In recent years, the frequency, duration and severity of fires in forest and bushland have not stopped surprising us, setting new records. From the “unstoppable” fire that burned for months in Australia (from September 2019 to March 2020 to be exact) to last year’s fires in Canada that darkened the sky of New York for days and from the fires that plague every summer the Iberian Peninsula to our own recent fires in Evia, Varybompi, Rhodes, Dadia, we have all become aware of the violence of these phenomena due to the climate crisis. Even those of us who have not experienced a fire up close now know the signs well: the haze in the atmosphere, the smell of burning, the sensation left in the throat, nostrils, eyes by the smoke that can be transported kilometers away from the source.
A long journey
How many kilometers away from the focus of the fire can the (by)products of the burning of forest lands be transported? And how big is their effect on air quality and by extension on human health? A Greek research group gave unexpected answers to the above questions, at the same time giving an explanation to a scientific paradox.
Spyros Pandis
The team was headed by Mr. Spyros Pandis, professor of the Department of Chemical Engineering of the University of Patras and collaborating researcher of the Institute of Chemical Engineering Sciences of the ITE (ITE/IEXMI), and as deduced from the recent article of the Greek scientists in the prestigious scientific journal “Nature PJ: Climate and Atmospheric Sciences”, the invisible to the naked eye particles resulting from the burning of trees are transported much farther and affect air quality much more and for a longer period of time than previously thought.
To understand this, it is enough to say that in July 2022 the fires burning forested areas in the Iberian Peninsula (Portugal, Spain) “shadowed” the sky (and) in Pertuli of Trikala two weeks later, making its atmosphere worse than that of Athens! BHMA-Science spoke to both postdoctoral researcher and first author of the article, Ms Christina Vasilakopoulou, as well as with Mr. Pandi, to learn the hows and whys of this research activity in the Thessalian mountains.
Technological excellence
«We met in Pertuli in July 2022 with the aim of studying the interaction of volatile organic compounds emitted by trees, that is, the compounds that reach our noses when we walk in the forest and which we all know as the smell of the forest, with anthropogenic pollutants , as, for example, is ozone. In other words, our original experimental design did not involve forest fires at all. We could say that the findings described in our recent article are a product of good timing and the use of high technology which we had at our disposal” Mrs. Vasilakopoulou told us and explained: “The precision instruments we had brought with us and installed in the ski resort shelter allowed us to detect the by-products of biomass burning at a time when there was no forest fire on Greek soil. We found that these represented the lion’s share of the air pollutants and that they originated from both the Iberian Peninsula and Ukraine, areas where fires were raging in the past.”
The (disturbing) findings and…
Forest fires release gases into the atmosphere (such as carbon monoxide, nitrogen oxides, aromatic polycyclic hydrocarbons, methane) but also particularly dangerous nanoparticles (i.e. particles with a diameter of less than 1 micrometer). The object of the study of the Greek scientists was mainly nanoparticles and indeed, as they describe in their article, those originating from the fires were found to represent 60% of the atmospheric nanoparticles at that time in Pertouli. Particles resulting from the reaction of VOCs produced by trees with anthropogenic pollutants (and which were the original focus of the study) accounted for just 20%, with the remaining 20% shared between urban and urban pollutants. industrial sources.
…the explanation of the paradox
The above finding of the Greek research team came to explain a scientific paradox: the hitherto underrepresentation of nanoparticles originating from forest fires in measurements of the atmosphere of Europe during the summer months, despite the high frequency of fires, mainly in the Mediterranean countries. In practice, the Greek researchers, detecting in Pertouli nanoparticles that had started their journey from Portugal two weeks earlier, demonstrated that the contribution of forest fires to the air pollution of Europe in the summer can be from 4 to 7 times greater than , what had been estimated due to the incomplete measurements until then, but also that the dispersion of the pollutants can extend hundreds or even thousands of kilometers away from the respective fire foci!
Air pollution from forest fires causes 10-16 thousand deaths in Europe every summer
Professor Spyros Pandis attributed the difficulty to measure these pollutants both to the lack of appropriate equipment and techniques and to the fact that “very soon after being released into the atmosphere these pollutants react and change their chemical signature“, adding that “these chemical reactions take place even within a few hours of exposure to the summer sun and lead to an increase in both the mass of the particles and their toxicity».
