Posted on 07/10/2010
Air pollutants damage the molecules in the lungs
Lungs are lined with a mixture of molecules to ensure that they function well. Some of these help with the removal of inhaled particles, while the retention of a moist film at the surface is also crucial. Scientists – including Dr Martin King from Royal Holloway, University of London – have now shown how some of these molecules are affected by ozone, which can arise as a pollutant in the atmosphere and is known to be a severe pulmonary irritant.
Dr King, of the Department of Earth Sciences, said: "An understanding of how common everyday air pollutants can damage the molecules at the lung’s surface is a first step to saving lives from atmospheric air pollution."
The new study, published in the journal ‘Langmuir’, has focused on phospholipids that are major components in both walls of biological cells and the fluid that covers the surface of the lungs. Simple measurements of the layers of these molecules spread at a water surface suggested that a few ppm (parts per million) of ozone in oxygen can cause rapid degradation of a certain type of phospholipids, followed – unexpectedly – by much slower changes over hours that arise from loss of the material from the surface.
Neutron reflection measurements at the ISIS facility near Oxford in the UK allowed the amount of the material and the structure of the layers to be studied. A process in which partially degraded parts of molecules, known as radicals, are formed is suggested. These radicals cause further reactions and loss of material from a surface that would on its own be stable in the presence of ozone.
Katherine Thompson, leader of the team at the Department of Biological Sciences, Birkbeck University of London, commented: “This work demonstrates how much we can learn about the reaction of a major air pollutant, ozone, with the fluid found at the surface of the lungs. We are keen to carry on our work and hope to better understand the damage caused by ozone. ”
“Neutron reflection is a unique tool to identify where particular parts of molecules are found in surface layers,” added Professor Adrian Rennie of Uppsala University. “We have a strong interest in applying our developments of this technique to a range of environmental issues.”
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