Rainwater is one of the main pollution tracers around the world. There are many reasons that can explain the presence of high concentrations of certain hazardous elements (HEs) in the rainwater (e.g. traffic, marine port activities, marine industry, etc.). Acid rain forms when certain atmospheric gases (primarily carbon dioxide, sulphur dioxide, and nitrogen oxides) come in contact with water in the atmosphere or on the ground and are chemically converted to acidic substances. Oxidants play a major role in several of these acid-forming process. The influence of rainwater composition on the conservation state of cementitious building materials. Rainwater may provide the best source of domestic water in areas affected by salinity, high fluoride or pollution from various sources.