Assessment of genetic effects and pesticide exposure of farmers in NW Greece.

The present study aims at evaluating potential genotoxic and cytotoxic effects caused by the occupational exposure of farmers to pesticide mixtures in the Aitoloakarnania Prefecture (Greece). The aforementioned assessment was conducted through in vivo Cytokinesis Block Micronucleus assay (CBMN assay) in peripheral blood lymphocytes, in relation to chemical analysis of pesticide residues in blood samples. The exposure of the farmers' population studied to different combinations of pesticides induced significant differences in the frequencies of micronuclei (MN) compared to those of the control group. Furthermore, our results indicated a possible clastogenic and aneugenic effect of pesticides on the genetic material of the farmers exposed. Five pesticides (trifluralin, chlorpyriphos methyl, metolachlor, fenthion and dimethoate) and three metabolites (fenthion sulfone, fenthion sulfoxide and 4,4' DDE) were detected in the 62.5% of blood samples, with mean concentrations ranging from 0.4 ng/ml to 48 ng/ml. Since the farmers studied probably exhibit detectable levels of systematic exposure to the pesticides applied, continuous educational programs focused on the rational and safe use of pesticides, together with implementation of risk communication strategies among farmers are highly recommended.

Temperature inversion characteristics in relation to synoptic circulation above Athens, Greece.

In this paper, the characteristic properties of inversions formed inside the lower boundary layer over Athens, Greece, were studied using 35-year radiosonde measurements of temperature, humidity, and atmospheric pressure. The analysis revealed that the inversion parameters demonstrate considerable seasonal variation. Specifically, inversions associated with weak anticyclonic conditions are more frequent during the winter and summer months, while during spring, weak lows are more probable to produce inversions. Some theoretically expected associations between synoptic circulation patterns and certain inversion parameters were also identified.

Human health damage caused by particulate matter PM10 and ozone in urban environments: the case of Athens, Greece.

Studies conducted over the past decades have provided substantial evidence that both the long- and the short-term exposures to ozone and particulate matter are responsible for mortality and cardiopulmonary morbidity. This paper examines the relationship between exposure to ambient concentrations of ozone (O3) and particulate matter with aerodynamic diameter of less than 10 µm (PM10) and public health and provides the quantification of the burden of disease from PM10 and O3-related mortality and morbidity through a Life Cycle Impact Assessment focused on the greater area of Athens, Greece. Thus, characterizations factors (CFs) for human health damage are calculated in 17 sites in Athens, in terms of the annual marginal change in the disability-adjusted life years (DALYs) due to a marginal increase in the ambient concentrations. It is found that the PM10 intake factors range between 1.25 × 10(-6) and 2.78 × 10(-6), suggesting that 1.25-2.78 µg of PM10 are inhaled by the Athenian population per kg of PM10 in the urban atmosphere. Mortality due to chronic exposure to PM10 has a dominant contribution to years of life lost with values ranging between 6.2 × 10(-5) and 1.1 × 10(-4). On the other hand, the mortality caused by short-term exposure to O3 is weaker with the CFs ranging between 1.58 × 10(-7) years of life lost in the urban/traffic areas and 4.71 × 10(-7) years in the suburbs. Finally, it is found that 9,000 DALYs are lost on average in Athens, corresponding to 0.0018 DALYs per person. This is equal to 0.135 DALYs per person over a lifetime of approximately 75 years, assuming constant emission rates for the whole period.

Correlation of local lightning activity with extra low frequency detector for Schumann Resonance measurements.

A dedicated extremely low frequency (ELF) detector has been constructed and used successfully for Schumann Resonance (SRs) measurements in N.W. Greece. The main objective of this work was to investigate the effect of local lightning activity on the signal of our ELF detector and consequently on the estimated SRs parameters, namely the power, the frequency and the quality factor of each mode. Therefore, several measurements were taken into account for the ELF signal continuously recorded and the lightning intensity in a specific range around the ELF detector. Additionally, a simple filtering technique was used, in order to reject the distorted SRs spectra. The statistical analysis performed showed a positive and statistically significant correlation between the lightning events and the recorded magnetic component of the ELF signal. It was found that local lightnings have a significant impact on the SRs measurements, and it is necessary to be removed from the background signal.

