Pollutant-induced decay of building materials

Abstract

There are major concerns on the effect of environmental pollution on humankind, other animals, ecosystems, and also on the built environment, where the action of pollutants can affect diverse materials, harming historical elements and modern constructions. Here we review the effects of pollutants on materials used in the built environment, e.g. housing, walls, stones, wood, plastics and coatings. Compositional characteristics that make materials susceptible to pollutants are presented. The role of materials as pollution sources and notions on decay features that affect building materials are shown. Then we review the decay effects of gases, particulate matter and solutions from wet deposition to capillary-rising and including circulation waters such as run-off and seawater. The effect of pollutants on materials is discussed, as well as the role of water in decay processes and the damage caused by neoformation minerals on the surface and pore system of the building materials. The main pollutants discussed are CO2, CH4, CO, hydrocarbons, SO2, NOx, NH3, NO2, O3 , F2, HF and atmospheric particles. Afterwards we discuss the use of tracers, e.g. elements, ions and isotopes, for the study of pollutants sources and migration pathways. Main isotopes include 2H, 13C, 15N, 18O, 34S, 3H, 14C, 238U, 232Th and 40K. We show the possible use of decay features to study main sources of air pollution, e.g. transport, industrial, domestic, since building materials can fix and interact with pollutants. Proposals regarding the use of some stable and radioactive isotopes for the study of pollutants that have strong potential but have not been tested yet are also presented. At the end of this chapter we discuss the durability assessment of materials, and the use of tracers to assess the origin of damaging compounds.