The influence of the vegetation cycle on the mitigation of air pollution by a deciduous roadside hedge. (February 2020)

• Record Type: Journal Article
• Authors: Ottosen, Thor-Bjørn; Kumar, Prashant
• Is Part Of: Sustainable cities and society. Volume 53(2020)
• Publication Date: 2020-02
• Subjects: Hedges -- Air pollution -- Vegetation cycle -- Gaseous pollutants -- Particulate matter -- iSCAPE project; Sustainable urban development -- Periodicals; Sustainable buildings -- Periodicals; Urban ecology (Sociology) -- Periodicals; 307.76
• DOI: 10.1016/j.scs.2019.101919
• Languages: English
• ISSNs: 2210-6707

Abstract

Graphical abstract: Highlights: The hedge causes concentration differences between −52 % to +10 %. A jump in concentrations is seen after the greenup for PM1, PM2.5 and PM10 . A similar jump was not seen for NO2 and CO. The effect of wind direction was found to be minor. Societal and meteorological factors were shown to influence absolute concentrations. Abstract: Vegetation barriers along roads can mitigate the effects of air pollution from traffic. Here, we measure a range of air pollutants in front and behind a hedge during the dormancy, greenup and part of the maturity vegetation cycle along with auxiliary variables. This is the first time a long time-series measuring multiple pollutants on both sides of a hedge is presented. This time-series allows assessing the influence of the annual vegetation cycle, wind direction and high versus low concentrations of both gaseous and particulate matter pollutants across a hedge. A marked jump in concentrations of particles happens after the hedge is greening up; this jump was not seen for gases. For example, a concentration difference for CO and PM1 of −8 %, −1 % for PM2.5 and −3 % for NO2 and +10 % for PM10 during dormancy and greenup was measured. At the beginning of the maturity phase, all three PM fractions experience a rapid increase in concentration difference, not seen for gases, to −52 % for PM1, −44 % for PM2.5 and −35 % for PM10 . The effect of wind direction is shown to be minor. These measurements are a first step towards an accurate assessment of city-scale air pollution mitigation potential of hedge-like vegetation.