Volume 15 - 2013

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 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 impacts of wind conditions to fine and coarse particle mass concentrations at four European urban centers, by multivariate regression analysis of particle measurements against categorized wind (direction and speed) conditions were estimated. Statistically significant associations (both positive and negative) were observed for all urban areas. Both fine and coarse particle mass concentrations were decreased for moderate and strong winds (speed > 2.2 m s-1) in Athens and Helsinki. Weak winds had a positive influence on particle mass, accounting for up to 40% of fine particles in Athens. For the three coastal urban areas (Amsterdam, Athens and Helsinki), positive correlations were observed for sectors encompassing ports and areas with intense marine traffic. For Birmingham, the association of both particle fractions with the eastern sector indicated the influence of emissions from central UK and continental Europe. The method described here may be used to screen the orientation of sources near receptor sites.

The Attica Peninsula has experienced the rapid expansion of the Athens urban area, prior to the Athens 2004 Olympics. As a result, the distribution of pollutant sources and emission patterns has changed with a subsequent effect on the distribution of photochemical pollutants and aerosols. The purpose of the present work is to perform a comparative study of the land use changes in the rapidly developing Attica Peninsula including the Greater Athens Area (GAA) before and after 2004, the year that the Olympic Games took place, as well as of the effect of these changes on the respective pollutant distribution profiles. The land use data were provided by USGS Global Land Use/Land Cover version 2.0 Database and the updating process was fulfilled with the help of a satellite image. The area was divided into cells using a spatial resolution of 5x5 km2. Results showed that the urban grid has expanded considerably the past fifteen years while a great shift of population has been made to the eastern area of Attica. Also, new towns were created while others expanded and many factories moved out of the center of the city of Athens. Moreover, the forest land has decreased considerably in the Attica Peninsula either by continuous and extended fires or by the residential burst. The Comprehensive Air Quality Model with extensions (CAMx) was used in order to estimate O3 distribution during a recorded pollution episode. Results revealed that land use changes affected slightly the O3 concentrations and the development of a new emission inventory related to the new LULC field is necessary.