Growing urbanization and industrialization heighten air pollution concerns. Tropospheric ozone, a challenging pollutant, draws scientific attention. Nitrogen oxides (NOx) and methane (CH4) are key, influencing ozone dynamics. Methane and NOx are primary precursors in tropospheric ozone’s complex formation. Elevated methane can substantially increase ozone, while excess NOx triggers self-regulation. Atmospheric reactions, including ozone destruction, illustrate this complexity, where NO reacts with O3.

Research on long-term NOx and methane emissions is crucial for understanding climate change. Analyzing scenarios fixing 2010 NOx levels while varying methane to 2100 offers insights into climate consequences. Elevated ozone has adverse effects: deteriorating air quality, respiratory issues, vegetation damage, and an enhanced greenhouse effect.

Advanced atmospheric chemistry modeling and data analysis are employed in this research. Global climate models like SOCOL-v3 simulate atmospheric processes and chemical reactions involving NOx and methane. These models, incorporating meteorological data, emissions inventories, and chemical reaction mechanisms, predict tropospheric ozone formation accurately. They enable the analysis of complex atmospheric interactions and forecast future air quality scenarios under varying emission conditions

Integrated chemical climate modeling, scenario analysis, and synergistic pollutant effects are crucial in current research. Understanding these interactions is vital for effective air quality management. Continued growth in pollutant concentrations underscores the need for emission control measures. This research's practical applications include enhancing air quality monitoring, developing pollution reduction strategies, forecasting atmospheric changes, and shaping environmental policies. Future studies should focus on detailed interactions between atmospheric components and innovative air quality control approaches. International cooperation is essential for effective tropospheric ozone management.

Funding: Russian Science Foundation project under the contract No.23-77-30008.

The present study aims to analyse the effects of climate change on the urban environment, focusing on sustainable urban planning and an analysis of microclimate and thermal comfort. The considered study area is composed of a square domain of app. 400 x 400 m in the city of Lecce (Italy), where temperature and relative humidity data are still being measured.

The analysis involves a modelling chain that uses ERA5 data to provide the boundary conditions for the 1D Multi-Layer Urban Canopy Model (MLUCM) based on the BEP+BEM (Building Effect Parameterization + Building Energy Model) model, which subsequently generates the inputs for ENVI-met, a CFD model used for microclimate simulations and thermal comfort studies. This methodology allows us to bridge the gap between different scales.

Another model applied in this work is PALM-4U, which is an advanced atmospheric simulator for the simulation of urban atmospheric boundary layers, as well as urban climate and the interactions between the built environment and the atmosphere. It can work in turbulence-resolving LES (Large Eddy Simulation) mode, and is suitable for a wide range of applications, such as urban climate, air quality and pollutant dispersion, urban ventilation, and thermal comfort. Among the advantages of PALM-4U are its high spatial and temporal resolution, its modular approach, and the fact that it represents support for real data, as well as being open-source.

The modelling outputs are first validated against measured data and are further employed to develop strategies for adapting to climate change by improving urban thermal comfort for citizens.

Globally, Particulate Matter (diameter 2.5 - PM_2.5) and other pollutants have created a lot of problems health wise. It is not possible to mitigate their effects without quantifying the amount within the environment both indoors and outdoors. On this premise, the PM_2.5 within the University of Lagos (UNILAG), Nigeria (Central Laboratory and the Main gate of the campus) was evaluated with the aim of disseminating the outcome to stakeholders who would work towards mitigating the potential pollution around the surroundings. Also, a HYSPLIT model was used to track backward trajectories and the potential source locations of PM_2.5. The eight-month (2023-08-01 to 2024-03-01) air quality data were obtained from AirQo at Makerere University, Uganda. The data were subjected to Anderson—Darling Normality Testing and were compared with the National Environmental Standards and Regulations Enforcement Agency (NESREA) and World Health Organization (WHO) standards. The results were as follows. Main gate: minimum (7.23 µg/m³), maximum (180.50 µg/m³), mean (26.69), Std. (19.07), and A-Squared (104.28); Central lab: gate: minimum (6.32 µg/m³), maximum (181.13 µg/m³), mean (24.26), Std. (20.86), and A-Squared (227.28). The means of the two locations were 5.34 times (Main gate) and 4.86 times (Central Lab) higher than the WHO annual limit, while they were 1.34 times (Main gate) and 1.21 times (Central Lab) higher than the NESREA annual limit, which may likely be due to high local emissions from solid fuel combustion, waste burning, and high vehicular movements within the vicinity. The air mass came from the ocean in a southwestern direction. These findings demonstrated the significance of local emission sources in determining fluctuations in PM2.5 within the university and the necessity of focused mitigation techniques to solve serious environmental air pollution issues.

