Analysis of air pollutants in Kagithane valley and Istanbul Metropolitan Area

Air pollution in mega cities becomes an important environmental problem. The purpose of this study is to investigate the variability of air pollutants of megacity Istanbul both in space and time for the period of 2010–2013. Monthly and hourly averages of PM₁₀, SO₂, NO_X, and CO monitored by 11 stations were analyzed. Cluster analyses were performed for each pollutant to quantify similarities or dissimilarities of air quality monitoring stations (AQS) within the city. The details of Kagithane AQS which has unfavorable conditions for air pollution were also examined. Meteorological data (temperature, wind speed, and wind direction) of Kagithane AQS were assessed to determine potential source locations and to examine the seasonal variation. Kagithane AQS was found to have the highest PM₁₀, SO₂, and CO values in hourly and monthly analyses while Besiktas and Aksaray AQS were evaluated to have the highest NO_X values. Cluster analyses for PM₁₀, CO, and SO₂ showed that Kagithane AQS falls into a detached cluster. Besiktas and Kagithane AQS, together, split up from other stations for NO_X clustering. PM₁₀, SO₂, NO_X, and CO measurements of Kagithane AQS showed seasonality. PM₁₀ was at lower bound in winter and fall while it was highest in spring in Kagithane AQS. Besides, averages of SO₂ and NO_X in winter were higher than in summer measurements. Average CO concentration showed the highest value in winter compared to other seasons. In detailed analysis for Kagithane AQS, PM₁₀ values increased when the wind direction was north (N). Higher SO₂ values were found when the wind direction was southerly, where the Bayrampasa Industrial Zone is located. NO_X and CO values indicated that higher concentrations are monitored when the wind direction is northerly. Potential sources for NO_X and CO could be evaluated as the Transit European Motorway (TEM) and Hasdal-Okmeydani junction which is located at north of Kagithane.