Ioanna Larissi - Academia.edu (original) (raw)

Papers by Ioanna Larissi

The main objective of the present work is the study of suspended particulate matter temporal evol... more The main objective of the present work is the study of suspended particulate matter temporal evolution in the greater Athens area (GAA). Towards this aim, the time series of the particulate matter with an aerodynamic diameter less than 10 µm (PM 10 ) recorded in six monitoring stations located in the GAA, for a seven-year period 2001-2006, is analysed.

ABSTRACT The main objective of the present work is the study of suspended particulate matter temp... more ABSTRACT The main objective of the present work is the study of suspended particulate matter temporal evolution in the greater Athens area (GAA). Towards this aim, the time series of the particulate matter with an aerodynamic diameter less than 10 μm (PM10) recorded in six monitoring stations located in the GAA, for a seven-year period 2001-2006, is analysed. The analysis leads to useful results concerning PM10 levels that exceed the European Union limit values. It appears that the different characteristics of each measuring site affect the number of exceedances. The major findings of this study are: (a) The mean seasonal variation of the examined air pollutant concentration, in peripheral stations, presents a maximum during the warm period of the year and a minimum during the cold period. On the contrary, in the traffic related stations, there is no clear seasonal variation of PM10 concentration. (b) The analysis shows that the PM10 levels remain higher than the corresponding thresholds for human health protection set by the European Union, in the majority of the examined monitoring sites, during the examined period. (c) The number of the days when the mean daily value of PM10 exceeded the threshold of 50 μg/m3 is appreciably higher than the permitted violations of 35 days per year that is assigned by the EU Directive.

Advances in Geosciences, 2010

In this study, the spatial and temporal variability of the mean annual rain intensity in Greece a... more In this study, the spatial and temporal variability of the mean annual rain intensity in Greece are examined during a 41-year period (1962-2002). The meteorological datasets concern monthly rain amounts (mm) and the respective monthly durations (h) recorded at thirty two meteorological stations of the Hellenic National Meteorological Service, which are uniformly distributed on Greek territory, in order to calculate the mean monthly rain intensity. All the rain time series used in the analysis were tested by the application of the shortcut Bartlett test of homogeneity. The spatial distribution of the mean annual rain intensity is studied using the Kriging interpolation method, while the temporal variability, concerning the mean annual rain intensity trends along with their significance (Mann-Kendall test), is analysed. The findings of the analysis show that statistically significant negative trends (95% confidence level) appear mainly in the west sub-regions of Greece, while statistically significant positive trends (95% confidence level) appear in the wider area of Athens and the complex of Cyclades Islands. Further analysis concerning the seasonal rain intensity is needed, because there are different seasonal patterns, taking into account that, convective rain in Greece occurs mainly within the summer season. 2 Data and analysis Rain variability in space and time is one of the most relevant characteristics of the Mediterranean climate that is associated with economic, social and ecological implications. Extreme

It is well-known that natural and anthropogenic emissions of ambient pollutants affect air qualit... more It is well-known that natural and anthropogenic emissions of ambient pollutants affect air quality, and as a consequence the public health. Air pollution indices are commonly used to indicate the level of severity of air pollution to the public. The objective of this study is the assessment of the air quality levels in the urban environment of Athens, Greece using the Air Quality Index (AQI), which presents advantages as an administrative tool for early warning in the context of public health protection. The AQI is a complex index and calculated by compounding appropriately the concentrations of surface ozone (O3), nitrogen dioxide (NO2), sulphur dioxide (SO2), carbon monoxide (CO) and particles with aerodynamic diameter less than 10 μm (PM10). For this purpose, available hourly data of the above ambient pollutants recorded by the Athens air pollution monitoring network, during the period 2001-2006, were analyzed for the development of the proposed index. The temporal and spatial di...

The goal of this work is the analysis of particulate matter with aerodynamic diameter less than 1... more The goal of this work is the analysis of particulate matter with aerodynamic diameter less than 10 µm (PM 10) recorded in the urban area of Volos, a medium-sized Greek coastal city on the eastern seaboard of Central Greece. For this purpose, concentration measurements of PM 10 , for a seven-year period (2001-2007) are analyzed. Air pollution data were obtained by a monitoring station, fully automated, that was established by the Hellenic Ministry of the Environment, Energy and Climatic Change, in order to measure air pollution levels in Volos. The extracted findings showed that the mean diurnal variation of the examined air pollutant concentrations within the cold and the warm period of the year show a double peak structure with respect to morning and evening hours. Additionally, the intra annual variation of PM 10 concentrations shows a double peak pattern. The dominant peak is observed in February and the secondary peak in May/ June. Besides, the role of wind seems to be significant as the PM 10 exceedances are strongly associated with predominant wind directions.

