectors than other sectors. Centres of mass of the root systems from the horizontal part of the site were not significantly clustered in any direction, but root systems of trees on the slope had centres of mass significantly clustered across the slope in the windward direction. For trees on the slope, the mean direction of the largest sector without structural roots was 4° from north, i.e. downslope. The results are discussed in relation to soil characteristics and the biomechanical behaviour of trees on slopes.     

浑善达克沙地不同微地形的土壤物理性质和草本群落分布及其相关性分析

采用样方调查和室内检测相结合法对内蒙古浑善达克沙地迎风坡、坡顶、背风坡和丘间地不同土层(0~10、10~20和20~40 cm)的土壤物理性质(包括含水量、田间持水量、容重、总孔隙度和毛管孔隙度)及草本群落的生产力(包括盖度和地上部生物量)和物种多样性(包括Margalef丰富度指数、Simpson多样性指数、Shannon-Wiener多样性指数和Pielou均匀度指数)进行比较分析;在此基础上,采用Pearson相关性分析法对不同微地形的土壤物理性质与草本群落各指标间以及草本群落生产力与物种多样性各指标间的相关性进行分析.结果表明:4种微地形的土壤物理性质总体上差异显著,但不同土层的土壤物理性质总体上无明显差异;从丘间地、背风坡、坡顶到迎风坡,土壤的含水量、田间持水量、总孔隙度和毛管孔隙度依次递减,而土壤容重则依次递增,说明迎风坡的土壤结构较差且水分散失较多,而丘间地的土壤结构和水分状况均相对较好.不同微地形间草本群落生产力和物种多样性总体上也存在明显差异,从背风坡、丘间地、坡顶到迎风坡,草本群落的生产力和物种多样性依次递减,仅Margalef丰富度指数表现为在丘间地最高、在迎风坡最低,说明迎风坡的草本群落物种多样性较低,群落稳定性差,而背风坡和丘间地的草本群落物种多样性和生产力水平均较高,群落稳定性较好.相关性分析结果表明:该区域的草本群落生产力和物种多样性与土壤容重呈负相关,与土壤的其他物理性状呈正相关,但仅部分指标间有显著或极显著相关性;草本群落生产力与物种多样性各指标间呈正相关,但多数指标间的相关性并不显著.研究结果显示:微地形能够显著影响浑善达克沙地的土壤物理性质和草本群落的分布特征,气候和人为干扰使该沙地的土壤物理性质受到严重破坏,导致草本群落生产力降低并处于不稳定状态.     

沙柳灌丛植株形态与气流结构野外观测研究

通过野外观测,研究了毛乌素沙地南缘平沙地人工栽种单行沙柳灌丛的植株形态与气流结构.结果表明,沙柳灌能降低迎风侧和背风侧的近地面风速,使沙粒在植株下部沉积.积沙体积(V₂)与植株体积(V₁)相关性较高(R=0.696).单行沙柳灌丛在4 m高处风速为6 m·s^-1时的气流结构特征为:迎风侧3H处风速已降低,2 H处风速又得到加强,之后在背风侧迅速降低,1 H处达到最低值,然后逐渐恢复到旷野风速.防护距离约为17H',有效防护距离约为13 H'.沙柳灌丛对植株高度以上高度处风速影响较小.     

Coexistence and geographical distribution of Leguminosae in an area of Atlantic forest in the semi‐arid region of Brazil

Abstract Understanding the factors that affect plant species distribution and coexistence in areas with high plant species diversity is a challenge for ecologists. According to some authors, species occupy specific niches, but for others, species coexistence and geographical distribution patterns are random. Floristic composition of the family Leguminosae was studied on moist and dry slopes of the Baturité mountains in semi‐arid northeastern Brazil and was compared with findings for other plant formations elsewhere in Brazil. Substantial floristic differences were found between the moist windward and dry leeward slopes of the Baturité mountains despite their close geographical proximity. The leeward slope was slightly more diverse than the windward slope. Similarity analyses showed that the windward face is floristically allied to the Amazon forest, whereas the leeward slope is similar to other dry‐area formations of northeastern Brazil, such as thorny woodland (caatinga) and seasonal forests. The strong floristic differences that were observed between the windward and leeward slopes corroborate the theory of ecological niche conservatism, which holds that species occurrence is closely linked to environmental factors, such as temperature and precipitation.     

