Impacts of urban roadside forest patches on NO2 concentrations

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Although it is commonly believed that trees can improve air quality, recent studies have shown that such pollution mitigation can be negligible – or that tree canopies can even increase pollutant concentrations near their sources compared to adjacent treeless areas. We explored the impacts of urban roadside forest patches on the concentrations of nitrogen dioxide in summer and winter in the Helsinki Metropolitan Area, Finland, and especially investigated if canopy cover can result in increased concentrations of NO2 below the canopy. Our results, however, did not show significantly higher – or lower – NO2 concentrations underneath tree canopies compared to levels above canopies. Neither did NO2 levels at the below-canopy sampling height differ significantly between forest patches and adjacent open, treeless areas. The lack of a canopy effect may derive from the rather small size of the forest patches, and – compared to previous studies with similar design – divergent tree species composition forming a dense canopy structure. Our results corroborate previous studies that the potential ecosystem services offered by urban near-road forests are more likely due to benefits other than those related to the removal of air pollutants.
Original languageEnglish
Article number117584
JournalAtmospheric Environment
Volume232
Number of pages7
ISSN1352-2310
DOIs
Publication statusPublished - 1 Jul 2020
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 1172 Environmental sciences
  • Forest
  • Urban forests
  • Urban ecology
  • Urban ecosystems
  • Nitrogen dioxide
  • Air pollution
  • Road traffic
  • Ecosystem services
  • Nature-based solutions

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