Characterisation of the Manchester Aerosol Chamber facility

This study describes the design of the Manchester Aerosol Chamber (MAC), initially developed in 2005, and presents for the first-time its comprehensive characterisation. The MAC is designed to investigate multi-phase chemistry and the evolution of aerosol physico-chemical properties from the real-world emissions (e.g. diesel engine, plants) or of secondary organic aerosol (SOA) produced from pure volatile organic compounds (VOCs). Additionally, the generated aerosol particles in MAC can be transferred to the Manchester Ice Cloud Chamber (MICC), which enables investigation of cloud formation in warm, mixed-phase and fully glaciated conditions (with T as low as -55 °C). MAC is an 18 m3 FEP Teflon chamber, with the potential to conduct experiments at controlled temperature (15-35 °C) and relative humidity (25-80 %) under simulated solar radiation or dark conditions. Detailed characterisations were conducted at common experimental conditions (25 °C, 50% RH) for actinometry and determination of background contamination, wall losses of gases (NO2, O3, and selected VOCs), aerosol particles at different sizes, chamber wall reactivity and aerosol formation. In addition, the influences of chamber contamination on the wall loss rate of gases and particles, and the photolysis of NO2 were estimated.