Advanced Oxidation Processes (AOP)

The chemistry of Earth’s atmosphere is remarkably stable, providing a relatively safe place for animals and plants to thrive. However, even small changes to the quality of the air that we breathe can have profound impacts on our health. Understanding that stability, the ways it could be impacted by humans and how it interacts with the broader Earth system are key research tasks in atmospheric chemistry.

The earth's atmosphere is less sensitive to pollutants than some researchers previously thought. An international team of researchers, including scientists from the Max Planck Institute for Chemistry in Mainz, has found that the concentration of hydroxyl radicals in the atmosphere has changed little in recent years. Hydroxyl radicals clean the air by breaking down organic substances such as climate-damaging methane. Because this self-cleaning capacity has scarcely varied over the past few years, the researchers believe that it is only marginally affected by environmental changes. These findings refute the view held by other scientists who believed that the atmosphere is very sensitive to air pollutants (Science, January 7, 2011).

Lightning could play an important role in flushing pollutants out of the atmosphere. Researchers knew lightning produces nitric oxide, which can lead to the formation of oxidants such as hydroxyl radicals. But no one had seen lightning directly create lots of these oxidants.