Clipping of news on Brazilian Culture, Law and Citizenship
08/06/2012
This article was translated by an automatic translation system, and was therefore not reviewed by people.
While new technologies do not emerge, cover the walls of the "concrete jungle" with green can lower the levels of pollution in large cities with more successful than previously thought. Researchers in England found that the use of green walls in so-called urban valleys - several tall buildings lined both sides of the same street - forming true vertical vegetation corridors in busy avenues, can reduce pollutants from the site within 30%.
The new study from the Universities of Birmingham and Lancaster contradicts the previous perception that improvement would be only 1 or 2% and indicates that the measure may be more effective than trees or green roofs. Through simulation on a computer program, scientists agreed that they knew about the way the air circulates in the cities and purifies it as vegetation.
The step forward, says the professor of atmospheric science Rob MacKenzie of the University of Birmingham, was the recognition that the air takes longer circulating within the urban valleys, where pollution is generated by cars and is more concentrated. Therefore, the living walls would more than indicated in this case the green roofs.
"As the wind blows on top of buildings, the air circulates slowly in the street between them, circling. If the vegetation is within the urban valleys, the removal is more efficient. The more pollution there is in place, the faster it is absorbed by vegetation. It's like the water that drains out of the tub faster in the beginning, when filled, than at the end, when is almost empty, "study co-author compares.
Plants clean the air by removing nitrogen dioxide and particulate matter - pollution particles that remain suspended in the atmosphere due to its small size - both harmful to health. The pollution can cause heart disease, lung cancer and asthma, among others, and the World Health Organization (WHO) estimates that the cause of more than 2 million deaths per year.
Climbers rather than technology - The new data on the efficiency of urban walls in valleys green comes at a time that scientific research must move forward to develop more efficient technology in combating the problem.
"You think buying a new vehicle would have less pollution than a car that is on the street five years ago. But it seems that we have not had the benefits we expected, because the technological solutions are not working the way we expected. So they are looking at alternatives such as green walls and suppressing dust (substances that act as an adhesive and prevents the movement of particulate pollutants), "notes Gary Fuller, an expert in measuring air quality in environmental research group at King's College in London.
Concerned with the problem, municipal agencies in the UK have gradually adopted the measure, but still far from forming green corridors, as the scientists suggest in Birmingham and Lancaster. England's second largest city, Birmingham account since 2010 with a temporary wall alive, along with some of the fences around the construction of the new library in the city center.
Already the Transport for London, the body responsible for public transport in the British capital, installed in July its second green wall especially to appease pollution near Blackfriars tube station, with 15 different varieties of plants in 120 square meters, and plans to include in the future more places with high levels of PM10, as it is called particulate matter that can be inhaled by humans. Researchers at the prestigious Imperial College analyzed the change in air quality at these points and some species work better as "filters" than others, but the results were not disclosed.
Reviews - The idea that green clean is not new, but in recent years, studies showed that trees can aggravate the problem. By forming a tunnel on a street with great movement of cars, the branches "hold" the pollutants in place - so the green walls would be more appropriate. Nevertheless, the alternative suffers criticism. "What really needs to have some kind of impact? All air must be in contact with vegetation. The best effects of green walls are expected to be very local, "Fuller questioned.
For MacKenzie, 10% coverage will make no difference, but 50% is achieved a remarkable result. Scholars also suggest the use of "green billboards" (outdoors, such as advertising, with vegetation) and ensure that the solution need not be costly - another recurring criticism of the green walls. Although companies offer hi-tech walls, with hydroponics, MacKenzie illustrates that a climbing like ivy, planted directly in soil, is a much cheaper version.
Even with similar levels of pollution, according to the WHO, which works in London may not work in Sao Paulo, warns Fuller. Besides the weather being distinct, the Brazilian car fleet uses ethanol, not used in Europe. But the recipe for pollution control in major cities including attacking the source of the problem, the experts note heard by the Earth.
"My vision for a clean city is that it has more plants sharing the space with us and much less emphasis on cars. If you combine that will be the best, "argues professor of atmospheric science at the University of Birmingham. (Source: Terra)
Source: Environment Brazil
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This article was translated by an automatic translation system, and was therefore not reviewed by people.