The smell of electrical discharge after photocopying is a tell-tale sign of ozone in the air. Ozone is a component of ‘smog’ and on hot sunny days, in cities with high traffic volumes, more ozone is formed. New research by scientists at Universities of Melbourne and Wollongong and QUT has provided a 1st glimpse at how free radical damage might be initiated in the human lung upon exposure to the urban air pollutant ozone.
They used a powerful combination of electrospray ionisation coupled with multistage mass spectrometry experiments to shed light on how radicals are formed in the reactions of ozone with models of lung proteins.
The team studied how the deprotonated form of the amino acid cysteine and related amino acids and peptides react with ozone when isolated under idealized near-vacuum conditions, and tracked the formation of primary oxidation products including radicals.
“Free radicals are ‘unhappy’ molecules that have an unpaired electron and so tend to react with other molecules around them, initiating a cascade of chemical transformations. When this occurs in the body, such as at the lining of the lung, damage occurs, which ultimately may result in inflammation and breathing difficulties,” said Richard O’Hair. “We have observed that the amino acid cysteine – a component of lung proteins – becomes ‘radicalised’ in the presence of ozone,” Richard O’Hair.
On days when ozone levels are high, people with asthma tend to experience a reduction in lung function, increased respiratory symptoms and increased frequency of asthma attacks, increased medication and health services use. “We hope this work will inspire scientists to search for ozone induced protein free radical formation and damage at the air-liquid interface of the lung.” said Professor O’Hair. http://sciencematters.unimelb.edu.au/new-research-finds-ozone-in-smog-may-cause-asthma/
About 10% of the Australian population (2 million people) currently have asthma, which is large by international standards (Asthma Foundation (link is external)) and lifetime prevalence is up to 11% in some Chinese cities (link is external).
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