Environmental Engineering Reference
In-Depth Information
2.25 Impact of Vegetation Along a Highway on Local
Air Quality: A CFD Simulation Approach
Stijn Janssen
1
, Bart De Maerschalck
1
, Jean Vankerkom
1
, Wouter Lefebvre
1
,
Clemens Mensink
1
, Aad van den Burg
2
, and Paul Fortuin
2
1
VITO - Flemish Institute for Technological Research, Boeretang 200, B-2400 Mol, Belgium
2
Rijkswaterstaat - Centre for Transport and Navigation (RWS-DVS), Delft, The Netherlands
Abstract
In this paper a CFD-based micro scale air quality model called ENVI-
met is presented. ENVI-met distinguishes itself from other CFD-models due the
implementation of a detailed vegetation model which describes the interaction of
local vegetation, not only on the wind field, but also on the thermodynamic pro-
cesses and the diffusion and deposition of gases and particulate matter. This makes
the model particularly suitable for a recent research programme initiated by the
Air Quality Innovation Programme (IPL), founded by the Dutch Ministry for
Transport, Public Works and Water Management (Rijkswaterstaat) and the Ministry
of Housing, Spatial Planning and the Environment (Ministry of VROM). One of
the seven branches of the IPL-programme is to investigate both by measurements
and modelling the effect of line vegetation along a motorway on local air quality.
Recently the model results have been compared to a first measurement campaign.
Keywords
Air quality, traffic emission, CFD, vegetation
1. Introduction
Computational Fluid Dynamics or CFD-based air quality models have the capability
to describe the local atmospheric conditions over a complex domain in a detailed
way. This makes them particularly useful for small scale air quality modelling in
complex areas like an irregular street canyon with vegetation objects, multiple
emission sources and chemical reactions.
ENVI-met is such a CFD-model. It was originally designed as a micro-climate
model (Bruse, 1998). Later it has been extended with an air quality module for
both quasi inert gases and particulate matter and recently the a chemical model
was included for the photo-chemical reactions of ozone and nitrogen oxides.
ENVI-met contains an extended vegetation module which not only describes the
effect on the wind-field and turbulent kinetic energy, but also describes the
thermodynamic effects of the vegetation on the ambient air, as well as the effects
