Cyprus Atmospheric Observatory (CAO) at Agia Marina Xyliatou


The Cyprus Atmospheric Observatory (CAO) is operating under the Energy Environment and Water Research Center (EEWRC) of The Cyprus Institute . It is situated at a remote site in the center of the island (35.04N; 33.06E; 535m above sea level), close to the villages of Agia Marina and Xyliatos, at the Forestry Department premises of “Agia Marina Xyliatou”. The station is co-operated with the Department of Labour Inspection, in charge of the air quality network in Cyprus, and is also the EMEP rural station for Cyprus since 1997.

cy map


The Cyprus Atmospheric Observatory (CAO) is located at a rural background site in Cyprus (picture left), in the foothills of the Troodos mountain (south view of the station below)





troodos foothills

The mission of CAO is to provide quality controlled long-term atmospheric observations of key atmospheric pollutants (gases/aerosols) relevant to climate change and air quality; observations that have not been performed in the region.

CAO offers modern facilities and supportive infrastructure for research, testing of technologies related to atmospheric measurements, and hands-on training through educational programs. With logistic facilities of high quality, CAO is ideally designed to host large intensive field studies and perform long term atmospheric observations. Consequently, The station benefits from EU funds (e.g., the H2020 ACTRIS-2 project) that facilitate transnational access to the international scientific community on a merit-based priority scheme.

atmos 1 atmos 2








Picture of the co-located CAO building facilities (left) and the concrete atmospheric platform (right) currently hosting wet/dry deposition samplers and sunphotometry observations

CAO is currently composed by two 15m² containers fully equipped with high capacity air condition units, electricity (single and three phase) up to 45A, two UPS units, remote video control and alarm system, lab benches, 19” racks, fast internet connection, standard atmospheric inlets for gases and aerosols, and a weather station (Campbell).

The CAO station is ideally located to document and contrast long-range transported pollution from three continents (Europe, Africa, and West Asia) and dust aerosols from the two largest desert regions in the world (Sahara, Middle East).

dust pollution map


Cyprus, at the crossroads of air masses transported from Europe, the Middle East and Africa.






The facility is equipped with state-of-the-art instrumentation partly provided by CNRS research teams in the frame of the French Chemistry-Aerosol Mediterranean Experiment (ChArMEx) program (list of equipment below)

Parameter Instrument Parameter Time Resolution
Aerosol chemistry Q-ACSM SO4, NH4, NO3, OM in PM1 30 min
Aerosol chemistry Leckel (filter sampling) + Lab analysis ions, carbon in PM1 24h
Aerosol chemistry Leckel (filter sampling) + Lab analysis ions, carbon in PM2.5 24h
Aerosol chemistry Leckel (filter sampling) + Lab analysis ions, carbon in PM10 24h
PM dichotomous TEOM-FDMS 1405 PM2.5, PM10 15 min
PM TEOM 1400 PM2.5 15 min
Aerosol physics TSI - APS Size dist. 0.3-10µm 1 min
Aerosol physics SMPS Grimm 5400 Size dist. 0.01-1µm 15 min
Aerosol optical properties Nephelometer TSI 3λ Light scattering (PM10) 5 min
Aerosol optical properties Aethalometer AE31 + AE33 (7λ) Absorption (PM10), BC 5 min
Aerosol optical properties Sunphotomer AOD -
Weather Station Campbell Scientific P, T, RH, WS, WD, SR 5 min
Reactive gases Ecotech NO, NO2 (NOx) 1h
Reactive gases Ecotech CO  
Reactive gases Ecotech SO2 1h
Reactive gases Ecotech O3 1h


aerosol instrumentation

View inside container #1 with the aerosol instrumentation to perform long-term observations





Ground-based observations performed at CAO benefit from a unique infrastructure (USRL) that allows regular in-situ vertical atmospheric observations above the station performed by Unmanned Aerial Vehicles (UAVs).

private runway           runway
Private (CyI) runway and airspace located close to CAO (picture left) and CyI UAV performing vertical profile of Black Carbon (picture right)

CAO is supported by CyI and the Horizon 2020 ACTRIS2 project, which is the European Research Infrastructure for the observation of Aerosol, Clouds, and Trace gases, currently on the roadmap of European Strategy Forum for Research Infrastructures (ESFRI).

Atmospheric Research Activities conducted at CAO
Since beginning of 2015, the atmospheric station provides real-time observations of key aerosol characteristics and radiative properties which are regularly quality controlled through harmonized international intercomparison procedures. These measurements are shared within the scientific community through world data centers and provide critical constraints for regional models addressing issues related to climate change and air pollution. Activities conducted at CAO encompass the following themes.

Regional air quality baseline: The position of the station, not influenced by local contamination sources, makes it a strategic background site to characterize regional air pollution that is transported to and across Cyprus from Europe/Africa/W-Asia. Such information is critical to discriminate long-range transported from locally generated air pollution in the Cypriot urban environment, and supports evaluation and optimization of national mitigation measures.

Crossroads of international air pollution transports : Cyprus is centrally located in the Eastern Mediterranean where a wide range of air pollution source regions can be monitored and compared; this includes eastern Europe, for example the Black Sea region, the Middle East and North Africa; the polluted air masses can be contrasted to clean air from the Atlantic-Mediterranean sector. To investigate the pollution transports in four dimensions and their role in regional climate change, we established multi-platform infrastructure by combining the Agia Marina Xyliatou station with UAV (Unmanned Aerial Vehicle) facilities to also probe the vertical structure of the atmosphere.

Desert dust aerosols: Cyprus is located downwind of major deserts in North Africa and the Middle East. This offers the opportunity to study the role of dust-air pollution interactions. The atmospheric processing or “ageing” of dust particles is expected to change their chemical/physical/optical/hygroscopic growth properties, their lifetime (wet and dry deposition), impacts on clouds (cloud droplet and ice nucleating properties) and the radiative forcing of climate.

CyI Scientists
Prof. Jean Sciare
Prof. Mihalis Vrekoussis
Prof. Nikos Mihalopoulos
Prof. G. Biskos
Prof. Jos Lelieveld
Prof. Evripides Stephanou
Dr. M. Pikridas
M. I Stavroulas

Major Partners

dept lab insp cy uni tech lsce loa max planck nat obs athens
Department of Labour Inspection (Cyprus) Cyprus University of Technology (Cyprus) LSCE (CNRS, CEA, UVSQ, France) LOA (CNRS, Univ. Lille, France) Max Planck Institute for Chemistry (Germany) National Observatory of Athens (Greece)

Research Projects

charmex MISTRALS/ChArMEx: Mediterranean Integrated STudies at Regional And Local Scales / The Chemistry-Aerosol Mediterranean Experiment
actris ACTRIS2 (H2020): European Research Infrastructure for the observation of Aerosol, Clouds, and Trace gases
bacchus BACCHUS (FP7): Impact of Biogenic versus Anthropogenic emissions on Clouds and Climate: towards a Holistic UnderStanding
wmo gaw WMO-GAW: World Meteorological Organization – Global Atmosphere Watch
emep EMEP: European Monitoring and Evaluation Programme
aeronet NASA-AERONET: National Aeronautics and Space Administration - Aerosol Robotic Network
gender equality