The oxidative potential (OP) of particulate matter (PM) is widely recognized as an important measure for evaluating the risk of oxidative stress imbalances caused by air pollution. Despite its significance, the primary sources of OP in different regions and the interactions among these sources remain unclear. This study investigates OP sources and their interactions using PM_2.5 samples from Suzu, Japan, collected during 2015–2016. Chemical composition analyses were conducted and positive matrix factorization (PMF) was applied to identify the sources of PM_2.5 in Suzu. The dithiothreitol (DTT) assay was used to quantify the OP of PM_2.5. To capture the nonlinear behavior of atmospheric processes, a multilayer perceptron (MLP), a type of artificial neural network, was utilized to model OP contributions from the PMF-identified sources. The constructed models were then applied to simulate the interactions between the pollution sources in different seasons by modifying their input intensities. The results indicate that while the contributions of PM_2.5 sources to OP are generally within the range of additive effects, there is a possibility of significant interactions between certain PM_2.5 sources, whether synergistic or antagonistic, which deviate from the additive assumptions of traditional linear models. Furthermore, some interactions intensify as PM_2.5 concentrations increase. These findings underscore the necessity of accounting for source interactions and call for detailed monitoring of various PM_2.5 sources to accurately assess OP risks and develop effective air pollution management strategies.

Space weather is a set of phenomena in the chain of solar–terrestrial connections observed at a certain point in time at a particular point in space. Usually, space weather connects processes occurring in the ionosphere and atmosphere of the Earth with processes on the Sun and near-Earth space.

Ozone plays a key role in the chain of solar–terrestrial connections and affects climate change, both local and global. Ozone is a gas that determines the temperature and circulation regime of the middle atmosphere, as well as effectively absorbing solar ultraviolet radiation, thereby protecting all living things from dangerous radiation. It is well known that the precipitation of energetic particles leads to the ionization of the Earth's atmosphere, initiating the formation of active chemical compounds that destroy ozone and can affect the composition and dynamics of the atmosphere down to the troposphere.

Here, we evaluate the vulnerability of the ozone layer to space weather processes. Seasonal and latitudinal effects of ozone depletion associated with strong geomagnetic storms and geoeffective solar events are considered separately. We investigate enhancements of mesospheric volume mixing ratios of HO2 and nitric acid HNO3 as well as ozone depletion in the Northern Hemisphere (NH) polar night regions during energetic particle precipitation. We utilize mesospheric observations of HO2, HNO3 and ozone from the Microwave Limb Sounder (MLS/Aura). The analysis of observations made with the MLS/Aura shows that the highest volume mixing ratios of HO2 and HNO3 and also the deepest ozone destruction are observed at a latitudinal range from 60NH to 80NH inside the north polar vortex right after the maximum flux of energetic particle precipitation. .

The work was supported by Saint Petersburg State University under research grant 116234986.

Polycyclic aromatic hydrocarbons (PAHs) are key atmospheric pollutants with significant carcinogenic potential that pose serious environmental and public health challenges due to their wide distribution and complex sources. In the atmosphere, PAHs exist in both gas and particle phases, with their concentrations and distributions influenced by atmospheric pollutants and meteorological conditions. This study systematically analyzed urban atmospheric PAHs using high-resolution spatiotemporal sampling data obtained from long-term monitoring. By integrating major atmospheric pollutants and meteorological parameters, spatiotemporal variations, potential sources, and complex environmental interactions of PAHs were comprehensively explored. Advanced machine learning algorithms and statistical methods were employed to identify the key factors driving PAH concentration changes and to reveal nonlinear associations with meteorological conditions and pollution sources. The results indicated significant seasonal and spatial variations in PAH concentrations, highlighting the influence of specific meteorological factors such as temperature, wind speed, and atmospheric pressure. Furthermore, the optimization of clustering and association rule mining algorithms allowed for more precise identification of emission sources and their interactions with environmental variables. These findings provide a novel perspective on the dynamic behavior of PAHs and contribute to a comprehensive understanding of their spatiotemporal distribution, sources, and environmental interactions. This study offers valuable insights for developing effective pollution control strategies, optimizing urban air quality management, and mitigating public health risks associated with PAHs exposure.

A method for retrieving the moments of rain drop size distributions (DSDs) from X-band polarimetric radars is tested using data from a warm rain event which occurred near Incheon, Republic of Korea. The method involves the use of attenuation-corrected radar reflectivity for horizontal polarization, attenuation-corrected differential reflectivity, and specific attenuation for horizontal polarization. The method had been previously tested for an event in Greeley, Colorado, USA, and had resulted in very encouraging results. In this paper, we apply the same method to an isolated warm rain cell which occurred during the summer season of 2020 in Incheon. The height profiles of the retrieved moments were examined. We showed that the application of our retrieval method results in very plausible results in terms of the dominant microphysical processes associated with warm rain events. We also included a convergence region where the drop break-up process is clearly highlighted as being the dominant process. With such encouraging results, our future plan will be to increase the accuracy of the retrieval method by reducing the parameterization errors, for example, by using finely tuned shape parameters to represent the underlying function of the DSDs for warm rain events. The tuning will entail accurate measurements of the full DSD spectra in Incheon.

