The Cyprus Atmospheric Observatory station in Nicosia (CAO-NIC) is located on the premises of the Cyprus Institute, within a low-density residential area. Approximately 800 meters from the nearest major road and adjacent to the Athalassa Forest Park, the station is minimally affected by immediate local pollution sources while still representing an urban background environment. This setting makes CAO-NIC ideal for observing the interaction between local and regional atmospheric influences.

Nicosia, the capital of Cyprus, is uniquely positioned at the heart of the island on the Mesaoria plain, where airflow is shaped by the surrounding Kyrenia and Troodos mountain ranges. This geography, combined with regional wind systems, facilitates the transport of air masses from Europe, the Middle East, and North Africa.

Throughout the year, CAO-NIC is exposed to a wide range of air mass types: sulfate-rich aerosols from Eastern Europe and Turkey in the summer; mineral dust and anthropogenic pollutants from the Middle East and North Africa in other seasons; and local emissions from traffic, biomass burning, power generation, and shipping. This dynamic and chemically diverse environment makes CAO-NIC a highly valuable site for source apportionment, aerosol chemistry, and urban air quality research.

Monitoring activities at CAO-NIC are carried out from a network of rooftop-based facilities, which include custom-built laboratory spaces and modular environmental enclosures. These spaces are specifically designed to support both permanent and campaign-based atmospheric measurements, offering the flexibility needed for collaborative research and visiting scientists.

The rooftop of the NTL building hosts several long-term monitoring systems, including greenhouse gas analyzers, remote sensing instrumentation such as LIDAR and a ceilometer, as well as PM₁₀ and PM_2.5 filter samplers, and dedicated setups for dust and pollen collection.

The GOB building rooftop is dedicated to in-situ aerosol and trace gas measurements. It also provides additional rack space for experimental campaigns and guest instrumentation. Notably, the site hosts the Total Carbon Column Observing Network (TCCON) station, operational since 2021. [More information on the CAO-NIC TCCON station is available here.]

As part of the EMME-CARE project, the CAO-NIC infrastructure is being expanded to include an 87 m² laboratory within the new EMME-CARE Headquarters. This upcoming facility will function as a calibration laboratory and provide additional space for atmospheric measurement instruments. [See presentation here.]