Millions of tons of highly reactive chemicals called hydrotrioxides can stay in the atmosphere for hours, a new study suggests – which could have implications for human health and global climate.
Chemicals interact with other compounds extremely quickly, and their presence means that chemists will have to rethink how processes in the atmosphere work.
Hydrotrioxides – chemical compounds that contain a hydrogen atom and three oxygen atoms – have long been thought to be too unstable to last long in the weather.
But the new study shows instead that hydrotrioxides are a regular product of many common chemical reactions and that they can remain stable enough to react with other compounds in the atmosphere.
“We have shown that the life of one of them is at least 20 minutes,” Henrik Groome Koorgaard, a chemist at the University of Copenhagen, told Live Science. “So that’s long enough to do things in the atmosphere.”
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Kjærgaard is one of the authors of a new study on the formation of hydrotrioxide in the atmosphere, published online on May 26 in Journal of Science (opens in a new section).
Discovery does not mean that something new is happening in the atmosphere; rather, it appears that hydrotrioxides have always formed there. But the new study is the first time the existence of these ultra-reactive chemicals in the atmosphere has been confirmed.
“We can now show, by direct observation, that these compounds are actually formed in the atmosphere, that they are surprisingly stable, and that they are formed from almost all chemical compounds,” said Jing Chen, a doctoral student at the University of Copenhagen. , said in a statement (opens in a new section). “Now all speculation must be stopped.”
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Hydrotrioxides are a type of hydrogen polyxide. Water is the simplest and most abundant hydrogen polyxide, with two hydrogen atoms and one oxygen atom, or H2O.
Another hydrogen polyxide is hydrogen peroxide, which has two oxygen atoms – H2O2 – and is commonly used as a bleach or disinfectant. The extra oxygen atom also makes many peroxides extremely flammable and is sometimes used as a component of rocket fuels.
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Hydrotrioxides are another step, as they have three oxygen atoms attached to each other, which makes them even more reactive than peroxides. They are written chemically as ROOOH, where R is any related group, such as a carbon group.
But although it is known that peroxides can be formed by chemical reactions in the atmosphere, it has not been known so far that hydrotrioxides can also be formed there, albeit for a relatively short time before decomposing into less reactive chemicals.
In the new study, researchers estimate that about 11 million tons (10 million metric tons) of hydrotrioxides are formed in the atmosphere each year as a product of one of the most common reactions: oxidation of isoprene, a substance produced by many plants and animals. the main component of natural rubber.
Researchers estimate that about 1% of isoprene released into the atmosphere produces hydrotrioxides and that they are produced by these reactions in very low concentrations – about 10 million hydrotrioxide molecules per cubic centimeter of the atmosphere, which is only a very faint trace.
“We are very happy to be able to show this [hydrotrioxides] are there and live long enough to be – most likely – important in the atmosphere, “lead author Thorsten Bernd, an atmospheric chemist at the Leibniz Institute for Tropospheric Research (TROPOS) in Leipzig, Germany, told Live Science in e-mail.
Bernd leads research laboratory experiments at TROPOS to find out if hydrotrioxides are actually produced by chemical reactions in the atmosphere, while a team from the University of Copenhagen studies the theoretical aspects of how hydrotrioxides are formed.
Bernd and his colleagues used very sensitive mass spectrometry to detect ultra-reactive hydrotrioxides, a technique that can determine the molecular weight of chemicals to determine what atoms they are made of.
The reactions for the production of hydrotrioxides are carried out in TROPOS free jet system (opens in a new section)which creates an unobstructed airflow of rigid boundaries.
And the study uses the results of experiments in an atmospheric chamber at the California Institute of Technology in Pasadena.
Now that their research has confirmed that hydrotrioxides are formed by common chemical reactions in the atmosphere, scientists will study how compounds can affect human health and the environment in minutes or hours of activity before compounds decompose, Bernd said.
“From the knowledge of organic chemistry we can expect this [hydrotrioxides] “It will also act as an oxidant in the atmosphere,” he said. Hydotrioxides may also have an effect when our lungs breathe air that contains them in very low concentrations, “but all this is very speculative at the moment.”
Bernd said hydrotrioxides can also penetrate atmospheric aerosols – very fine solid particles or liquid droplets suspended in the atmosphere, such as ash from volcanic eruptions or soot from large fires – and can initiate chemical reactions there. But “experimental investigations into this are very challenging,” he said. – There is a lot of work.
Originally posted on Live science.