Transport and distribution of air pollutants in Athens (Greece): aircraft measurements during MEDCAPHOT - TRACE

摘要

A series of flights was conducted within the MEDCAPHOT - TRACE project between 06 and 15 September, 1994. The goals were to help understand the distribution, transport, and chemical reaction rates of pollutant gases emitted in the large urban agglomeration of the city of Athens. The flight routes covered the Greater Athens Area (about 60 x 60 km), including the inner basin, with low level (50 - 150 m above water or ground) flight legs. Additionally, vertical profiles were flown southwest and northeast of the city in order to characterize the physical and chemical structure of the boundary layer upwind and downwind of the city. In some cases, a relatively strong northeasterly synoptic flow guaranteed good ventilation in most parts of the Athens basin and thus made an intense build-up of pollution impossible. In other cases, when a strong sea breeze developed during the day, the near-surface flow direction was into the basin from all sides. Therefore, pollutants could escape the basin only vertically, and high concentrations of primary and secondary pollutants built up in layers which were located NE of the city in altitudes of several 100's of meters. From these layers, pollutants were probably incorporated into long range transport towards S.