23 Modelling the Potential of Green Infrastructures to Reduce …
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23.4 Conclusion
This study presents a CFD model as a valid tool to assess climate change effects at
local scale, and the role of green infrastructure as adaptation measures to increase
resilience of Porto’s urban area. The CFD model presents a good performance for the
simulation of CO and NO 2 concentrations, while the results point out some weakness
to simulate particulate matter dispersion. Therefore, the understanding of the influence of turbulent flow dynamics and the distinct emission sources contributing to fine
particulate matter pollution still presenting a set of uncertainties. The results are an
important contribution regarding the impact of green parks and green roofs at street
level, both presenting similar effects on flow dynamics and pollutants dispersion.
Questions and Answers
Questioner: David Niemi
Question: Was the impact of green areas on the turbulence and wind tunneling
between large buildings also considered?
Answer: The impact of green areas on the turbulence and wind velocity components
was also assessed for the same case study, using as inflow wind conditions data from
a recent meteorological year. These results were already published in the chapter
book [6], and some other results are also being included in the articles entitled
“Numerical and physical modeling of the impact of GI on flow dynamics in urban
street canyons” and “CFD modeling of the impact of GI on flow dynamics and air
quality in urban areas”, both authored by Rodrigues et al., to be published at the
Building and Environment and the Atmospheric Environment journals, respectively.
Questioner: Shuzhan Ren
Question: CFD is such a high resolution model; when being used for forecast the
results can be very sensitive to the initial conditions from downscaling regional model
results. Have you test such sensitivity?
Answer: The sensitivity of the initial meteorological conditions from regional model
results was assessed in terms of wind velocity components and turbulence. These
sensitivity tests were performed by comparison of the regional model results with
meteorological measurements for recent meteorological years. Furthermore, the performance and accuracy of the CFD model was previously evaluated in terms of flow
dynamics by Rafael et al. (2018) in the paper entitled “Impacts of green infrastructures on aerodynamic flow and air quality in Porto’s urban area”, published in the
Atmospheric and Environment journal. In this paper, the authors initialize a set of
CFD simulations with meteorological data from WRF results, using a grid cell from
WRF simulations nearest the locations of the CFD domain boundaries.
Questioner: Fabian Lewartz
Question: Have you tried to evaluate the impact of vertical green infrastructures? Do
you think they can improve air quality in a 50-m radius, as advertised by a company
selling green walls?
151
23.4 Conclusion
This study presents a CFD model as a valid tool to assess climate change effects at
local scale, and the role of green infrastructure as adaptation measures to increase
resilience of Porto’s urban area. The CFD model presents a good performance for the
simulation of CO and NO 2 concentrations, while the results point out some weakness
to simulate particulate matter dispersion. Therefore, the understanding of the influence of turbulent flow dynamics and the distinct emission sources contributing to fine
particulate matter pollution still presenting a set of uncertainties. The results are an
important contribution regarding the impact of green parks and green roofs at street
level, both presenting similar effects on flow dynamics and pollutants dispersion.
Questions and Answers
Questioner: David Niemi
Question: Was the impact of green areas on the turbulence and wind tunneling
between large buildings also considered?
Answer: The impact of green areas on the turbulence and wind velocity components
was also assessed for the same case study, using as inflow wind conditions data from
a recent meteorological year. These results were already published in the chapter
book [6], and some other results are also being included in the articles entitled
“Numerical and physical modeling of the impact of GI on flow dynamics in urban
street canyons” and “CFD modeling of the impact of GI on flow dynamics and air
quality in urban areas”, both authored by Rodrigues et al., to be published at the
Building and Environment and the Atmospheric Environment journals, respectively.
Questioner: Shuzhan Ren
Question: CFD is such a high resolution model; when being used for forecast the
results can be very sensitive to the initial conditions from downscaling regional model
results. Have you test such sensitivity?
Answer: The sensitivity of the initial meteorological conditions from regional model
results was assessed in terms of wind velocity components and turbulence. These
sensitivity tests were performed by comparison of the regional model results with
meteorological measurements for recent meteorological years. Furthermore, the performance and accuracy of the CFD model was previously evaluated in terms of flow
dynamics by Rafael et al. (2018) in the paper entitled “Impacts of green infrastructures on aerodynamic flow and air quality in Porto’s urban area”, published in the
Atmospheric and Environment journal. In this paper, the authors initialize a set of
CFD simulations with meteorological data from WRF results, using a grid cell from
WRF simulations nearest the locations of the CFD domain boundaries.
Questioner: Fabian Lewartz
Question: Have you tried to evaluate the impact of vertical green infrastructures? Do
you think they can improve air quality in a 50-m radius, as advertised by a company
selling green walls?