Study of the variations in the Schumann resonances parameters measured in a southern Mediterranean environment.

Schumann resonances (SRs) provide a unique tool for exploring continuous and long-term monitoring of global environmental parameters, although their detection and study is a very complex task. This paper presents diurnal and seasonal variations of principal parameters, namely the resonance frequency, the Q-factor, and the power of SRs, in the North-South (NS) magnetic field component for the first five modes from Extra Low Frequency (ELF) measurements. These were acquired at the observation site located at Doliana, Kalpaki, in the Region of Epirus, North West Greece. These variations are the first ones reported for the principal parameters in the South Eastern Mediterranean area and correspond to the one-year measurement period from 2016 to 2017. The comparison with variations at several observations sites is also discussed. Moreover, correlation with global lighting centers, as well as local lightning activity, and SRs parameters variation is attempted.

On the evaluation of box model results: the case of BOXURB model.

In the present paper, the BOXURB model results, as they occurred in the Greater Area of Athens after model application on an hourly basis for the 10-year period 1995-2004, are evaluated both in time and space in the light of observed pollutant concentrations time series from 17 monitoring stations. The evaluation is performed at a total, monthly, daily and hourly scale. The analysis also includes evaluation of the model performance with regard to the meteorological parameters. Finally, the model is evaluated as an air quality forecasting and urban planning tool. Given the simplicity of the model and the complexity of the area topography, the model results are found to be in good agreement with the measured pollutant concentrations, especially in the heavy traffic stations. Therefore, the model can be used for regulatory purposes by authorities for time-efficient, simple and reliable estimation of air pollution levels within city boundaries.

A comparative study on various statistical techniques predicting ozone concentrations: implications to environmental management.

The objective of the present work is to compare various techniques for modeling the dependence of the tropospheric ozone concentrations on several meteorological and pollutant parameters. The study focuses on two different sites in the metropolitan area of Athens, Greece; one in the city centre and another one in the suburbs. It is found that although simple Linear Regression Analysis fails to construct accurate equations due to the existence of multicollinearity among the independent variables, still various combinations of a Multivariate Method (PCA) and Stepwise Regression Analysis manage to produce equations free of the multicollinearity issue. The derived formulas are validated and prove to have R(2) values in the order of 0.8 approximately. However, the equations are found to be unsuccessful in case of severe episodes. For this reason, a new procedure is followed for estimating the ozone values in case of episodes exclusively. The new R(2) value is estimated to be 0.9, approximately.

An overview of the PM10 pollution problem, in the Metropolitan Area of Athens, Greece. Assessment of controlling factors and potential impact of long range transport.

The present study analyzes PM(10) concentration data collected by the Greek air quality monitoring network at 8 sites over the Greater Athens Area, for the period of 2001-2004. The primary objectives were to assess the degree of compliance with the EU-legislated air quality standard for PM(10) and also provide an overall statistical examination of the factors controlling the seasonal and spatial variation of concentrations, over the wider urban agglomeration. Daily concentrations, averaged over the whole study period, ranged between 32.3 and 60.9 microg m(-3). The four-year average concentration of PM(10) at five sites exceeded the annual limit value of 40 microg m(-3), while most of the sites surpassed the allowed percentage of exceedances of the daily limit value (50 microg m(-3)), for each of the four years. The seasonal variation of PM(10) levels was not found to be uniform across the eight sites, with average cold-period concentrations being higher at four of them and warm period concentrations being significantly higher at three sites, which also displayed recurring annual variation of monthly concentrations. Concentration levels displayed moderate spatial heterogeneity. Nevertheless significant inter-site correlations were observed (ranging between 0.55 and 085). The determination of the spatial correlation levels relied mainly on site types rather than on inter-site distances. Monitoring sites were classified accordingly using cluster analysis in two groups presenting distinct spatiotemporal variation and affected by different particle formation processes. The group including urban sites was mainly affected by primary, combustion-related processes and especially vehicular traffic, as it was also deduced through the examination of the diurnal distribution of particulate levels and through factor analysis. On the contrary, suburban background sites seemed more affected by particle transport from more polluted neighboring areas and secondary particle formation through gaseous precursors, both processes aided from favoring meteorological conditions. The association of the PM(10) levels with backwards trajectories was also examined, in an attempt to account for the possible long range transport of particles in Athens. It was found that a notable part of area-wide episodic events could be attributed to trans-boundary transport of particles, with the origins of some severe dust outbreaks traced back to the Sahara desert and the Western Mediterranean.