The growth of the city of Athens in the last decades and the phenomenon of urbanisation obviously... more The growth of the city of Athens in the last decades and the phenomenon of urbanisation obviously have led to the creation of a microclimate with explicit effects on human thermal comfort-discomfort. The knowledge of population thermal comfort-discomfort levels, predictable for the next days, is very important for suitable actions in order to protect public health. In this work, an effort has been made to use Artificial Neural Networks (ANNs) for the forecast of the maximum daily value of Thom's Discomfort Index, and the minimum daily value of an index known as Cooling Power by Siple and Passel, as well as the number of consecutive hours of thermal discomfort due to high temperatures, for the next day. For this aim, the values of air temperature, relative humidity, wind speed, and the corresponding values of two thermal comfort-discomfort indices for the two previous days were used for the daily forecast. Initially, meteorological data, recorded during period 2001-2004 in eight stations of the network of the Greek Ministry of the Environment, Physical Planning and Public Works (GMEPPPW) in the greater Athens area, were statistically treated. Two of these stations, Patission and Thrakomakedones, which presented maximum and minimum temperatures, were selected. For these two stations ANNs were used in order to forecast the values of the above-mentioned thermal comfort-discomfort indices, as well as the number of consecutive thermal discomfort hours during the day, 24 hours predicted before their appearance.

Fresenius Environmental Bulletin, 2014

Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering, Jan 30, 2015

Journal of Environmental Science and Health, Part A, 2015

There is great consensus among the scientific community that suspended particulate matter is cons... more There is great consensus among the scientific community that suspended particulate matter is considered as one of the most harmful pollutants, particularly the inhalable particulate matter with aerodynamic diameter less than 10 μm (PM10) causing respiratory health problems and heart disorders. Average daily concentrations exceeding established standard values appear, among other cases, to be the main cause of such episodes, especially during Saharan dust episodes, a natural phenomenon that degrades air quality in the urban area of Volos. In this study the AirQ2.2.3 model, developed by the World Health Organization (WHO) European Center for Environment and Health, was used to evaluate adverse health effects by PM10 pollution in the city of Volos during a 5-year period (2007-2011). Volos is a coastal medium size city in the Thessaly region. The city is located on the northern side of the Gulf of Pagassitikos, on the east coast of Central Greece. Air pollution data were obtained by a fully automated monitoring station, which was established by the Municipal Water Supply and Sewage Department in the Greater Area of Volos, located in the centre of the city. The results of the current study indicate that when the mean annual PM10 concentration exceeds the corresponding European Union (EU) threshold value, the number of hospital admissions for respiratory disease (HARD) is increased by 25% on average. There is also an estimated increase of about 2.5% in HARD compared to the expected annual HARD cases for Volos. Finally, a strong correlation was found between the number of days exceeding the EU daily threshold concentration ([PM10] ≥ 50 μg m(-3)) and the annual HARD cases.

Synoptic meteorological observations all over the world are usually carried out on the basis of 3... more Synoptic meteorological observations all over the world are usually carried out on the basis of 3-hour intervals, as specified by the World Meteorology Organization. However, in many cases, e.g. for the detailed calculation of buildings' energy balance and the energy production of solar power systems, cognition of the hourly time series of some meteorological parameters such as air temperature, air relative humidity, atmospheric pressure, etc. is necessary. For this purpose, in the specific study, artificial neural networks are developed and applied in order to transform 3-hour meteorological data files of air temperature, relative humidity and atmospheric pressure of different regions to full 24-hour data files. The hourly values predicted by the developed artificial neural networks are accordingly compared with the actual hourly values of parameters examined with the results obtained showing a very satisfying agreement at a statistical significance level of p<0.01.

EXTENDED ABSTRACT This study is an attempt for a detailed and accurate calculation of Cooling Deg... more EXTENDED ABSTRACT This study is an attempt for a detailed and accurate calculation of Cooling Degree Days (CDD) and Heating Degree Days (HDD) using hourly air temperature values from ten different regions within the greater Athens area (GAA), Greece. For this purpose hourly values of air temperature from ten different locations of the GAA were used in order to calculate the monthly CDD and HDD as well as the annual number of CDD and HDD for each one of the examined regions separately. Concretely the ten examined regions of the GAA are: Agia Paraskevi, Maroussi, Lykovrissi, Thrakomakedones, Liossia, Elefsina, Galatsi, Geoponiki, Patission (Athens' city centre) and Piraeus. The hourly air temperature data have been recorded by the network of the Greek Ministry of Environment, Energy and Climatic Change (GMEECC) and cover the time period 2001-2005. The energy needs in the building sector for cooling and heating, are proportional to the number of CDD and HDD respectively. The result...

