Everyone knows that trees give us all oxygen so we can breathe, but according to an Australian scientists they also affect the concentration of positive and negative ions in the air. In an Avatar-esque revelation, a team from the Queensland University of Technology in Brisbane believes the world’s trees could ‘electrify the atmosphere’.
A team from QUT’s International Laboratory for Air Quality and Health (ILAQH), led by Professor Lidia Morawska, and including Dr. Rohan Jayaratne and Dr. Xuan Ling, ran experiments in six locations all over Brisbane and found that positive and negative ion concentrations in the air were twice as high in heavily wooded areas than in open grassy areas, such as parks.
Dr. Jayaratne, who is also a member of QUT’s Institute of Health and Biomedical Innovation (IHBI), said that natural ions in the air were mainly created by ionisation due to two processes – radiation from the trace gas radon in air and cosmic radiation from space. Don’t worry, that doesn’t mean the air is radioactive – radon is a byproduct of the radioactive decay of radium which is present in minute quantities in rocks and is continually exhaled by the ground.
“Because radium is found in rocks and radon is soluble in water, ground water is particularly rich in radon,” Dr. Jayaratne said. “Trees act as radon pumps, bringing the gas to the surface and releasing it to the atmosphere through transpiration – a process where water absorbed by the root system is evaporated into the atmosphere from leaves. This is especially prevalent for trees with deep root systems, such as eucalyptus.”
In a eucalyptus forest, the QUT scientists estimated that trees could account for up to 37 percent of the radon in the air when transpiration rates were highest.
“Although there is an established link between airborne particles and human health, the role of ions is largely unknown,” he said. “However, we do know that approximately one-half of the particles that we inhale during normal breathing are retained in our respiratory system and it has been shown that charged particles were more likely to be deposited in the lungs than uncharged particles.
“We do not believe that ions are dangerous – the danger comes from the pollutants. If there are no dangerous particles in the air to attach to the ions there is no risk of ill health.”
The ground-breaking research is still in the preliminary stages, but you can read more about the team’s findings in the journal Environmental Science and Technology.