A sensitive and fast method for the simultaneous determination of gaseous nitric acid (HNO3) and particulate nitrate (NO3-) in ambient air is presented. HNO3 is continuously sampled using a wet diffusion denuder and analysed online by a newly developed continuous flow analyser, while NO3- bound to aerosol particles is collected in parallel using a continuous aerosol sampler and analysed by the previously developed continuous flow analyser. Chemiluminescence detection in both CFAN and CFAO enables sensitive determination of NO3- directly in sampler concentrates without preconcentration, with limits of detection (LOD = 3 S/N) of 5.1 nM and 12.8 nM, respectively. The corresponding LODs are 0.13 μg m-3 (49.7 ppt) for HNO3 and 0.10 μg m-3 for NO3-. The developed method enables continuous online measurement of the HNO3/NO3- distribution in ambient air, with chemiluminescence signal recorded at 1 s intervals. The optimised method was applied to the determination of HNO3 and NO3- in urban air in Brno during winter and summer campaigns conducted between 2022 and 2023. Results obtained using the developed method were compared with those from a reference method based on sampling on filters and dry diffusion denuders coated with sodium fluoride.

Exposure to cadmium (Cd), a toxic heavy metal, is a severe threat to organismal health, causing a wide range of pathological alterations in various tissues and organs. Alterations in the composition and function of the gut microbiome have been indicated across numerous animals exposed to Cd. However, the impact of Cd inhalation exposure on the pulmonary microbiome has not been well investigated yet. Therefore, in this study, we investigated the effects of exposure to CdONPs and its clearance on both colonic and pulmonary microbiomes in mice. The diversity of both colonic and pulmonary microbiomes of exposed mice was significantly affected after 9 weeks of CdONPs inhalation. The effects of CdONPs exposure on bacterial composition and function were more pronounced in the colonic microbiome than in the pulmonary microbiome. The clearance was more efficient in the restoration of gut microbiome composition in comparison to the lung microbiome. Moreover, we evaluated a bidirectional interaction between Cd exposure and gut microbiota. Duncaniella, Odoribacter, and Pontibacter were the prominent biomarkers that significantly positively correlated with dysregulated functions in the colonic microbiome of exposed mice. Based on the PICRUSt2 prediction analysis, our results suggested that perturbations in the gut microbiota balance due to Cd exposure were associated with the increase in the proportion level of bacteria with excessive membrane transporters, which may potentially augment the absorption of this metal by intestinal microbiota thereby leading to the accumulation of Cd in intestinal bacteria and the potential alleviation of the Cd toxicity effect. Furthermore, genes related to metal chelators were consistent with the colonic microbiome of exposed mice, suggesting possible promotion of Cd excretion and its eventual fecal elimination. However, these observations derived from 16S rRNA profiling and PICRUSt2 predictions would need to be verified experimentally to establish any functional or mechanistic implications. This could be considered a key factor in determining the intestinal bacterial species able to minimize the toxicity of heavy metals in future therapeutic approaches. • Inhalation of CdO nanoparticles significantly alters both gut and pulmonary microbiome composition and diversity in mice. • Microbiome changes are more pronounced in the gut than in the lungs following inhalation exposure. • Partial recovery of microbiome composition occurs after the clearance period, with greater restoration in the gut than in the lung. • Predicted functional profiles indicate shifts in microbial metabolic potential associated with Cd exposure. • The findings support a potential interaction between inhaled Cd exposure and the gut microbiome, highlighting the relevance of the gut–lung axis.

Forest springs represent important sources of groundwater. They are important for ecology, hydrology and, in many cases, as drinking water. This study focuses on the assessment of water quality in selected forest springs located in three regions of Czechia, namely South Moravia, Zlín and Vysočina. The assessments were undertaken during the spring and autumn seasons. A total of 50 springs were analysed for basic physicochemical parameters i.e. temperature, yield, pH, specific electrical conductivity, total water hardness and acid neutralizing capacity. The chemical analysis included anions, cations, and elements, while microbiological analysis covered intestinal enterococci, Escherichia coli and coliform bacteria. The results showed notable differences in water quality between the regions, reflecting local geological conditions, land use and anthropogenic influence. While the majority of samples met the recommended limits for drinking water in terms of chemical composition, microbiological contamination was detected in most locations, thus posing potential health risks.

