Imec and Holst Centre have developed a small NO₂ sensor featuring a low power consumption in the mW range. The sensors have a low detection limit for NO₂ (<10 ppb) and a fast response time. They are particularly well suited for air quality monitoring and serve as a solution to the increased demand for accurate local air quality monitoring for indoor and outdoor environments. The sensors are being tested in real-life situations, as part of an environmental monitoring platform.

While wearable technology that measures body parameters has become increasingly popular in recent years, the Intuitive Internet of Things (I²oT) is next on the horizon: connecting everybody and everything everywhere with data stored in the cloud, turning the massive amount of data in information to make the right decisions, to take the right actions exactly as we need or want. The I²oT is expected to manage the sustainability, complexity and safety of our world. It will increase our comfort and wellbeing in many ways.

Health issues resulting from poor air quality are a growing concern for consumers and accurate monitoring is becoming more and more in demand, for both outdoor and indoor environments.

Air quality is typically measured on just a few distinct locations per city, with specialized equipment. Many current gas sensors are large in size, have high power consumption and are too cost prohibitive to be implemented on a large scale for I²oT applications. Imec and Holst Centre have developed small, simple, low power and high quality autonomous sensors that wirelessly communicate with the environment and the cloud.

Imec and Holst Centre’s NO₂ sensors were integrated in the Aireas air quality network, a multiple sensor network in the city center of Eindhoven (the Netherlands). The purpose was to test -in actual outdoor conditions and long term- the stability of the sensors, and benchmark them against established reference sensors. The sensors are operational since early May 2015 and contribute with valuable outdoor sensor data since then. During traffic rush hours, the sensors detect a significant increase of NO₂ concentration up to the health safety limits.

Imec and Holst Centre are currently deploying a similar sensor network inside the Holst Centre building in Eindhoven to test the sensors for indoor air quality monitoring. This environmental monitoring platform today includes it proprietary NO₂ sensor and commercial sensors for temperature, relative humidity and CO₂. The measured levels can be monitored live, over the internet. In a next step, proprietary low-cost low-power sensors will be added for CO₂, VOCs (Volatile Organic Compounds), Ozone, and particle matter.

The generated sensor data are transferred to the cloud, stored in a database and immediately available on (mobile) applications, explained Kathleen Philips, director of imec’s perceptive systems for the intuitive internet of things R&D program.

“Data fusion methodology and advanced algorithms enable us to combine data from different sensors such as temperature, several gasses, humidity, human presence detection and to derive contextual knowledge. This information contributes to a correct interpretation of the situation and helps us to take adequate actions to solve the problem. In this way, we have developed a context-aware intuitive sensing system.”

Companies interested in early application validation and development for distributed IoT networks and/or in the innovative technology and circuits to realize them are invited to become a partner in our R&D program. IP can also be licensed.

Photo: NO2 sensor + network hardware for wireless sensor network