The role of vegetation in enhancing radon concentration and ion production in the atmosphere
Jayaratne, Rohan, Ling, Xuan, & Morawska, Lidia (2011) The role of vegetation in enhancing radon concentration and ion production in the atmosphere. Environmental Science and Technology, 45(15), pp. 6350-6355.
The role of ions in the production of atmospheric particles has gained wide interest due to their profound impact on climate. Away from anthropogenic sources, molecules are ionized by alpha radiation from radon exhaled from the ground and cosmic gamma radiation from space. These molecular ions quickly form into ‘cluster ions’, typically smaller than about 1.5 nm. Using our measurements and the published literature, we present evidence to show that cluster ion concentrations in forest areas are consistently higher than outside. Since alpha radiation cannot penetrate more than a few centimetres of soil, radon present deep in the ground cannot directly contribute to the measured cluster ion concentrations. We propose an additional mechanism whereby radon, which is water soluble, is brought up by trees and plants through the uptake of groundwater and released into the atmosphere by transpiration. We estimate that, in a forest comprising eucalyptus trees spaced 4m apart, approximately 28% of the radon in the air may be released by transpiration. Considering that 24% of the earth’s land area is still covered in forests; these findings have potentially important implications for atmospheric aerosol formation and climate.
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|Item Type:||Journal Article|
|Keywords:||radon, cluster ions, atmospheric ions, environmental radioactivity, atmospheric aerosols|
|Subjects:||Australian and New Zealand Standard Research Classification > EARTH SCIENCES (040000) > ATMOSPHERIC SCIENCES (040100) > Atmospheric Sciences not elsewhere classified (040199)|
|Divisions:||Past > QUT Faculties & Divisions > Faculty of Science and Technology
Current > Institutes > Institute of Health and Biomedical Innovation
|Copyright Owner:||Copyright 2011 American Chemical Society|
|Deposited On:||18 Jul 2011 01:11|
|Last Modified:||09 Nov 2013 10:52|
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