PAUL SCHERRER’S INgenuity
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IMAGE: HOUSSNI LAMKADDAM, RESEARCH IN PSI ATMOSPHERIC CHEMICAL WEBSITE, AT THE HONORABLE RESULTS. see more CREDIT: PAUL SCHERRER INSTITUTE / MAHIR DZAMBEGOVIC
Researchers at the Paul Scherrer Institute PSI have studied for the first time how chemical reaction in clouds affects global climate. They found that isoprene, the main non-metallic organic material released into the atmosphere, can strongly contribute to the formation of organic aerosols in clouds. They published their findings today in the journal Science Advances.
Aerosols, a mixture of solid grains or liquids suspended in the air, play an important role in the Earth’s climate. Aerosols come from natural or human sources. They affect the balance of the Earth’s radiation by interacting with sunlight and creating clouds. However, their impact is the single most important uncertainty in climate models.
One material that is very common in the atmosphere is isoprene, an organic fertilizer in which their impurities in the gas phase are well understood. Isoprene is removed by trees and can produce aerosol when oxidized. It is not yet known how isoprene and its regenerative products in cloud droplets. That’s why researchers at the Paul Scherrer Institute PSI have used a type of wet-walled flow reactor, along with the most advanced cosmetic spectrometers, to study what could be happening chemically alongside interior of clouds for the first time under conditions relevant to the atmosphere.
“Our experimental establishment allows for the first time a detailed study of the circulation of organic valves at the air-water interface under conditions that are close to the environment,” said Houssni Lamkaddam, a researcher at PSI’s Atmospheric Chemistry laboratory. “With our equipment, we can now simulate what happens in clouds.”
What exactly happens in clouds?
In the special equipment, called a wetting reactor, a thin film of water is maintained on the inside of a quartz tube. A mixture of gases containing, among other materials, isoprene, ozone, and so-called hydroxyl radicals is fed into the glass cylinder. UV lamps are placed around the glass cylinder to simulate daylight conditions for some tests.
Using this establishment, the researchers found that up to 70 percent of isoprene oxidation products can be dispersed in the aqueous film. The subsequent aqueous oxidation of the diffuse species produces a large amount of secondary organic aerosol. On the basis of these studies, they found that the chemical reactions that occur in clouds are responsible for up to 20 percent of the global organic organic aerosols.
“This is another important contribution to better understanding the processes in the atmosphere,” summarizes Urs Baltensperger, head of science at PSI’s Atmospheric Chemistry Laboratory. The balance of the Earth’s radiation is very important in the whole climate process and therefore also in climate change. “And aerosol plays a vital role in this,” says the atmosphere scientist. While aerosolas create droplets of clouds, this research shows that clouds can also create aerosols through the aqueous chemistry of organic valves, a process known for sulfate aerosols but here also shown for the organic ration. This new experimental setup, developed at PSI, opens up the opportunity to study the formation of aerosols in clouds under near-atmospheric conditions so that these processes can eventually be incorporated. in climate models.
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Text: Paul Scherrer / Sebastian Jutzi Institute
In PSI
The Paul Scherrer Institute PSI develops, builds and operates large, complex research facilities and makes them available to the national and international research community. The institute’s own main research priorities are in the subject areas and materials, energy and environment and human health. PSI is committed to the training of future generations. So about a quarter of our staff are postmasters, postgraduates or apprentices. In total PSI employs 2100 people, making it the largest research institute in Switzerland. The annual budget comes to around CHF 400 million. PSI is part of ETH Domain, with the other members such as the two Swiss Federal Institutes of Technology, ETH Zurich and EPFL Lausanne, as well as Eawag (Swiss Federal Institute of Aquatic Science and Technology), Empa (Federal Laboratory of -Swiss for Materials Science and Technology) and WSL (Swiss Federal Institute for Forest, Snow and Landscape Research).
Original publication
Great help with secondary organic aerosol from isoprene cloud chemistry
H. Lamkaddam, J. Dommen, A. Ranjithkumar, H. Gordon, G. Wehrle, J. Krechmer, F. Majluf, D. Salionov, J. Schmale, S. Bjeli ?, KS Carslaw, I. El Haddad, U . Baltensperger
Scientific advances, 24.03.2021
DOI: 10.1126 / sciadv.abe2952
From EurekAlert!
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