Aerosol Measurements for Better Air and Health
By improving the measurement and characterization of aerosols — tiny particles suspended in the air — using large-scale research facilities like MAX IV, air quality and public health can be improved.
An aerosol is a mixture of small particles or liquid droplets suspended in a gas, such as air. They affect our health and can be linked to allergies, respiratory diseases, cardiovascular diseases, and cancer. Aerosol particles occur naturally, such as pollen or droplets formed when we sneeze, but are also a result of emissions, wear and tear on roads or tires, combustion, and industrial processes.
“Certain metals have been specifically linked to negative health effects. There are methods to measure the concentration of aerosol particles in the air, and the metal content in them, but to better understand the actual causes of the negative health effects, or determine where the particles come from, we need to continue to develop measurement methods”, says Jenny Rissler, senior researcher in aerosol physics and expert in X-ray spectroscopy methods.
Calibrated Measuring Instruments Require References
For reliable measurements, calibrated measuring instruments are needed, and to calibrate measuring instruments, something to compare with, a reference, is needed. By developing better references, in this case for aerosols with very well-known properties, one can evaluate and develop measuring instruments and methods. This is, among other things, what the European research project AEROMETII has worked on.
“At RISE, for example, we evaluated how different low-cost instruments for aerosol measurements perform in different environments, at different places, in different temperatures, and so on. Advanced instruments are often more precise, but it's also important with cheaper instruments since this enables more measurements and in more places. At the same time, these instruments are often limited in their performance, and it's important to have knowledge about what the limitations are and when they work as well as the advanced instruments. In another work package, we looked at what chemical form metals in aerosol particles from different European cities have”, says Jenny Rissler.
With better knowledge, we could trace the origin of different particles based on their chemical form and use this information to improve air quality
Chemical Form Affects Health Effects
The chemical form of a substance, i.e., what chemical compound the atoms form, can vary depending on how and where the particles were formed.
“For example, zinc in particles generated from tires probably forms other chemical compounds than zinc in particles from brakes, and lead from a battery factory forms different compounds than those from traffic related emissions. With better knowledge, we could trace the origin of different particles based on their chemical form and use this information to improve air quality.”
For some elements, it has been seen that the chemical form also affects health effects. Through developed methods to characterize chemical form, we can contribute to continued research on these health effects.
The Beamline Balder
In the AEROMETII project, Jenny Rissler and her colleagues used advanced spectroscopy techniques at the beamline Balder at the synchrotron laboratory MAX IV in Lund.
“We used x-ray absorption spectroscopy to compare samples from different parts of Europe, and could see that the chemical form of, for example, zinc actually differed depending on where the sample came from. But more research is needed, this was one of the first European studies. Most previous studies have been conducted in China.”
Pollen Measurement with AI
In the coming years, the plan is for aerosol research to continue along with European colleagues.
“Emissions from traffic and roads would be interesting to investigate. If we assume that exhaust gases decrease because of electric car development, aerosols still remain as an effect of wear and tear on roads and vehicles, for example, from brakes or tires.”
This summer, the project BIOAIRMET, which deals with measuring and quantifying pollen, will also start.
“When measuring pollen today a lot is done manually, but in this project, we want to develop new AI methods. To do this, reference pollen, i.e., pollen with very well-known properties, is needed, which we can use to teach the AI system to measure correctly. These references will be developed in Switzerland, and then we at RISE will characterize them so that we know what chemical and physical properties they have”, says Jenny Rissler.
Big Science and RISE
RISE supports and contributes to the development of large international research facilities, known as Big Science, such as MAXIV and ESS in Sweden, and CERN and ITER in Europe. As part of the consortium Big Science Sweden, funded by the Swedish Research Council and Vinnova, RISE helps companies, institutes, and universities to collaborate and do business with these research facilities. We also have a special effort to make resources at research facilities like MAX IV and ESS more useful and accessible for industrial research. Expertise in neutron and photon-based techniques makes RISE a leading party in making research infrastructure more relevant and accessible for the industry.
National Metrology Institute and European Cooperation
RISE is the National Metrology Institute (NMI) of Sweden, tasked with maintaining metrological traceability through National Laboratories for the various physical quantities. Through chains of calibrations, national measurement standards, and international comparison measurements, we ensure that a kilogram weighs the same and that a meter is the same length no matter where in the world we are. As an NMI, we are engaged in the European metrology organization EURAMET and participate in many European research projects, for example within the European Partnership on Metrology program.