Viippola , V , Yli-Pelkonen , V , Järvi , L , Kulmala , M & Setälä , H 2020 , ' Effects of forests on particle number concentrations in near-road environments across three geographic regions ' , Environmental Pollution , vol. 266 , no. Part 2 , 115294 . https://doi.org/10.1016/j.envpol.2020.115294
Title: | Effects of forests on particle number concentrations in near-road environments across three geographic regions |
Author: | Viippola, Viljami; Yli-Pelkonen, Vesa; Järvi, Leena; Kulmala, Markku; Setälä, Heikki |
Contributor organization: | Urban Ecosystems Ecosystems and Environment Research Programme Helsinki Institute of Sustainability Science (HELSUS) Institute for Atmospheric and Earth System Research (INAR) Urban meteorology Helsinki Institute of Urban and Regional Studies (Urbaria) SUSTAINABLE URBAN DEVELOPMENT EMERGING FROM THE MERGER OF CUTTING-EDGE CLIMATE, SOCIAL AND COMPUTER SCIENCES |
Date: | 2020-11 |
Language: | eng |
Number of pages: | 9 |
Belongs to series: | Environmental Pollution |
ISSN: | 0269-7491 |
DOI: | https://doi.org/10.1016/j.envpol.2020.115294 |
URI: | http://hdl.handle.net/10138/318580 |
Abstract: | Trees and other vegetation have been advocated as a mitigation measure for urban air pollution mainly due to the fact that they passively filter particles from the air. However, mounting evidence suggests that vegetation may also worsen air quality by slowing the dispersion of pollutants and by producing volatile organic compounds that contribute to formation of ozone and other secondary pollutants. We monitored nanoparticle (>10 nm) counts along distance gradients away from major roads along paired transects across open and forested landscapes in Baltimore (USA), Helsinki (Finland) and Shenyang (China) − i.e. sites in three biomes with different pollution levels − using condensation particle counters. Mean particle number concentrations averaged across all sampling sites were clearly reduced (15 %) by the presence of forest cover only in Helsinki. For Baltimore and Shenyang, levels showed no significant difference between the open and forested transects at any of the sampling distances. This suggests that nanoparticle deposition on trees is often counterbalanced by other factors, including differing flow fields and aerosol processes under varying meteorological conditions. Similarly, consistent differences in high frequency data patterns between the transects were detected only in Helsinki. No correlations between nanoparticle concentrations and solar radiation or local wind speed as affecting nanoparticle abundances were found, but they were to some extent associated with canopy closure. These data add to the accumulating evidence according to which trees do not necessarily improve air quality in near-road environments. Trees and other vegetation have been advocated as a mitigation measure for urban air pollution mainly due to the fact that they passively filter particles from the air. However, mounting evidence suggests that vegetation may also worsen air quality by slowing the dispersion of pollutants and by producing volatile organic compounds that contribute to formation of ozone and other secondary pollutants. We monitored nanoparticle (>10 nm) counts along distance gradients away from major roads along paired transects across open and forested landscapes in Baltimore (USA), Helsinki (Finland) and Shenyang (China) − i.e. sites in three biomes with different pollution levels − using condensation particle counters. Mean particle number concentrations averaged across all sampling sites were clearly reduced (15 %) by the presence of forest cover only in Helsinki. For Baltimore and Shenyang, levels showed no significant difference between the open and forested transects at any of the sampling distances. This suggests that nanoparticle deposition on trees is often counterbalanced by other factors, including differing flow fields and aerosol processes under varying meteorological conditions. Similarly, consistent differences in high frequency data patterns between the transects were detected only in Helsinki. No correlations between nanoparticle concentrations and solar radiation or local wind speed as affecting nanoparticle abundances were found, but they were to some extent associated with canopy closure. These data add to the accumulating evidence according to which trees do not necessarily improve air quality in near-road environments. |
Subject: |
1172 Environmental sciences
Air pollution Particles Nanoparticles Urban forest Parks near-road environment Forests Ecosystem services Urban ecology Urban ecosystems URBAN ATMOSPHERE Urban meteorology particle concentrations Air quality traffic Urban trees Field study Air pollution Particulate Matter Particles Nanoparticles particle concentrations Urban forest Forests Urban trees Parks Urban ecology Urban ecosystems URBAN ATMOSPHERE Urban meteorology near-road environment Road traffic Air pollution mitigation Ecosystem services Air quality Urban vegetation particle pollution Nanoparticles Air pollution Air quality Urban forest Urban trees AIR-POLLUTION GREEN INFRASTRUCTURE ECOSYSTEM SERVICES URBAN VEGETATION QUALITY NANOPARTICLES DEPOSITION IMPACT DISPERSION HELSINKI |
Peer reviewed: | Yes |
Rights: | cc_by |
Usage restriction: | openAccess |
Self-archived version: | publishedVersion |
Total number of downloads: Loading...
Files | Size | Format | View |
---|---|---|---|
Viippola_et_al_2020_Environmental_Pollution.pdf | 1.500Mb |
View/ |