The aim of the present work is an investigation of air quality within the greater Thessaloniki ar... more The aim of the present work is an investigation of air quality within the greater Thessaloniki area (GTA), Greece. For this purpose, daily concentrations of five different pollutants (CO, SO2, NO2, O3 and PM10) from six different locations in the GTA are used. The air pollution data have been recorded by the stations of the monitoring network of the Hellenic Ministry of Environment, Energy and Climatic Change covering the time period 2001-2011. For the estimation of air quality levels, at the five examined monitoring sites, the daily values of an air quality index known as European Regional Pollution Index (ERPI) are calculated. ERPI is an air quality index which is based on the directives on ambient air qual-ity and cleaner air for Europe, by the European Union (EU). The assessment of the results reveals great variability of air quality levels between neighboring regions within the GTA. More concretely, the total percentage of days with ERPI values above the EU threshold values ran...

Springer Atmospheric Sciences, 2012

The study of atmospheric concentration levels at a local scale is one of the most important topic... more The study of atmospheric concentration levels at a local scale is one of the most important topics in environmental sciences. Multivariate analysis, fuzzy logic and neural networks have been introduced in forecasting procedures in order to elaborate operational techniques for level characterization of specific atmospheric pollutants at different spatial and temporal scales. Particularly, procedures based on artificial neural networks (ANNs) have been applied with success to forecast concentration levels of PM 10 , CO and O 3. The present study deals with the development and application of ANN models as a tool to forecast daily concentration levels of PM 10 in five different regions within the greater Athens area (GAA). Modeling was based on mean daily PM 10 concentration, the maximum hourly NO 2 concentration, air temperature, relative humidity, wind speed and the mode daily value of wind direction from five different monitoring stations for the period 2001-2005. Model performance showed that the ANN models could successfully forecast the risk of daily PM 10 concentration levels exceeding certain thresholds. In addition, despite the limitations of the models, the results of the study

Theoretical and Applied Climatology, 2014

ABSTRACT The degree-day method is considered to be a fun-damental and a rather simple method to e... more ABSTRACT The degree-day method is considered to be a fun-damental and a rather simple method to estimate heating and cooling energy demand. This study aims in a detailed and accurate assessment of cooling and heating degree days in different locations within the Greater Athens area (GAA), Greece. To achieve this goal, hourly values of air temperature from eight different locations within the GAA, covering the period 2001–2005, were used. Thus, the monthly and the annual number of cooling and heating degree days for each one of the examined locations could be estimated separately. Furthermore, an effort is made to evaluate the energy con-sumption for a specific building, based on the degree-day method, to indicate the impact of the canopy layer urban heat island on neighboring regions within the GAA. Results reveal that there is great spatial variability of energy demand and energy consumption along with significant differences in ex-penses for heating and cooling among neighboring regions within the GAA. Finally, regarding the energy demands of buildings, it is important to take into account intra-urban variability of canopy layer climates against an ensemble mean throughout the city, because the latter can result in inaccurate estimations and conclusions.

Springer Atmospheric Sciences, 2012

The surface ozone is a pollutant of major concern due to its impact on receptors, at currently oc... more The surface ozone is a pollutant of major concern due to its impact on receptors, at currently occurring ambient levels in many regions of the world. The aim of this work is to present the results derived from an analysis of hourly surface ozone concentrations, measured at the urban station of Volos, a coastal mediumsized city at the eastern seaboard of Central Greece, during the 10-year period 2001-2010. The regional climate, which is characterized by hot and dry summers with intense sunshine, plays an important role in the observed exceedances of the air quality ozone limits. The analysis showed that, ozone diurnal patterns depict daytime photochemical ozone built up, during the sunlight hours of the day. It is remarkable that the maximum daily 8-h averages often exceeded the standard value that is assigned by the EU Directive for human health protection, during almost the warm period of the year, mainly at noon and afternoon hours.

