Particulate matter pollution capture by leaves of seventeen living wall species with special reference to rail-traffic at a metropolitan station

• Published in: Urban forestry & urban greening 2017-10, Vol.27, p.173-186
• Main Authors: Weerakkody, Udeshika, Dover, John W., Mitchell, Paul, Reiling, Kevin
• Format: Article
• Language: English
• Subjects: Green walls; Outdoor air pollution; Railway pollution; Urban green infrastructure
• ISSN: 1618-8667; 1610-8167
• DOI: 10.1016/j.ufug.2017.07.005

•The living wall located by New Street Station, Birmingham, UK has a promising potential for removal of atmospheric PM (PM1, PM2.5 and PM10).•Inter-species variation in the ability to capture PM is significant, careful species selection is crucial to optimize living walls as PM filters.•Smaller-leaved species, hairy leaf surfaces and epicuticular wax enhance the PM capture potential of living wall-plants. Atmospheric Particulate Matter (PM) constitutes a considerable fraction of urban air pollution, and urban greening is a potential method of mitigating this pollution. The value of living wall systems has received scant attention in this respect. This study examined the inter-species variation of particulate capture by leaves of seventeen plant species present in a living wall at New Street railway station, Birmingham, UK. The densities of different size fractions of particulate pollutants (PM1, PM2.5 and PM10) on 20 leaves per species were quantified using an Environmental Scanning Electron Microscope (ESEM) and ImageJ image-analysis software. The overall ability of plant leaves to remove PM from air was quantified using PM density and LAI (Leaf Area Index); any inter-species variations were identified using one-way Anova followed by Tukey’s pairwise comparison. This study demonstrates a considerable potential for living wall plants to remove particulate pollutants from the atmosphere. PM capture levels on leaves of different plant species were significantly different for all particle size fractions (P