Deposition of particles on gypsum-rich coatings of historic buildings in urban and rural environments

Deposition of gaseous and particulate atmospheric pollutants causes decay of historic mortars to give gypsum-rich coatings by sulphation of lime mortars and blackening of gypsum mortar, resulting in gypsum coatings. Particulate pollution emitted by industrial sources and vehicular traffic is responsible for the deterioration. XRF and SEM analyses of these coatings and their comparison with both the composition of dust coatings formed by the deposition of gaseous and particulate matter in an urban and a rural locality allows assessing which pollution sources are the most damaging for these materials, knowing the elemental composition of these emissions.