The Irish Atmospheric Simulation Chamber: a national facility for atmospheric sciences

The Irish Atmospheric Simulation Chamber (IASC) was established in the Centre for Research into Atmospheric Chemistry at University College Cork (UCC), Ireland to enable the study of fundamental atmospheric processes and to quantify parameters needed in air quality and climate models. This national research infrastructure consists of a custom-built chamber (~27 m³) made of Teflon FEP foil, supported in an aluminium frame, and surrounded by a temperature-controlled enclosure containing 140 UV lamps for experiments on light-driven reactions. Standard parameters such as temperature, pressure (absolute and differential), relative humidity, and CO₂ mixing ratios are continuously monitored. The facility is also equipped with a range of commercial instruments for continuous, online measurements of atmospheric constituents including NO_X (chemiluminescence detector), O₃ (photometer) and particulate matter (scanning mobility particle sizer, SMPS). A time-of-flight chemical ionization mass spectrometer (ToF-CIMS), typically operated using I^– or C₆H₆⁺ as the reagent ion, is used for detecting trace gases and particle phase species, especially organic compounds.

At the core of the facility, however, is a selection of ultra-sensitive optical detector systems, which are based on cavity-enhanced absorption methodologies developed in UCC. The methodologies comprise cavity ring-down spectroscopy (CRDS) and incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) in conjunction with dispersive and high resolution Fourier Transform detection schemes. Target species that can be detected are NO₂, NO₃ radicals, HONO, glyoxal (CHOCHO), methylglyoxal (CH₃COCHO), H₂O, and CO₂.

With this suite of instrumentation, the IASC can derive much needed information and parameters to constrain predictive atmospheric models and improve forecasts. It enables detailed investigations of a wide range of atmospheric processes including chemical reactions of radicals, volatile organic compound oxidation, secondary pollutant formation, as well as secondary organic aerosol formation and ageing in day and night cycles.

The IASC is an internationally recognized facility with involvement in European research and training networks such as EUROCHAMP-2020 and ATMO-ACCESS. The versatile and highly instrumented nature make the IASC an ideal test bed for the development, testing and benchmarking of new atmospheric monitoring technologies and sensors under controlled (not field) conditions. The current capabilities of IASC will be presented at the EGU conference and typical characterization experiments will be outlined to demonstrate some of its performance.

This work was supported by Science Foundation Ireland (grants 21/FFP-A/8973 & 15/RI/3209).