Comparative Assessment of Ambient Air Quality of Major Cities of Pakistan

The deterioration of ambient air quality is one of the emerging environmental problems in developing countries of South Asia. Unplanned urbanization, population growth, degradation of vegetation cover and industrial and vehicular emissions, particularly in urban areas, have resulted in substantial rise in the level of air pollutants and emission sources. This study focused on monitoring of different cities as per traffic volume and flow. Air quality monitoring was conducted on hourly basis to determine the major parameters; i.e. PM10, NOx, SO2, CO by using fixed station for 8 h from 1:30 pm to 9:30 pm. All the measuring values were then compared with the National Environment Quality Standards (NEQS) and Air Quality Index (AQI). Results revealed that the concentration of PM10 at the selected areas of these cities ranged from 156 to 390 mu g/m(3), CO ranged from 1.18 to 6.01 mg/m(3), and NOx ranged from 32.65 to 129.47 mu g/m(3). It was evident that all these concentration had been higher than the permissible limits of NEQS, whereas only SO2 was found within the permissible limits (15.60-110.52 mu g/m(3)). Air Quality Index (AQI) of all the designated points of cities was also assessed, and most of the vehicular and commercial areas had shown unhealthy and severe conditions ranging from 191 to 320, respectively.