q&more
My watch list
my.chemie.de  
Login  

News

How particulate matter arises from pollutant gases

International research project observes ultrafast particle growth through ammonia and nitric acid

Photo by Nick van den Berg on Unsplash

Symbolic image

15-May-2020: When winter smog takes over Asian mega-cities, more particulate matter is measured in the streets than expected. An international team, including researchers from Goethe University Frankfurt, as well as the universities in Vienna and Innsbruck, has now discovered that nitric acid and ammonia in particular contribute to the formation of additional particulate matter. Nitric acid and ammonia arise in city centres predominantly from car exhaust. Experiments show that the high local concentration of the vapours in narrow and enclosed city streets accelerates the growth of tiny nanoparticles into stabile aerosol particles.

In crowded urban centres, high concentrations of particulate matter cause considerable health effects. Especially in winter months, the situation in many Asian mega-cities is dramatic when smog significantly reduces visibility and breathing becomes difficult.

Particulates, with a diameter of less than 2.5 micrometres, mostly form directly through combustion processes, for example in cars or heaters. These are called primary particulates. Particulates also form in the air as secondary particulates, when gases from organic substances, sulphuric acid, nitric acid or ammonia, condense on tiny nanoparticles. These grow into particles that make up a part of particulate matter.

Until now, how secondary particulates could be newly formed in the narrow streets of mega-cities was a puzzle. According to calculations, the tiny nanoparticles should accumulate on the abundantly available larger particles rather than forming new particulates.

Scientists in the international research project CLOUD have now recreated the conditions that prevail in the streets of mega-cities in a climate chamber at the particle accelerator CERN in Geneva, and reconstructed the formation of secondary particulates: in the narrow and enclosed streets of a city, a local increase of pollutants occurs. The cause of the irregular distribution of the pollutants is due in part to the high pollutant emissions at the street level. Furthermore, it takes a while before the street air mixes with the surrounding air. This leads to the two pollutants ammonia and nitric acid being temporarily concentrated in the street air. As the CLOUD experiments demonstrate, this high concentration creates conditions in which the two pollutants can condense onto nanoparticles: ammonium nitrate forms on condensation cores the size of only a few nanometres, causing these particles to grow rapidly.

“We have observed that these nanoparticles grow rapidly within just a few minutes. Some of them grow one hundred times more quickly than we had previously ever seen with other pollutants, such as sulphuric acid,” explains climate researcher Professor Joachim Curtius from Goethe University Frankfurt. “In crowded urban centres, the process we observed therefore makes an important contribution to the formation of particulate matter in winter smog – because this process only takes place at temperatures below about 5 degrees Celsius.” The aerosol physicist Paul Winkler from the University of Vienna adds: “When conditions are warmer, the particles are too volatile to contribute to growth.”

The formation of aerosol particles from ammonia and nitric acid probably takes place not only in cities and crowded areas, but on occasion also in higher atmospheric altitudes. Ammonia, which is primarily emitted from animal husbandry and other agriculture, arrives in the upper troposphere from air parcels rising from close to the ground by deep convection, and lightning creates nitric acid out of nitrogen in the air. “At the prevailing low temperatures there, new ammonium nitrate particles are formed which as condensation seeds play a role in cloud formation,” explains ion physicist Armin Hansel from the University of Innsbruck, pointing out the relevance of the research findings for climate.

The experiment CLOUD (Cosmics Leaving OUtdoor Droplets) at CERN studies how new aerosol particles are formed in the atmosphere out of precursor gases and continue to grow into condensation seeds. CLOUD thereby provides fundamental understanding on the formation of clouds and particulate matter. CLOUD is carried out by an international consortium consisting of 21 institutions. The CLOUD measuring chamber was developed with CERN know-how and achieves very precisely defined measuring conditions. CLOUD experiments use a variety of different measuring instruments to characterise the physical and chemical conditions of the atmosphere consisting of particles and gases. In the CLOUD project, the team led by Joachim Curtius from the Institute for Atmosphere and Environment at Goethe University Frankfurt develops and operates two mass spectrometers to detect trace gases such as ammonia and sulphuric acid even at the smallest concentrations as part of projects funded by the BMBF and the EU. At the Faculty of Physics at the University of Vienna, the team led by Paul Winkler is developing a new particle measuring device as part of an ERC project. The device will enable the quantitative investigation of aerosol dynamics specifically in the relevant size range of 1 to 10 nanometres. Armin Hansel from the Institute for Ion Physics and Applied Physics at the University of Innsbruck developed a new measuring procedure (PTR3-TOF-MS) to enable an even more sensitive analysis of trace gases in the CLOUD experiment with his research team as part of an FFG project.

