The effect of exhaust emissions from a group of moving vehicles on pollutant dispersion in the street canyons

Shi, Tianhao; Ming, Tingzhen; Wu, Yongjia; Peng, Chong; Fang, Yueping; Richter, Renaud de

doi:10.1016/j.buildenv.2020.107120

Cited by 37 publications

(14 citation statements)

References 58 publications

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“…Further, Qin and Kot [122] found that TPT significantly influenced the distribution of turbulence up to a height of approximately 7 m. Even at 30 m downstream of the traffic flow, Sedefians et al [134] observed that the contribution of TPT to the total turbulence was as high as 50%. Accordingly, the reduction in the pollutant concentration in the traffic region is attributed to higher TKE near the ground level [129]. Besides, both Kondo and Tomizuka [133] and Woodward et al [135] reported that the maximum pollutant concentration was reduced, and the peak was smoothed out in the direction of traffic flow due to TPT.…”

Section: Effects Of Vehicular Motionmentioning

confidence: 97%

“…Enhanced turbulence (TPT) near the target road was observed in most studies. For instance, Shi et al [129] reported that moving vehicles generated a continuous turbulence source at the bottom of the canyons, which is in line with other studies [130][131][132][133]. Further, Qin and Kot [122] found that TPT significantly influenced the distribution of turbulence up to a height of approximately 7 m. Even at 30 m downstream of the traffic flow, Sedefians et al [134] observed that the contribution of TPT to the total turbulence was as high as 50%.…”

Section: Effects Of Vehicular Motionmentioning

confidence: 99%

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Review on pollutant dispersion in urban areas-part A: Effects of mechanical factors and urban morphology

Ming

Liu

et al. 2021

Building and Environment

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Section: Effects Of Vehicular Motionmentioning

confidence: 97%

Section: Effects Of Vehicular Motionmentioning

confidence: 99%

Review on pollutant dispersion in urban areas-part A: Effects of mechanical factors and urban morphology

Ming

Liu

et al. 2021

Building and Environment

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“…The results show that highemission vehicles are the main cause of aggravating air pollution in street canyon [51] . Shi et al [52] found in their study that it takes about 7s for a vehicle traveling at a uniform speed to reach a stable state of DIFFUSION of VIT and exhaust pollutants. At the same time, it is suggested that a "healthy distance" of 8m should be maintained between vehicles based on the diffusion range of tail gas emission of wake in steady state.…”

Section: Impact Of Motor Vehicle Flow On the Distribution Of Air Poll...mentioning

confidence: 99%

Research status and control measures of air pollutants in urban areas caused by traffic sources

Zhai

Huang²,

Ma³

et al. 2022

E3S Web Conf.

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With both the social and the economic development, air pollution has become a matter of high concern to both the public and the government. Vehicle exhaust emissions on traffic roads are the main source of urban air pollution in urban area, which poses a significant threat and impact on the health of urban residents. In order to solve the excessive urban pollutants in a better and more efficient way, reasonable and economic solutions should be investigated from the three aspects, including source identification, pollutant distribution and treatment measures. As for the distribution of pollutants in regional urban scale, this paper analyzes and summarizes the four influencing factors, including different urban layout schemes, meteorological conditions, roadside tree configurations and motor vehicle flows. The methods to study the distribution of air pollutants are summarized. Meanwhile, China has promulgated many standards and policies for the treatment of pollutants, which has achieved good results. To control urban pollutants from the root, it is necessary to look at the problem of urban pollutants from various aspects with appropriate methods, affordable human and material resources and reasonable relevant policies. This study provides a scientific support for control of traffic-related pollutants in urban area.

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“…Under low wind speed conditions, solar radiation and convective heat transfer play leading roles in the ventilation of street canyons and intersections [ 36 ] and need to be further studied using non-isothermal simulations. Moreover, to further explore the impact of ventilation at intersections, pedestrian exposure to traffic-related pollutants, indices such as the personal intake fraction [ 14 ] and detailed modeling methods for sidewalks, trees, and moving vehicles [ 37 ], need to be considered. Notably, the pollutant concentration in the near-wall zone affects the indoor air quality in complex ways.…”

Section: Limitations and Prospectsmentioning

confidence: 99%

Ventilation and Pollutant Concentration for the Pedestrian Zone, the Near-Wall Zone, and the Canopy Layer at Urban Intersections

Zhang

Gao

Guo

et al. 2021

IJERPH

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To gain further insight into the ventilation at urban street intersections, this study conducted 3D simulations of the ventilation at right- and oblique-angled intersections under eight wind directions by using the Reynolds-averaged Navier–Stokes (RANS) κ-ε turbulence model. The divergent responses of ventilation and pollution concentration for the pedestrian zone (ped), the near-wall zone (nwz), and the canopy layer to the change in intersection typology and wind direction were investigated. The flow characteristics of the intersections, taken as the air flow hub, were explored by employing indices such as the minimum flow ratio (β) between horizontal openings. The results show that oblique wind directions lead to a lower total volumetric flow rate (Qtotal) but a higher β value for right-angled intersections. For T-shaped intersections, a larger cross-sectional area for the outflow helps to increase Qtotal. Oblique-angled intersections, for example, the X-shaped intersection, experience a more significant difference in Qtotal but a steady value of β when the wind direction changes. The vertical air-exchange rate for the intersection was particularly significant when the wind directions were parallel to the street orientation or when there was no opening in the inflow direction. The spatially averaged normalized pollutant concentration and age of air (τ*¯) for the pedestrian zone and the canopy layer showed similar changing trends for most of the cases, while in some cases, only the τped*¯ or τnwz*¯ changed obviously. These findings reveal the impact mechanism of intersection configuration on urban local ventilation and pollutant diffusion.

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The effect of exhaust emissions from a group of moving vehicles on pollutant dispersion in the street canyons

Cited by 37 publications

References 58 publications

Review on pollutant dispersion in urban areas-part A: Effects of mechanical factors and urban morphology

Review on pollutant dispersion in urban areas-part A: Effects of mechanical factors and urban morphology

Research status and control measures of air pollutants in urban areas caused by traffic sources

Ventilation and Pollutant Concentration for the Pedestrian Zone, the Near-Wall Zone, and the Canopy Layer at Urban Intersections

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