In Dhaka city the daily total emissions of NOx, HC, CO, PM, and SOx are estimated whish is equivalent to: 42, 39, 314, 14, and 42 tons/day, respectively. Daily average concentration of NOx (NO2, NO) were measured at 28 street locations in Dhaka city during November, 1996.
Carbon monoxide (CO), hydrocarbons (HC), photochemical oxidants e.g., ozone (O3), nitrogen oxides (NOx), particulate matter (PM), and lead (Pb) are the pollutant species. In spite of great improvements in most developed countries due to reduced use of leaded fuels, highway emissions of lead remain a persistent air quality problem. Recent studies indicate that motor vehicles are also a major or primary source of other toxic air pollutants including 1.3-butadiene, benzene and a number of carcinogens, associated with particulate matter.
As the vehicle fleet continues to grow, motor vehicle emissions and the products of their transformation in the atmosphere, random acceleration-deceleration due to non-motorized vehicles in developing countries, are becoming increasingly important contributors to nearly every major air pollution problem facing the world today. In urban areas, where more than 70% of the population live, levels of motor-vehicle related pollutants frequently exceed internationally agreed air quality guidelines.
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