Research Group of Aerosol Chemistry and Physics

Thermal energy storage is an important part of technologies that make use of intermittent renewable energy sources in that it contributes to better efficiency and lower energy demand. The TTSM research group addresses studies of properties of phase-change materials and thermal fluids that can be used in thermal batteries in the research project Thermal Energy Storage Materials: Thermophysical Characteristics for the Design of Thermal Batteries and in collaboration with the teams of the Institute of Thermomechanics of the CAS (the Joint Laboratory of Energy Storage of ICPF CAS and IT CAS) and the Faculty of Nuclear Sciences and Physical Engineering of the CTU Prague. Their research interests are focused on experimental studies of the thermophysical properties of compounds relevant to thermal energy storage and mathematical modeling of heat and mass transfer in porous thermochemical materials.

One of the department's current research areas is the topic of wet deposition of atmospheric aerosol by horizontal hydrometeors (e.g. fog, clouds). The research uses experimental data measured at the Milešovka observatory, where these hydrometeors occur for most of the year (225 out of 365 days). The data consist of particle number size distributions with sizes ranging from 10 nm to 20 μm, distribution of hydrometeors of sizes from 3 to 50 μm, and sizes and concentrations of drops larger than 0.16 mm, all determined before, during, and after hydrometeor exposure. The properties of the aerosol are examined both without the influence of hydrometeors and during their action. This will allow us to assess the impact of these hydrometeors on the aerosol, depending on particle number size distribution and its origin and modeled sources, and also on the properties of the hydrometeors.

Another area of DACP research is focused on source apportionment of size-resolved atmospheric aerosol (AA) based on mass concentration data, chemical composition and particle number size distribution. The application of receptor models using AA chemical and physical characteristics data at the measurement site, receptor, combined with meteorological and other indicators, is appropriate to explain temporal and spatial changes in air quality. AA source receptor modelling by Factor Analysis (FA) enables us to estimate the number and composition of the sources, as well as their contribution to the receptor. Proper identification of AA sources is essential for qualified decision-making in air quality management. The research identifies AA anthropogenic sources using online and offline measurement methods and advanced receptor modelling. Receptor modelling results enable assessment of the long-term evolution of the contribution of individual AA sources to the air quality at a given site, and affect the spatial variability of AA sources of a larger region and the temporal variability of AA sources at a selected site.

• Synthesis of nanoparticles and their health effects
• Nucleation phenomena
• Transfer of mass and heat in aerosols
• Measurement of thermophysical properties of clean substances and mixtures (thermal capacity, density, and speed of liquid sound)
• Advanced data analysis using mathematical gnostics

The analysis of isotopes in aerosol particles is a modern, still developing method that offers great potential for determining the sources of these particles, but also for studying the processes that take place in the atmosphere. This topic is also the subject of a recent study carried out by a research team from the Department of Aerosol Chemistry and Physics in collaboration with Prof. Kawamura's team from Chubu University in Japan. The paper, which deals with a systematic seasonal study of the isotopic composition of stable carbon ¹³C in atmospheric aerosol, was recently published in the prestigious journal Science of the Total Environment.

The paper describes research carried out on gas phase and fine aerosol (PM_2.5) samples collected directly at the Institute of Chemical Processes Fundamentals in Prague-Suchdol. The samples represent the urban background with the initial assumption that the sources of aerosol particles would be different for different seasons. And indeed, the different δ¹³C isotope composition especially in winter and summer confirmed different seasonal sources of carbonaceous aerosols. In winter, the isotopic composition corresponded more to anthropogenic sources from heating, while in summer it was more likely to be emissions from biogenic sources. However, the main objective of the study was to determine whether different sources and thus different chemical compositions of the total aerosol would affect the distribution of carbon isotopes between the gas and aerosol phases. The knowledge of the isotope fractionation between these two phases is important for a more detailed study of the processes taking place in the atmosphere. These data can also serve as input parameters for models that are used to determine the source of aerosols. However, contrary to assumptions, detailed analysis has shown that despite the different isotopic compositions of δ¹³C in different seasons, its fractionation between the gas and aerosol phases is almost invariant. This points to the fact that the fractionation of stable carbon isotopes in the total carbonaceous aerosols in the atmosphere is mainly a physical process, which is not significantly affected by the detailed chemical composition of the aerosol or gas phase. Overall, however, this is still a valuable result that has resulted in a simplified parameter for the development of isotope models for aerosol source determination. 

• Vodička P., Kawamura K., Schwarz J., Ždímal V., Seasonal changes in stable carbon isotopic composition in the bulk aerosol and gas phases at a suburban site in Prague, Sci. Total Environ. 803, 149767, 2022. DOI

RNDr. Nadezda Zikova Ph.D. was awarded the Otto Wichterle Premium in 2019, a prestigious award for young scientists under 35 from the Czech Academy of Sciences. She received financial support for her project Studying wet deposition of atmospheric aerosol using horizontal hydrometeors, funded by the Grant Agency of the Czech Republic.

• Data v mlze (Věda a výzkum, AV ČR, 3/2019) http://pdf.avcr.cz/A/2019-03/#page=65

At the same time, a calibration laboratory is currently being built in DACP, (under the auspices of the ACTRIS IMP project, where DACP is also the main beneficiary for the Czech Republic), which will serve to calibrate instruments measuring the microphysical properties of aerosol particles. The calibration laboratory, operated as part of the thematic centre for ground-based aerosol particle measurement under the ACTRIS project, will provide services both at the national level, to state, academic and other institutions concerned with air quality and climate change, and to the scientific community at the European level. The calibration laboratory is a very important part of the Aerosol–in-Situ thematic centre within the built-up European research infrastructure ACTRIS ERIC and will contribute to the prestigious position of the Czech Republic within the international scientific community of the field. At the same time, this activity will enable the Czech Republic's air quality monitoring programme to remain at the top level within the European research infrastructure for measuring atmospheric aerosols while contributing to further research in this field.

