An operational centre for managing major chemical industrial accidents.

The most important characteristic of major chemical accidents, from a societal perspective, is their tendency to produce off-site effects. The extent and severity of the accident may significantly affect the population and the environment of the adjacent areas. Following an accident event, effort should be made to limit such effects. Management decisions should be based on rational and quantitative information based on the site specific circumstances and the possible consequences. To produce such information we have developed an operational centre for managing large-scale industrial accidents. Its architecture involves an integrated framework of geographical information system (GIS) and RDBMS technology systems equipped with interactive communication capabilities. The operational centre was developed for Windows 98 platforms, for the region of Thriasion Pedion of West Attica, where the concentration of industrial activity and storage of toxic chemical is immense within areas of high population density. An appropriate case study is given in order to illuminate the use and necessity of the operational centre.

Urban emissions measured with aircraft.

Detailed knowledge of the quantity and composition of urban emissions is a prerequisite for successful application of atmospheric models to predict transport and distribution of primary and secondary air pollutants in the troposphere. We investigate the prospects and limitations of aircraft measurements in the determination of emission fluxes from urban areas. Our analysis focuses on data collected in September 1994 in and around Athens, Greece. Generally, emission fluxes from cities can be quantified with aircraft and with the minimum acceptable precision (uncertainty better than a factor of 2) only under very favorable meteorological conditions, namely in a homogeneous flow field in a well-mixed boundary layer. Better accuracy can be achieved only through ensemble averaging of repeated measurements. From our measurements in the Athens area, we deduced relative emission ratios of pollutant gases. With the support of ground-based measurements in a street canyon, the emission ratios NOx/CO, SO2/CO, and volatile organic compounds/CO (34 individual VOCs) could be determined with high precision. These results are very useful in analyzing differences between various existing emission inventories. Our data for VOCs reveal that the non-traffic emissions are of the same magnitude as the emissions originating from traffic.

Neural network model for predicting peak photochemical pollutant levels.

In this paper, an attempt is made for the 24-hr prediction of photochemical pollutant levels using a neural network model. For this purpose, a model is developed that relates peak pollutant concentrations to meteorological and emission variables and indexes. The analysis is based on measurements of O3 and NO2 from the city of Athens. The meteorological variables are selected to cover atmospheric processes that determine the fate of the airborne pollutants while special care is taken to ensure the availability of the required input data from routine observations or forecasts. The comparison between model predictions and actual observations shows a good agreement. In addition, a series of sensitivity tests is performed in order to evaluate the sensitivity of the model to the uncertainty in meteorological variables. Model forecasts are generally rather insensitive to small perturbations in most of the input meteorological data, while they are relatively more sensitive in changes in wind speed and direction.

Emissions of air pollutants from the road transport sector in Greece: year to year variation and present situation.

It is common knowledge that atmospheric emissions of various pollutants, from mobile and stationary sources, affect quality of life and public health. The impact of these emissions can be of a small (urban smog) or regional scale (acid deposition, troposheric ozone), as a result of the transportation of pollutants in the atmosphere. In terms of a local scale, road traffic is considered to be the most important pollutants source. In the present work, air pollutants emissions from road transport in Greece will be presented. The reference date for the calculations is the year 2000, but additionally, a year-to-year variation (from 1992 to 2000) of the emissions will be examined in order to clarify the impact of the vehicle fleet and the engine technology changes. To calculate emissions, a methodology developed for the European Commission in the framework of the CORINAIR project has been applied. This methodology was further improved and adjusted to the greek fleet characteristics taking into account the vehicle age, the level of the vehicle maintenance etc. Calculations have shown that, despite during the last years the amount of the emitted pollutants per vehicle has significantly decreased, the total pollutants emitted have increased as a result of the increase the number of circulating vehicles. More specifically, in heavy duty vehicles and passenger cars have the most important role for emitting NOx, whilst motorcycles are the most important polluters for non-methene article organic compounds.

The effect of environmental pollution on the respiratory system of lignite miners: a diachronic study.