Air pollution is a global environmental and health issue and is also strongly interlinked with the issue of climate change. A thorough understanding of the complex nonlinear phenomena that govern the spatiotemporal variability of air pollution is still lacking, although this knowledge is essential for defining effective strategies to safeguard public health and environmental sustainability, and to counteract climate change.

In recent decades, machine learning models (MLMs) have shown great potential in the air pollution research sector due to their capability in describing complex non-linear phenomena. Moreover, thanks to interpretability methods developed in the fields of the Explainable Artificial Intelligence (XAI), MLM results can be interpreted for assessing the impact of individual factors and their interrelationships on the model output, also providing visual representations which can facilitate the comprehension of such complex phenomena.

In this study, the XGBoost algorithm and SHAP (SHapley Additive exPlanations) method have been employed to explore the influence of several driving factors, namely air pollutants (including surface ozone (O₃) and fine particulate matter (PM_2.5)) and meteorological parameters, on air quality index (AQI) variability.

Based on the air pollutant and meteorological data, acquired at different typologies of air quality monitoring stations over the 2018-2022 period, an XGBoost MLM has been developed to simulate the AQI temporal pattern, obtaining good model performance. Subsequently, the SHAP method has been employed to explore the importance of each driving factor and the relationship with the model output. Special focus is given to the interaction effect among driving factors on AQI.

This study, conducted within the framework of the PNRR Italian National Centre for Sustainable Mobility CNMS (European Union – Next Generation EU - PNRR – MISSIONE 4 – COMPONENTE 2- INVESTIMENTO 1.4 – Spoke 7 - Code CN00000023, CUP: F83C22000720001), investigates the impact of urban morphology on the dispersion of vehicular pollutants, specifically nitrogen dioxide (NO₂) and particulate matter ≤10 µm (PM₁₀). The aim is to analyse pollutant concentration patterns in areas characterised by different urban forms and to evaluate potential strategies for improving air quality in sensitive locations such as school environments.

The primary phase of this study focuses on the city of Lecce, integrating modelling with ADMS-Roads, QGIS elaborations and meteorological analyses to estimate pollutant dispersion under varying urban morphologies. In this initial phase, traffic data is kept constant for consistency. The preliminary modelling results indicate a strong influence of urban morphology on the dispersion of traffic-related pollutants. Urban forms characterised by a low planar area index (λ_p) have been observed to lead to increased NO₂ and PM₁₀ levels, with concentrations decreasing in areas with higher λ_p.

In addition to modelling efforts, experimental measurement campaigns will be carried out near two schools in Lecce to assess real-world pollutant concentrations. These campaigns will employ an air quality monitoring station, a meteorological station and a traffic-counting camera. The meteorological and traffic flow data collected will enable the reproduction of real scenarios in ADMS-Roads and will be used to validate the model through comparison with measured air quality data and enabling future scenario simulations that assessmitigation measures to reduce traffic-related emissions. This, in turn, will improve air quality in sensitive areas such as school environments.