DACP is one of the partners of the large research infrastructure project ACTRIS (Aerosol, Clouds and Trace Gases Research Infrastructure Network), which brings together over 100 research organizations from 22 countries in Europe. The project partner stations provide their data on three key components of the atmosphere (aerosols, trace gases, and clouds). Data from all stations are obtained through standardized procedures, which allows them to be compared. Currently DACP, under the ACTRIS project, operates the urban background atmospheric station Suchdol and performs standardized measurement of atmospheric aerosols at the National Atmospheric Observatory Košetice. Huge measured sets of experimental data are included in the forecast meteorological models and also form the basis for modeling the impact of aerosols on climate change. It also serves to verify data obtained from satellite measurements (project CAMS21a, where DACP is a partner representing the Czech Republic, in cooperation with project COPERNICUS).

Ionic liquids based on a saccharinate anion were selected in this study because of their low toxicity and possible application potential in thermal energy storage. Heat capacity in the liquid phase and phase transitions were measured in a series of 1-alkyl-3-methylimidazolium saccharinates (alkyl=butyl, hexyl, octyl, decyl, and hexadecyl). Heat capacity in the solid phase was also measured for the 1-hexadecyl-3-methylimidazolium saccharinate. It was shown from the results that the studied ionic liquids show a high energy density comparable to the widely used thermal oil Therminol VP-1 and a relatively high melting enthalpy close to 100 J/g for the 1-hexadecyl-3-methylimidazolium saccharinate. Advanced analysis of the experimental data using mathematical gnostics then enabled a critical assessment of the measured values.

The studied compounds have not yet been characterized in terms of their energy storage potential. They represent an interesting alternative to materials currently used in heat storage, as it appears from our data that they could be used as thermal fluids (and/or their additives), e.g. in so-called thermal batteries, and allow for a more efficient use of energy from renewable sources.

• Bendová M., Čanji M., Wagner Z., Bogdanov M.G., Ionic Liquids as Thermal Energy Storage Materials: On the Importance of Reliable Data Analysis in Assessing Thermodynamic Data, J. Solution Chem. 48(7), 949–961, 2019. DOI
• Čanji M., Bendová M., Bogdanov M.G., Wagner Z., Zdolšek N., Quirion F., Jandová V., Vrbka P., Phase transitions in higher-melting imidazolium-based ionic liquids: Experiments and advanced data analysis, J. Mol. Liq. 292, 1–8, 2019. DOI
• Bendová M., Wagner Z., Bogdanov M.G., Čanji M., Zdolšek N., Ionic liquids based on saccharinate anion for energy storage: Heat capacity of 1-hexadecyl-3-methylimidazolium based ionic liquids in solid and liquid phase, J. Mol. Liq. 305, 112847, 2020. DOI

As proper identification of atmospheric aerosol sources is essential for qualified decision-making in air quality management, work addressing this issue is one of the DACP's directly applicable results. This especially holds for the study Comparing the PM2.5 chemical composition and sources at a rural background site in Central Europe between 1993/1994/1995 and 2009/2010: Effect of legislative measures and economic transformation on air quality. This work presents the PM_2.5 chemical composition data from the first half of the 1990s compared to analogous data from the end of the first decade of the millennium. Comparing these two data sets forms a basis for assessing the effect of legislative measures and economic transformation on air quality in the Czech Republic. It turned out that industrial sources of regional origin, combustion of coal/oil/gasoline/diesel in the 1990s, had been replaced by coal/biomass burning for residential heating. The decreasing trend in PM_2.5 elemental concentrations and in the share of sources of PM_2.5 over 15 years has confirmed the positive impact of legislative regulations, especially on large and medium-sized stationary sources, but this trend is also a by-product of the economic transformation that has taken place in the Czech Republic.

• Pokorná P., Schwarz J., Krejci K., Swietlicki E., Havránek V., Ždímal V., Comparison of PM2.5 chemical composition and sources at a rural background site in Central Europe between the years 1993/1994/1995 and 2009/2010, Environ. Pollut. 241, 841-851, 2018. DOI

DACP has been cooperating with the Department of Occupational Medicine, 1st Faculty of Medicine, Charles University in Prague, and the Technical University of Liberec since 2015 to determine the acute and chronic effects of nanoparticle inhalation in nanoparticle manufacturing workers. Over the monitoring period, more than 10 impactful papers have been published, describing the effects of inhaled metal oxide nanoparticles (e.g. TiO2) and a variety of composite materials on upper respiratory tract inflammation, and impairment of metabolism of fats, proteins, and nucleic acids. Chronic studies indicate that the effect of these particles on the human organism is statistically significant and in some cases irreversible. In all these studies, DACP is involved in the development and application of methods to determine workers' real exposure to aerosol particles. The published results have been widely cited by the international scientific community.

• Pelclova D., Zdimal V., Komarc M., Vlckova S., Fenclova Z., Ondracek J., Schwarz J., Kostejn M., Kacer P., Dvorackova S., Popov A., Klusackova P., Zakharov S., Bello D., Deep Airway Inflammation and Respiratory Disorders in Nanocomposite Workers, Nanomaterials 8, 731, 2018. DOI