Evangelos Gerasopoulos

• Research Director
• Managing Director at National Observatory of Athens

Air quality simulations were performed for Athens (Greece) in ~1 km resolution applying the models WRF-CAMx for July and December 2019 with the secondary organic aerosol processor (SOAP) and volatility basis set (VBS) organic aerosol (OA) schemes. CAMx results were evaluated against particulate matter (PM) and OA concentrations from the regulatory...

The Mediterranean, with its extensive climatic history, stands as a unique repository for tracing and estimating climate change, drawing from historical and proxy data spanning vast timeframes. This abstract navigates through the diverse climatic landscapes of the Mediterranean, spanning historic epochs to the present, offering insights into projec...

Secondary inorganic aerosols (SIAs) are major components of fine particulate matter (PM2.5), having substantial implications for climate and air quality in an urban environment. In this study, a state-of-the-art thermodynamic model has been coupled to the source dispersion and photochemistry city-scale chemistry transport model EPISODE–CityChem, wh...

A historically large percentage of the world’s population has moved to urban areas in the past few decades, causing various negative effects for the environment, such as air, noise, water, and light pollution; land degradation; and biodiversity loss. Under the current climate crisis, cities are anticipated to play an essential part in adaptation st...

To study the spatiotemporal variability of particle-bound polycyclic aromatic hydrocarbons (PAHs) and assess their carcinogenic potential in six contrasting urban environments in Greece, a total of 305 filter samples were collected and analyzed. Sampling sites included a variety of urban background, traffic (Athens, Ioannina and Heraklion), rural (...

Secondary inorganic aerosols (SIA) are major components of fine particulate matter (PM2.5), having substantial implications for climate and air quality in an urban environment. In this study, a state-of-the-art thermodynamic model has been coupled to the source dispersion and photochemistry city-scale chemistry transport model EPISODE-CityChem, abl...

This section analyses the temporal evolution (from diurnal to seasonal time scales) of atmospheric aerosols and their chemical composition in order to examine and compare the variations in aerosol characteristics from the near surface to the vertical column at different sites across the Mediterranean. Examining the seasonality and diurnal cycles of...

The Mediterranean basin is a climate-sensitive region of particular interest for examining atmospheric aerosols and their chemical composition due to the large variety of source regions, contrasting air masses, and mixing processes between anthropogenic emissions, sea salt, and desert dust. Apart from the major contribution of mineral and desert du...

The main aim of this chapter is to review the trends in PM concentrations and chemical composition in carbonaceous and inorganic aerosols and trace elements at contrasting environments (urban, regional background, and remote sites) across the Mediterranean basin. Long-term observations at some stations allow the detection of changes in atmospheric...

While Earth observation (EO) increasingly provides a multitude of solutions to address environmental issues and sustainability from the city to global scale, their operational integration into the Sustainable Development Goals (SDG) framework is still falling behind. Within this framework, SDG Indicator 11.6.2 asks countries to report the “annual m...

Biomass burning is a major source of Brown Carbon (BrC), strongly contributing to radiative forcing. In urban areas of the climate-sensitive Southeastern European region, where strong emissions from residential wood burning (RWB) are reported, radiative impacts of carbonaceous aerosols remain largely unknown. This study examines the absorption prop...

This paper reports on major outcomes of the ERA-PLANET (The European network for observing our changing planet) project, which was funded under Horizon 2020 ERA-net co-funding scheme. ERA-PLANET strengthened the European Research Area in the domain of Earth Observation (EO) in coherence with the European participation to Group on Earth Observation...

97% of the urban population in the EU in 2019 were exposed to an annual fine particulate matter level higher than the World Health Organization (WHO) guidelines (5 μg/m 3). Organic aerosol (OA) is one of the major air pollutants, and the knowledge of its sources is crucial for designing cost-effective mitigation strategies. Positive matrix factoriz...

IntroductionFine particulate matter with an aerodynamic diameter < 2.5 μm (PM2.5) in the ambient air has been associated with increased blood pressure (BP) levels and new-onset hypertension. However, the association of BP with a sudden upsurge of PM2.5 in extreme conditions has not yet been demonstrated.AimTo evaluate the association between PM2.5...

Air pollution is exacerbated in cities, where pollution sources are numerous and located in a restrained area. Paved surfaces represent more than 40% of urban areas [Akbari et al., 2003], but the impact of asphalt surfaces on urban air quality has been overlooked. Although road abrasion particulate matter (PM) emissions have been well documented, a...

