I was in China in January and it was awful. There wasn’t a single clear day out of five. Then you look out onto the city and flat roof, one after the other. If they would just plant green roofs, people could breath easier.

I found a lot of good info at http://www.cleanerairforcities.blogspot.com

Shail

Jorg Breuning

Increasing roof life span: This is not always true. First before creating a kind of additional systems on the roof the design capacity and utility of the roof has to be properly studied. Most of the houses are designed for a particular life span and the design usually takes into consideration the weathering. Theoretically speaking if the construction is good a concrete roof (RCC) should increase in its strength as the time goes by. Therefore it lives for ever. But this is not practically true. The same is the case with planting stuff on the roof tops increasing the life span. It’s a theoretical concept but does not take into consideration many practical aspects. For example a small damage to the water proofing element say half an inch can bring down a 100 year life span roof in 5-10 years. And the possibility of noticing the damage becomes quite difficult in a covered space as in comparison with an open space.

Reducing storm water run off: This is really funny I would say. In order to make efficient use of the storm water run off people should really think about recharging and infiltration methods to help the ground water system. There are several manuals and procedures available for installation of such systems within the urban environment. While grass on the roof top uses 2% of the rainfall the recharge system if designed effectively utilizes around 80%. This kind of recharging will help in future water supply for drinking and of course some for the grass growing on your roof.

Filtering pollutants: I am not sure how much one feet of vegetation is going to help. Since my knowledge on plants and their effect on pollution is limited I am not going to comment on this.

Providing locally grown food and increasing wild life habitat: Yes might be possible but once again depends on the type of vegetation grown (definitely roof top grass is not going help any), the type of the building (i don’t know how much food could be provided by a roof top vegetation on top of a high rise for its occupants and during what period of the year). We have a green house on top of our laboratory but the green house does not help create green spaces the glass on the top still reflects, absorbs and emits quite an amount of heat and the amount of electricity used to maintain the green house is exorbitantly high. Ah I almost forgot of one thing I hope busy people living in the city do think about the time required to maintain these vegetations and stuff.

Reducing heating and Urban Heat Island effect: Ah that’s a strong statement made over there. Firstly people should be clear about what kind of heat these people are talking about. For a person living in a city there are various kinds of heats which affect them. Ok. Let me put things a bit more clear generally speaking there are two kinds of heat especially when people talk about urban heat islands. One is the surface temperature and the other is air temperature. The surface temperature is the temperature of particular object and air temperature is the temperature of the atmosphere around. It’s like wearing a cotton shirt and going shirtless on a sunny day. It makes a little bit of difference but not enough to make you feel cold. Secondly here the people do not take the sun’s angle and number of storey into consideration. A high rise building for that matter a three storey building having a garden on its roof will have no effect on its lower floors. And generally the heat on the lower floors are caused by the air temperature and the sun’s rays hitting the building sides which are generally made of concrete and glass leading to the heat island effect. The roof in this case could be taken care of by just painting them white. Further from the research its been proved that residential areas (with sufficient trees and grass) around the CBD and near highways are more hot as compared to their rural counterparts. There by a reduction in the use of traffic by incorporating public transportation system might be a little useful.

Overall I am not against this effect. But I just want people to make a sensible decision before adapting to any of the commercial products. Most of the companies are there to make money and have little or no concern to the chain reaction/ negative role which it might play and they are mostly hesitant to invest on research as they fear that might lead to a hold on their projects. I believe this comment would provide a little bit of insight. There are many ways to conserve electricity and make life more easy for example things like putting solar panel over house might lead to energy saving and at the same time utilizing the natural resource to the fullest. Things like ground water recharge will help not only your house but the whole society for years to come. So think before making any decision. Ask an expert and cortically analyze what’s good for your family, your society and your country.

I am not a consultant but I do care for my environment so if my research or what I have learned so far so help any one in the society I will be more than happy to do so. If you have any comments or questions do feel free to contact me at rumahesh45@yahoo.co.in.

Cheers
Mahesh

But has anyone done any background one this besides trying to sell it?

Most grasses don’t really lower the Co2 in the air and bring down heat outside. And they consume huge amounts of water – another very precious resource. Cities are usually choked for water already. What are they kinds of plant life suitable for this?

Induvidual houses are a different proposition, but high rises usually have associations. They’ll need to maintain it, else the purpose is defeated. But of course, there is hope.

I mentioned the factory in my book, Blood, Sweat and Tears, The Evolution of Work, published by Texere.

Andreas