Introduction According to epidemiological research data, the regional quality of atmospheric air is the cause of considerable population morbidity growth, its vulnerable groups in particular.

Methods The assessment of carcinogenic risk (ICR) for the health of children aged 3-6 years living in four zones of Kazan was performed corresponding to atmospheric air monitoring points. Data on air pollution (with formaldehyde, soot, and benzol) were obtained based on the research results of FSFHI “The Center of Hygiene and Epidemiology in the Republic of Tatarstan” for the years 2017-2023. A daily dose via the chronic inhalation route was calculated at the level of the upper 95^th % of the confidence bound of average annual concentrations.

Results An average annual level of carbon (soot) exceeded the standards in all zones by a factor of 2, 32 - 9,96. A high level of ICR for children’s health was observed in all zones: 2,69х10^-3 in the first zone; 6,68х10^-2 in the second; 7,4х10^-3 in the third, and 1,18х10^-2 in the fourth zone. The highest levels of ICR exceeding the allowable level (1х10^–4) registered in the territories, where enterprises of the first and second classes of hazard (chemical complex) were concentrated, which was especially true of zones 2 and 4. In the residential area of the first and third zones with a high level of truck traffic load, the levels of ICR varied from 2,69х10^-3 to 7,4х10^-3, with the largest contribution of soot to its concentration value.

Conclusion The results dictate the necessity of developing and implementing of such strategies reducing atmospheric emissions as transport and industry modernization and regulation, as well as organizing the continuous monitoring of pollutants for the efficient assessment of the total level of carcinogenic substances in residential zones.

Water scarcity has become a critical and concerning global issue due to climate variability and demographic changes. The increasing demand for food and fiber places immense pressure on the agricultural sector to meet the needs of a growing population, which often requires large volumes of water for irrigation in water-limited environments. This leads to significant water loss through evapotranspiration (ET), which is the combined water loss through evaporation and plant transpiration. ET also shows the volume of water that must be replenished in subsequent irrigation schedules. In South Africa, a major challenge in irrigation management is the lack of measured actual evapotranspiration (ETa) data due to the limited availability of measurement devices. To address this, micrometeorological models offer a practical alternative. This study estimated crop evapotranspiration (ETc) using the Priestley–Taylor and Makkink models, validated against the Penman–Monteith standard model. The results revealed that both the Priestley–Taylor and Makkink methods effectively quantified ETc, with the Priestley–Taylor method showing higher accuracy. These findings show that in the absence of direct ETa measurements, ETc can be reliably estimated using meteorological data, enabling precise adjustments to irrigation schedules. This contributes to improved irrigation water management, promoting the conservation of scarce water resources while ensuring irrigation efficiency.

Carbonaceous components are important components of fine atmospheric particulate matter (PM_2.5) and can affect the local environment, climate, and human health. In this study, the daily atmospheric PM2.5 and carbonaceous aerosol (organic carbon (OC) and elemental carbon (EC)) concentrations were measured at Arconville in Abomey Calavi and Mahoule in Cotonou, Benin, Southwest Africa, from December 2016 to March 2017. The mass concentration and ratios of PM2.5 aerosol and organic and elemental carbon and the OC/EC radio were evaluated together to obtain better insight into their possible local and regional sources. For the studied period, the mean mass concentrations of PM2.5 aerosol were 64 ±16 µ.gm⁻³ and 79 ±18 µ.gm⁻³ at the traffic sites in Arconville and Mahoule, respectively. The OC and EC concentrations were 31 ± 13 μg·m⁻³ and 9 ± 06 μg·m⁻³ for Arconville's traffic and 38 ± 16 μg·m⁻³ and 13 ± 08 μg·m⁻³ at Mahoule, respectively. Adding together the total carbon (TC), it accounted for 62.5% and 64.56% of the PM2.5 at Arconville and Mahoule. The OC/EC ratio was 3.44 at Arconville and 2.92 at Mahoule, exceeding 2.0, which confirmed the presence of secondary organic aerosols during the long dry period at these two traffic sites.