The purpose of this research is to demonstrate the strong potential of Earth-observation (EO) data and techniques in support of migration policies, and to propose actions to fill the existing structural gaps. The work was carried out within the “Smart URBan Solutions for air quality, disasters and city growth” (SMURBS, ERA-PLANET/H2020) project. Th...

The creation of Smart Cities is an emerging research and application field that has the objective to increase city resilience and improve the quality of life for citizens. In this paper an extensive and thorough gap analysis that was performed in the framework of the SMURBS¹ project is presented. The gap analysis identified 117 gaps in the legal, m...

Over the course of the 21st century, a century in which the urbanization process of the previous one is ever on the rise, the novel smart city concept has rapidly evolved and now encompasses the broader aspect of sustainability. Concurrently, there has been a sea change in the domain of Earth observation (EO) where scientific and technological brea...

This study examines the concentrations and characteristics of carbonaceous aerosols (including saccharides) and inorganic species measured by PM2.5 filter sampling and a multi-wavelength Aethalometer during two campaigns in a mountainous, medium-sized, Greek city (Ioannina). The first campaign was conducted in summer and used as a baseline of low c...

Understanding how multiphase processes affect the iron-containing aerosol cycle is key to predicting ocean biogeochemistry changes and hence the feedback effects on climate. For this work, the EC-Earth Earth system model in its climate–chemistry configuration is used to simulate the global atmospheric oxalate (OXL), sulfate (SO42-), and iron (Fe) c...

Ambient concentrations and sources of non-Methane Hydrocarbons (NMHCs) with 6–9 carbon atoms were investigated at an industrialized coastal location within the Port of Piraeus in Greece. Measurements were performed for a yearlong period during 2019 by means of an automated gas chromatograph with flame ionization detector (GC-FID). N-Hexane register...

Samples of black crust from the Roman-era monument of the Library of Hadrian (Athens) have been collected to perform chemical and mineralogical characterization of the degradation products on built heritage, utilizing a synergy of analytical techniques. The decay features consist of typical black crusts and a Fe-rich aluminosilicate patina. The che...

Port cities are affected by a wide array of emissions, including those from the shipping, road transport, and residential sectors; therefore, the characterization and apportionment of such sources in a high temporal resolution is crucial. This study presents measurements of fine aerosol chemical composition in Piraeus, one of the largest European p...

Long-term nitrogen dioxide (NO2) slant column density measurements using the MAX-DOAS (multi-axis differential optical absorption spectroscopy) technique were analyzed in order to demonstrate the temporal and horizontal variability of the trace gas in Athens for the period October 2012–July 2017. The synergy with in situ measurements and model simu...

Understanding how multiphase processes affect the iron-containing aerosol cycle is key to predict ocean biogeochemistry changes and hence the feedback effects on climate. For this work, the EC-Earth Earth system model in its climate-chemistry configuration is used to simulate the global atmospheric oxalate (OXL), sulfate (SO42−), and iron (Fe) cycl...

As cities are growing in size and complexity, the estimation of air pollution exposure requires a detailed spatial representation of air pollution levels, rather than homogenous fields, provided by global- or regional-scale models. A critical input for city-scale modeling is a timely and spatially resolved emission inventory. Bottom–up approaches t...

This study analyzes the spectral characteristics of in situ measured aerosol properties, namely scattering, absorption and single scattering albedo (SSA), explicitly examining the curvature characteristics of their wavelength dependence. Measurements were performed at an urban background site in Athens, Greece, during December 2017 and March 2018 c...

This study examines the spectral properties and source characteristics of absorbing aerosols (BC: Black Carbon; BrC: Brown Carbon, based on aethalometer measurements) in the urban background of Athens during December 2016 – February 2017. Using common assumptions regarding the spectral dependence of absorption due to BC (AAEBC=1) and biomass burnin...

Levels and sources of non-Methane Hydrocarbons (NMHCs) were investigated at the urban background Thissio station, close to the historical center of Athens (Greece) from March 2016 to February 2017 (12 months), by means of an automated GC-FID. Alkanes dominated over aromatics and alkenes, with hourly mean levels ranging from detection limit up to 60...

The evaluation of chemical transport models, CTMs, is essential for the assessment of their performance regarding the physical and chemical parameterizations used. While regional CTMs have been widely used and evaluated over Europe, their validation over Greece is limited. In this study, we investigate the performance of the Long Term Ozone Simulat...