Ammonium in urban fine aerosol (Particulate Matter, [PM2.5]) was analysed in parallel using two different methods. The first method, a continuous Condensation-Growth Unit-Aerosol Counterflow Two-Jets Unit sampler combined with a fluorescence detector (FLD), allowed the ultrasensitive (limit of detection = 1.04 ng m-3, 3 S/N) and fast (1 s time resolution) online determination of NH4+, while the second method was based on a sampling of aerosols on a high-flow cascade impactor (HFI) with 7 size fractions. The aerosols collected by the HFI were analysed offline for ammonium using the FLD and for seven water-soluble anions using ion chromatography. Comparison of the results from both methods allowed quantification of NH4+ losses of semi-volatile NH4+ salts in aerosols collected on the HFI. The measurement of mass size distribution was used to distinguish the sources of ions in the fine PM. Nitrate and sulphate were the most abundant anions, accounting for 80.4 % and 76.1 % of total ion concentration and 7.93 % and 10.2 % of aerosol mass during summer and winter campaigns, respectively. Sampling of atmospheric aerosol during 2-week campaigns in summer 2021 and winter 2022 provided seasonal variations of analysed ions in urban PM2.5 aerosols in Brno, Czech Republic.

TiO2 nanoparticles (NPs) are extensively used in various applications, highlighting the importance of ongoing research into their effects. This work belongs among rare whole-body inhalation studies investigating the effects of TiO2 NPs on mice. Unlike previous studies, the concentration of TiO2 NPs in the inhalation chamber (130.8 μg/m3) was significantly lower. This 11-week study on mice confirmed in vivo the presence of TiO2 NPs in lung macrophages and type II pneumocytes including their intracellular localization by using the electron microscopy and the state-of-the-art methods detecting NPs' chemical identity/crystal structure, such as the energy-dispersed X-ray spectroscopy (EDX), cathodoluminescence (CL), and detailed diffraction pattern analysis using powder nanobeam diffraction (PNBD). For the first time in inhalation study in vivo, the alterations in erythrocyte morphology with evidence of echinocytes and stomatocytes, accompanied by iron accumulation in spleen, liver, and kidney, are reported following NP's exposure. Together with the histopathological evidence of hyperaemia in the spleen and kidney, and haemosiderin presence in the spleen, the finding of NPs containing iron might suggest the increased decomposition of damaged erythrocytes. The detection of TiO2 NPs on erythrocytes through CL analysis confirmed their potential systemic availability. On the contrary, TiO2 NPs were not confirmed in other organs (spleen, liver, and kidney); Ti was detected only in the kidney near the detection limit.

This paper presents the findings from a collaborative interlaboratory comparison exercise designed to assess oxidative potential (OP) measurements conducted by 20 laboratories worldwide. This study represents an innovative effort as the first exercise specifically aimed at harmonising this type of OP assay, setting a new benchmark in the field. Over the last decade, there has been a noticeable increase in OP studies, with numerous research groups investigating the effects of exposure to air pollution particles through the evaluation of OP levels. However, the absence of standardised methods for OP measurements has resulted in variability in results across different groups, rendering meaningful comparisons challenging. To address this issue, this study engages in an international effort to compare OP measurements using a simplified method (with a dithiothreitol (DTT) assay). Here, we quantify the OP in liquid samples to focus on the protocol measurement itself, while future international OP interlaboratory comparisons (ILCs) should aim to assess the whole chain process, including the sample extraction. We analyse the similarities and discrepancies observed in the results, identifying the critical parameters (such as the instrument used, the use of a simplified protocol, the delivery and analysis time) that could influence OP measurements and provide recommendations for future studies and interlaboratory comparisons even if other crucial aspects, such as sampling PM methods, sample storage, extraction methods and conditions, and the evaluation of other OP assays, still need to be standardised. This collaborative approach enhances the robustness of the OP DTT assay and paves the way for future studies to build on a unified framework. This pioneering work concludes that interlaboratory comparisons provide essential insights into the OP metric and are crucial to move toward the harmonisation of OP measurements.

With decreasing size of atmospheric aerosol particles, their ability to penetrate deeper into the respiratory system increases. Ultrafine particles (UFPs) and nanoparticles (NPs), defined as atmospheric aerosol particles smaller than 100 nm, have been identified as potentially the most dangerous to human health due to their ability to penetrate easily the lung epithelial wall into the blood, which transports them to other organs. Despite considerable toxicological evidence of the potential harmful effects of these particles on human health, the appropriate metric for assessing their health effects is still unclear. This article describes various methods used to assess particle toxicity, the mechanism of toxic action of particles and the use of NPs in medicine.

