Air quality in Belgrade during 2025: Seasonal dynamics, meteorological conditions, and the potential of urban forests and greenery in mitigating air pollution

Changes of Urban and Suburban Air Quality Patterns during the Pandemic Year 2020: Longitudinal Evidence from Three Romanian Citie

Urban areas must develop and implement air pollution-reduction strategies in order to comply with progressively stricter air quality standards. Various measures imposed during the lockdowns associated to COVID-19 pandemic worldwide made the year 2020 an exceptional period for global air pollution: air pollutant emission patterns were significantly and differently altered. Atmospheric pollutant levels varied from the lowest to the highest values. Within this context, present study aim is to emphasize comparatively the changes in major air pollutants’ concentrations PM10, PM2.5, NO, NO2, NOx, CO, SO2, O3 in three important urban centers (Bucharest, Brașov, Iași) in Romania during 2020. The contrast in mass concentrations of major air pollutants in the urban and the suburban areas of above cities has been studied using longitudinal analysis, probability density functions and change point analysis. The study outcomes extend the knowledge about air pollution at local/regional scale and are of help in designing air pollution control strategies.

Investigating the pollution and air quality situation in Kabul city: Focusing on the concentration of major pollutants and the air quality index

Concentration of different pollutants such as O₃ , NO₂ , SO₂ , CO, PM₁₀ , and PM2.5 in the atmosphere is called air pollution, which created several challenges in the environment and is considered one of the dangerous phenomenal in the current world, in Afghanistan urbanization in last two decades had significant impact on air quality. There is different source of air pollution in urban areas such as industries, more population, transportation system, less vegetation covers and etc. The main goal of this of this research is to analyze the pollutant levels from 2021 to 2024 in Kabul city by analyzing of six major pollutants including O₃ , NO₂ , SO₂ , CO, PM₁₀ , and PM2.5 and comparing them with national standard and by using the AQI to analyses the air quality. This is a quantitative research; data has been collected from National Environmental protection Agency air quality station based in Darulaman area of Kabul city. Significant annual and seasonal variations in pollutant concentrations were found by the results. O₃ concentrations exceeded the national norm during the winter months, ranging from 14 µg/m³ (June 2023) to 181 µg/m³ (December 2022). Particularly in late 2024, NO₂ and SO₂ exhibited significant peaks, with NO₂ reaching 258 µg/m³ and SO₂ reaching 150 µg/m³, both of which exceeded allowable limits. With maximum readings of 221 µg/m³ and 157 µg/m³, respectively, PM₁ 0 and PM₂ .5 were continuously over national norms for a number of months. According to the analysis of the Air Quality Index (AQI), PM₂ . ₅ was the main pollutant affecting the general quality of the air. The AQI rating was at its lowest (79) in September 2022 (Moderate) and at its worst (207) in January 2021 (Very Unhealthy). Seasonal trends revealed that while air quality improved somewhat during some summer months, especially in 2022, it deteriorated during the winter months of November through January. Overall, the results show a trend toward worsening air quality in 2023 and 2024, particularly as a result of particle matter pollution.

Interplay Between Meteorology and Seasonality in Urban Air Pollution Across Selected Cities in East, South, and Southeast Asia: A Comparative Review

Air pollution is a growing environmental issue in rapidly urbanizing Asian cities, where meteorological conditions and seasonal variability strongly influence pollutant concentrations. This review synthesizes published evidence on the interactions between meteorology, seasonality, and urban air pollution across selected cities in East Asia, South Asia, and Southeast Asia. The literature was collected from major scientific databases and organized according to meteorological drivers, seasonal characteristics, and dominant emission sources. Particular emphasis was placed on particulate matter (PM2.5 and PM10), SO2, NO2, NOx, CO, and O3. The reviewed studies indicate that wind speed and direction, precipitation, temperature, atmospheric stability, and monsoon circulation strongly influence pollutant transport, dispersion, and removal. Pollutant concentrations generally reach their highest in winter due to stagnant conditions and higher human emissions. In contrast, the summer and monsoon seasons tend to have lower PM levels due to better atmospheric mixing and wet deposition. Regional differences in dominant sources were also observed, including coal combustion and heating in East Asia, traffic and biomass burning in South Asia, and biomass burning and transboundary transport in Southeast Asia. These findings highlight the importance of seasonally adaptive and region-specific air quality management strategies in Asian cities.

Air pollution risks to wheat and mustard in Delhi agricultural airshed during the winter cropping season (2022–2025)

Assessing the spatiotemporal characteristics of urban air pollution in Ado-Ekiti and its environs, southwest Nigeria

Air pollution poses significant environmental and public health challenges in rapidly urbanising regions of sub-Saharan Africa, where ground-based monitoring infrastructure remains limited. This study examined the spatiotemporal distribution of key air pollutants in Ado-Ekiti and its environs, Nigeria, from 2019 to 2024. Columnar concentrations of carbon monoxide (CO) and formaldehyde (HCHO) were retrieved from Sentinel-5P, while MODIS aerosol optical depth data was used to estimate particulate matter (PM2.5 and PM10). Meteorological variables (rainfall, wind speed, and wind direction components u and v) were derived from the Weather Research and Forecasting model, and one week of ground-based measurements of pollutants were collected to enable correlation analysis with satellite-derived estimates. All datasets were aggregated to monthly and annual timescales, resampled to a 1 km spatial resolution and re-projected to UTM Zone 31 N. Results indicated that particulate matter dominated the pollutant profile, with annual mean concentrations of 59.37–65.29 µg/m³ for PM2.5 and 89.35–99.51 µg/m³ for PM10, exceeding WHO guideline limits. Peak concentrations occurred during the Harmattan season, with PM₂.₅ > 100 µg/m³ and PM₁₀ > 200 µg/m³, driven primarily by Saharan dust transport and local activities. Mann-Kendall trend analysis revealed significant increasing trends in HCHO, PM2.5, and PM10, whereas CO showed no significant trend. Satellite-derived particulate estimates showed positive but weak correlations with ground-based particulate concentrations (r < 0.20), whereas rainfall significantly reduced particulate levels, and meridional winds (v) facilitated long-range PM₁₀ transport. This study provides a significant integrated satellite model for air quality assessment in data-scarce urban environments while providing evidence to support targeted emission control strategies.

Geochemical Assessment of the Air Quality Index for Urban Areas (Case Study of Ben-ghazi, Al Byada, Zliten and Tripoli Cities).

One of the biggest environmental issues in cities is air pollution. Over 80% of urban dwellers are thought to be exposed to air pollution levels above the World Health Organization's (WHO) recommended limits. This work aims to compare the air quality index (AQI) with the WHO 2014 guideline during 2024 and to determine the sources of air pollution in the study areas, as well as to compare carbon dioxide (CO2) emissions in Libya with global emissions. The AirVisual Outdoor monitors were used in this work to measure AQI, PM2.5 PM10 and CO2, The finding revealed the AQI in Benghazi city during the February period was unhealthy for sensitive groups (level 3) and in April period was unhealthy (level 4), in Al Byada city was moderate throughout all periods (level 2), the air quality in  Zliten city from January to May period was unhealthy for sensitive groups (level 3) and in the air quality in Tripoli city during February period was unhealthy for sensitive groups (level 3).  Zliten city is considered the most polluted city due to the lack of infrastructure and afforestation in the city. Based on PM2.5/PM10 ratios, the natural source and coarse particles of pollution were more prevalent in the studied areas. The concentration of CO2 in Libya was approximately 441 ppm, while the global average reached about 444 ppm, indicating that the distribution of CO2 in the atmosphere is nearly uniform worldwide.