ON THE IMPORTANCE OF BIOGENIC EMISSIONS IN AIR POLLUTION IN THE GREATER ATHENS AREA: THE EPISODE OF JUNE 22 25, 2003

摘要

The photochemical pollution that is present in almost all urban areas, especially during the summer, has adverse health effects. In order to prevent its appearance, timely prediction of high concentrations of pollutants by well-evaluated photochemical models, is necessary so that precautionary measures - massive or individual - can be imposed. There are several modeling systems for transport and transformation of pollutants. In this work the Comprehensive Air quality Model with extensions (CAMx) and UAM-AERO (Urban Airshed Model with Aerosol) have been used to examine the causes of air pollution in the Greater Athens Area. These models have been used to simulate atmospheric processes during the episode of June 22 to 25, 2003. The estimated concentrations of O_3, and NO_2 were compared with measured values, in order to evaluate the performance of the models. Comparison of the results reveals that CAMx simulated the ozone diurnal pattern better than UAM, as the predicted by (JAM maximum daytime concentrations were much higher than those of CAMx and way above the measured ones. CAMx also shows signs of superiority in terms of its ability to predict the NO_2 concentrations. Its predictions are much closer to the observations for all stations, which may indicate that CAMx has not the reported weakness UAM had in predicting NO_2 concentrations. Finally, the simulations show that a fraction of the observed ozone concentrations in the suburbs is caused by the interaction of biogenic VOCs and NOx. This 'biogenic' ozone dominates in the agricultural regimes of the Greater Athens Area.Keywords: Biogenic emissions; Ozone; Nitrogen dioxide; VOCs, Modeling, CAMx, UAM