Science That Takes Your Breath Away
The breath you "see" on a cold winter's day may become a useful diagnostic tool for identifying lung changes or damage from air pollutants. At EPA's Office of Research and Development, scientists are at the forefront of new biomarker research to determine if exhaled breath can be used to detect changes in the body at the molecular or cellular level.
Over the last 20 years, researchers have used a medical procedure called bronchoscopy that involves taking lung cells with a scope to study the effects of air pollutants on the lungs. The procedure must be done in a clinic under medical supervision. In contrast, EPA scientists expect the breath-borne biomarkers to be usable in more situations outside the clinic, cost less to administer, and provide much more comfort to the volunteer.
This new diagnostic tool can help researchers more easily determine if individuals are being adversely impacted by air pollutants. Breath biomarkers also will help to link the source of a pollutant more directly to the health effect. This is important because it will enable EPA to develop more effective and strategic controls for dealing with air pollution.
"The promise of these biomarkers is that we can sample them non-invasively in the field at sites of interest where people are exposed to pollutants." said Michael Madden, an EPA biologist who is conducting the study in collaboration with Joachim Pleil, an analytical chemist.
At body temperature, the exhaled breath contains air, carbon dioxide, acetone, and other gases resulting from metabolism or inhaled pollutants. The breath also contains tiny droplets of fluid containing water, bits of proteins, DNA, and cell particles shed by the airways in the lungs. When we breathe out onto a cold surface, the water vapor condenses and captures the gases and particles. The resulting fluid is called EBC, or exhaled breath condensate. It can be collected and used as a diagnostic tool much like urine or blood.
Samples can be analyzed for a variety of interesting constituents. According to Pleil, "We can measure the gases absorbed in the EBC fluid with sensitive analytical chemical methods to investigate rapid changes in metabolism, and we can also use new protein and DNA analyses to determine longer term effects such as chronic inflammation of the lungs."
Researchers are studying EBC to find out if they can be used to evaluate whether a person has been exposed to an air pollutant. They also are investigating if EBC can tell them if the lungs have been adversely impacted, even if symptoms are not obvious.
The researchers have great hope that improvement in collecting and analyzing breath constituents will lead to an easier way to protect public health and meet EPA's goal of cleaner air.