Search results for "Street canyon"
showing 6 items of 6 documents
An evaluation of the estimation of road traffic emission factors from tracer studies
2010
Road traffic emission factors (EFs) are one of the main sources of uncertainties in emission inventories; it is necessary to develop methods to reduce these uncertainties to manage air quality more efficiently. Recently an alternative method has been proposed to estimate the EFs. In that work the emission factors were estimated from a long term tracer study developed in Ho Chi Minh City (HCMC) Vietnam. A passive tracer was continuously emitted from a finite line source placed in one side of an urban street canyon. Simultaneously, the resulting tracer concentrations were monitored at the other side of the street. The results of this experiment were used to calculate the dispersion factors an…
On the relationship between the sky view factor and the land surface temperature derived by Landsat-8 images in Bari, Italy
2015
This study investigates the impact of landscape composition and urban morphology on land surface temperature LST in the city of Bari, Italy. For this purpose, correlation between sky view factor SVF and LST was done assigning weights to the output results and moreover expressing the latter according to the four main surface classes of the Corine land cover CLC classification method. To do this, several daytime Landsat 8 and night-time Landsat 7 ETM+ images acquired during different months of the year were used to retrieve LST by using the radiative transfer equation. The results show a positive relationship between LST and SVF, and this trend is emphasized particularly in the more dense urb…
Evaluation of Local Scale PM Pollution Levels in Typical Street Canyon in Riga
2013
The present study describes long term PM10 and PM2.5 changes in typical street canyon with particular emphasis on seasonal, diurnal variations in context with meteorological data. In order to understand PM10 pollution sources during 28 April 2007-31 December 2007, chemical composition measurements were done with particular emphasis on heavy metals (As, Cd, Ni, and Pb), crustal material (Ca, Mg, Na, and K) and anions (sulphates, nitrates, chlorides). Meteorological data used for this evolutional analysis were measured close to traffic related stations and several meteorological parameters were analyzed in relation to particulate measurements. Keep in mind that atmospheric aerosols are genera…
High Resolution Dispersion Modeling near Tunnel Exits
1996
This contribution is concerned with a critical problem which usually occurs at motortraffic tunnels within towns. All exhaust gases accumulating along the entire tunnel distance readily leave the tunnel exits in a very concentrated form. Since modern urban traffic management affords more and more tunnel constructions within highly built-up areas, a reliable calculation of the resulting immission distribution in the neighbourhood of tunnel exits is of great importance.
TRAFFIC FLOW HYPOTHETICAL MODELLING FOR AIR QUALITY IMPROVEMENT AND PLANNING PURPOSES
2019
The main emphasis of this research was to describe air pollution level and dispersion in a typical street canyon (Valdemara Street in Riga (Latvia) city centre), afterward to postulate potential development scenarios and perform modelling in order to understand the influence on air pollution level. For this purpose special mathematical model was used - Operational Street Pollution Model (OSPM), which was developed by the National Environmental Research Institute in Denmark. Following development scenarios were tested: (1) realistic environmentally friendly - decrease of traffic flow by 50 %, as according to street interviews about 36 - 50 % of drivers are ready to change driving habits from…
Ultraviolet radiation protection by a beach umbrella.
2010
A beach umbrella intercepts all direct UV irradiance, but only part of the diffuse component. Using a simple sky view factor model, we have determined the fraction of the hemispheric diffuse irradiance that is not intercepted by the umbrella. Assuming a sensor at the surface and close to the center of the umbrella, isotropic diffuse irradiance and for an umbrella of 80 cm radius and 100 cm high, our results show that approximately 34% of the incident horizontal irradiance is not intercepted by the umbrella. These results agree with irradiance measurements conducted with and without the umbrella. The model is next extended to examine receipt of UV radiation by a human figure in a vertical po…