26 September 2017
PSI researchers have developed an experimental chamber in which they can recreate atmospheric processes and probe them with unprecedented precision, using X-ray light from the Swiss Light Source SLS. In the initial experiments, they have studied the production of bromine, which plays an essential role in the decomposition of ozone in the lower layers of the atmosphere. In the future, the new experiment chamber will also be available for use by researchers from other scientific fields.
21 September 2017
The interfacial ionization of strong acids is an essential factor of multiphase and heterogeneous chemistry in environmental science, cryospheric science, catalysis research and material science. Using Near Ambient Pressure X-ray Photoelectron (NAPP) spectroscopy, we directly detected a low surface coverage of adsorbed HCl at 253 K in both molecular and dissociated states and interpret the results as physisorbed molecular HCl at the outermost ice surface and dissociation occurring upon solvation deeper in the interfacial region. This study gives clear evidence for nonuniformity across the air−ice interface and questions the use of acid−base concepts in interfacial processes.
13 July 2017
In contrast to nitrogen oxides, modern gasoline cars emit much more cancerogenic primary soot (black carbon + primary organic aerosol) and lead to more toxic secondary organic aerosol than modern diesel vehicles.
22 February 2017
Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Based on a 6500 year ice-core Cu record from Illimani glacier in Bolivia we provide the first complete history of large-scale Cu smelting activities in South America. Earliest anthropogenic Cu pollution was found during the Early Horizon period ~700-50 BC. We attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.
5 January 2017
Media Releases Energy and Environment Research Using Synchrotron Light Micro- and Nanotechnology
Eighty percent of all products of the chemical industry are manufactured with catalytic processes. Catalysis is also indispensable in energy conversion and treatment of exhaust gases. Industry is always testing new substances and arrangements that could lead to new and better catalytic processes. Researchers of the Paul Scherrer Institute PSI in Villigen and ETH Zurich have now developed a method for improving the precision of such experiments, which may speed up the search for optimal solutions.
27 October 2016
Media Releases Energy and Environment Environment
Clouds consist of tiny droplets. These droplets form when water condenses around so-called aerosols – small particles in the atmosphere. To understand how in turn aerosols come into existence scientists have now created a comprehensive computer model simulation based on profound experimental data. This simulation revealed that in addition to sulphuric acid, two other substances are crucially involved in the formation of aerosols: organic compounds and ammonia. These results have now been published in the renowned journal Science
13 October 2016
Aerosols, suspended fine liquid or solid particles in the air we breathe, play a central role in many environmental processes through their influence on climate, the hydrological cycle, and their adverse effects on human health. While the mechanisms by which aerosol particles affect our health remain uncertain, the atmospheric oxidation of organic vapors has been shown to be related to the formation of oxygenated organic matter with high oxidative potential, the so-called reactive oxygen species (ROS). These species may damage our lung cells through oxidative stress. Also, if we want to understand the impact of human activity on our climate, we need to be able to reconstruct the conditions before the industrial era, and to determine the main ingredients responsible for the formation of aerosols and clouds. New results obtained from the cloud chamber at CERN revealed that new aerosol particles may originate from highly oxygenated organic molecules (HOMs). They are produced upon the oxidation of natural emissions and are composed of peroxides. This class of molecules seems to have important implications for climate and health.
7 July 2016
Media Releases Energy and Environment Renewable Energies
Despite its great potential, solar energy still faces one big problem: the sun doesn’t always shine and its energy is hard to store. Now, researchers at the Paul Scherrer Institute PSI and the ETH Zurich have unveiled a chemical process that uses the sun’s thermal energy to convert carbon dioxide and water directly into high-energy fuels: a procedure developed on the basis of a ground-breaking material combination of cerium oxide and rhodium.
24 May 2016
The chemical kinetics of organic nitrate production during new particle formation and growth of secondary organic aerosols (SOA) were investigated using the short-lived radioactive tracer 13N in flow-reactor studies of α-pinene oxidation with ozone. Direct and quantitative measurements of the nitrogen content indicate that organic nitrates accounted for ∼40% of SOA mass during initial particle formation, decreasing to ∼15% upon particle growth to the accumulation-mode size range (>100 nm). Experiments with OH scavengers and kinetic model results suggest that organic peroxy radicals formed by α-pinene reacting with secondary OH from ozonolysis are key intermediates in the organic nitrate formation process
26 May 2016
Media Releases Energy and Environment Environment
Researchers have shown how fine particles are formed from natural substances in the atmosphere. These findings will improve our knowledge about clouds in the pre-industrial era and thus will contribute to a more accurate understanding of both the past and future evolution of our climate.
10 March 2015
Exploitation of the extensive polymetallic deposits of the Andean Altiplano in South America since precolonial times has caused substantial emissions of neurotoxic lead (Pb) into the atmosphere; however, its historical significance compared to recent Pb pollution from leaded gasoline is not yet resolved. We present a comprehensive Pb emission history for the last two millennia for South America, based on a continuous, high-resolution, ice core record from Illimani glacier. Illimani is the highest mountain of the eastern Bolivian Andes and is located at the northeastern margin of the Andean Altiplano.
11 July 2014
We present a highly time-resolved historical record of polychlorinated biphenyls (PCBs) from an Alpine ice core (Fiescherhorn glacier, Switzerland). Introduced in the 1940s, PCBs were widely used industrial chemicals. Because of their persistence they are still found in the environment, long after their production phase-out. The Fiescherhorn ice core record covers the entire time period of industrial use of PCBs, that is, 1940?2002. The total concentration of six PCBs varies from 0.5 to 5 ng/L and reveals a temporal trend, with an 8-fold increase from the early 1940s to the peak value in the 1970s.
14 February 2014
The development of strategies and policies aiming at the reduction of environmental exposure to air pollution requires the assessment of historical emissions. Although anthropogenic emissions from the extended territory of the Soviet Union (SU) considerably influenced concentrations of heavy metals in the Northern Hemisphere, Pb is the only metal with long-term historical emission estimates for this region available, whereas for selected other metals only single values exist.
29 April 2013
Using in-situ X-ray photoelectron spectroscopy at the vapor-water interface, the affinity of nanometer-sized silica colloids to adsorb at the interface is shown to depend on colloid surface charge density. In aqueous suspensions at pH 10 corrected Debye-Hückel theory for surface complexation calculations predict that smaller silica colloids have increased negative surface charge density that originates from enhanced screening of deprotonated silanol groups by counterions in the condensed ion layer.