Determination of transport processes of nocturnal ozone in Istanbul atmosphere

Ozone, usually having a minimum value at night, often increase its concentration level which is known as nocturnal ozone. in this study, the magnitude, frequency and timing of nocturnal ozone maxima were determined between May and September for four years (2001-2004) for stations in the Asian and European sides of Istanbul, Turkey. The magnitude and frequency of late and early peaks for peak ozone nights were monitored. A total of 40 days, having secondary ozone maxima due to horizontal transport processes, have been selected, and HYSPLIT model with back trajectory analysis was conducted at different ground levels.