Analysis of the synoptic winter mortality climatology in five regions of England: Searching for evidence of weather signals.

Although heat-related mortality has received considerable research attention, the impact of cold weather on public health is less well-developed, probably due to the fact that physiological responses to cold weather can vary substantially among individuals, age groups, diseases etc., depending on a number of behavioral and physiological factors. In the current work we use the classification techniques provided by the COST-733 software to link synoptic circulation patterns with excess cold-related mortality in 5 regions of England. We conclude that, regardless of the classification scheme used, the most hazardous conditions for public health in England are associated with the prevalence of the Easterly type of weather, favoring advection of cold air from continental Europe. It is noteworthy that there has been observed little-to-no regional variation with regards to the classification results among the 5 regions, suggestive of a spatially homogenous response of mortality to the atmospheric patterns identified. In general, the 10 different groupings of days used reveal that excess winter mortality is linked with the lowest daily minimum/maximum temperatures in the area. However it is not uncommon to observe high mortality rates during days with higher, in relative terms, temperatures, when rapidly changing weather results in an increase of mortality. Such a finding confirms the complexity of cold-related mortality and highlights the importance of synoptic climatology in understanding of the phenomenon.

What are the most fire-dangerous atmospheric circulations in the Eastern-Mediterranean? Analysis of the synoptic wildfire climatology.

Wildfire management is closely linked to robust forecasts of changes in wildfire risk related to meteorological conditions. This link can be bridged either through fire weather indices or through statistical techniques that directly relate atmospheric patterns to wildfire activity. In the present work the COST-733 classification schemes are applied in order to link wildfires in Greece with synoptic circulation patterns. The analysis reveals that the majority of wildfire events can be explained by a small number of specific synoptic circulations, hence reflecting the synoptic climatology of wildfires. All 8 classification schemes used, prove that the most fire-dangerous conditions in Greece are characterized by a combination of high atmospheric pressure systems located N to NW of Greece, coupled with lower pressures located over the very Eastern part of the Mediterranean, an atmospheric pressure pattern closely linked to the local Etesian winds over the Aegean Sea. During these events, the atmospheric pressure has been reported to be anomalously high, while anomalously low 500hPa geopotential heights and negative total water column anomalies were also observed. Among the various classification schemes used, the 2 Principal Component Analysis-based classifications, namely the PCT and the PXE, as well as the Leader Algorithm classification LND proved to be the best options, in terms of being capable to isolate the vast amount of fire events in a small number of classes with increased frequency of occurrence. It is estimated that these 3 schemes, in combination with medium-range to seasonal climate forecasts, could be used by wildfire risk managers to provide increased wildfire prediction accuracy.

Tracking the association between metro-railway construction works and PM levels in an urban Mediterranean environment.

Metro-railways are considered to be a sustainable means of public transportation, as they contribute substantially to the reduction of air pollutant emissions through the decrease in the number of cars and heavy vehicles circulating in the road network. However, the works related to their construction may pose an extra burden in air quality status and consequently in public health. In the present study, we studied the possible effects of the metro-railway construction works in Thessaloniki, Greece, on public health through 2 well-established air quality indices, namely the PI and DAQI. The analysis suggested that there were excess high levels of PM10 measured in the close vicinity of the construction-sites during the period studied (2008-2014). These concentrations are likely to have originated from local construction sources rather than transport or continental secondary dust sources and might have an adverse health impact, as according to the PI index, the majority of days in the construction sites were grouped as "low pollution" or "moderate pollution", while a small percentage of days (1.84%) were suggested to be unhealthy for the most vulnerable groups of the population. Similarly, the DAQI index revealed that the vast majority of days were grouped as "poor" air quality, while 5.50% of the days reflected the most oppressive conditions for public health, as they were characterized as "very poor" air quality. Given the need of reaching a compromise between future transportation sustainability and public health during the construction works, the feasibility of appropriate measures in the area should be examined.

