The system described in this paper notifies the user about possible indoor environmental hazards through a smartphone application. Events such as house fires or increasing levels of dangerous substances are detected; thus, raising the awareness level in regard to the quality of the indoor environment. Our solution is a system that monitors the environment within a room in order to avoid undesired health hazards. It consists of a data collection subsystem, a cloud database which stores the collected information and a mobile application that displays and notifies the user in case of critical events that might negatively affect the health condition.