Toxicity measurements
Greek researchers do not use the word “toxicity” by chance: forest fires are not only a direct danger to human life, but also an indirect and perhaps more insidious one not related to burns or smoke poisoning. This danger comes from the nanoparticles which, as it turned out, one can inhale even on an apparently clear summer day, without any fire on Greek soil, even in an area where one would flee precisely to get fresh air!
Christina Vasilakopoulou
As for their toxicity, Mrs. Vasilakopoulou explained that it is deduced through the calculation of their oxidizing potential, “that is, their ability to create oxidative stress in the body, something that has been linked to a number of diseases». Indeed, the measurements of the research team showed that the oxidizing potential of the particles in Pertouli per unit mass for the specific dates of July 2022 was greater than that of the center of Athens and specifically Thisio! And as the researcher noted, “the concentrations of these microparticles may not be huge, but their toxicity is also related to the fact that our exposure to them is more or less continuous during the summer. An exposure that leads to thousands of European deaths in the summer months».
The (visible and invisible) contributors to the study
The research team that produced the study (which can be seen in its entirety on the website below) was coordinated by Professor Spyros Pandi (University of Patras and ITE/IEXMI) and consisted of the researchers: Christina Vasilakopoulou, Angeliki Matralli, Xakousti Skyllakou, Maria Georgopoulou, Andrea Aktypi, Kalliopi Florou, Christos Kaltsonoudis, Evangelia Siouti, David Patoulia and Ioannis Kioutsiuki (ITE/IEXMI and University of Patras), Evangelia Kostenidou (Democritus University), Agata Błaziak (Polish Academy of Sciences), Athanasios Nene (EPFL Switzerland and ITE/IEXMI), Stefanos Papagianni and Costas Eleftheriadis (Dimokritos).
The study was funded by the Hellenic Research and Innovation Foundation (ELIDEK) and it is no coincidence that, concluding our conversation, Professor Spyros Pandis wanted to point out the key contribution of our national research funding body to the successful outcome of his team’s research effort saying: “Without the precision instruments we recently acquired thanks to funding from ELIDEK, and which are unique in Greece, it would not have been possible to carry out this study”.
The… detectives of the atmosphere
Going up to Pertouli, the Greek research team had at their disposal a state-of-the-art mass spectrometer (Aerosol Mass Spectrometer, AMS) specialized for the measurement of nanoparticles. Thanks to him, he was able to perform real-time qualitative and quantitative analysis of atmospheric particles. The details of the experimentation were described in BHMA-Science by postdoctoral researcher Christina Vasilakopoulou: “We had installed the mass spectrograph in the ski chalet and for a month we were taking readings every three minutes. So we got a very detailed picture of the chemical composition, size, mass and concentrations of the particles that were in the atmosphere during that time.”
The study by Greek scientists showed that the levels of nanoparticles in the air were 4-7 times higher than the levels expected from the literature
Obviously, the huge amount of data collected in July 2022 had to be analyzed to make it possible to investigate the origin of the particles as well. But how can researchers be sure of the origin of the particles? “Indeed, this is one of the most difficult questions to answer” Mrs. Vassilakopoulou told us and added: “Many of the primary products of biomass burning when in the atmosphere react and their footprint is lost. However, there are also so-called fire detectors. These are non-volatile and relatively inert elements that we use as biomass burning indicators. A typical such case is potassium, which we used in our study.”
Another characteristic compound of biomass burning is levoglucose “a sugar derived from burning wood that is not found in industrial or automotive pollutants. This is how we know that what we are measuring has come from a forest fire” Mr. Pandis explained.
Forest fires cost 1,455 megatons of carbon dioxide emissions worldwide in 2022 (data from Copernicus Atmosphere Monitoring Service)
As for investigating the geographic origin of pollutants, this is equivalent to solving a multivariate equation and is obviously deduced with the help of computational models. It goes without saying that the accuracy of the calculations is a function of the data supplied to the model. Thus, in addition to the increase in the number of fire detectors, the model in the case of the Greek researchers was also fed with data from the movement of gas masses and of course the existing fires during that period of time. In this way it was revealed that the pollutants that clouded the horizon in Pertuli on July 20 and 21, 2022 had started their journey from Portugal two weeks earlier and had arrived in our country after a route that included France, England among others and the Scandinavian countries!
Concentrations (in micrograms per cubic meter) of fine particles from forest fires in Portugal, which broke out in early July 2022, in the EU atmosphere on different dates of the same month (from top to bottom 14/7, 21/7 and 28/7 of 2022).
#Forest #fires #burn #air #Europe