Particulate matter and black smoke concentration levels in central Athens, Greece.

This study presents the statistical analysis of PM(10) and PM(2.5) concentrations (measured at a central site, in the Athens area), along with black smoke (BS) data, for a 2-year period. The biennial average concentrations of PM(10) and PM(2.5) were 75 and 40 microg m(-3). The respective average concentration of BS, as estimated by the OECD method, was 108 microg m(-3). Severe exceedances of the PM(10) air quality standards were recorded. The seasonal variation of PM(10) and BS was less pronounced than the variation of PM(2.5), which concentration was elevated by 14.2% during the cold period. Concentrations of all three pollutants were significantly lower during weekends; however, PM(2.5) and BS displayed a more uniform weekly distribution pattern. PM(10) particles were found to be almost equally comprised by PM(2.5) and PM(10-2.5) particles (PM(2.5)/PM(10) ratio=0.53+/-0.09 microg/m(3)). The average PM(10)/BS value was found lower than unity revealing the inappropriateness of the used reflectance conversion method, for the estimation of mass-equivalent BS concentrations, in the study area, where diesel-powered vehicles mainly control emissions of light-absorbing substances. Important reductions in concentrations were observed during days when drivers of diesel-powered taxies and transportation buses went on strike (reaching 40% for BS). Calm wind conditions were found to have an incremental effect on particle concentrations and were also associated with the appearance of persistent episodic events. Increased PM levels were also observed during southern-southwestern wind flows while significantly lower-than-average concentrations were measured during precipitation events. Separate regression analyses were performed for PM(10), PM(2.5) with BS and NO(x) as independent variables, in an attempt to estimate the relative contribution of specific source types (diesel-powered vehicles) to measured particle levels. The contribution of the diesel-exhaust component to PM(10) mass was estimated at 49.9%, while the corresponding contributions to PM(2.5) mass concentrations was 53.8%. These results may have important implications with the oncoming decision of national authorities to allow the purchase of diesel-powered private cars to the residents of the Greater Athens Area, which was forbidden up to this day.

Disaggregating the contribution of local dispersion and long-range transport to the high PM10 values measured in a Mediterranean urban environment.

The EU daily PM10 limit-value of 50 µg m(-3) is frequently breached in the center of Athens, Greece. A total of 852 daily exceedances were recorded in the city-center during the 6-year period 2001-2006. These exceedances were more frequent in winter, followed by spring and autumn. For the needs of the study, the PM10 episodes (i.e., concentrations 30% above the median value) were grouped in two categories: (a) the City-Center episodes and (b) the Wider Metropolitan Area episodes. It was assumed that City-Center episodes occurred when elevated PM10 values were measured in the city-center exclusively, whereas Wider Metropolitan Area episodes occurred when high PM10 concentrations were also measured in the suburbs. Then back-trajectory cluster analysis was performed in an attempt to associate high PM10 levels with local dispersion or long-range transport. The City-Center episodes were associated according to the origin of air parcels with six types of air-masses (slow and fast moving from northern, northeasterly and southern directions, or stagnated around Athens) and were mainly due to traffic or other local sources, whereas the Wider Metropolitan Area episodes were mainly associated with air-masses coming from southern directions and were linked to long-range transport. On the whole, the analysis provided evidence of Sahara-dust events and sea-spray transportation.

Atmospheric circulation types and daily mortality in Athens, Greece.

