Spatial Distribution of Air Quality in Narayanganj District Town, Bangladesh

Globally air pollution is a major concern as it poses serious health risks, damages the environment, contributes to climate change, and incurs substantial economic costs. The objective of this study is to monitor the Particulate Matters (PM<sub>1</sub>, PM<sub>2.5</sub>, and PM<sub>10</sub>) and Carbon Monoxide (CO) concentration based on different land use in Narayanganj District town. This study was conducted in seven land uses, 60 locations of Narayanganj District, a district of Dhaka Division; by using portable Air Quality Monitor, Indoor Outdoor Formaldehyde (HCHO) Detector (Model: DM106) and CO Meter (Model: AS8700A). Descriptive statistics and whisker box plots were also employed to analyze and visualize the variations in pollutant concentrations across different locations. Additionally, a dendrogram plot was created to classify and interpret data clusters, providing a deeper understanding of the spatial distribution of pollutants. Results indicated that the average concentration of PM<sub>2.5</sub> of different land-use were found 3.37 times higher than the Bangladesh National Ambient Air Quality Standard (NAAQS) level. NAAQS set for PM<sub>2.5</sub>, and PM<sub>10</sub> at 65 and 150 µg/m<sup>3</sup>, respectively by Department of Environment (DoE). Consequently, the most polluted location was found in Industrial location with PM<sub>1</sub>, PM<sub>2.5</sub> and PM<sub>10</sub> concentration of 230, 389 and 496 µg/m<sup>3</sup>, respectively. Also, the concentration of CO was 1.3 to 2.3 times higher than NAAQS level which is 9 ppm (8-hour) set By Department of Environment (DoE). Besides, the study estimated that the average PM<sub>2.5</sub>/PM<sub>10</sub> ratio was 77.32%, while the PM<sub>1</sub>/PM<sub>2.5</sub> ratio was 60.85%, which indicated significant presence of finer particles in the air. Therefore, the study underscores the urgent need for enhanced air quality policies and public awareness in Narayanganj District due to critically high levels of air pollution.