The guideline describes methods of simulating gaseous air pollution effects on materials and products. Two alternatives of simulating corrosive environmental conditions are depicted: Weathering experiments for studies of materials and products without significant effects of solar and/or artificial radiation on their ageing and durability as well as such involving a significant effect of radiation. The guideline presents procedures so that on the basis of comparison recommendations can be made for selecting materials and for their use in construction components with respect to their resistance to corrosion and ageing.