The derivation of a model to evaluate the potential impactof gaseous pollutants on paintings installed in microclimateframes (mc-frames), and some examples of modellingresults, is presented. The model can be used to study howbasic design properties of microclimate frames, such astheir air exchange rate, their volume and/or the inclusion ofabsorbers can affect the pollution fluxes to paintings insidethe frames. The modelling indicated that a magnitudeincrease in air exchange rate from a low level of ~1 d-1can significantly increase the impact of infiltrating pollutants,but will give only a small reduction in the potential impactof the small molecular weight organic acids (i.e. acetic andformic acid) that are emitted inside the frames. The reasonfor this is the small amount of pollutant removed by eachsingle air exchange, as compared to the large internalemission and deposition fluxes of these gases.