Air pollution and why green roofs are a breath of fresh air
From Beijing to Bangkok and from Los Angeles to London air pollution is killing millions. The World Health Organisation (WHO) states that more than three million people die every year as a result of air pollution and has described the problem as the "world’s largest single environmental health risk." WHO says that tackling the sources of this pollution — such as emissions from traffic, manufacturing and power production — should be an international priority. Unfortunately, reducing the emission of new air pollutants does not remove those that are already in the air.