According to the European Union (EU) Green Deal, the greenhouse gas (GHG) emissions from water resources should be reduced by 30% until 2030. Dam lake treatment is one of the main important GHG resources according to the European Union (EU) Green Deal. Due to the natural texture of dam lakes, they emit nitrous oxide (N₂O) emissions at higher amounts. The main aim of this study was the reduction of the N₂O emissions resulting from dam lake treatment using malt dust-derived biochar. The biochar was derived from malt dust using a slow pyrolysis process under three various temperatures:250 (M1), 300 (M2) and 500 °C (M3). A biochar adsorption process was applied as not only as a water treatment technique but also a nitrous oxide emission reduction method. Before and after the biochar adsorption process, N₂O was sampled and measured seasonally using gas chromatography equipped with an electron capture detector (GC-ECD). The water samples were taken seasonally from Ataturk Dam Lake inTurkey. Also, the GHGs originating from water treatment was collected and adsorbed using the same biochar to determine the experimental nitrous oxide capture ability of biochar in a gas adsorption column. On average, a 21.1% reduction in N₂O emissions from dam lake treatment was reported using malt dust-derived biochar. The maximum nitrous oxide capture capacity corresponded to the malt dust-derived biochar produced at the minimum temperature (M1). This study verified that malt dust-derived biochar was an efficient N₂O adsorbent and air pollutant disposer. The Box–Behnken experimental design method was performed using MATLAB to determine the optimum operating parameters for the minimum N₂O emission. The statistical analysis results revealed that the optimum parameters were 4 mg/L of dissolved oxygen (DO) and 11 mg/L of nitrate (NO₃^-) concentration for the minimum N₂O emission.

Air quality for neodymium (Nd) was biomonitored in the English county of Leicestershire after low levels of the element were detected in topsoils from various urban parks in the city of Leicester. Thin layers of bark were collected from 55 and 41 trees growing in the city of Leicester and surrounding rural areas, respectively. Nd was monitored by ICP-MS in clean/ground/homogenised samples [LoD=0.504 ng/g dry weight (dw)]. The levels of Nd were higher in bark samples collected in Leicester city (median and ranges, in ng/g dw): 8.382 (2.021-198.91) and 7.778 (1.577-59.123). The higher concentrations of Nd in bark collected from trees growing in Leicester could be attributed to its technological uses. The Nd content varied between bark samples collected in the four cardinal sub-areas into which the city was divided (medians, ng/g dw): 45.132 (SE) > 14.397 (SW) > 7.709 (NE) > 5.950 (NW). This trend differed from the concentrations found in trees growing in the three Leicestershire cardinal points (medians, ng/g dw): 28.175 (NW) > 7.215 (NE) > 1.772 (SE). Finding a hypothesis that could explain the differences found in airborne Nd content across the monitored region is challenging as the atmospheric transport of Nd is poorly understood. Our results show a high dispersion of Nd across Leicestershire, which would be little influenced by its distribution in the topsoil, as the enrichment factors obtained as a function of the average Nd and scandium content in the upper continental crust were lower than unity in both areas (0.383 and 0.423). However, further studies are needed to identify the potential sources of Nd that could have contributed to the observed trends, because the levels found were higher than those described in bark from trees growing in uncontaminated areas. The development of a ¹⁴³Nd/144Nd isotope map could help to distinguish sources of pollution.

The presence and distribution of lanthanum (La) in the topsoil and wild edible mushrooms in the English city of Leicester could pose some risks to the population. A biomonitoring study was carried out to determine the air quality for La across the region of Leicestershire. Bark samples (2–6 mm thick) were collected from 55 trees in the city and 41 surrounding rural areas. La was measured using ICP-MS in appropriately mineralised samples [LoD = 0.00068 ng/g dry weight (dw)]. Higher levels were found in the bark collected from the trees growing in Leicester (median and ranges, in ng/g dw)—9.679 (2.128-150.769) vs. 8.344 (1.815-59.801)—a distribution consistent with the trend found in the topsoils and which could be attributed to its technological use and traffic volumes. The La content varied between the bark samples collected in the three cardinal sub-areas into which Leicestershire was divided (medians, ng/g dw): 29.772 (NW) > 7.855 (NE) > 2.027 (SE). However, this pattern was different to the distribution of La in the topsoil samples monitored across Leicestershire, which showed statistical significance (p-value = 0.03997, medians, mg/kg): 25.874 (SE) > 24.290 (NE) > 19.470 (SW) > 13.401 (NW). In general, our results showed lower airborne La contamination in Leicestershire, which is supported by the lower levels of La in the bark from the monitored trees compared to those reported in the literature for trees growing in uncontaminated areas, and low enrichment factors (0.383 and 0.393) in the urban and rural areas, which were calculated using the averages in the Earth’s continental crust and the scandium content. Moreover, the enrichment calculated in the topsoils (1.118 and 0.909) also suggests little anthropic influence on the presence/distribution of this metal in the English region studied. Leicestershire's atmosphere represents a minimal risk to the population in terms of La.