Scientists have detected a new type of substance that is extremely reactive in the Earth’s atmosphere that could pose a threat to human health as well as the global climate.
Researchers at the University of Copenhagen have shown that trioxides, chemical compounds with three oxygen atoms joined together, form under atmospheric conditions.
Trioxides are even more reactive than peroxides, which have two oxygen atoms joined together, making them highly reactive and often flammable and explosive.
Peroxides are known to exist in the air around us, and it was predicted that there were probably trioxides in the atmosphere as well, but so far it has never been unequivocally proven.
“This is what we have achieved now,” says Professor Henrik Grum Kjærgaard of the Department of Chemistry at the University of Copenhagen.
‘The type of compounds we have discovered are unique in their structure. And because they are extremely oxidizing, they are more likely to have a number of effects that are yet to be discovered. “
Scientists have detected a new type of substance that is extremely reactive in the Earth’s atmosphere that could pose a threat to human health as well as the global climate.
When chemical compounds oxidize in the atmosphere, they often react with OH radicals, usually forming a new radical. When this radical reacts with oxygen, it forms a third radical called peroxide (ROO), which in turn can react with the OH radical, forming hydrotoxides (ROOOH). Reaction: ROO + OH → ROOOH
How hydrotrioxides are formed
When chemical compounds oxidize in the atmosphere, they often react with OH radicals, usually forming a new radical.
When this radical reacts with oxygen, it forms a third radical called peroxide (ROO), which in turn can react with the OH radical, forming hydrotoxides (ROOOH).
Reaction: ROO + OH → ROOOH
The specific trioxides they have detected, called hydrotrioxides (ROOOH), are a completely new class of chemical compounds.
Hydrotrioxides are formed in a reaction between two types of radicals (molecules that contain at least one unpaired electron).
Researchers have shown that hydrotrioxides are formed during the atmospheric decomposition of various known and widely emitted substances, such as isoprene and dimethyl sulfide.
Isoprene is one of the most frequently released organic compounds in the atmosphere. It is produced by many plants and animals and its polymers are the main component of natural rubber.
The study shows that about one percent of all isoprene released is converted to hydrotrioxides.
However, researchers expect that almost all chemical compounds form hydrotoxides in the atmosphere and estimate that their useful life ranges from minutes to hours.
This makes them stable enough to react with many other atmospheric compounds.
Researchers estimate that the concentration of hydrotrioxides in the atmosphere is about 10 million per cm.
In comparison, OH radicals (one of the most important oxidants in the atmosphere) are found in about one million radicals per cm.
“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 in the Department. of Chemistry and second. author of the study.
“All speculation must end now.”
Laboratory configuration of the free flow experiment, which provided the first direct evidence that the formation of hydrotrioxides (ROOOH) also takes place under atmospheric conditions.
The research team says hydrotoxides are likely to penetrate tiny particles in the air, known as aerosols, which pose a health hazard and can cause respiratory and cardiovascular disease.
“They will probably enter the aerosols, where they will form new compounds with new effects,” said Professor Kjærgaard.
“It’s easy to imagine new substances being formed in aerosols that are harmful if inhaled. But more research is needed to address these possible health effects.”
Hydrotoxides are also highly likely to affect how many aerosols are produced, according to the researchers, which in turn has an impact on the climate.
“Because sunlight is reflected and absorbed by aerosols, it affects the Earth’s thermal balance, that is, the proportion of sunlight that the Earth absorbs and sends back into space,” said the co-author. and doctorate. student Eva R. Kjærgaard.
“When aerosols absorb substances, they grow and contribute to the formation of clouds, which also affects the Earth’s climate.”
Researchers hope the discovery of hydrotrioxides will help scientists learn more about the effect of the chemicals we emit.
“Most human activity leads to the emission of chemicals into the atmosphere,” said co-author and postdoctoral fellow Kristan H. Møller.
“Therefore, knowledge of the reactions that determine atmospheric chemistry is important if we are to predict how our actions will affect the atmosphere in the future.”
Professor Kjærgaard added: “These compounds have always existed; we just didn’t know them.
“But the fact that we now have evidence that compounds form and live over a period of time means that it is possible to study their effect more specifically and respond to whether they are dangerous.”
The study was published in the journal Science.
The Moon may have been diverting water from the Earth’s atmosphere for billions of years
A new study has found that the moon may have been diverting water from the Earth’s atmosphere for billions of years, storing it as ice inside craters.
Research from the University of Alaska Fairbanks suggests that the ions that make up water are carried by the moon as it passes through part of the Earth’s magnetosphere.
This is in addition to other suspicious methods, such as the asteroid bombardment 3.5 billion years ago and the solar wind delivering oxygen and hydrogen ions.
The team estimates that there are up to 840 cubic miles of surface permafrost or liquid groundwater on the Moon that escaped from the Earth’s atmosphere, enough to fill Lake Huron in North America, the eighth largest lake on the planet. .
The work, by lead author Professor Gunther Kletetschka, adds to growing research on water at the north and south poles of the Moon, the main goals for a base.