Homer T. Mantis

Assessment of the potential for photochemical air pollution in Athens - A comparison of emissions and air-pollutant levels in Athens with those in Los Angeles

Abstract The average areal density of pollutant emissions in Athens is estimated to be two to six times greater than in the Los Angeles basin. Concentration levels of the primary air pollutants, CO and SO2, are several times larger in Athens than in Los Angeles. Concentrations of the photochemical pollutants, NO2 and O3, however, are greater at Los Angeles stations inland 20 or more kilometers from the coast. The relatively lower levels of photochemical pollution in Athens are partially explained by differences in the summer atmospheric-circulation systems and the scale of the basins. Also, the concentration of NO in central Athens is so great as to inhibit the formation of O3.

Case study of UV-B modification during episodes of urban air pollution

Examination of the record of solar ultraviolet measurements made during the MEDCAPHOT study of air pollution in the Athens basin revealed a substantial reduction of UV-B on days with high levels of pollution. The magnitude of this relation is illustrated by a comparison of the UV on two days of a pollution episode with that on two days of low pollution.

Solar ultraviolet absorption by sulphur dioxide in Thessaloniki, Greece

Abstract This work presents the climatology of the sulphur dioxide column over Thessaloniki derived from three years of observation with the Brewer spectrophotometer. The SO2 column averages 2.5 m atm‐cm and the shielding of UV‐B by SO2 is investigated and compared with the changes in shielding resulting from an anticipated ozone reduction. Columnar and surface SO2 concentrations over Thessaloniki appear to be typical of those in major industrial‐urban regions of the world. It is concluded that, for urban regions, predictions of changes in UV‐B as a result of mans activities must consider projections of changes in the SO2 column as well as ozone.

A 5‐year climatology of the solar erythemal ultraviolet in Athens, Greece

Observations of solar ultraviolet (UV) irradiance in Athens for the period 1993-1997 employing the Yankee Environmental Systems (YES) pyranometer (model UVB-1) are analysed to provide a climatological description of the erythemally active UV component in this urban Mediterranean environment. The role of cloud cover and the ozone column in the determination of the UV climate are estimated by a comparison of the record of UV irradiance with daily observations of total ozone at the University of Athens and of total solar radiation at the National Observatory of Athens. During the warmer months, June to September, there appears to be a substantial reduction of solar UV by atmospheric components other than ozone and clouds, a conclusion that is supported by comparing the observations with the predictions of radiative transfer models and with UV observations in a rural southern hemisphere environment reported by McKenzie et al. (1991).