tailieunhanh - Quantifying air pollution removal by green roofs in Chicago

Following a brief overview of the state of the evidence regarding household energy interventions, indoor air pollution and health, the presentation "Why evaluate?" describes multiple evaluation perspectives. Target audiences and purposes for evaluation can range from informing the community that their needs and concerns have been addressed to contributing to the international evidence base by carefully documenting intervention impacts. Moreover, data on the costs and benefits of an intervention project or programme can feed into economic evaluation. In general, impact evaluation tries to assess whether an intervention has been adopted and implemented in the community and whether it has been effective in achieving its intended impacts. In contrast, economic evaluation tries to demonstrate the. | Atmospheric Environment 42 2008 7266-7273 Contents lists available at ScienceDirect Atmospheric Environment journal homepage locate atmosenv Quantifying air pollution removal by green roofs in Chicago Jun Yanga c Qian Yub Peng Gongc a Department of Landscape Architecture and Horticulture Temple University 580 Meetinghouse Road Ambler PA 19002 USA b Department of Geosciences University of Massachusetts 611 N Pleasant Street Amherst MA 01003 USA c State Key Lab of Remote Sensing Science Jointly Sponsored by Institute of Remote Sensing Applications Chinese Academy of Science and Beijing Normal University Beijing 100101 China ARTICLE INFO ABSTRACT Article history Received 17 March 2008 Received in revised form 30 June 2008 Accepted 2 July 2008 Keywords Extensive green roofs Intensive green roofs Dry deposition Cost The level of air pollution removal by green roofs in Chicago was quantified using a dry deposition model. The result showed that a total of 1675 kg of air pollutants was removed by ha of green roofs in one year with O3 accounting for 52 of the total NO2 27 PM10 14 and SO2 7 . The highest level of air pollution removal occurred in May and the lowest in February. The annual removal per hectare of green roof was 85 kg ha 1 yr 1. The amount of pollutants removed would increase to metric tons if all rooftops in Chicago were covered with intensive green roofs. Although costly the installation of green roofs could be justified in the long run if the environmental benefits were considered. The green roof can be used to supplement the use of urban trees in air pollution control especially in situations where land and public funds are not readily available. 2008 Elsevier Ltd. All rights reserved. 1. Introduction City air often contains high levels of pollutants that are harmful to human health Mayer 1999 . The American Lung Association ALA 2007 reported that over 3700 premature deaths annually in the United States could be attributed to a