Lead nanoparticles (PbNPs) in air pollution pose a significant threat to human health, especially due to their neurotoxic effects. In this study, we exposed mice to lead(II) oxide nanoparticles (PbONPs) in inhalation chambers to mimic real-life exposure and assess their impact on the brain. PbONPs caused the formation of Hirano bodies and pathological changes related to neurodegenerative disorders through cytoskeletal disruptions without the induction of inflammation. Damage to astrocytic endfeet and capillary endothelial cells indicated a compromised blood-brain barrier (BBB), allowing PbONPs to enter the brain. Additionally, NPs were detected along the olfactory pathway, including fila olfactoria, suggesting that at least a proportion of PbNPs enter the brain directly by passing through the olfactory epithelium. PbNP inhalation severely damaged the apical parts of olfactory epithelial cells, including the loss of microtubules in their ciliary distal segments. Inhalation of PbONPs led to the rapid accumulation of lead in the brain, while more soluble lead(II) nitrate NPs did not accumulate significantly until 11 weeks of exposure. PbNPs induced disruption of the BBB at multiple levels, ranging from ultrastructural changes to functional impairments of the barrier; however, they did not induce systemic inflammation in the brain. The clearance ability of the brain to remove Pb was very low for both types of NPs, with significant pathological effects persisting even after a long clearance period. Cation-binding proteins (ZBTB20 and calbindin1) were distributed unevenly in the brain, with the strongest signal located in the hippocampus, which exhibited the greatest defects in nuclear architecture, indicating that this area is the most sensitive structure for PbNP exposure. PbNP exposure also altered the PI3K/Akt/mTOR signaling pathway, and tau phosphorylation in the hippocampus and inhibition of tau phosphorylation by GSK-3 inhibitor rescued the negative effect of PbONPs on the intracellular calcium level in trigeminal ganglion cultures. In zebrafish larvae, PbONPs affected locomotor activity and reduced calcium levels in the medium enhanced negative effect of PbONP on animal mobility, even increasing lethality. These findings suggest that cytoskeletal disruption and calcium dysregulation are key factors in PbNP-induced neurotoxicity, providing potential targets for therapeutic intervention to prevent neurodegenerative changes following PbNP exposure.

Background Biogenic volatile organic compounds (BVOCs) play a key role in atmospheric chemistry and air quality. Accurate quantification of individual BVOCs remains challenging due to their volatility and reactivity in atmosphere. In this study, a wet diffusion denuder used for the continuous sampling of BVOCs into an absorption liquid was evaluated under controlled laboratory conditions in order to determine the collection efficiencies for a large number of BVOCs. All samples with collected BVOCs were offline analysed using gas chromatography with mass spectrometry. Results The influence of denuder temperature, air flow rate, relative humidity, type of absorption liquid, and liquid flow rate was systematically investigated. Optimal conditions for field application were selected as a denuder temperature of 20 °C, an air flow rate of 500 mL/min, n-heptane as the absorption liquid, and a liquid flow rate of 0.40 mL/min. Under these conditions, collection efficiencies for most BVOCs exceeded 89 %. Field sampling conducted at two contrasting sites, an agricultural location and a spruce forest, confirmed the applicability of the method and highlighted large differences in monoterpene concentrations between environments. A connection of denuder output with automatic sample collector enables long-term fully automatic sampling of BVOCs in the air at short time intervals. The temporal resolution sampling allows the study of rapid changes in BVOC concentrations in the air. Significance A key advantage of the method is that it minimizes the exposure of captured BVOCs in an absorption liquid (n-heptane) to airborne oxidants, thereby reducing the risk of photochemical reaction with air oxidants during sampling, and also the determination of the concentration of individual BVOCs using off-line gas chromatography with mass spectrometry analysis.

Inhaled cadmium oxide nanoparticles (CdONPs) represent an underrecognized environmental and occupational hazard because of their potential for systemic bioaccumulation and organ-specific toxicity. In this study, mice were exposed to subchronic inhalation of CdONPs, and cadmium distribution, clearance, and tissue responses were assessed over a 21-day recovery period using atomic absorption spectrometry, laser ablation inductively coupled plasma mass spectrometry, histopathology, and gene expression analysis. Cadmium accumulated predominantly in the lungs, where clearance was slow and accompanied by persistent inflammation and foam cell formation. The intestines exhibited efficient cadmium reduction, likely due to high epithelial turnover, while the liver showed minimal accumulation and no overt damage. By contrast, the kidneys retained cadmium primarily in the cortex, with partial clearance and ultrastructural changes, including mitochondrial disorganization and lipid accumulation. Bone tissues demonstrated differential retention: jaw bones effectively cleared cadmium, whereas femurs showed sustained or increased levels, suggesting redistribution from other organs. Gene expression analysis revealed moderate but consistent upregulation of Abca1, Apoe, and Ptch1 in the kidneys of clearance groups, indicating adaptations in lipid metabolism and membrane transport. These findings highlight organ-specific clearance kinetics and molecular responses to inhaled CdONPs, underscoring the need for tissue-targeted risk assessment frameworks in nanoparticle toxicology.

