IntroductionDhaka, the capital of Bangladesh, where more than 12 million people live within 400 km 2 is one of the most densely populated cities in the world and facing a high level of air pollution. High influx of people from rural areas, emissions from various kinds of diesel vehicles and badly maintained automobiles, biomass/coal burning for cooking and in the brick kilns, huge number of construction works, re-suspended road dust etc. are making Dhaka as one of the most polluted cities in the world. According to a recent World Bank Report, it has been estimated that every year in the Dhaka City around 10,800 premature deaths along with several million cases of illness are being caused by the air pollution. The economic cost of this sickness and deaths is estimated to be $132 -$583 million per year for Dhaka (Brandon C., 1997).This high level of air pollution and its economic cost demands a comprehensive air quality management plan to improve the air quality of Dhaka City. The urban air quality management plan usually consists of four important components and these are: (i) air quality monitoring, (ii) emission inventories, (iii) air quality modeling, and (iv) control strategy development. An effective air quality management for any urban area can only be achieved through a comprehensive approach built upon these key areas.In Dhaka City, the Air Quality Management Project (AQMP), Department of Environment is carrying out air quality monitoring program at the Continuous Air Monitoring Station (CAMS) in the national parliament house premises since 2002. Moreover, AQMP is also conducting Satellite Air Monitoring Station (SAMS) at four different places in the city. Concentration of PM 10 (particles, which are less than 10 micrometers in diameter) and PM 2.5 (particles, which are less than 2.5 micrometers in diameter) are measured at all of these stations. Monitoring results of PM 10 and PM 2.5 at these stations are available now. Several studies have shown that both the particle size has the significant negative impact on human health (Dockery et. al., 1993, Dockery et. al., 1989. The monitoring activities and results of these harmful particulate matter along with other gaseous pollutant should be disseminate to the general public as well as policy makers to identify the areas where the ambient air quality standards are being violated and plans are needed to reduce pollutant concentration levels to be in attainment with the standards.Motorized transports are suspected to be the single largest contributor of air pollution in Dhaka, with annual vehicular growth rate of about 7 to 10% in last ten years. The phase-

The ambient air quality data for particulate matter as well as criteria of gaseous pollutants were collected during December 2006 to December 2008 at the Continuous Air Quality Monitoring Station (CAMS) located at TV center, Pahartoli, Chittagong. It was observed that during April-October, 24 hour average concentration of PM 10 and PM 2.5 were within the National Ambient Air Quality Standard (NAAQS) level but it increased occasionally by more than two and a half times during the whole non-monsoon period (November-March