Temporal Analysis of AQI and Meteorological Influence on Air Quality In Gazipur

Abstract

This study explores the long-term trends of air quality and their relationship with meteorological conditions in Gazipur, Bangladesh, using data from the Department of Environment (DoE) collected between 2013 and 2024. The analysis focused on six key air pollutants — SO₂, NOₓ, CO, O₃, PM₂.₅, and PM₁₀ — through exceedance evaluation, temporal trend analysis, and correlation with meteorological parameters. Among all pollutants, PM₂.₅ was found to be the most critical, exceeding the WHO 2021 24-hour guideline (15 µg/m³) on about 89.92% of days and the national standard on 81.35% of days. The 12-year average PM₂.₅ concentration was 94.43 µg/m³, with the highest monthly average of 220.88 µg/m³ in January and the lowest of 19 µg/m³ in July, showing strong seasonal variation. The annual average AQI ranged from 176 to 271, which corresponds to “Unhealthy” to “Very Unhealthy” conditions. Meteorological analysis for 2020–2024 revealed that wind speed (r = –0.48) and rainfall (r = –0.42) had the strongest negative relationships with PM₂.₅, while temperature (r = –0.19) and relative humidity (r = –0.27) also contributed moderately. The combined influence of these factors explained about 58% (R² = 0.58) of the variation in PM₂.₅ levels. Seasonal assessment showed that winter had the highest pollution levels due to low wind speed, temperature inversion, and minimal rainfall, whereas monsoon conditions helped to dilute and wash out pollutants. The results highlight Gazipur’s ongoing air quality crisis, mainly driven by rapid industrialization, dense traffic, and unfavorable weather conditions. These findings underline the need for stronger emission control strategies, better urban air management, and the integration of meteorological forecasting in air pollution mitigation plans.