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“CERN is heaven for researchers”

Collaboration between researchers from the Department of Applied Physics and the European Organisation for Nuclear Research, CERN, dates back several years. The researchers’ aerosol measurements constitute part of the large, international CLOUD project involving research groups from all over the world.

“We proposed collaboration with CERN already in 2000. The first pilot study was carried out in 2006, and the first ‘real’ measurements in 2009. At that time, we also initiated our first Marie-Curie Initial Training Network (CLOUD-ITN), which secured funding and internship opportunities for ten students and post-doc researchers. Nine research institutes were involved in the network back then,” says Assistant Professor Siegfried Schobesberger from the Department of Applied Physics.

“The CLOUD project, on the other hand, initially included some 15 partners from Europe, Russia and the US. Our researchers have been involved in CLOUD ever since the beginning, and they’ve carried out 12 measurement campaigns so far. At first, the project was more focused on the effects of cosmic radiation on aerosol formation.”

“All in all, more than 200 researchers have participated in the CLOUD measurements, approximately 15 of them from the University of Eastern Finland. Today, the CLOUD project has more than 20 partners, research institutes and industrial collaborators,” Schobesberger says.

Mass spectrometer can detect a one-in-a-trillion molecule

Last autumn, researchers from the University of Eastern Finland spent a couple of months at CERN, and they even took two pieces of their own measurement equipment with them.

“At CERN, we aerosol researchers have access to a large steel chamber, where we study aerosol formation under various atmospheric conditions in different ways. One of the objectives of our measurements is to create increasingly realistic climate models,” Postdoctoral Researcher Tuomo Nieminen says.

Tuomo Nieminen in the photo.

“All measurement devices were located outside the chamber. We used one of the devices to measure particle hygroscopicity, that is, how much water can become condensed in particles under certain conditions.  This provides insight into their chemical composition. A mass spectrometer, on the other hand, was used to accurately measure the mass of very small charged clusters of molecules, providing information on their atomic composition.”

“The thermally insulated steel chamber has 26 cubic metres of space, and we can make precise adjustments to the temperature, relative humidity and gas mixtures. The inside of the chamber is filled with artificial air made of liquid nitrogen and oxygen,” Nieminen explains.

Tiny amounts of other gases, such as sulphur dioxide produced by human activity or monoterpenes, volatile organic compounds produced by plants, are introduced in the chamber. These gases interact with one another, creating new compounds and, eventually, aerosols.

“The amounts are really small, one billionth to one trillionth of all air molecules, but our mass spectrometer can detect that one-in-a-trillion molecule. We have to wait for a couple of hours in between the experiments for the chamber air to become balanced.”

“At the moment, for example, we are studying how aerosols from forests and marine aerosols differ from one another,” Postdoctoral Researcher Angela Buchholz says.

Even though researchers work during a measurement campaign in three shifts around the clock, that is often not enough: measurements have to be made over the course of several years in order to obtain sufficient data.

“The next measurements will be conducted next autumn. Before that, we of course need to define what we want to investigate. The measurement data generated in the project is made openly accessible to all research groups. We work together to plan new campaigns and discuss our findings, and we also co-author publications.”

Measurement data can influence legislation

During the measurement campaign, the researchers’ lives revolve around CERN. They live in the nearby hostels and eat at the research centre’s diner.

“CERN is heaven for researchers – science is everywhere around you. One can really focus on scientific research there. The scientific community at CERN is also very laid-back and inclusive,” Buchholz adds.

When it comes to technology, working in a large research centre has its advantages, as plenty of technical support is available to researchers. Research groups can share research equipment, and new devices can also be built as needed.

“In measurement campaigns, even Master's level students take responsibility for the work, and that’s just great! One shift lasts for eight hours, and those on call at night may have to wake others up in the event of a power outage, for example.  This is a world and time zone of its own. Getting back to normal life after CERN is a bit like coming out of a jet lag,” Buchholz says.

“There are several monitors providing access to real-time measurement data.  When not working, there are possibilities for outdoors activities – but some researchers prefer staying at the research centre all the time,” Nieminen adds.

“CERN and CLOUD are good platforms for networking. This allows us to gain international visibility and to significantly strengthen our research. By meeting new people, one also learns about new ways of doing research, and that is immensely valuable. Finding common interests within the network is easy,” the researchers say.

Aerosol formation is more complex than previously thought

In the future, researchers will be able to create an increasingly accurate model of climate change, making it possible to predict possible courses of events.

“The measurements can be used to prove that small changes can have great impacts on the climate, and this is our gateway to influence legislation. The measurement data also makes it easier for ordinary people to understand the mechanisms behind climate change.”

“We need to understand the behaviour of aerosols especially if we want to actively modify the climate by creating artificial clouds, for example. This may be possible in the future, but I’m a bit worried about this alternative,” says Nieminen.

“The next measurement campaigns, CLOUD 13 and CLOUD 14, are already being planned, and we will participate in them, too.  CERN will maintain its role as the most advanced environment for aerosol research,” Schobesberger adds.

“There is plenty to study, since aerosol formation has turned out to be more complex than previously thought. Chemical measurements in particular take a long time, as there is time to study only a small amount of different chemicals during a single measurement campaign."

Text: Marianne Mustonen
Photos: Raija Törrönen and Angela Buchholz