While examining how the orientation of particles and droplets in the air subject to static electric fields during atmospheric transport affect sedimentation processes, an important point that has been overlooked throughout the history of electricity was realized. The type of lightning and its refraction angle with respect to the pathway of the electrical discharges seen in the air column, which is pushed by a buffer area of atmospheric fronts, or in the lower stable air flows moving from upper unstable air layers are the same in a given geographical region. The similarity seen in the refraction angles within the whole column of a lightning strike during grounding is quite impressive, as is the similarity in the shape of different lightning strikes at different times in history. When historical lightning photographs taken in the same geological region are examined, we can see that this shape has not changed in 100 years. The shape of lightning strikes seen at different times in the same region and relevant visual evidence have been collected.

The characteristic atmospheric features that create stable erosion and transportation properties are more important than geological stratigraphy and have a greater effect on our findings. The geological lithography of these areas is the second most impactful feature. The different types of suspended material involved in float laminarization processing during transportation is the reason a separated laminar column flow occurs under the same atmospheric conditions. The physical multi-layered separation these materials experience is the result of their varying physical properties, such as their static electric field, humidity, or internal relative displacements. Multi-laminar volumetric leakages of the same air density by the same type of suspended material occur at different heights in the main air column, with an increased number of layers occurring due to static electricity. The pathway of a lightning strike always hasthe same refraction shape, making this a regional marker of constant atmospheric conditions in a stable climate.

Introduction: The state policy of many countries is aimed at reducing atmospheric air pollution. The purpose of this work is to assess the health risk of adolescents and adults associated with the impact of atmospheric air chemicals in the city of Kazan.

Materials and methods: This study was carried out on the basis of the data of socio-hygienic monitoring (2015-2022). Non-carcinogenic risk assessments werecarried out in accordance with Guideline 2.1.10.3968-23 to calculate the average daily doses for adolescents (14-17 years old) and the adult population. The total risk of carcinogenic effects (HQs) and the hazard index of non-carcinogenic effects (HIs) were calculated..

Results: The main contributors to the risk (HQ) for adolescents and adults in Kazan are carbon at 32.8%, nitrogen dioxide at 21.7%, PM10 at 20.7%, formaldehyde at 8.5%, and PM2.5 at 8.2%. Annual mean concentrations for the city of Kazan for carbon were 0.189 mg/m3, for nitrogen dioxide 0.081 mg/m3, for PM10 0.074 mg/m3, for formaldehyde 0.004 mg/m3, and for PM2.5 0.02 mg/m3. The cumulative risk of non-carcinogenic effects is 4.1 (high risk) for adolescents and 2.9 (alarming risk) for adults. The highest toxic load is respiratory: HI=3.8 for adolescents (alarming risk) and HI=2.7 for adults (acceptable risk). Mortality indices are HI=1.7 and HI=1.2, respectively, remaining within acceptable limits. Dental and systemic diseases ranked third, with HI=1.4 for adolescents and HI=1.0 for adults.

Conclusions: The comparative assessment of non-carcinogenic effects in adolescents corresponds to a high level, requiring comprehensive risk reduction measures, while for adults it is alarming, requiring routine wellness interventions.

Drought is among the most severe climate-related hazards, posing significant threats to ecosystems and economies worldwide. Consequently, numerous countries have conducted locally focused studies to develop effective adaptation strategies. In this study, we examined the occurrence and evolution of drought in Austria, a relatively small country (83,878 km²) in Central Europe. Our analysis was based on long-term ERA5-Land monthly datasets spanning 1950–2023, incorporating precipitation, surface net radiation, surface pressure, 2 m air and dew point temperatures, and 10 m wind speed components. The precipitation and temperature data from this source exhibited strong agreement with observed datasets, supporting their reliability for this study. These datasets enabled the calculation of the Standardised Precipitation Index (SPI) and the Standardised Precipitation-Evapotranspiration Index (SPEI) at 1-, 3-, 6-, and 12-month timescales. Drought episodes were identified using a threshold of -0.84, with duration determined from the first month the index falls below zero, continuing until it reaches -0.84, and ending before the last month the index becomes positive. Severity was calculated as the sum of all SPI/SPEI values throughout each episode. Given that index variability decreases as the temporal scale increases, the highest number of drought episodes was identified using SPI1 (123) and SPEI1 (124), primarily affecting the western half of the country. The spatial distribution of drought episodes suggests a strong influence of topography. Furthermore, we found a statistically significant relationship between the severity of drought episodes and the affected area. However, differences between SPI and SPEI were consistently small across all temporal scales, indicating that evapotranspiration does not play a crucial role in the severity of drought episodes. These findings contribute to a historical understanding of drought in Austria and will be extended to future periods under different socioeconomic and climate scenarios.

