Air pollution and inversion features in Istanbul

Air pollution in the Istanbul metropolitan area arises from three significant sources: industrial and residential fossil fuels and road traffic. In winter this combination pushes air pollution to levels that are dangerous to humans and to plant life. As far as fossil fuels are concerned, total suspended particulates (TSP) and sulfur dioxide are the chief pollutants. In order to investigate the problem, five-year winter-season monthly pollution concentration records are used, starting from 1989. Classical statistical methods, such as frequency distribution functions, are examined and found to have exponential (SO2), logarithmic normal (TSP) and Weibull (inversion height) distributions. A simple concept of 'pollutant polygon' is presented in order to make detailed interpretations of the relationship between the monthly averages of SO2 and TSP. These levels were affected by the weak dispersion conditions in the lower atmosphere over the city.