With the new “super-microscope”, MAX IV, we are now able to zoom in directly on the molecular building blocks of tiny airborne particles. We can see not only the building blocks themselves, but also how they are organized inside the particles. This new knowledge could provide a window into the hidden workings of climate change.
The new MAX IV synchrotron facility opened in Lund, Sweden, on Midsummer 2016, the brightest day of the year. This symbolic gesture underscores the unprecedented power of the new source of light, the brightest ever built. And unlike the sun, researchers can control the energy and direction of the synchrotron light to suit many different scientific experiments.
Synchrotron light is created when charged subatomic particles, most often electrons, are accelerated close to the speed of light inside a large ring. MAX IV has several such rings, which are several hundred meters wide. When the path of the electrons bends along the ring, light is emitted. At first, this light was seen as an annoying by-product of the particle acceleration experiments. But then researchers discovered a way to harvest the light and use it as a giant microscope. Now, MAX IV’s main purpose is to produce this synchrotron light.
At MAX IV, the light is so powerful that we can now study materials at their most fundamental level. For example, we can see which molecules different samples are made of and how these molecules are organized inside the material. This gives us important clues about how the materials work and affect their surroundings.
Aerosol particles are both harmful and helpful
I’m a climate researcher and the materials I study are tiny aerosol particles in the air. These aerosol particles are everywhere in our atmosphere. They come from both industry and traffic, as well as trees and oceans. Even in the cleanest places on Earth, such as the pristine Arctic, there are hundreds of particles per cubic centimeter of air. In polluted cities, there can be millions of particles in every cubic centimeter. We constantly breathe the particles in along with the air and they can have a profound effects on our health, causing asthma strokes and cancer. In Europe alone, particle pollution causes hundreds of thousands of premature deaths every year.
But aerosol particles also have some very positive effects. They are especially critical in the formation of clouds in the atmosphere. Every single cloud droplet is formed when water condenses onto the surface of a particle much in the same way that droplets form on a cold can of soda or beer when you take it from the fridge. Clouds act like sunscreen or big white beach umbrellas, and shade the Earth from the sun. This helps prevent some of the global warming created by the greenhouse effect.
The many roles of aerosol particles leave us between a rock and a hard place. When we clean the air from particle pollution to protect people from the health effects of aerosols, we simultaneously lose the protection against global warming. This could lead to even more severe global warming than what we already produce from fossil fuel emissions. On the other hand, there have even been suggestions that we should put more particles into the air in order to get greater protection. But what will be the health effect of that?
We need to know more to predict the future
We don’t yet have much knowledge on what the exact roles of aerosols are in climate change. This leaves us highly uncertain about the future of our climate. Until we understand aerosols better, we can neither predict the effects that our actions and regulations have on the future climate, nor how doing nothing might affect it.
To answer our questions about how aerosols affect our lives in different ways, we need to understand how the particles are made. We must understand which molecules they contain and how these molecules are organized inside the particles. This will reveal many secrets about how the particles affect their surroundings, the human body and clouds in the atmosphere.
And that brings us back to MAX IV. Aerosol particles in the air are so small that they are invisible to the naked eye. To see the aerosol particles and the molecules they contain, we need very powerful magnifying tools or microscopes. Synchrotron light sources such as MAX IV and others elsewhere in the world make it possible to do just that. With the power of the light at the new MAX IV facility, we will be able to see details of the particles that have never been visible before. This new knowledge will bring us an important step closer to understanding where the particles come from and how they form clouds. With this knowledge, we will be able to more accurately predict the effects of our actions on the future climate.
Original article written by Nønne Prisle, Nano and Molecular Systems Research Unit, University of Oulu.
Assoc. Prof. Nønne Prisle is leading the ATMOS (Synchrotron based Atmospheric Research) group and was recently awarded a European Research Council (ERC) starting grant under the European Union’s Horizon 2020 research and innovation programme (2016) for her project SURFACE. As part of Oulu University and the Finnish synchrotron research community, Finnish-Estonian beamline FinEstBeaMS at MAX IV plays a central role in the research and collaborations of her group.