In this paper an indoor air quality monitoring system based on a wireless sensor network (WSN) is presented, within the Internet of Things (IoT) concept, to help preventing asthma crisis. The system not only monitors indoor environmental conditions, to prevent the triggering of an asthma crisis, but it also provides comfort-related conditions and information for people with obstructive pulmonary diseases, highlighting critical air quality conditions. The monitoring system consists of multiple sensing nodes designed to acquire temperature, humidity and the concentration levels of relevant gases. The data is wirelessly sent by each node to a coordinator node and then to an online database. A Web-based application was developed to provide data analysis, system control and alert mechanisms. Information mechanisms and environment conditions, such as a coded ambient lighting system, are also designed to generate a simple and efficient visual alert mechanism.

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