Organic aerosols (OA) contribute remarkably to total mass of fine aerosols in the lower troposphere, exerting effects on air pollution, global climate and human health. Therefore, analysis of chemical composition of OA in real-time is vital to understanding the formation and reaction mechanisms of organic aerosols. In this work, vacuum ultraviolet (VUV) photoionization mass spectra of squalane aerosol, a good proxy for long chain hydrocarbons often detected in ambient OA, has been performed with a home-made thermal desorption/tunable VUV photoionization aerosol time-of-flight mass spectrometer based on synchrotron radiation (SR). The dependence of photoionization mass spectra of squalane aerosols upon the vaporization temperature and ionization energy were investigated in detail. The ionization energy (IE) of parent molecule (IEsq = 9.43 eV) and the corresponding appearance energies (AEs) of fragments ions were determined. It is shown that the choice of the appropriate vaporization temperature is helpful for analysis of mass spectra of OA, and the measurement of the photoionization efficiency (PIE) curve is crucial to identifying the molecular chemical components of the fragment ions. The dissociative photoionization of squalane aerosol was further studied theoretically with ab initio calculations at M062X level. The qualitative agreement between experimental and theoretical results on dissociative photoionization channels demonstrated that the mechanism of dissociative photoionization of squalane aerosol can be studied by controlling the vaporization temperature, which is important for chemical composition analysis of OA in atmosphere. The findings in this work indicate the potential application of soft ionization aerosol mass spectrometry based on SR for characterization of atmospheric aerosols, especially OA.

Sensitive and fast analysers using chemiluminescent detection for the determination of nitrogen dioxide (NO2) and ozone (O-3) are presented. A newly modified detection cell with a continuously wetted wick enables continuous real time NO2/O-3 analysis with a resolution of 1 s. The calibration of the NO2/O-3 analysers is provided by individual calibration sources during measurement. The calibration curves of both the NO2 and O-3 analysers are linear over the full range of measurement (8.58-824 and 5.64-888 mu g m(-3), respectively) and to the limits of detection (LOD = 3 S/N) are 2.58 and 1.69 mu g m(-3), respectively. These analysers were used to determine NO2/O-3 levels and thus urban air quality in Brno over three campaigns in 2022 and 2023.

This article briefly introduces the Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic. The introductory part illustrates the historical development of the Institute and characterizes its focus in general. In the following five sections, each of the five scientific departments of the Institute describes selected topics from its current activities.

Atmospheric aerosol particles are considered to be a significant health risk worldwide. Although the exact mechanisms of aerosol toxicity are still not fully understood, several studies report that the generation of reactive oxygen species (ROS) is one of the main mechanisms responsible for chronic and acute health problems. For this reason, oxidative potential (OP) which is defined as the ability of an aerosol to generate ROS, has been proposed as a relevant parameter for assessing aerosol toxicity. This article describes different acellular in vitro methods to determine OP and the influence of chemical composition and aerosol size on OP.

Atmospheric aerosol particles are considered to be a significant health risk worldwide. Although the exact mechanisms of aerosol toxicity are still not fully understood, several studies report that the generation of reactive oxygen species (ROS) is one of the main mechanisms responsible for chronic and acute health problems. For this reason, oxidative potential (OP) which is defined as the ability of an aerosol to generate ROS, has been proposed as a relevant parameter for assessing aerosol toxicity. This article describes different acellular in vitro methods to determine OP and the influence of chemical composition and aerosol size on OP.

An automated on-line preconcentration and detection method for determination of dicarboxylic acids (DCAs) in aqueous samples is proposed. Parameters of two different off-line preconcentration methods (solid phase extraction - SPE, and concentrator columns) were tested and optimised. Compared with SPE columns, the concentrator column AC15 was chosen as the best choice for the next optimization followed by separation and detection by ion chromatography (IC). The sensitive method for determination of 7 DCAs (oxalic, malonic, succinic, maleic, glutaric, pimelic and azelaic acid) was devised with detection limits of 0.12-0.40 nM. The presented system describes an alternative on-line method usable for automated monitoring of selected analytes.