We investigated the short-term effects of synoptic and mesoscale atmospheric circulation types on mortality in Athens, Greece. The synoptic patterns in the lower troposphere were classified in 8 a priori defined categories. The mesoscale weather types were classified into 11 categories, using meteorologic parameters from the Athens area surface monitoring network; the daily number of deaths was available for 1987-1991. We applied generalized additive models (GAM), extending Poisson regression, using a LOESS smoother to control for the confounding effects of seasonal patterns. We adjusted for long-term trends, day of the week, ambient particle concentrations, and additional temperature effects. Both classifications, synoptic and mesoscale, explain the daily variation of mortality to a statistically significant degree. The highest daily mortality was observed on days characterized by southeasterly flow [increase 10%; 95% confidence interval (CI), 6.1-13.9% compared to the high-low pressure system), followed by zonal flow (5.8%; 95% CI, 1.8-10%). The high-low pressure system and the northwesterly flow are associated with the lowest mortality. The seasonal patterns are consistent with the annual pattern. For mesoscale categories, in the cold period the highest mortality is observed during days characterized by the easterly flow category (increase 9.4%; 95% CI, 1.0-18.5% compared to flow without the main component). In the warm period, the highest mortality occurs during the strong southerly flow category (8.5% increase; 95% CI, 2.0-15.4% compared again to flow without the main component). Adjusting for ambient particle levels leaves the estimated associations unchanged for the synoptic categories and slightly increases the effects of mesoscale categories. In conclusion, synoptic and mesoscale weather classification is a useful tool for studying the weather-health associations in a warm Mediterranean climate situation.

Aspects of atmospheric flow and dispersion of air pollutants in a mountainous basin.

The variety of physicogeographic characteristics, the complex topography and channeling of the synoptic/regional flow are among the main reasons for the formulation of local flow patterns, and consequently for the dispersion conditions in a mountainous area. In this paper, an attempt is made to investigate the mechanisms responsible for these phenomena and to explain the dispersion of air pollutants in a mountainous basin, especially the impingement of plumes released by elevated stacks. A coupled atmospheric and Lagrangian dispersion model was used for the analysis. As it was found significant, mesoscale circulation, such as lake effects in mountainous terrain, up/downslope and valley winds, was calculated. It was proved that the plume impingement, along with pollutant recirculation, could explain the nighttime maximum air-pollutant concentrations measured in the city of Kozani.

Comparison of air pollutant concentrations between weekdays and weekends in Athens, Greece for various meteorological conditions.

The objective of the present study is to contribute to the understanding of the "ozone weekend effect" as it occurs in the Greater Area of Athens, Greece both in the summer and wintertime. Therefore, weekly cycles of CO, NO and O3 concentrations for the 18-year-period 1983-2000 are studied. Each day of the week is considered separately, while sites with different levels of primary pollutants are examined. The reduction of the meteorological influence in the O3 mechanisms is achieved by applying meteorological classifications. The analysis for the cold period reveals that CO and NO display decreasing concentrations from weekdays to weekends, whereas O3 shows increasing concentrations. During the warm period, although primary pollutants display decreased concentrations compared to the cold period, their weekly cycles remain the same. On the other hand, meteorological changes affect the weekly cycle of ozone peaks. During days with unfavourable meteorology to ozone production, weekend ozone concentrations are higher than weekday O3 concentrations. The reverse is observed during days with favourable meteorology to ozone production.

Assessment of the air-quality over urban areas by means of biometeorological indices. The case of Athens, Greece.

This article deals with the part of air pollution, which has a particular relevance to the objective assessment of the quality of urban air. The correct understanding of the pollution levels over an urban region is of great importance to both authorized government services and to the community. This is particularly true for high polluted urban regions such as the Athens basin; so, it is important to recognize the levels of atmospheric quality by means of an easily understandable manner even for non-specialists. Thus, in this study an attempt is made for the application of two different groups of air quality indices (AQI) (statistical and biometeorological) by utilizing air pollutants measured into Athens basin, in a network of 17 measuring stations, during the period 2001-2002. The calculations of the (AQI) are referred to data of all 17 measuring stations and concern levels of air-pollution concentrations to both short (daily) and long time periods. Then comparisons were made between the obtained statistical and biometeorological indices in order to identify whether or not there is any existence of consistency between them. The compositions of the calculated indices were also determined, as well as, the most important air-pollutant for them. This procedure was applied for each day of the week in order to reveal the weekly cycle of indices and perhaps to isolate air-quality differences between weekdays and weekends. Finally, the varying forms of both frequency distributions are mainly caused by the impact related concentrations ranges of single air-pollutants which are typical of air-quality indices. Especially, PM10 and O3 seem to have a stronger influence on the determination of values of air quality indices.

