April 20, 2024

Athens News

News in English from Greece

Potentially dangerous oxidizers found in Earth’s atmosphere

Scientists have discovered new dangerous substances in the Earth’s atmosphere that can affect human health and the global climate as a whole.

A new class of highly active substances – hydroxides – was first discovered in the Earth’s atmosphere by European and American scientists. These are oxidizing chemicals that can affect both human health and the global climate, so they need to be further studied. Their concentration in the atmosphere is estimated at about 10 million per cubic centimeter of air.

Trioxide (ROOOH), containing three oxygen atoms and one hydrogen atom, is more reactive than peroxides (ROOH), containing two oxygen atoms, found in the atmosphere for many years. When chemicals are oxidized in the atmosphere, they often react with free hydroxyl (OH) radicals to form a new radical. When this radical reacts with oxygen, it forms a third radical called peroxide. When a peroxide reacts with another hydroxyl radical, hydroxides are formed.

Unexpectedly stable elements

Hydrogen trioxide is surprisingly stable and is produced by the atmospheric decomposition of a number of other known and widely discarded substances, in particular hydrocarbons such as isoprene. It is estimated that about 1% of all emissions of the latter are converted into hydroxides, and every year in the earth’s atmosphere, only due to the oxidation of isoprene, 10 million metric tons of hydroxides are formed. Their lifespan ranges from a few minutes to several hours. This is enough to react with many other substances in the atmosphere.

The problem is being dealt with by scientists from the Department of Chemistry at the University of Copenhagen in Denmark, the Institute for Tropospheric Research. Leibniz in Germany and the California Institute of Technology in California under the guidance of Professor Hendrik Gergri from Denmark. According to Kjærgaard, “Because they are highly oxidizing, hydroxides probably have a number of effects that we have not yet discovered.”

They penetrate aerosols

Researchers suspect that the trioxide can be absorbed into tiny airborne particles known as aerosols, potentially inhaled and lead to respiratory and cardiovascular disease, though further research into their potential health effects will be needed. Also, given that sunlight is reflected and absorbed by aerosols, it is likely that hydrogen trioxide indirectly plays a role in how much aerosols and clouds form, so they also affect our planet’s climate.

“These substances have always been around us, we just didn’t know it. We can react in this way if they prove dangerous in the process,” Kjærgaard said. “The discovery shows that there are still many things in the air that we do not know about. Indeed, the air around us is a huge patchwork of complex chemical reactions,” said researcher Jing Chen.

The lower atmosphere is a large chemical reactor that converts hundreds of millions of metric tons of hydrocarbons each year, producing, among other things, carbon dioxide and water. These hydrocarbons are emitted from artificial sources or forests. While various oxidation processes occur in air, only a few of them are well understood, as evidenced by the delayed detection of hydroxides.



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