The rapid growth of the global urban population in recent years emphasises the need to understand urban environments in order to build sustainable, resilient cities and enhance residents' quality of life. Despite its significance, the urban microclimate remains one of the most complex and least understood phenomena, largely due to the heterogeneity of urban environments. The physical structure of cities alters the exchange of momentum, energy, and pollutants between the surface and the atmosphere, creating an urban surface layer where classical turbulence laws no longer apply.

This study uses LES (PALM-4U) simulations to analyse key micrometeorological parameters with high spatio-temporal resolution in the Bolognina district of Bologna. The area is a typical example of Italian urbanisation. PALM-4U is coupled with the GLOBO-BOLAM-MOLOCH system. The MOLOCH model, developed specifically for Italy, provides more accurate mesoscale predictions than models like COSMO and WRF, which is crucial for LES simulations. Data from remote sensing, municipal datasets, and a census of over 5,000 trees within a 1 km² area were used as static drivers for the Bolognina study.

The case study spans three days, from 23 to 25 August 2023, characterized by clear skies, intense daytime solar radiation, and light winds—optimal conditions for turbulent flow detachment from the surface and the development of the UHI effect.

The study aims to investigate i) the role played by the type of pavement and urban vegetation in mitigating or amplifying the UHI effect and influencing thermal comfort; ii) how different pavements and vegetation affect the micrometeorological processes in the roughness sublayer (RSL), thereby influencing the flow in the inertial sublayer (ISL); and iii) the intensity of the coupling between the RSL and ISL and how it modifies the closure of the energy balance in the urban boundary layer.

Powerful volcanic eruptions are among the most significant natural factors global affecting Earth's climate system, capable of causing substantial changes in temperature, atmospheric circulation, and air chemical composition.

This study presents a powerful volcanic eruption (similar to the Tambora eruption in 1815) impact on the climate system under various background conditions. We performed a series of experiments with the chemistry–climate model SOCOL-MPIOM for three time periods: present conditions and two future climate scenarios: SSP3-70 and SSP2-45. The experimental design is based on quasi-random sampling methodology, allowing the optimal exploration of key model parameter space with minimal numerical experiments.

The climatic effect of a powerful volcanic eruption intensifies in the warmer climate of the late 21st century, manifesting in a deeper temperature drop (up to 2.5-3K for SSP2-45) and a longer recovery period, compared to the present period (1-1.5K).

Unlike the temperature response, the ozone layer reaction demonstrates a complex spatial structure with pronounced latitudinal asymmetry: a decrease in ozone content at high latitudes (up to -8 DU) and an increase in tropical latitudes (+4-6 DU). This effect is associated with changes in circulation and the photochemical processes of ozone formation.

The most intense analog of the historical 'year without summer' is observed in the SSP2-45 scenario, which may be related to higher concentrations of methane and NOx in this scenario, affecting photochemical processes in the atmosphere and enhancing the radiative effect of volcanic aerosols.

The recovery timescales of the ozone layer (5-7 years) exceed the period of temperature relaxation (3-4 years), indicating the long-term impact of volcanic forcing on the chemical composition of the atmosphere and highlighting the importance of considering chemical feedback when assessing the climatic consequences of powerful volcanic eruptions. This work was supported by Saint Petersburg State University under research grant 116234986.