کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6462001 1421868 2017 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Air quality affected by trees in real street canyons: The case of Marylebone neighbourhood in central London
ترجمه فارسی عنوان
کیفیت هوا تحت تأثیر درختان در کانین های واقعی واقع شده است: مورد محله مریلوبون در مرکز لندن
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک جنگلداری
چکیده انگلیسی


- The effectiveness of trees on dispersing road traffic emissions is assessed.
- CFD simulations of NOx and PM2.5 is performed using the OpenFOAM software.
- Deposition of PM2.5 on trees is modelled.
- The aerodynamic effects are more important than deposition.
- On average, trees increase pollution, but reduce pollution for winds parallel to street.

This paper discusses the combined influence of building morphology and trees on air pollutant concentrations in the Marylebone neighbourhood (central London). Computational Fluid Dynamics (CFD) simulations are performed with OpenFOAM using the k-ε model. Aerodynamic and deposition effects of Platanus acerifolia trees are considered. While aerodynamic effects are treated as typically done in the literature, i.e. as a porous media, for the deposition an enhanced model with an additional sink term was implemented. CFD results are compared with UK AURN (Automatic Urban and Rural Network) station concentrations. Several meteorological conditions are analysed based on London City Airport weather station data, with attention to prevailing winds.CFD simulations show that trees trap air pollution by up to about 7% at the Marylebone monitoring station in the spring, autumn and summer seasons, suggesting that the aerodynamic effects are similar over the different leaf seasons. Aerodynamic effects are more important at lower wind speeds causing little turbulent dispersion. Deposition effects are found to be 4 times less important with reductions of up to about 2%, with more deposition in summer due to a greater leaf area density. Furthermore, for winds parallel to Marylebone Road, the aerodynamic effects decrease concentrations suggesting that in such cases trees could be considered as a mitigation measures. This is different from perpendicular winds for which trees exacerbate trapping, as found in previous studies. The analysis of concentration levels obtained from CFD simulations across the whole street confirms a beneficial aerodynamic dispersive effect of trees of 0.7% in summer time for all wind directions averaged at a wind speed of 5 m/s (yearly average wind speed observed in the area). Results highlight the need to account for both aerodynamic and dispersion effects of trees in CFD modelling to achieve a comprehensive evaluation and help city planners with a sustainable design of trees in urban environments.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Urban Forestry & Urban Greening - Volume 22, March 2017, Pages 41-53
نویسندگان
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