The course aims to provide methodological elements through which the chemist may face problems in the world around him. In this perspective, environmental issues are emblematic, as they require to exploit sinergically basic knowledge in various areas, such as regulatory, technological, analytical and biological. Topics covered include: the dynamics of the natural cycles, environmental regulatory standards and their evolution, pollution control and problem solving, sampling methods and analysis in environmental matrices (with particular focus to issues related to the information value of the data collected). The areas covered include the ecosystem air (emissions, immissions and workplace) and water (wastewater, intended for human consumption, bathing). In the case of municipal wastewater it will be presented the whole technological cycle of purification with a peculiar focus to the conceptual aspects and plant responses with the aim of highlighting the importance of a methodological approach, which applies as a principle even in very different fields.