Cut street-Canyon air Pollution

Rows of tall buildings can create a unique urban habitat known as a street canyon. These canyons trap traffic pollutants, limiting their dispersal into the atmospheric boundary layer that extends as high as 2,000 meters above the ground. A new study suggests that vegetation in street canyons may reduce air-pollutant con-centrations much more than previously report-ed and suggests innovative planting configura-tions to improve city pollution hot spots.1 Outdoor air pollution is believed to cause an estimated 1.3 million annual deaths worldwide,2 as well as an increased risk of respiratory and cardiovascular diseases.3 Plantings are often promoted as a partial solu