Climatic and Air Pollution Effects on Building Facades

Abstract

The paper provides the basic characterization of the principal agents that affect the durability of building materials and the description of the degradation mechanisms. The degradation factors are classified according to their nature (mechanical, electromagnetic, thermal, chemical and biological agents) as well as to their origin (atmosphere, ground etc.). The interactions between materials and climatic factors with pollutants are very complex and many variables are involved. Deposition of pollutants onto surfaces depends on concentrations of the atmospheric pollutants as well as the climate including the microclimate next to a surface. In case the pollutants are on the surface, interactions will vary depending on the amount of exposure, the reactivity of different materials and the amount of moisture. General effects and their causes include surface material cracking, splitting, spalling, softening and staining, due to salt or water crystallizations and acid-base chemical dissolution reactions. The article focuses on the specific problems connected with the atmospheric pollution and climatic effects on building materials, new accelerated ageing tests, including the simulation of atmospheric acidic precipitations.