Good news in Science from an international team of atmospheric chemists, including researchers from NOAA and the Dutch universities of Wageningen and Utrecht. Hydroxyl, atmosphere’s enthusiastic cleaning agent, proves to be produced in quite stable quantities from year to year.

The natural variation is now thought to be no more than a few percent, after being feared much larger. It means we can now better rely on our forecasts for the concentrations of different polluting gases.

Hydroxyl is one oxygen atom covalently bound to one hydrogen atom. It makes for a gassy compound, with radical characteristics. In Earth’s atmosphere hydroxyl plays an important role in breaking down gassy molecules that are often air pollutants. These include pollutants like surface-level ozone, carbon monoxide and sulfur dioxide – and the greenhouse gas methane, but not the greenhouses gases nitrous oxide (laughing gas), CFCs or CO2.

Due to its reactive nature, hydroxyl has a very short lifespan. Usually within a second after being created it bumps into another gas to react with. That’s part of the reason why the substance has been shrouded in mystery. We did realize hydroxyl was important for keeping our atmosphere clean. We did not know how well we could count on nature’s free cleaner.

© Rolf Schuttenhelm | www.bitsofscience.org