Finnish-German cooperation gives boost to research on combustion emissions

Residential wood combustion, diesel engines and combustion of brown coal cause emissions that may have an impact on our health. Fresh smoke coming out of chimneys and exhaust pipes is different from smoke dispersed in the air, because its characteristics transform over time, especially when exposed to sunlight.

Emission transformations and their adverse health effects were studied in an international measurement campaign in Kuopio this spring, with some thirty researchers from Finland and Germany participating.  The campaign focused on emissions from residential wood combustion, diesel engines and combustion of lignite (brown coal), which is typical in Central Europe. A particular goal was to study the chemical composition of fine particles in combustion gas emissions, how that composition transforms in outdoor air, and what the related adverse health effects are.

Cooperation between the University of Eastern Finland and Helmholtz Zentrum München in Germany dates back several years. There is a strong foundation not only for joint research projects and student and staff mobility, but also when it comes to research funding: the German institute provides direct funding for the measurement campaign carried out in the University of Eastern Finland.

“Here in Kuopio, our laboratory focusing on the health and environmental effects of aerosols and fine particles, and its state-of-the-art equipment, are unique and cutting edge level in Europe,” says Professor Jorma Jokiniemi from the Fine Particle and Aerosol Technology Laboratory, FINE, of the University of Eastern Finland.

In the photo: Jorma Jokiniemi.

“This is why German researchers are so keen to work with us. We just started a new, five-year funding period during which costs associated with the organisation of these joint measurement campaigns can also be covered directly from Germany.  It is quite unusual to get funding to this extent from a foreign research institute.”

The measurement campaign this spring was also funded by the Academy of Finland and the EU, among others. The four-week emission measurement campaign constitutes part of a joint project by an extensive European research consortium. The University of Eastern Finland has been a member of the Helmholtz Virtual Institute of Complex Molecular Systems in Environmental Health, HICE, since 2012. The institute studies the characteristics of human-induced emissions and their effects on the climate and human health.

“A particular focus of the measurement campaign was to study how combustion aerosols coming out of a chimney or exhaust pipe change as they age,” Professor, Dr Ralf Zimmermann from Helmholtz Zentrum München explains.

In the photo: Ralf Zimmermann.

“Over the past five years, our studies have mainly focused on emissions measured directly from combustion processes. In the next five years, we’ll also focus on how emissions transform in the atmosphere and how they interact, and what role that plays in air quality and health effects. For us, the measurement campaign is a huge effort, as the number of researchers participating in it is high. However, the collaboration is smooth, and we’ve received plenty of support from the University of Eastern Finland.  Our junior researchers are extremely motivated,” he says.

“In the future, it is possible that we’ll work with other laboratories here as well. The problems related to combustion emissions are global, and increasingly close collaboration is needed.”

Fresh smoke is different from aged smoke

The measurement campaign studies emissions resulting from the combustion of brown coal, as well as their ageing when exposed to sunlight. Fresh smoke is different from aged smoke: the composition and characteristics of emissions change in the atmosphere over time. Photochemical transformations are simulated in the laboratory by diluting the emission and exposing it to, for example ozone and UV radiation, which initiates oxidation processes that take place in outdoor air.

The ageing of emissions was simulated in a transformation chamber of 29 cubic metres, which constitutes part of the European network of atmospheric simulation chambers, Eurochamp 2020.  The ageing of emissions was also studied in an Academy of Finland project led by Associate Professor Olli Sippula. The project has developed a new device that accelerates the aging reactions to simulate the photochemical transformation potential of the emissions with high time response.

“We seek to create a mobile version of this ageing device – one that could be placed next to the engine of a ship or an aeroplane to measure emissions,” Jokiniemi explains.

“We are currently looking for funding to utilise this device also in other international joint projects as well as in real-life conditions outdoors, where the variables can’t be optimised.”

According to Sippula, emissions from transportation are influenced by, for example, engine technology and exhaust after-treatment techniques, which have an impact on combustion emission characteristics.  In the future, it is important to study, in greater detail, how chemical and physical factors affect toxicity.

“Certain compounds may play a role in human health and climate change alike, as is the case with black carbon originating from various combustion processes. This has an impact on the Arctic regions, for example, as residential wood combustion emits high amounts of black carbon particles, which contribute to global warming and poorer air quality,” Jokiniemi says.

New cell exposure device is well suited for studying health effects

The health effects of emissions are studied by using cells and animal testing in Professor Maija-Riitta Hirvonen’s Inhalation Toxicology Research Group.

The group’s researchers use a new cell exposure system, in which human lung tissue cells are grown in plastic cups half in the air, and they are exposed to aerosols.

“The air flows evenly inside this cell exposure device, and after exposure, we let the cells recover for 24 hours,” Early Stage Researcher Tuukka Ihantola explains.

“Then we dye the cells and analyse if for example oxygen free radicals are present. The cell exposure device uses thermophoresis, in which temperature differences force particles into the cell.”

“We also study cell death and genotoxicity, among other things. The Academy of Finland project I’m working on is now halfway completed, and we can already say that the cell exposure device we have built is well suited for coordinated emission research,” Academy Research Fellow Pasi Jalava says.

“Different emissions have different impacts, and cell models can help explain some of these differences. Toxicological experiments, on the other hand, are used to study the role of emission in the pathogenesis of different diseases, such as heart and respiratory diseases. We also have some evidence of emissions having an impact on the central nervous system. Indeed, together with researchers from the A.I. Virtanen Institute for Molecular Sciences, we have applied for funding to study the neurotoxic effects of air pollution.”

In the photo: Pasi Jalava.

Text: Marianne Mustonen
Photos: Raija Törrönen

ILMARI - Aerosol Physics, Chemistry and Toxicology Laboratory (www.uef.fi/ilmari)

FINE - Fine Particle and Aerosol Technology Laboratory  (http://www.uef.fi/fine)

INTOLA - Inhalation Toxicology Laboratory (https://www.uef.fi/fi/web/intola)

HICE, Helmholtz virtual Institute of Complex Molecular Systems in Environmental Health, www.hice-vi.eu

Eurochamp project https://www.eurochamp.org