Intracanopy plasticity under strong wind conditions in the wild olive tree (Olea europaea L.): a conserved response between closely related taxa?

Trees have the ability to respond to local environmental cues by expressing particular phenotypes across their canopy through a mechanism known as intracanopy plasticity. In this study, intracanopy plasticity of Olea europaea subsp. europaea was analyzed by sampling leeward and windward canopy exposures of individuals occurring in an area with sustained strong wind conditions. A suite of morphofunctional and reproductive traits was measured at these contrasting canopy positions and, for comparison, also in wind-protected trees. Furthermore, the pattern of intracanopy plasticity of these plants was compared to that previously documented in a closely related species, Olea europaea subsp. guanchica. Plants exposed to strong winds displayed substantial differences between leeward and windward exposures in most of the study traits. Leeward exposures experienced a mean reduction of 73% in wind speed as compared to windward ones, and displayed a modular phenotype matching that observed in wind-protected plants. Wind-exposed plants, however, were comparatively smaller and had fewer and smaller inflorescences, since inflorescence size was positively associated with crown size. The two closely related species showed similar crown and leaf sizes between populations exposed to strong winds, and intracanopy responses were comparable for most traits. These observations suggest that intracanopy plasticity resulted in the expression of contrasting phenotypes within individuals, which allowed trees to persist under sustained wind stress, although at the cost of a reduced reproductive fitness. In addition, this study gives support to the idea that intracanopy responses are conserved among closely related taxa evolving in different habitats, but experiencing a comparable limiting factor.     

AEROBIOLOGY AND POLLEN CAPTURE OF ORCHARD-GROWN PISTACIA VERA (ANACARDIACEAE)

The phenology of pollen release and pollen capture by Pistacia vera was studied in the field and laboratory respectively. Inflorescences of Pistacia vera were examined in a wind tunnel to determine whether the behavior of airborne conspecific pollen around receptive flowers differed as a result of changes in the shape and size of the inflorescence. In addition, the behavior of unclumped (single) and clumped pollen grains was studied to determine differences in the probability of their capture. Wind speeds within a commercial orchard during pollen shedding averaged 0.9–2.2 m/sec and atmospheric pollen concentrations were highest between 0900–1100 hr MST. Each of three stages in inflorescence development (defined on the basis of the number of exserted stigmas) was examined under identical ambient airflow conditions with equal concentrations of airborne pollen (1,000 grains/m³). The general pattern of pollen grain motion involves direct inertial collision by windward surfaces and by sedimentation of pollen onto leeward surfaces; clumped pollen rarely sedimented onto leeward surfaces. Small changes in ambient wind speed (0.5 m/sec to 1.0 m/sec) produced significant changes in the pattern of pollen motion around inflorescences and altered the number of pollen grains captured by leeward surfaces. Thus, wind pollination in P. vera is affected both by windspeed and by the shape or size of flower clusters. Differences in the behavior of clumped and unclumped pollen result from their inertial properties and responsiveness to local changes in the direction and speed of airflow. Unclumped pollen has a higher probability of being captured by leeward surfaces. The apparent insensitivity of pollen motion to differences in inflorescence size may ensure equitable pollination during the acropetal development of flowers.     

Impact of vehicular exhaust emissions on pedestrian health under different traffic structures and wind speeds

Abstract

To explore the effects of different traffic structures and wind speeds on concentration distribution of multi-component pollutants, CO, C₄H₈, and NO₂ with proportions of 81%, 12%, and 7%, respectively, were selected for computational fluid dynamics simulations. Their concentrations were estimated in a reference scenario and five contrast scenarios. When the number of cars is reduced by 15%, their concentrations at point 1 (–28, 1.5) and point 2 (28, 1.5) will decrease by more than 10%. When the number of cars is reduced by 25%, their concentrations will decrease by 20%. The largest concentration in 1.5 m above the ground level under six scenarios is measured on the leeward side when x=–3.3 m. Even if the wind speed increases to 3.0 m/s, the position where the largest concentration occurs remains the same. When wind speed increased to 3.0 m/s, the pollutants concentration on the leeward side decreased by an average of 4%, whereas that on the windward side decreased by an average of 11%. An additional 3.2%, 3.4%, 3.4%, 2.8%, 3.3%, and 3.1% reduction in CO concentration on the leeward side occurred. These results can help to strengthen the policy-making to create a good travel environment for pedestrians.