Indoor simulations reveal differences among plant species in capturing particulate matter

PLoS One. 2017 May 16;12(5):e0177539. doi: 10.1371/journal.pone.0177539. eCollection 2017.

Abstract

A number of studies have focused on the capacity of urban trees and shrubs to serve as efficient biological filters to mitigate air pollution. In this study, five different tree species were assessed for this function. Kerria japonica, Sophora japonica, Philadelphus pekinensis, Gleditsia sinensis, and Prunus persica 'Atropurpurea' were tested in a deposition chamber using (NH4)2SO4 particles. We quantified and compared the capability of all tested trees to remove particles by assessing deposition velocity, a measure of the ability to remove particles. When placed in the deposition chamber, S. japonica had the greatest deposition velocity, followed by Philadelphus pekinensis, G. sinensis, Prunus persica 'Atropurpurea,' and K. japonica, in descending order. In addition, the comparison of deposition velocities among these species suggested that certain leaf geometries and surface characteristics of broadleaf trees, such as trichomes and grooves, increased particle capture. However, these results change under a different simulation condition using ambient air, suggesting that some trees actually increase pollutant number concentrations more than reduce particle concentration. This outcome can be explained by the aerodynamic effect of trees exceeding the filtering capacity of vegetation under some conditions. This highlights the difficulty of generalizing species selection criteria for practice use. Accordingly, our results indicate that using vegetation to reduce particle pollution and improve the air quality is not a universally advisable and viable solution.

MeSH terms

  • Air Pollution, Indoor*
  • Algorithms
  • Computer Simulation
  • Environmental Monitoring* / methods
  • Models, Theoretical
  • Particle Size
  • Particulate Matter* / analysis
  • Particulate Matter* / chemistry
  • Plant Leaves
  • Plants*
  • Quantitative Trait, Heritable

Substances

  • Particulate Matter

Grants and funding

This study was supported by the research projects of forestry public welfare project of China (No.201304301) and Graduate Training and Development Program of Beijing Municipal Commission of Education (No.BLCXY201617) and Special Found for Beijing Common Construction Project. The authors are grateful to our partners in the program for their support and comments on the manuscript. We would like to express our gratitude to the authorities at the Beijing Olympic forest park and Beijing Forestry University for their help and giving us access to the park to conduct experiments.