Volume 15 [2013]

The scope of the present work was to examine exposure to airborne particulate matter (PM) at a marble cutting and treatment facility. Measurements were conducted inside all sections of the facility, as well as at selected outdoor locations. PM10 concentrations were monitored continuously, with a 1-min time resolution, by the use of DustTrak (Model 8520, TSI, Inc.).

Mean PM10 concentration levels during cutting operations were measured equal to 997 μg m-3, when all machines were in use and 710 μg m-3, when only half of the machines were functioning. Higher levels were measured at the artistic department, where marble is cut and processed manually (mean PM10 concentration equal to 3,860 during a heavy cutting procedure and 1,000 μg m-3during a light duty period). When sampling was conducted next to the workers during the cutting process, mean personal exposure reached up to 63,000 μg m-3. The use of water during cutting operation was found to effectively decrease PM emissions. Significant concentrations were also measured at the different administrative offices. The highest levels (mean concentration equal to 220 μg m-3) were measured at the accounting office which is located at ground level, in close vicinity to the cutting section.

The aim of this study, which took place in a dental environment located at the centre of Athens, Greece, is to quantify the amount of Total Volatile Compounds (TVOCs), which were emitted from commonly used dental substances in a controlled dental micro-environment (8 surface disinfectants including both sprays and tissues, 8 bonding agents and 4 acrylic substances). TVOCs concentrations were monitored at three distances from the source (right above the source, 50cm and 100 cm distance from the source) for a period of minutes using a ppbRAE monitor. The environmental factors were complementary assessed using a prototype experimental setup consisted of a sonic anemometer and a hygrometer right above the source. Ventilation rates were estimated via CO2 concentrations.

High TVOCs concentrations were found to be emitted from three out of the four acrylic substances, with average values as high as 42.000 ppb. Concentrations were substantially reduced away from the source (average values below 500 ppb for all substances). For disinfectants, above the source the concentrations ranged between 30.430 ppb and 10 ppb with an average value of 5.393 ppb. Significant differences were observed between TVOCs emitted from sprays which in general, were substantially higher than TVOCs emitted from wipes (average TVOCs conc. from sprays 8.327 ppb, while the respective value for tissues is 496 ppb).
An effort was made to assess the dependence of the measured TVOCs concentrations on environmental factors such as wind speed and ventilation rates. It was found that the influence of environmental factors is not traceable, indicating the importance of emission patterns.

The complex terrain basin of Amyntaio – Ptolemais – Kozani in Western Macedonia of Greece is an area characterized by increased industrial activity and therefore it demands continuous and assiduous environmental monitoring. A prolonged particulate matter air pollution episode was recorded in the area during November 2009. Basic meteorological aspects are analyzed, during the episode period. Daily and hourly PM10 and PM2.5 concentration measurements were used along with surface and lower atmosphere hourly meteorological parameters from 13 measuring stations. The observational data were supported by data produced by the meteorological component of an air pollution model.

The overall analysis showed that the episode was primarily the result of the synoptic setting of the middle and lower troposphere. An Omega blocking pattern which gradually transformed to a high-over-low pattern prevailed over central and southern Europe during the episode’s period. The examination of the vertical wind field in the lower troposphere and appropriate stability indices, revealed a continuous absence of significant convection. The weak horizontal wind field near the surface and the reduced mixing height combined with the lack of synoptic forcing resulted in the trapping of the pollutants in the lower troposphere and the recording of increased airborne particulate matter concentrations. The radical change of the synoptic setting in the first days of December marked the end of the episode.

The influence of microscale and mesoscale meteorology on the local scale variation of air temperature cannot be correctly simulated by the coarse resolution Global Climate Models. The scope of this work is to develop a hybrid dynamic-statistical downscaling procedure and quantify its predictive ability to estimate air temperature variability at finer spatial scales. The study focuses on the warm period of the year (June – August) and the method is applied to eight sites located in Greece with different topographical characteristics. The two-step methodology initially involves the dynamic downscaling of coarse resolution climate data via the RegCM4 regional climate model and subsequently the statistical downscaling of the modeled outputs by training site-specific artificial neural networks (ANN). The RegCM4 model is employed to enhance the representativity of the dataset, while the ANNs are used as function approximators to model the relationship between a number of atmospheric predictor variables and the observed air temperature time series. An insight of the ANN transfer function is obtained by examining the relative contribution of each input variable. The performance of the methodology is evaluated and the results indicate significant improvement from the inclusion of the ANN models in downscaling air temperature.