Original publication:
Wang, M., Kong, W., et al.; "Rapid growth of new atmospheric particles by nitric acid and ammonia condensation"; Nature; 2020

Facts, background information, dossiers

More about Uni Frankfurt am Main

  • News

    Pool testing of SARS-CoV-02 samples increases worldwide test capacities many times over

    Researchers at the German Red Cross Blood Donor Service in Frankfurt headed by Professor Erhard Seifried, and the Institute for Medical Virology at the University Hospital Frankfurt at Goethe University headed by Professor Sandra Ciesek succeeded in developing a procedure that makes it poss ... more

    Construction kit for custom-designed products

    Microorganisms often assemble natural products similar to product assembly lines. Certain enzymes, non-ribosomal peptide synthetases (NRPS), play a key role in this process. Biotechnologists at Goethe University have now succeeded in changing these enzymes so that entirely new natural produ ... more

    Inert Nitrogen Forced to React with Itself

    Direct coupling of two molecules of nitrogen: chemists from Würzburg and Frankfurt have achieved what was thought to be impossible. This new reaction is reported in Science magazine and opens new possibilities for one of the most inert molecules on earth. Constituting over 78 % of the air ... more

  • q&more articles

    From feast to famine and back – no problem for bacteria

    Bacteria are true survivors. In the course of evolution, they have developed numerous strategies to adapt to rapidly changing, uncertain environmental conditions. Their metabolism is much more sophisticated than that of human beings. Within minutes they can regulate their gene expression an ... more

    Why biosimilars and not biogenerics?

    Medicines produced using genetic techniques have existed since 2006, called “similar biological medicinal products” or “biosimilars”. Until a year ago, this was a fairly low-profile group, even in expert circles. This has all changed now, however, with the recent licensing of the first bios ... more

    Paradigm shift

    What would medicine be without drugs? But are these drugs being used optimally today? Not at all, as we now know thanks to the findings of molecular medicine. Because for the use of these drugs, it is important to observe two aspects: the disease and the patient. Only slowly is it becom ... more

  • Authors

    Prof. Dr. Jörg Soppa

    Jörg Soppa, born in 1958, studied biochemistry in Tübingen and then went on to do his doctorate at the Max Planck Institute of Biochemistry in Martinsried near Munich. In 1990 he established his own research group there and held courses at the Institute of Genetics and Microbiology of Munic ... more

    Prof. Dr. Heinfried H. Radeke

    Heinfried H. Radeke studied medicine at the Hannover Medical School (MHH) and received his medical license in 1985. His Ph.D. thesis was recognized as the best research dissertation of 1986. After two years as an assistant physician at the Göttingen University Hospital, he began his career ... more

    Prof. Dr. Theo Dingermann

    Theodor Dingermann, born 1948, studied pharmacy in Erlangen ­and received his doctor title in 1980 to become Dr. rer. nat. In 1990 he was offered the C4 professorship at the Institute for Pharmaceutical Biology, University of Frankfurt.  From 2000 to 2004 he was President of the German Phar ... more

More about Universität Innsbruck

  • News

    Creative support in the laboratory

    On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum o ... more

    A ranking of environmental chemicals

    How dangerous are environmental chemicals and what is their effect on human health? In a project funded by the Austrian Science Fund FWF, the pharmacist Daniela Schuster is currently developing a computer-based "early warning system" for potentially dangerous substances.In our daily lives w ... more

  • q&more articles

    Knowledge instead of ignorance

    Biology is naturally complex, and even the results of the simplest biochemical experiments are afflicted with experimental noise that cannot be ignored. However, biochemical measurements are the backbone of modern pharmaceutical research. If the experimental uncertainty is underestimated, b ... more

  • Authors

    Prof. Dr. Christian Kramer

    born in 1980, studied Molecular Sciences in Erlangen and Zürich. He did his doctorate between 2007–2009 at the University of Erlangen in close collaboration with Boehringer-Ingelheim/Biberach, developing novel QSAR and QSPR methods for the statistical prediction of physicochemical and bioch ... more

More about Universität Wien

  • News

    Identifying virus killers in ancient medicinal plants

    Many organisms have to defend themselves against predators, diseases or pests. Their metabolic products constitute a chemical arsenal that has been used for medical purposes since time immemorial. Using state-of-the-art methods, a team led by Judith Rollinger is screening traditional knowle ... more

    New simulation-experiment combination allows deeper insights into ultrafast light-induced processes

    Researchers from Graz University of Technology and the University of Vienna are demonstrating for the first time how the energy flow between strongly interacting molecular states can be better described. Since the 1990s, femtochemistry has been researching ultrafast processes at the molecul ... more

    Atomic images reveal unusually many neighbors for some oxygen atoms

    The identification of new chemical bonds is crucial for the design of new material structures. A team led by Jani Kotakoski at the University of Vienna and Jannik Meyer at the University of Tübingen has found unexpected new configurations of oxygen and nitrogen in graphene. Direct images of ... more

  • q&more articles

    An all-round superfood?

    Whether the web community wants to lose weight or eat healthily, chia is their constant companion and seen by some as an all-round “superfood”. The relevant internet forums are busy swapping a whole host of recipes for chia pudding and chia fresca, followed by ideas for muffins and even mar ... more

  • Authors

    Prof. Dr. Susanne Till

    Susanne Till holds a doctorate in biology (main subject botany) and has worked as a lecturer in the Dept. of Nutritional Sciences at the University of Vienna for over 30 years. In her teaching work, Dr Till focuses on botany and biology, spices and native wild plants in human nutrition, as ... more

q&more – the networking platform for quality excellence in lab and process

The q&more concept is to increase the visibility of recent research and innovative solutions, and support the exchange of knowledge. In the broad spectrum of subjects covered, the focus is on achieving maximum quality in highly innovative sectors. As a modern knowledge platform, q&more offers market participants one-of-a-kind networking opportunities. Cutting-edge research is presented by authors of international repute. Attractively presented in a high-quality context, and published in German and English, the original articles introduce new concepts and highlight unconventional solution strategies.

> more about q&more

q&more is supported by:

 

Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE