Performance Evaluation for Museum Enclosures. Measurement, Modelling and Mitigation of Pollutant Impact on Objects in Museum Enclosures

Results of measurement and modelling of pollutant gases inside and outside 11 enclosures used to protect exhibited objects in 10 European museums are presented. Monthly average values for ozone, nitrogen dioxide, formic and acetic acid, temperature and relative humidity inside the enclosures, and yearly average values for the pollutants inside and outside the enclosures are presented for each enclosure. An available pollution impact model was adapted to the use with enclosures. Model calculations are presented for the expected change in concentrations of the oxidizing: ozone and nitrogen dioxide, and acidic: acetic and formic acid, pollutants depending on possible change in the ventilation rate of the enclosures and on inclusion of active carbon absorber to reduce the concentrations. The modelling results are presented as the ‘impact concentration’ of the pollutants by weighing the measured concentrations with their respective recommended levels. In several of the enclosures a clear correlation was observed between temperature and/or relative humidity and the concentration of acetic and formic acid. The modelling showed that all of the enclosures protected against air pollutants, but that only one of the 11 enclosures satisfied the recommended level. The recommended level could be reached for all the enclosures by reducing the ventilation or including active carbon absorber to cover the floor area.