Hazardous substances in the workplace, often in the form of invisible microscopic particles, are a leading cause of occupational disease. In the Netherlands, thousands of people die every year as a result of being exposed to hazardous substances at work. TNO develops methods and technologies to enable early detection and elimination of these silent killers in the workplace. Sensors are the latest development in this domain.

Wealth of data

The methods currently used to measure exposure to hazardous substances in the workplace are time consuming and laborious: measurements are taken in certain places for a number of hours, a sample is sent to a lab for analysis and the results are received days later. This makes it impossible to identify relationships between the time and level of exposure and the source of the hazardous substance. The new sensor allows measurements to be recorded in far more places and read in real time. Immediate action can then be taken if necessary. The sensor simultaneously provides a comprehensive set of data that shows the hazardous substances in the workplace, the concentrations in which they occur, and where levels are potentially dangerous to human health.

Combined expertise

TNO has developed a prototype of a sensor that has recently been extensively tested on a construction site. This first prototype is designed to measure concentrations of carcinogenic crystalline silica, better known as silica dust. The ultimate aim is to create a flexible sensor that can detect a wide range of hazardous substances in all kinds of sectors. This will provide clear data on where and at what time there are potentially dangerous levels of particular substances. Complex and time-consuming processes can be replaced by a fast, user-friendly and inexpensive solution that works in real time. TNO has achieved this by combining expertise in working conditions, chemistry, big data, computational models, data communication and human behaviour.


The system basically consists of a cyclone separator that sucks up particles in situ and a spectrometer that operates at infrared wavelengths. The data is processed by a computer in real time and sent to the cloud for further analysis, the issuing of warnings or storage. TNO has created a special data infrastructure for this purpose. This makes it possible to also display the data in an app. A large construction company tested the system while carrying out a range of activities. This provided detailed insight into the places where silica dust occurs, the levels at which it occurs, and which activities involve exposure. TNO can use this knowledge of the company’s experience and the preferences of its employees to further optimise the design.

Wearable sensor

The current prototype is relatively large. In the foreseeable future TNO expects to reduce it to a small wearable sensor that can easily be attached to workwear. The ability to constantly monitor risks and acute hazards in the workplace in real time will significantly contribute to occupational health and safety across a range of sectors.

TNO is keen to talk to entrepreneurs who are interested in using the sensor and companies that want to help further develop the sensor.

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Dr. Joe Trimboli