Improve air quality
Facts from World Health Organisation and Office of United Nations Human Rights
Air pollution kills more people every year than wars, and with increased urbanisation the phenomena will increase - (predicted that 7 billion people will be city dwellers by the end of the century).
- 7 million premature deaths every year linked to outdoor pollution in 2012
- 90% of the world’s population are at risk from air pollution
- 600 000 children die prematurely every year from polluted air
- Air pollution plays a significant role in cardiovascular illness and related deaths
- Small airborne Particulates (2.5 to 10 micro-meters) carried in the air are closely related to increased rates of lung cancer
- Outdoor air pollution has been observed as a factor increasing cancer of the urinary tract and bladder
- Nitrogen Dioxide and Sulphur Dioxide are causes of inflammation associated with asthma, bronchitis, and impaired pulmonary function
- Ozone (at ground level) - a breakdown product of Nitrogen Dioxide - the vehicle pollutant - causes asthma and impaired lung function
References:
https://www.who.int/airpollution/data/en/
https://www.ohchr.org/en/NewsEvents/Pages/DisplayNews.aspx?NewsID=24248&LangID=E
Green Facades, Walls, and Roofs Reduce Air Pollution by….
Why Green Facades and Roofs?
- Plant leaves and vegetation trap atmospheric particulates reducing airborne levels by 10-20%
- Reduce low level Ozone
- Plants absorb Nitrogen Oxide and Sulphur dioxide
Green Facades, Walls, and Roofs reduce Noise Pollution
Green Facades, Walls, and Roofs reduce Noise Pollution
- Reducing ambient noise leads to improved wellbeing
- Reducing night noise in cities improves sleep patterns and reduces anxiety
- Green Walls and Roofs increase the building’s sound insulation by reducing noise reflection
- Plants and vertical gardens can reduce noise by up 8-9 dB dependent on the frequency, by absorption and scattering
Reduce the Urban Heat-Island (UHI) effect
Scientific Facts:
Urban areas are heating up. The UHI is effect is a comparison of the relative temperatures of a build-up urban area and surrounding areas
[Ref Arup]
A number of variables affect the amount of heat gain in urban areas: including the grid, solar surface radiation, building (canyon) height-to-width ratio, thermal mass and the percentage if green space
[Arup] pp 15
In more densely build cities (example Hong-Kong and Melbourne) modelling indicates up to 10°C reductions are possible with effective green facades
Examples
>New York City average temperature 7.2-8.9°C higher than surrounding rural areas
Nasa Study : https://www.nasa.gov/pdf/665642main_NASA_and_Green_Roof_Research.pdf
>If Greater Manchester increased Green infrastructure by 10% - in areas with low green cover, average temperatures would decrease by 2.5°C
[Arup p 44]
Causes of UHI effect
Hard surfaces in cities: concrete pavements, roadways, steel and glass facades
Consequences of UHI effect
- Increased energy consumption for building cooling systems
- Exacerbation of the effects of air pollution
- Reduced water quality
- Modified micro weather patterns - wind and precipitation effects
- Heat-related illnesses (US EPA - study showed that an urban area with population greater than 1 million - has an increased day time temperature of 1-3°C and up to 12°C at night - when compared to local areas
- Increased mortality rates
Green Facades, Walls, and Roofs reduce UHI effects
- Green roofs are accumulatively effective at reducing heat gain by reducing roof temperatures (compared with green roofs - normal roofs are up to 20 °C higher during the day and 8°C higher at night)
- Reduced ‘heat-flow’ through the green roof (A study in 2003 by the National Research Council of Canada - showed significant reduction in temperatures on roof membrane -with a reduce heat -flow through a green roof of 75%)
- Green roofs reduce indoor temperatures by 4 degrees Fahrenheit
- Green roofs absorb 80% of rainfall compared to 2% by standard roofs
[NASA study]