How the Detergent of Our Atmosphere Regenerates: Air Cleans Itself

Hydroxyl (OH) radicals are known as the detergent of the atmosphere. They have the ability to decompose isoprene in the air, which leads to the creation of new OH radicals, which are then able to purify the air of other pollutants and trace gases. Now, scientists have discovered exactly how these radicals are regenerated, which may allow them to better understand how our atmosphere functions.

The Earth's atmosphere has the astonishing ability to cleanse itself. Chemical processes ensure that trace gases and pollutants are removed, including isoprene. This gas In particular is largely produced by forests. In fact, without these processes it would be very likely that global warming would be even more severe and air quality would be poorer.

Some mechanism, though, keeps the warmer temperatures and poorer air quality at bay. Troposphere researchers in China have detected high concentrations of both OH radicals and trace gases such as isoprene. Other researchers made similar observations above North American forests and tropical rainforests.

"In the past few years, there has been an intensive discussion in the scientific community about what this mechanism could be," said Hendrik Fuchs, one of the researchers, in a news release. "But without actual proof this remained pure speculation. Now we have succeeded in demonstrating this process."

In order to examine exactly what happens in the atmosphere, the researchers recreated the natural conditions that prevail above China and the tropical rainforests. How did they do this? They used the Julich simulation chamber, SAHPHIR. This chamber enables researchers to simulate the degradation of even slight quantities of trace gases and is equipped with exactly the same measuring instruments as are used in field experiments.

In the end, the researchers were able to confirm the basic principles of the mechanism behind "cleaning" the atmosphere and to quantify its impact on OH regeneration. Since the degradation process is now understood for isoprene, the researchers can now begin to quantitatively investigate feedback effects.

"We may possibly have identified an important interaction between air quality and climate change leading to the accelerated degradation of trace gases in an atmosphere that is heating up," said Andreas Hofzumahaus, one of the researchers, in a news release.

The findings are published in the journal Nature Geoscience.