Study on the air pollution control system for Dhaka, Bangladesh

An Eulerian 3-dimensional transport/chemistry/deposition model was applied to simulate the dispersion, chemical transformation and deposition of air pollutants, and to formulate an effective air quality control strategy for Dhaka, Bangladesh. The model predicted the observed concentrations well. Simulation based on a projected emission scenario in 2010 was performed which suggests that SO(2 )concentration at all places of central Dhaka will largely exceed 40 ppb in 2010 if no emission abatement measure is taken. A series of control strategy simulations was conducted to find out: an appropriate method to reduce pollutant concentrations. Only abatement of traffic emissions by 50% would reduce SO2 concentration in 2010 to just below the air quality standard in the city center of Dhaka. The control scenario simulations also involved reduction of sulfur content (to 0.5%) in diesel fuel for traffic vehicles, and changing fuel type from diesel oil to gasoline and natural gas for vehicles which suggests that any one is sufficient to meet air quality standard for SO2 in downtown Dhaka by 2010, but natural gas technology is most efficient. The NO2 concentration in the city center would be about to exceed and would be well below the standard value in 2010 if the diesel fuel used in motor vehicles is replaced by gasoline and natural gas respectively. The simulation results suggest that industrial emissions have to be cut by 50%, together with substituting natural gas for current diesel fuel for vehicles if the air quality standard of SO(2 )is to be satisfied in the highly polluted south-east industrial area of Dhaka.