Status of Air Quality with Potential Linkage to the Metrological Conditions in Three Major Cities of Pakistan

Environmental pollution being fatal for all living organisms is growing adversely due to excessive industrialization and urbanization. Vehicular emissions have aggravated the situation and pose detrimental effects on human health. In this study, the trend of ambient air quality was analyzed in the three metropolitan cities of Pakistan, including Karachi, Lahore and Islamabad for a period of three years (2008-2010). Air pollutants, such as NO, NO_x, NO₂ and PM_2.5 were recorded usingmobile air quality monitoring stations in the target areas. Results from statistical analysis revealed PM_2.5 with highest levels in all the cities, albeit exceeded the World Health Organization (WHO) guideline limits. Spearman correlation revealed that the levels of air pollutants were negatively correlated with the temperature and rainfall, whereas positively correlated with the wind speed. Annual and seasonal variations in the concentrations of the air pollutants was also observed and the highest concentration was recorded in Karachi during the winter season that could be attributed to inversion phenomenon. In addition, the elevated vehicular emissions were observed in Lahore, implied comparatively high air pollution loads, comparison to those of Karachi and Islamabad. The widespread use of low-quality fuel, coupled with a dramatic expansion in the number of vehicles has led to significant air pollution problems, especially in Lahore and Karachi. Therefore, the efficient mass transit system and urban forests should be introduced to abate the ever-increasing levels of organic pollutants and improve the state of ambient air quality in the major cities of Pakistan.