 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
| . |  |
. |
 by Staff Writers Pittsburgh PA (SPX) May 14, 2020
Carnegie Mellon University researchers working with an international team of scientists have discovered a previously unknown mechanism that allows atmospheric particles to very rapidly form under certain conditions. The research, which was published in the journal Nature, could aid efforts to model climate change and reduce particle pollution in cities. "The only real uncertainties in our understanding of climate in the atmosphere have to do with fine particles and clouds, how these have changed over time and how they will respond to climate change," said Neil Donahue, Thomas Lord University Professor of Chemistry and a professor in the departments of Chemical Engineering, and Engineering and Public Policy. The number of particles in the atmosphere at any given time can have major effects locally and globally, including contributing to unhealthy smog in cities and influencing the Earth's climate. However, particles need to reach a certain size - around 100 nanometers in diameter - to contribute to those effects, Donahue noted. If particles don't reach that size, they quickly get subsumed into other, larger particles. This means that one would expect few new particles to be created in polluted urban environments where the air is already full of larger particles that could gobble up small, new particles. Yet new particle formation is relatively common in those environments, as plainly seen when haze reforms rapidly after rainfall in cities around the world. Donahue thinks the answer to that mystery may lie in this new research. "We found a new way for tiny nucleated particles in the atmosphere to grow up quickly to become large enough to affect climate and health," he said. Donahue's lab group has long been part of the CLOUD experiment, an international collaboration of scientists that use a special chamber at CERN in Switzerland to study how cosmic rays affect the formation of particles and clouds in the atmosphere. The chamber allows researchers to precisely mix vaporous compounds and observe how particles form and grow from them. In this study, designed by Carnegie Mellon chemistry doctoral candidate Mingyi Wang, the CLOUD team condensed nitric acid and ammonia vapors across a wide range of temperatures and found that the resulting new particles can grow 10 to 100 times faster than previously observed, allowing them to reach sizes large enough to avoid being consumed by other particles. The compound formed from those two vapors, ammonium nitrate (a common fertilizer), was previously known to be a contributor to atmospheric pollution within larger particles, but its role in helping tiny particles grow was not known. "This may help explain how nucleated particles grow up in polluted urban conditions in mega-cities, which has been a big puzzle, as well as how they form in the upper parts of the atmosphere, where they can have a strong climate effect," Donahue explained. The team is now working to study how this mechanism plays out in Earth's upper atmosphere. For Wang, who served as co-leader of the study, this research has roots in his keen desire to understand air pollution. After an undergraduate research project where he got to sample and analyze PM2.5, Wang decided to continue in this field of research to better explore how these small particles can have such a big impact on the planet and how that impact could be remedied. "I realized that those atmospheric particulate matters have never been a simple air quality problem that only Asia needs to deal with," Wang said. "Rather, they are a global challenge due to their health and climate effects."
Cold air rises - what that means for Earth's climate Davis CA (SPX) May 07, 2020 Conventional knowledge has it that warm air rises while cold air sinks. But a study from the University of California, Davis, found that in the tropical atmosphere, cold air rises due to an overlooked effect - the lightness of water vapor. This effect helps to stabilize tropical climates and buffer some of the impacts of a warming climate. The study, published in the journal Science Advances, is among the first to show the profound implications water vapor buoyancy has on Earth's climate and energ ... read more
|
|||||||||||||
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |
del.icio.us
Digg
Reddit
Google
