Assessing the potential impacts of LULC change on urban air quality in Dhaka city

Abstract

Dhaka is among the top five metropolises with the most particulate pollution and polluted air alone, responsible for 17.6% of the risk of mortality and disability. As a result of recent global episodes of urban air pollution, policymakers and administration agencies are endeavoring to regulate urban land use and land cover change (LULC) and sustainably enhance air quality. This study aims to establish a relationship between alterations in PM2.5 concentration and LULC features. The Bangladesh Meteorological Department provided PM2.5 and meteorological data for 2012 and 2018, and RapidEye image data was used to classify land-use for 2012 and 2018. Between 2012 and 2018, waterbodies and vegetation fell by 2% and 5.3%, and construction and bare land increased by 4% and 3.4%, respectively. Reduced vegetation and waterbodies might result in an increase in barren land and built-up areas. Numerous industrial sites and the unlawful acquisition of canals may also contribute to the growth of barren land. In 2018, homogeneity of the landscape pattern is higher than 2011. The aggregation and contagion indices, landscape metrices, have inverse correlation of −0.01 and −0.158 respectively with PM2.5 concentrations. However, the landscape index has positive correlation of 0.06 with PM2.5 concentrations. On the other hand, the variability in PM2.5 concentrations is correlated with the altered characteristics of LULCs and related landscape indicators. According to the spatial correlation, PM2.5 levels have decreased as vegetation and waterbodies have increased, as the PM2.5 concentration is negatively correlated with vegetation and waterbodies by −0.212 and −0.028, respectively. Furthermore, meteorological indices are significantly correlated with PM2.5 concentration, which was used as an independent variable to estimate the annual average PM2.5 concentration levels for 2024 using an Artificial Neural Network, which range from 312 to 188 μg/m3. The government should take appropriate measures to curb polluting air emissions, ensuring a livable city in the future.