Evaluation of a multiple regression model for the forecasting of the concentrations of NOx and PM10 in Athens and Helsinki.

Forecasting models based on stepwise multiple linear regression (MLR) have been developed for Athens and Helsinki. The predictor variables were the hourly concentrations of pollutants (NO, NO(2), NO(x), CO, O(3), PM(2.5) and PM(10)) and the meteorological variables (ambient temperature, wind speed/direction, and relative humidity) and in case of Helsinki also Monin-Obukhov length and mixing height of the present day. The variables to be forecasted are the maximum hourly concentrations of PM(10) and NO(x), and the daily average PM(10) concentrations of the next day. The meteorological pre-processing model MPP-FMI was used for computing the Monin-Obukhov length and the mixing height. The limitations of such statistical models include the persistence of both the meteorological and air quality situation; the model cannot account for rapid changes (on a temporal scale of hours or less than a day) that are commonly associated, e.g., with meteorological fronts, or episodes of a long-range transport origin. We have selected the input data for the model from one urban background and one urban traffic station both in Athens and Helsinki, in 2005. We have used various statistical evaluation parameters to analyze the performance of the models, and inter-compared the performance of the predictions for both cities. Forecasts from the MLR model were also compared to those from an Artificial Neural Network model (ANN) to investigate, if there are substantial gains that might justify the additional computational effort. The best predictor variables for both cities were the concentrations of NO(x) and PM(10) during the evening hours as well as wind speed, and the Monin-Obukhov length. In Athens, the index of agreement (IA) for NO(x) ranged from 0.77 to 0.84 and from 0.69 to 0.72, in the warm and cold periods of the year. In Helsinki, the corresponding values of IA ranged from 0.32 to 0.82 and from 0.67 to 0.86 for the warm and cold periods. In case of Helsinki the model accuracy was expectedly better on the average, when Monin-Obukhov length and mixing height were included as predictor variables. The models provide better forecasts of the daily average concentration, compared with the maximum hourly concentration for PM(10). The results derived by the ANN model where only slightly better than the ones derived by the MLR methodology. The results therefore suggest that the MLR methodology is a useful and fairly accurate tool for regulatory purposes.

A tool for determining urban emission characteristics to be used in exposure assessment.

The exposure of citizens to elevated air pollution concentrations is one of the major factors leading to the deterioration of the quality of life and possibly to health problems in urban areas. The concentration of air pollutants depends largely on pollutant emission levels. If the statistical probability distribution function of the concentration of an air pollutant is known, it is possible to estimate how many times this concentration exceeds the air quality standards, or estimate changes in the emission levels in an area. It can be also used to estimate the long term exposure of population to certain pollutants. In this paper fifteen theoretical probability distribution functions, were used to fit the actual concentration frequency distributions of CO, NO(2), O(3,) SO(2), and Black Smoke (BS) in Athens, Greece for a 23-year period. The results showed that the theoretical distribution type best describing the distribution of the pollutants is Inverse Gaussian followed by the Extreme value distribution. The number of exceedances of air quality limits was used to validate the performance of the theoretical distributions that were best fitted to the observed ones. The temporal evolution of emission strength was estimated through the temporal evolution of the parameters of the probability distribution functions. Missing periods were accounted for by estimating the respective distribution functions through interpolation or extrapolation from the existing ones. The derived variation of emission levels consistently represents the emission reduction strategies enforced over the years, as well as the escalating growth of the passenger car fleet volume, and could be a useful tool for the design and assessment of emission control strategies.