The Eastern Mediterranean is a highly populated area with air quality problems. It is also where climate change is already noticed by higher temperatures and s changing precipitation pattern. The anthropogenic aerosol affects health and changing concentrations and properties of the atmospheric aerosol affect radiation balance and clouds. Continuous...

Year-round carbon dioxide (CO2) and methane (CH4) concentration measurements, performed for the first time in the city of Athens, Greece from 21/12/2018 to 31/12/2019, are presented in this study and analyzed in relation to atmospheric circulation patterns at a local, regional and long-range transport scale. Clear diurnal and seasonal variations of...

COVID-19 is evolving into one of the worst pandemics in recent history, claiming a death toll of over 1.5 million as of December 2020. In an attempt to limit the expansion of the pandemic in its initial phase, nearly all countries imposed restriction measures, which resulted in an unprecedented reduction of air pollution. This study aims to assess...

The Eastern Mediterranean is a highly populated area with air quality problems as well where climate change already is noticed by higher temperatures and changing precipitation pattern. The anthropogenic aerosol affects health and changing concentra-tions and properties of the atmospheric aerosol affect radiation balance and clouds. Continuous long...

Citizen Science (CS) projects vary greatly. The aims and goals of a CS project determine the type of citizen involvement and the tools to be used, which in most cases also entail information and communication technology (ICT) that facilitates public participation in scientific research. Resource limitations in CS projects often require adopting sub...

In this study, we report on the retrieval of aerosol extinction profiles from ground-based scattered sunlight multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements, carried out at Athens, Greece. It is the first time that aerosol profiles are retrieved from MAX-DOAS measurements in Athens. The reported aerosol vertical dis...

The lockdown measures implemented worldwide to slow the spread of the COVID-19 pandemic have allowed for a unique real-world experiment, regarding the impacts of drastic emission cutbacks on urban air quality. In this study we assess the effects of a 7-week (23 March-10 May, 2020) lockdown in the Greater Area of Athens, coupling in situ observation...

The evaluation of chemical transport models, CTMs, is essential for the assessment of their performance regarding the physical and chemical parameterizations used. While regional CTMs have been widely used and evaluated over Europe, their validation over Greece is limited. In this study, we investigate the performance of the LOTOS-EUROS v2.2.001 re...

Recent advances in particle sensor technologies have led to an increased development and utilization of low-cost, compact, particulate matter (PM) monitors. These devices can be deployed in dense monitoring networks, enabling an improved characterization of the spatiotemporal variability in ambient levels and exposure. However, the reliability of t...

A three dimensional (3D) variant of the Potential Source Contribution Function (PSCF) model was used in this study, aiming to identify the source areas and altitudinal atmospheric layers associated with PM10 exceedances of the daily EU limit value (>50 μg/m³) during the different seasons in Athens (Greece). The analysis covers the period 1 May 2015...

Twenty-one archaeological sites in Greece were selected to study their exposure to particulate pollution, in terms of aerosol loading and chemical type, to infer on the potential impact on the structural materials (specifically stone) of the monuments, using Space-Borne Remote Sensing instruments, MODIS and CALIPSO. The analysis revealed three geog...

Monoterpenes and isoprene are important constituents of the volatile organic compounds (VOCs) due to their high reactivity and participation in ozone and secondary aerosol formation. The current work focuses on the results of a 13-month intensive campaign of high resolution time-resolved measurements of these compounds, at an urban background site...

The aim of this study is to present the development-and field evaluation-of an IT platform for the monitoring and recording of atmospheric conditions in urban environments, mainly through a wireless network of sensor-based air quality monitoring systems that can supplement existing infrastructures.

Abstract. In this study, we report on the retrieval of aerosol extinction profiles from ground-based scattered sunlight multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements, carried out at Athens, Greece. It is the first time that aerosol profiles are retrieved from MAX-DOAS measurements in Athens. The reported aerosol ve...

To evaluate air quality in Athens (Greece), hourly concentrations of PM10, NO2, O3, and CO from an urban background monitoring station and a suburban sampling site, covering the years 2014–2018, were used for the calculation of individual daily air quality indices (AQIs), reflecting the impact of each pollutant on air quality. Individual AQIs were...

Atmospheric new particle formation (NPF) is an important source of submicron particles. In remote background environments where local sources are scarce such processes may impact significantly on climate-relevant parameters. On the other hand, in urban environments, newly-formed particles are adding up to submicron particles emitted from primary so...

Long‐term ground-based measurements of aerosol optical properties in Athens, Greece, for the period 2008–2018 performed by the National Observatory of Athens are used in order to investigate the aerosol climatology of the area. In this study, we utilize quality-assured measurements of the aerosol optical depth (AOD), Single Scattering Albedo (SSA)...

