Study on atmospheric ozone levels in Izmir

The objectives of this study were to measure ozone concentrations in air and investigate ozone formation and degradation mechanisms in urban and suburban atmospheres in the city of Izmir. Ozone concentrations were measured at two urban and suburban sites in Izmir, Turkey. In addition to ozone, nitrogen oxides (NO, NO2, NOx) were also measured continuously at the suburban station. It was observed that O3 concentrations were at the lowest levels during rush hours of 07:00-09:00 based on the hourly results of continuous measurement devices. NO2, resultant of a reaction between traffic based NO and O3, showed high concentration levels during rush hours (morning time 07:00-09:00 and evening time 19:00-21:00). Highest O3 concentration levels were observed between May and August during the sampling period. The highest maximum level of European Union standard (180 µg m-3) was exceeded only during that timeframe. Whereas NO2 concentrations were measured at well below the limit value of 200 µg m-3.Ozone, nitrogen dioxide (NO2), and volatile organic compounds (VOCs) were also measured by diffusive sampling technique at 16 additional sites representing urban, industrial, and suburban areas in the study area of Izmir. As a result of these measurements, concentration changes due to area and time were noted for pollutants within the scope this study. NO2, and VOC concentrations were relatively high at urban sites and industrial areas while ozone concentrations were higher at suburban sites. O3 concentrations were higher at semi-suburban sites compared to other sites. The highest average weekly ozone concentrations were measured at two suburban sites.