Water Can Spontaneously Form Hydrogen Peroxide, And We Finally Understand Why

In humid air or expelled by a cough, sneeze or talking, these droplets can carry tiny particles with them.

The basic chemistry of these motes of environmental water surprised researchers, as they discovered ordinary, otherwise benign water droplets could somehow spontaneously form small but significant quantities of hydrogen peroxide.

It's the same weakly acidic stuff we use to wash hair.

A team of researchers have found that the reaction occurs on contact with solid surfaces and that it may play a part in flu season.

Richard Zare, who was part of both discoveries, said that they think they know a lot about water, but then they realize they are not.

Water is fairly stable in bulk, but it seems to change in comparison when it is divided into droplets.

The relative volume of objects shrinks as they get smaller. The amount of water droplets exposed to the environment will be much higher than those in a glass, a bucket, or a lake.

The hydrogen peroxide forms at this exposed surface, according to Bolei Chen, Zare and colleagues.

The team used a dye that glows in the presence of H 2 O 2 to map its occurrence in droplets contacting a glass surface and found it was most concentrated at the interface between the two types of matter.

The researchers showed that H 2 O 2 was produced when droplets touched nine other objects.

When water condenses from the air onto cold surfaces, it's a natural phenomenon. There was an increase in the amount of H 2 O 2.

According to Zare, hydrogen peroxide is a universal phenomenon at water-solid interface.

The researchers treated the glass surface with a heavy oxygen isotope in order to find out where the extra oxygen atom comes from.

The droplets formed hydrogen peroxide by attaching the glass's surface 18 O atoms to the hydrogen and oxygen in the air.

Chen and the team were able to measure the electric current flowing from the solid to the ground as the acid formed.

It was confirmed that an exchange of electrons was taking place in the process of contact electrification.

The team states in their paper that some of the raw materials may be provided by other sources in the environment. Water droplets and a solid surface are all that is needed.

A chemical basis for explaining why there is seasonality to respiratory diseases is provided by contact electrification.

With warm summer air carrying small amounts of hydrogen peroxide, it could be a problem for circulating diseases.

The cold, dry winter air might give viruses an advantage in jumping from one nose to another.

The research was published in a journal.