Atmospheric Research, 2014

ABSTRACT Extreme daily precipitation events are involved in significant environmental damages, ev... more ABSTRACT Extreme daily precipitation events are involved in significant environmental damages, even in life loss, because of causing adverse impacts, such as flash floods, in urban and sometimes in rural areas. Thus, long-term forecast of such events is of great importance for the preparation of local authorities in order to confront and mitigate the adverse consequences. The objective of this study is to estimate the possibility of forecasting the maximum daily precipitation for the next coming year. For this reason, appropriate prognostic models, such as Artificial Neural Networks (ANNs) were developed and applied. The data used for the analysis concern annual maximum daily precipitation totals, which have been recorded at the National Observatory of Athens (NOA), during the long term period 1891–2009. To evaluate the potential of daily extreme precipitation forecast by the applied ANNs, a different period for validation was considered than the one used for the ANNs training. Thus, the datasets of the period 1891–1980 were used as training datasets, while the datasets of the period 1981–2009 as validation datasets. Appropriate statistical indices, such as the coefficient of determination (R2), the index of agreement (IA), the Root Mean Square Error (RMSE) and the Mean Bias Error (MBE), were applied to test the reliability of the models. The findings of the analysis showed that, a quite satisfactory relationship (R2 = 0.482, IA = 0.817, RMSE = 16.4 mm and MBE = + 5.2 mm) appears between the forecasted and the respective observed maximum daily precipitation totals one year ahead. The developed ANN seems to overestimate the maximum daily precipitation totals appeared in 1988 while underestimate the maximum in 1999, which could be attributed to the relatively low frequency of occurrence of these extreme events within GAA having impact on the optimum training of ANN.

Water, Air, & Soil Pollution, 2013

ABSTRACT The study of atmospheric concentration levels at a local scale is one of the most import... more ABSTRACT The study of atmospheric concentration levels at a local scale is one of the most important topics in environmental sciences. Multivariate analysis, fuzzy logic, and neural networks have been introduced in forecasting procedures in order to elaborate operational techniques for level characterization of specific atmospheric pollutants at different spatial and temporal scales. Particularly, approaches based on artificial neural networks (ANNs) have been proposed and successfully applied for forecasting concentration levels of PM10, NO2, SO2, CO, and O3. The present study explores the development and application of ANN models for forecasting, 24 h ahead, not only the daily concentration levels of PM10 but also the number of hours exceeding the PM10 concentration threshold during the day in five different regions within the greater Athens area (GAA). The ANN modeling was based on measurements and estimates of the mean daily PM10 concentration, the maximum hourly NO2 concentration, air temperature, relative humidity, wind speed, and the mode daily value of wind direction from five different monitoring stations for the period 2001–2005. The evaluation of the model performance showed the risk of daily PM10 concentration levels exceeding certain thresholds as well as the duration of the exceedances can be successfully predicted. Despite the limitations of the model, the results indicate that ANNs, when adequately trained, have considerable potential to be used for 1 day ahead PM10 concentration forecasting and the duration within the GAA.

Theoretical and Applied Climatology, 2012

In this work, artificial neural networks (ANNs) were developed and applied in order to forecast t... more In this work, artificial neural networks (ANNs) were developed and applied in order to forecast the discomfort levels due to the combination of high temperature and air humidity, during the hot season of the year, in eight different regions within the Greater Athens area (GAA), Greece. For the selection of the best type and architecture of ANNs-forecasting models, the multiple criteria analysis (MCA) technique was applied. Three different types of ANNs were developed and tested with the MCA method. Concretely, the multilayer perceptron, the generalized feed forward networks (GFFN), and the time-lag recurrent networks were developed and tested. Results showed that the best ANNs type performance was achieved by using the GFFN model for the prediction of discomfort levels due to high temperature and air humidity within GAA. For the evaluation of the constructed ANNs, appropriate statistical indices were used. The analysis proved that the forecasting ability of the developed ANNs models is very satisfactory at a significant statistical level of p<0.01. 1 Introduction During the hot period of the year, the human body activates defense mechanisms such as perspiration in order to maintain

Indoor and Built Environment, 2013

The objective of this study is to present and analyse the indoor and outdoor temporal variability... more The objective of this study is to present and analyse the indoor and outdoor temporal variability of the particulate matters of different sizes (namely: PM10, with diameter less than 10 µm; PM7, with diameter less than 7 µm; PM2.5, with diameter less than 2.5 µm and PM1, with diameter less than 1 µm) found in Athens, Greece. Four detectors were used for indoor and outdoor recordings. More specifically, the indoor recordings were performed in seminar rooms, full of students attending lectures, at the University of Athens and the Technological Education Institute of Piraeus. Findings of this research show that on one hand, the indoor particulate matter concentrations remained at lower levels than the thresholds set by the European Council Directives, but on the other hand, the outdoor particulate matter concentrations exceeded the thresholds many times.

Advances in Geosciences, 2010

Fresenius Environmental Bulletin, 2014

Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering, Jan 30, 2015

Journal of Environmental Science and Health, Part A, 2015

Springer Atmospheric Sciences, 2012

Theoretical and Applied Climatology, 2014

Springer Atmospheric Sciences, 2012

Atmospheric Research, 2014

Water, Air, & Soil Pollution, 2013

Theoretical and Applied Climatology, 2012

Indoor and Built Environment, 2013