The interplay between ozone and urban vegetation – BVOC emissions, ozone deposition and tree ecophysiology
- 1Forest Ecology, Dept. of Forest and Soil Sciences, University of Natural Resources and Life Sciences Vienna, Austria
- 2Forest Ecology, Dept. of Forest and Soil Sciences,, University of Natural Resources and Life Sciences Vienna, Austria
- 3Institute of Atmospheric and Cryospheric Sciences,, University of Innsbruck, Austria
- 4Research Centre for Forestry and Wood, Council for Agricultural and Economics Research, Italy
- 54Institute of Research on Terrestrial Ecosystems, Italian National Research Council (CNR), Italy
- 6Institute of Meteorology and Climate Research, Atmospheric Environmental Research Division, Karlsruhe Institute of Technology (KIT), Germany
- 76Department of Environmental and Biological Sciences, University of Eastern Finland, Finland
Tropospheric ozone (O3) is one of the most prominent air pollution problems in Europe and other countries worldwide. Human health is affected by O3 via the respiratory as well the cardiovascular systems. Even though trees are present in relatively low numbers in urban areas, they can be a dominant factor in the regulation urban O3 concentrations. Trees affect the O3 concentration via emission of biogenic volatile organic compounds (BVOC), which can act as a precursor of O3, and by O3 deposition on leaves. The role of urban trees with regard to O3 will gain further importance as NOx concentrations continue declining and climate warming is progressing—rendering especially the urban ozone chemistry more sensitive to BVOC emissions. However, the role of urban vegetation on the local regulation of tropospheric O3 concentrations is complex and largely influenced by species-specific emission rates of BVOCs and O3 deposition rates, both highly modified by tree physiological status. In this review, we shed light on processes related to trees that affect tropospheric ozone concentrations in metropolitan areas from rural settings to urban centers, and discuss their importance under present and future conditions. After a brief overview on the mechanisms regulating O3 concentrations in urban settings, we focus on effects of tree identity and tree physiological status, as affected by multiple stressors, influencing both BVOC emission and O3 deposition rates. In addition, we highlight differences along the rural-urban gradient affecting tropospheric O3 concentrations and current knowledge gaps with the potential to improve future models on tropospheric O3 formation in metropolitan areas.
Keywords: biogenic volatile organic compounds, ozone formation and deposition, Roadside trees, Rural-urban gradient, stress, Urban forest
Received: 03 Jun 2019;
Accepted: 13 Aug 2019.
Edited by:Mark Potosnak, DePaul University, United States
Reviewed by:Dasa Gu, Hong Kong University of Science and Technology, Hong Kong
Xu Yue, Nanjing University of Information Science and Technology, China
Copyright: © 2019 Fitzky, Sandén, Karl, Fares, Calfapietra, Grote, Saunier and Rewald. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Hans Sandén, University of Natural Resources and Life Sciences Vienna, Forest Ecology, Dept. of Forest and Soil Sciences,, Vienna, Austria, firstname.lastname@example.org