Free Radical Link Suggested Between Pollution And Asthma

In new research Ms Sigmund and Dr Uta Wille, both chemists at the University of Melbourne, have discovered that the atmospheric nitrate radical irreversibly damages amino acids, which are the building blocks for proteins in the human body. This, they suggest, could be a cause of some respiratory diseases.

The nitrate radical is formed by two common atmospheric pollutants; nitrogen dioxide, which itself is emitted from car exhausts, and ozone, which is an important greenhouse gas that is harmful to humans. During the day the sun’s UV radiation breaks down the nitrate radicals, but the concentrations rise as soon as the sun goes down.

"We were very interested to see what these nitrate radicals do to the human body since we breath them in at night," says Sigmund.

The duo have found that the nitrate radical reacts with amino acids to form compounds such as beta-nitrate esters, beta-carbonyl, and aromatic nitro-compounds. Some of these compounds have been associated with increased immune response in some respiratory diseases, creating worse symptoms.

"Our results suggest that the nitrate radical could be a real culprit for respiratory diseases, yet until this study the nitrate radical has been previously entirely overlooked in regard to causes for diseases such as asthma," says Sigmund.

"We are now focusing our research on the cell membrane, to see if these radicals can migrate inside and cause damage to cells," adds Wille. If this is found to be significant, then health researchers might have to factor in the role of the nitrate radical when examining other respiratory diseases.

This work will be published in the upcoming issue of the U.K. Royal Society of Chemistry¹s Chemical Communications.