Featured Research

from universities, journals, and other organizations

Too Many Trees Planted In Central Strip Of Roads Can Be Worse Than None; Can Trap Vehicle Exhaust Fumes

Date:
July 21, 2009
Source:
Inderscience
Summary:
A new study suggests that we can improve city environments by planting trees down the middle of streets provided they are not too close together. Too many trees planted close together along a central strip, as is common in many major European cities could lead to more vehicle exhaust fumes being trapped in the urban canyon than would occur if there were no trees.

A new study published in the International Journal of Environment and Waste Management suggests that we can improve city environments by planting trees down the middle of streets provided they are not too close together.

Christof Gromke now of the WSL Institute for Snow and Avalanche Research SLF in Davos, Switzerland, and Bodo Ruck of the Institute for Hydromechanics at the University of Karlsruhe, Germany, have investigated the effects of trees on ventilation and pollution levels along city streets lined with densely packed tall buildings, so called urban canyons.

The team's wind tunnel study investigated how air flows along canyon-like city streets and how this is affected by the street having a central line of trees. They looked at how air flows along and upward from the urban canyons and the effect of different spacing for trees and how stationary or moving traffic affects air flow.

Their results suggest that streets with too many trees planted close together along a central strip, as is common in many major European cities could lead to more vehicle exhaust fumes being trapped in the urban canyon than would occur if there were no trees. Specifically, the leafy canopies of a high density tree line hinder the upward flow of pollutants. They also damp down the swirling eddies of air that would otherwise help exhaust gases escape the street.

The study does not advocate removing trees from city streets, of course. Further investigation revealed that a wider spacing of trees, with trees separated by at least the width of their crowns enables pollution-carrying eddies to form and allows the air at street level to clear much more quickly especially when traffic is not at a standstill.

The research could help town planners improve city environments by choosing the optimum spacing of trees when planting new streets or to pollard more appropriately to improve airflow in streets with established tree lines.


Story Source:

The above story is based on materials provided by Inderscience. Note: Materials may be edited for content and length.


Journal Reference:

  1. Effects of trees on the dilution of vehicle exhaust emissions in urban street canyons. Int. J. Environment and Waste Management, 2009, 4, 225-242

Cite This Page:

Inderscience. "Too Many Trees Planted In Central Strip Of Roads Can Be Worse Than None; Can Trap Vehicle Exhaust Fumes." ScienceDaily. ScienceDaily, 21 July 2009. <www.sciencedaily.com/releases/2009/07/090720105127.htm>.
Inderscience. (2009, July 21). Too Many Trees Planted In Central Strip Of Roads Can Be Worse Than None; Can Trap Vehicle Exhaust Fumes. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2009/07/090720105127.htm
Inderscience. "Too Many Trees Planted In Central Strip Of Roads Can Be Worse Than None; Can Trap Vehicle Exhaust Fumes." ScienceDaily. www.sciencedaily.com/releases/2009/07/090720105127.htm (accessed September 16, 2014).

Share This



More Plants & Animals News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

AFP (Sep. 16, 2014) Since the arrival of Ebola in Ivory Coast, Ivorians have been abandoning their pets, particularly monkeys, in the fear that they may transmit the virus. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

      Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins