Ambient aerosols cause millions of premature deaths annually, play a key role in the climate’s water cycle, affect the reflectivity of the atmosphere, and transport pathogens. In each of these areas are fundamental knowledge gaps that require single particle composition measurements.
In his doctoral dissertation M.Sc. (Tech.) Paavo Heikkilä explored novel methodology to measure the composition of aerosol particles on a single-particle basis utilising laser-induced breakdown spectroscopy (LIBS).
“We lack information about the exact mechanisms and compositions that cause air pollution to be fatal. Aerosols are still the number one cause of error in climate and weather models. We also do not have measurement technologies that could distinguish pathogens from the ambient air in real time”, says Heikkilä.
To date, the composition of individual aerosol particles can be measured with single-particle mass spectrometers (SPMS), which can discover composition up to the molecular level. However, such equipment is expensive and hard to use, and requires time-consuming data processing.
The new method efficiently focuses the individual particles to the laser beam
Earlier research includes similar ideas of measuring aerosol composition with pulsed lasers. However, the breakthrough of the method presented by Heikkilä is the focusing of individual particles into the laser beam.
The next steps of the research will be deploying the platform for extensive field and laboratory measurements. The measurement system has vast potential in many fields of aerosol research.
The research for the doctoral dissertation was conducted in the Aerosol Physics and Photonics laboratories of Tampere University and was part of the Research Council of Finland’s flagships of ACCC and PREIN.
Public defence on Friday 9 August
The doctoral dissertation of MSc (Tech.) Paavo Heikkilä in the fields of aerosol physics and photonics titled Ambient Single Particle Composition Measurement with Laser-Induced Breakdown Spectroscopy will be publicly examined at the Faculty of Engineering and Natural Sciences at Tampere University at 12 o’clock on Friday 9 August 2024. The venue is auditorium S2, Sähkötalo building (address: (Korkeakoulunkatu 3, Tampere). The Opponent will be Professor Ilona Riipinen, Stockholm University. The Custos will be Professor Jorma Keskinen from Tampere University.
The doctoral dissertation is available online
The public defence can be followed via a remote connection.
Photograph: Maria Äystö