BACKGROUND: It is not known whether working in surface lignite mines can cause x-ray lesions or disorders of respiratory function. OBJECTIVES: The aim of the study was to investigate the diachronic impact of environmental pollution on the respiratory system of lignite miners at mines in Eordea, Greece. METHODS: Cases of 199 workers (Group A) residing permanently in the Eordea valley and 151 (Group B) living outside the Eordea valley were studied during Phase I and then re-examined after three years (Phase II). These cases were compared to those of 71 office workers living in Eordea valley (Group C) and to 96 living in Grevena, a region without pollution (Group D). The study included the completion of the MRC questionnaire for the detection of respiratory diseases, pulmonary function tests, measurement of diffusion capacity, otorhinolaryngologic examination, rhinomanonetry as well as chest and paranasal cavity X-rays. RESULTS: Chronic bronchitis was reported by 26.8%, 24.8%, 17.9% and 10.6% respectively of the subjects of groups A, B, C and D according to the answers of the questionnaire (p<0.001). The spirometry and diffusion capacity findings presented no considerable differences either in the 4 groups or between phases I and II of the study. The main problems were detected in the upper airways. A very high prevalence of severe nasal obstruction (73%, 71.2%, 55.7% and 19.3% in Groups A, B, C and D respectively) was detected. Furthermore, a high percentage of atrophic rhinitis (14%) was detected both among workers (Groups A and B) and subjects living in the Eordea valley who participated as controls (Group C). From the X-rays, hypertrophy of nasal turbinates-cartilage and polyposis was observed as follows: Group A: 53.9%, Group B: 48.1%, Group C: 46.5% and Group D: 20.3% (p<0.001). The findings related to the upper respiratory system may be due to excessive pollution by airborne particles (fly ash) pollution in the region and particularly to chromium, nickel, cobalt and lead found at high concentration levels in airborne dust. A marked association between the total air-flow in the nose and the mid-expiratory flow (p<0.01) was detected. CONCLUSIONS: We conclude that subjects working in lignite mines under conditions of excessive pollution by airborne contaminants have a high prevalence of atrophic rhinitis and, in addition to other standard examinations, should undergo rhinomanometry testing and X-ray imaging of the paranasal cavities.

A study on the atmospheric concentrations of primary and secondary air pollutants in the Athens basin performed by DOAS and DIAL measuring techniques.

In this work an analysis of continuous Differential Optical Absorption Spectroscopy (DOAS) measurements of primary and secondary air pollutants (SO(2), NO(2) and O(3)) in the Athens basin is performed combined with Differential Absorption Lidar (DIAL) vertical ozone measurements obtained inside the Planetary Boundary Layer (PBL) and the lower free troposphere. The measurements took place during the period May 2005-February 2007, at the National Technical University of Athens Campus (200 m above sea level (asl.), 37.96 °N, 23.78 °E). The SO(2) and NO(2) DOAS measurements showed maximum 1-hour mean values (around 20 µg/m(3) and 74 µg/m(3), respectively) in winter and did not exceed the current European Union (EU) air quality standards (European Council Directive 2008/50/EC), in contrast to ozone, which shows its maximum (around 128 µg/m(3)) in summer and frequently exceeds the EU standard for human health protection (120 µg/m(3)). If the measurements are classified according to the two most frequent flow-patterns of the air masses in the Athens basin (northern-southern circulation), it is observed that in general the atmospheric concentrations of all measured pollutants including ozone are higher when the southern circulation occurs, in comparison to the corresponding values under the northern circulation. The vertical ozone profiles obtained by DIAL were also higher under the southern circulation. During the summer months a mean difference (between the southern-northern circulations) of the order of 15-20 µg/m(3), maximized at the 0.9-1.1 km and 1.7-1.8 km height, was observed within the PBL. It was also observed that the summer surface ozone levels remained relatively high (around 80-110 µg/m(3)) even during strong northerly winds, verifying the high levels of rural surface ozone in the surrounding area reported by previous studies.