Titanium dioxide nanoparticles (TiO2 NPs) are used in a wide range of applications. Although inhalation of NPs is one of the most important toxicologically relevant routes, experimental studies on potential harmful effects of TiO2 NPs using a whole-body inhalation chamber model are rare. In this study, the profile of lymphocyte markers, functional immunoassays, and antioxidant defense markers were analyzed to evaluate the potential adverse effects of seven-week inhalation exposure to two different concentrations of TiO2 NPs (0.00167 and 0.1308 mg TiO2/m3) in mice. A dose-dependent effect of TiO2 NPs on innate immunity was evident in the form of stimulated phagocytic activity of monocytes in low-dose mice and suppressed secretory function of monocytes (IL-18) in high-dose animals. The effect of TiO2 NPs on adaptive immunity, manifested in the spleen by a decrease in the percentage of T-cells, a reduction in T-helper cells, and a dose-dependent decrease in lymphocyte cytokine production, may indicate immunosuppression in exposed mice. The dose-dependent increase in GSH concentration and GSH/GSSG ratio in whole blood demonstrated stimulated antioxidant defense against oxidative stress induced by TiO2 NP exposure.

Comparison of gaseous and particulate emissions from the combustion of hard (beech) and soft (spruce) wood in four types (old and modern) boilers used for household/residential heating was studied. The boilers were run with three different heat outputs, i.e. nominal (85-100%) and two reduced outputs (60-70% and 35-45%), to cover the expected usage of these boilers in real households during different outdoor air winter temperatures. Gaseous emission factors (CO2, CO, NOx, OGC - organic gaseous compounds), particulate pollutants (n-alkanes and polycyclic aromatic hydrocarbons) and particulate organic markers (monosaccharide anhydrides, methoxyphenols and diterpenoids) were determined. In general, modern-type boilers emitted lower amounts of products of incomplete combustion than those old-type boilers. The emission factors (EFs) of total suspended particles varied between 562 and 2150 mg kg-1 (beech logs, the oldest-type boiler), and 69.1 and 118 mg kg-1 (spruce pellets, the modern-type boiler). The trends between the heat outputs of boilers and the EFs of particulate organic compounds/markers were observed for all boilers (especially the automatic boiler) with some exceptions and mostly increased with a decreasing output of boilers. The ratios levoglucosan/mannosan varied in the range of 13.4-18.6 for the combustion of beech, and 2.11-4.16 for the combustion of spruce.

Copper oxide nanoparticles (CuO NPs) are increasingly used in various industry sectors. Moreover, medical application of CuO NPs as antimicrobials also contributes to human exposure. Their toxicity, including toxicity to the immune system and blood, raises concerns, while information on their immunotoxicity is still very limited. The aim of our work was to evaluate the effects of CuO NPs (number concentration 1.40×106 particles/cm3, geometric mean diameter 20.4 nm) on immune/inflammatory response and antioxidant defense in mice exposed to 32.5 µg CuO/m3 continuously for 6 weeks. After six weeks of CuO NP inhalation, the content of copper in lungs and liver was significantly increased, while in kidneys, spleen, brain, and blood it was similar in exposed and control mice. Inhalation of CuO NPs caused a significant increase in proliferative response of T-lymphocytes after mitogenic stimulation and basal proliferative activity of splenocytes. CuO NPs significantly induced the production of IL-12p70, Th1-cytokine IFN-γ and Th2-cytokines IL-4, IL-5. Levels of TNF-α and IL-6 remained unchanged. Immune assays showed significantly suppressed phagocytic activity of granulocytes and slightly decreased respiratory burst. No significant differences in phagocytosis of monocytes were recorded. The percentage of CD3+, CD3+CD4+, CD3+CD8+, and CD3-CD19+ cell subsets in spleen, thymus, and lymph nodes did not differ between exposed and control animals. No changes in hematological parameters were found between the CuO NP exposed and control groups. The overall antioxidant protection status of the organism was expressed by evaluation of GSH and GSSG concentrations in blood samples. The experimental group exposed to CuO NPs showed a significant decrease in GSH concentration in comparison to the control group. In summary, our results indicate that sub-chronic inhalation of CuO NPs can cause undesired modulation of the immune response. Stimulation of adaptive immunity was indicated by activation of proliferation and secretion functions of lymphocytes. CuO NPs elicited pro-activation state of Th1 and Th2 lymphocytes in exposed mice. Innate immunity was affected by impaired phagocytic activity of granulocytes. Reduced glutathione was significantly decreased in mice exposed to CuO NPs.