title: Does urban vegetation mitigate air pollution in northern conditions?
abstract: It is generally accepted that urban vegetation improves air quality and thereby enhances the well-being of citizens. However, empirical evidence on the potential of urban trees to mitigate air pollution is meager, particularly in northern climates with a short growing season. We studied the ability of urban park/forest vegetation to remove air pollutants (NO2, anthropogenic VOCs and particle deposition) using passive samplers in two Finnish cities. Concentrations of each pollutant in August (summer; leaf-period) and March (winter, leaf-free period) were slightly but often insignificantly lower under tree canopies than in adjacent open areas, suggesting that the role of foliage in removing air pollutants is insignificant. Furthermore, vegetation-related environmental variables (canopy closure, number and size of trees, density of understorey vegetation) did not explain the variation in pollution concentrations. Our results suggest that the ability of urban vegetation to remove air pollutants is minor in northern climates.
authors.affiliation: University of Helsinki, Department of Environmental Sciences, Niemenkatu 73, FIN-15140 Lahti, Finland. Electronic address: heikki.setala@helsinki.fi.
authors.forename: Heikki
authors.initials: H
authors.lastname: Setälä
authors.forename: Viljami
authors.initials: V
authors.lastname: Viippola
authors.forename: Anna-Lea
authors.initials: AL
authors.lastname: Rantalainen
authors.forename: Arto
authors.initials: A
authors.lastname: Pennanen
authors.forename: Vesa
authors.initials: V
authors.lastname: Yli-Pelkonen
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data; D001673:Biodegradation, Environmental; D002947:Cities; D002980:Climate; D004784:Environmental Monitoring; D012621:Seasons; D014197:Trees / Q000502:physiology*
chemical_list: D000393:Air Pollutants