Betterment of neighborhood air quality in megacities : planning and policy implications for socio-economic and built environments in Dhaka

Abstract

This study explores the complex association between air quality and the built environment in Dhaka, a typical megacity grappling with the issues of rapid urbanization and environmental degradation. This research primarily examines the influence of several components of the built environment at the neighborhood level, such as land use types and building heights, on air quality, with a particular focus on PM2.5 levels. It also analyses the connections between air quality and socioeconomic profiles, providing valuable insights into how geographical and demographic factors contribute to environmental issues. The findings reveal significant associations between increased concentrations of PM2.5 and areas that include industrial facilities, transit hubs, and tall buildings, particularly near major roads with substantial automotive exhaust emissions. Conversely, areas designated for agriculture or left in their natural state exhibit lower concentrations of PM2.5, underscoring the significance of green and unoccupied areas in mitigating air pollution. The research highlights the morning increase in PM2.5 levels in densely populated areas with high-rise buildings, linking this occurrence to limited natural ventilation and increased energy consumption. At the neighborhood level, this emphasises the immediate requirement for integrated land use planning and targeted policy measures to address air quality problems. The dissertation suggests the adoption of zoning restrictions that limit the coexistence of industrial and high-density residential zones, the encouragement of mid-rise construction projects, and the enhancement of urban green spaces as strategies to improve air quality. Ultimately, this work contributes to the broader discourse on the effective management of air quality in urban regions of developing countries. It accomplishes this by providing reliable information and offering practical suggestions that can be utilized to influence policy and direct future scholarly research. These observations are crucial for establishing sustainable and equitable urban environments that safeguard public health while facilitating the rapid growth of megacities like Dhaka.