In the last few years, the concern about pollutants present in indoor environments has greatly increased since in developed countries people spend large amounts of time indoors. The markedly growing consumption of cosmetics, air fresheners, house-cleaners, biocides, as well as the increase in the use of new building materials in carpeting, paints, furnishings, etc, may turn our homes, schools, offices and workplaces into harmful microenvironments. Inadequate ventilation coupled with the slow indoor degradation processes may increase indoor pollution levels. This book presents methodological developments for the analysis of pollutants in indoor air, focusing the attention on emerging contaminants and biocides that can be found both in the air gas phase, as well as associated to the suspended particulate matter and settled dust.