Determination of the Variations in Air Quality Due to the Construction of the Atani–Obosi Second Niger Bridge Access Route: Assessment of Aerosol, Nitrogen Dioxide (No₂), Formaldehyde (Hcho), and Carbon Monoxide (Co)

Short-term monitoring of air pollutants at the port-urban exposure zone: a case study of Alexandria Port, Egypt

Comparative analysis of seasonal air quality around an industrial area: A case study using air dispersion modelling and pollution index assessment

Background: Manufacturing activities can release combustion gases and fine particles whose ambient distribution varies with meteorology and source characteristics. Integrating source oriented dispersion modelling with Indonesia’s air pollutant standard index/indeks standar pencemar udara (ISPU) can provide complementary spatial and regulatory interpretations. Methods: This secondary-data case study combined facility monitoring records with archived 24 hour AERMOD outputs for rainy and dry season scenarios in Banten, Indonesia. Carbon monoxide (CO), nitrogen oxides/nitrogen dioxide (NOx/NO2), fine particulate matter (PM2.5), and sulfur dioxide (SO2) were assessed. Model output consistency, units, seasonal differences, and ISPU calculation were independently cross checked. Because complete AERMOD input files, receptor level time series, and co-located monitoring series were unavailable, independent calibration and statistical model observation validation were not performed. Findings: Dry-season maximum concentrations were higher for all modelled pollutants: CO increased from 42.745 to 51.226 µg/m³, NOx from 467.8 to 561 µg/m³, PM₂.₅ from 274 to 329 µg/m³, and SO₂ from 483.9 to 580 µg/m³. The relative increase was approximately 20% for each pollutant. ISPU values were good for CO (39.36), NO₂ (22.64), and SO₂ (36.65), while PM₂.₅ reached 68.68 and was classified as moderate. Conclusion: The combined assessment identifies the dry season as the higher-concentration scenario and PM₂.₅ as the principal ambient-air management priority. Facilities should strengthen dry-season surveillance, fugitive-dust control, filtration maintenance, and combustion-efficiency checks. The results are screening-level and comparative because the study relied on secondary model outputs and one monitoring dataset. Novelty/Originality of this article: The article demonstrates how seasonal AERMOD outputs and pollutant specific ISPU values can be used together to prioritize industrial air quality controls while explicitly distinguishing modelled maxima from measured ambient concentrations.

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.

Low-Cost Sensor-Based Spatial Screening of Urban Air Quality in a Medium-Sized City: A Case Study in Alba-Iulia, Romania

Urban air pollution remains a major public health concern, with road traffic representing one of the dominant sources of particulate matter and volatile organic compounds in growing cities. This study evaluates the level of chemical air pollution in Alba-Iulia municipality (Romania) through two measurement campaigns (May 2025 and October 2025), carried out at 26 and 19 points, respectively, selected based on traffic intensity and population vulnerability criteria (schools, kindergartens, hospitals, and the food market). Measurements targeted PM2.5, PM10, total volatile organic compounds (TVOC) and formaldehyde (HCHO), as well as carbon dioxide (CO2), correlated with road traffic intensity. Statistical analysis revealed significant differences between the two seasons for PM2.5, PM10, and CO2 (p < 0.01), as well as a strong correlation between particulate matter concentrations and vehicle counts (r = 0.60–0.95), consistent with road traffic being an important local contributor to particulate matter, though correlation alone cannot establish source dominance in a strict causal sense. A multiple regression controlling for both traffic and season explained over 73% of the variance in PM2.5 and PM10 and showed that traffic and season each contribute independently to particulate levels. Both mean PM2.5 and PM10 exceeded WHO and EU limit values in both campaigns, and the low-cost sensor over-read absolute concentrations by roughly 2–4× relative to the official monitoring network, so absolute values should be treated as orientative. Despite this bias, the consistent spatial and seasonal patterns show that portable low-cost sensors can reliably rank exposure hotspots and support the targeting of traffic-mitigation measures, such as selective catalytic reduction (SCR) systems, in medium-sized cities that lack dense reference monitoring networks.

Assessment of the Impact of Vehicular Carbon Dioxide Emissions on Climate Change in Zaria Metropolis, Kaduna State, Nigeria

Urban transport is one of the key contributors to greenhouse gas emissions in rapidly developing cities. In Zaria metropolis, three nodes are identified to be hotspots for carbon dioxide (CO2) and other greenhouse gas emissions. They are: Kofar Doka Cloverleaf, PZ Junction, and Flyover at Kwangila. This study assessed CO2 emission levels at the three designated spots. Temperature rise at the spots was attributed to the increased CO2 emission. A multi-user instrument for measuring greenhouse gases Multi-Gas Analyser (Model: Testo 350 Portable Emission Analyser), was used to measure the CO2 levels. The analyser was calibrated before each session to ensure accuracy. Surface temperature conditions from NiMET; standards from NESREA, and the WMO, were compared with the data collected from the field, and correlation and regression analysis were carried out. Findings indicated the concentrations of carbon dioxide above the world average. They are: 455 ppm, 586 ppm, and 620 ppm for Kofar Doka, PZ, and Kwangila, respectively. Findings further revealed a significant correlation between vehicular density and carbon dioxide concentration at (r = 0.81, p < 0.05) and CO₂ concentration, and a moderate correlation (r = 0.67, p < 0.05) between mean temperature and CO₂ levels, revealing significant local warming effects. The study concluded that vehicular emissions highly increase the climate change vulnerability in the transport sector of Zaria Metropolis. The study therefore recommended the provision of efficient public transport systems, emission testing, and urban greening to mitigate impacts.

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.