This study examines the carbonaceous-aerosol characteristics at three contrasting urban environments in Greece (Ioannina, Athens, and Heraklion), on the basis of 12 h sampling during winter (January to February 2013), aiming to explore the inter-site differences in atmospheric composition and carbonaceous-aerosol characteristics and sources. The wi...

This study describes the first replication of a state-of-the-art high resolution photochemical model, migrating from central European implementations to south-eastern Europe. The model is based on the Eulerian urban dispersion model EPISODE coupled with the newly developed CityChem extension, and offers a more advanced treatment of the photochemica...

A first assessment of the spatial variability of ambient black carbon (BC) concentrations in the Greater Area of Athens (GAA) was carried out during an intensive wintertime campaign, when ambient levels are exacerbated by increased biomass burning for residential heating. Short-term daytime BC measurements were conducted at 50 sites (traffic and ur...

This study aims to delineate the characteristics of Black Carbon (BC) in the atmosphere over Athens, Greece, using 4-year (May 2015 - April 2019) Aethalometer (AE-33) measurements. The average BC concentration is 1.9 ± 2.5 µg m−3 (ranging from 0.1 to 32.7 µg m −3; hourly values), with a well-defined seasonality from 1.3 ± 1.1 µg m−3 in summer to 3....

This study analyses 4-years of continuous 7-λ Aethalometer (AE-33) measurements in an urban-background environment of Athens, to resolve the spectral absorption coefficients (babs) for black carbon (BC) and brown carbon (BrC). An important BrC contribution (23.7 ± 11.6%) to the total babs at 370 nm is estimated for the period May 2015 – April 2019,...

Athens, Greece has been in economic and social crises after the 2008 global recession, resulting in an increase in wood burning as a cheaper method of residential heating in the winter. Reducing wood burning emissions is a source-specific method to address air quality degradation, and indirectly climate change, through instituting policies aimed at...

During the summer of 2012 a coordinated field campaign was conducted in multiple locations in Greece in order to characterize the ambient particulate matter (PM) levels, its chemical composition and the contribution of the regional and local sources. PM1, PM2.5 and PM10 samples were collected simultaneously at seven different sites in Greece: an ur...

In order to study the years of the outbreak of the financial crisis in Greece, we use a continuous eight-year record (2008–2015) of formaldehyde, HCHO, columns retrieved from the GOME-2/MetOp-A and GOME-2/MetOp-B satellite instruments over two urban Greek regions, Thessaloniki and Athens. A statistical linear regression analysis that was applied to...

This study examines year-long (April 2015-March 2016) measurements of black carbon (BC) concentrations acquired with a 7-wavelength Aethalometer (ΑΕ-42) at Panchgaon, in the southern Delhi outskirts. We assess the seasonality of BC concentrations and focus on the quantification of the relative contributions from fossil-fuel combustion (BC ff) and w...

The oxidative potential (OP) of fine and coarse fractions of ambient aerosols was studied in the urban environment of Athens, Greece. OP was quantified using a dithiothreitol (DTT) assay, applied to the water soluble fraction of aerosol that was extracted from 361 fine and 84 coarse mode of 24-h and 12-h filter samples over a one-year period. Durin...

Global transport demand is increasing and the associated emissions of GHGs are becoming a key factor in the environmental planning of networks and the actual operational management stage. We describe the development of a novel methodology for the calculation of the carbon footprint of a major motorway (Egnatia Odos) in Northern Greece. Total GHG em...

Submicron aerosol chemical composition was studied during a year-long period (26 July 2016–31 July 2017) and two wintertime intensive campaigns (18 December 2013–21 February 2014 and 23 December 2015–17 February 2016), at a central site in Athens, Greece, using an Aerosol Chemical Speciation Monitor (ACSM). Concurrent measurements included a partic...

This work examines the variability of aerosol optical properties (absorption and scattering) over the course of 5 years (2013-2017) at the background site of Navarino Environmental Observatory (NEO, located at Pylos, Western Greece) and its covariance with another background location that of Finokalia (Crete), to shed light on regional aspects of a...

To assess the chemical composition and sources of particulate matter (PM) at the remote coastal location of Navarino Environmental Observatory (NEO) at Pylos, PM 10 aerosol samples were collected on quartz filters from May to October 2016, covering the warm period of the year. Filters after weighting for mass determination, were consequently analyz...

In this study long term measurements of the following parameters are presented : (a) Scattering coefficient at 532 nm monitored by nephelometer (M903, Radiance Research) under a flow of 5 lpm on five minute integration intervals. (b) Absorption coefficient quantified as a function of Black Carbon (BC) with a single wavelength aethalometer (model...

Non-methane hydrocarbons (NMHCs) play an important role in atmospheric chemistry, contributing to ozone and secondary organic aerosol formation. They can also serve as tracers for various emission sources such as traffic, solvents, heating and vegetation. The current work presents, for the first time to our knowledge, time-resolved data of NMHCs, f...

In an attempt to take effective action towards mitigating pollution episodes in Athens, precise knowledge of PM2.5 composition and its sources is a prerequisite. Thus, a 2-year chemical composition dataset from aerosol samples collected in an urban background site in central Athens from December 2013 to March 2016 has been obtained and a positive m...

The scope of this study was to estimate the contribution of fossil fuel and wood burning combustion to black carbon (BC) and carbon monoxide (CO) during wintertime, in Athens. For that purpose, in situ measurements of equivalent black carbon (eBC) and CO were simultaneously conducted in a suburban and an urban background monitoring site in Athens d...

Submicron aerosol chemical composition has been studied during a year-long period (26/07/2016–31/07/2017) and two winter-time intensive campaigns (18/12/2013–21/02/2014 and 23/12/2015–17/02/2016), at a central site in Athens, Greece, using an Aerosol Chemical Speciation Monitor (ACSM). Concurrent measurements include a Particle-Into-Liquid Sampler...

In an attempt to take effective action towards mitigating pollution episodes in the Greater Athens Area (GAA), precise knowledge of PM2.5 composition and their sources is a prerequisite. Thus, a two year chemical composition data set from aerosol samples collected in an urban-background site of central Athens, from December 2013 till March 2016, ha...

Aerosol absorption profiling is crucial for radiative transfer calculations and climate modelling. Here, we utilize the synergy of lidar with sun-photometer measurements to derive the absorption coefficient and single scattering albedo profiles during the ACTRIS-2 campaigns held in Germany, Greece and Cyprus. The remote sensing techniques are compa...

One-year measurements (October 2016–September 2017) of aerosol optical properties in the Athens urban environment were analyzed; for closure purposes, the results were supported by data of chemical composition of the non-refractory submicron aerosol fraction acquired with an Aerosol Chemical Speciation Monitor (ACSM). Both the spectral scattering (...

Non-methane hydrocarbons (NMHCs) play an important role in atmospheric chemistry, contributing to ozone and secondary organic aerosol formation. They can also serve as tracers for various sources such as traffic, solvents, heating and vegetation. The current work presents, for the first time to our knowledge, time-resolved, uninterrupted data of NM...

The scope of this study was to estimate the contribution of fossil fuel and wood burning combustion to black carbon (BC) and carbon monoxide (CO) during wintertime, in Athens. For that purpose, in-situ measurements of equivalent Black Carbon (eBC) and CO were simultaneously conducted in a suburban and an urban background monitoring site in Athens d...

For the past 8 years, Greece has been experiencing a major financial crisis which, among other side effects, has led to a shift in the fuel used for residential heating from fossil fuel towards biofuels, primarily wood. This study simulates the fate of the residential wood burning aerosol plume (RWB smog) and the implications on atmospheric chemist...

To evaluate the role of biomass burning emissions, and in particular of residential wood heating, as a result of the economic recession in Greece, carbon monoxide (CO) atmospheric concentrations from five (5) stations of the National Air Pollution Monitoring Network in Athens, spanning the period 2000–2015, in conjunction with black carbon (BC) con...

This study assesses the impact of dust on surface solar radiation focussing on an extreme dust event. For this purpose, we exploited the synergy of AERONET measurements and passive and active satellite remote sensing (MODIS and CALIPSO) observations, in conjunction with radiative transfer model (RTM) and chemical transport model (CTM) simulations a...

ERA-PLANET is a wide European network comprised of 118 researchers from 35 partner institutions located in 18 countries, aiming to strengthen the European Research Area in the domain of Earth Observation (EO) in coherence with the European participation to the Group on Earth Observation (GEO) and the program for the establishment of a European capa...

According to contemporary observations and analyses an increase in the number of warm days is evident, associated to global warming and the air temperature increase. At the same time, many questions regarding the variation of the yearly number of warm (and cold) day anomalies remain unanswered. In the present work, we used a 99-year long time serie...