iSPEX – using citizen science to measure particulate matter

The iSPEX is a small attachment that can be fitted to any mobile phone to measure particulate matter in the air. The fact that this piece of technology empowers anyone to monitor air quality (citizen science) creates a raft of new possibilities to collect large volumes of data in a highly efficient and cost-effective manner. Aside from that, it raises awareness of particulate matter among the population.

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The Dutch National Institute of Public Health and Environmental Protection is a knowledge and research institute that works to protect the health of the people of the Netherlands. One of this organisation's duties is to conduct independent research into the quality of the living environment in the Netherlands, which includes monitoring air quality. For several years now, the institute has been using citizens to measure the level of particulate matter in the air.

The iSPEX was developed by a consortium made up of the Leiden Observatory, Leiden University (NOVA), the Netherlands Institute for Space Research (SRON), the National Institute of Public Health and Environmental Protection (RIVM), and the Royal Netherlands Meteorological Institute (KNMI). The iSPEX is basically a small version of the Spectropolarimeter for Planetary Exploration (SPEX), which was designed to measure particulate matter and cloud particles in the atmospheres of planets in our solar system from a satellite. By measuring the (intensity) spectrum and degree of polarisation of visible light, it is possible to establish the average size and chemical properties of particles.

The iSPEX attachment is a plastic nozzle with various filters inside it to pick up a modulated spectrum of light. This spectrum is subsequently captured by the camera of the mobile phone to which the iSPEX is attached. The associated app also records the GPS location, date, time, and angle at which the photo is taken, following which the data is processed in a centralised system. The iSPEX allows systems to supply measuring data for particulate matter maps that, thanks to their high accuracy, can complement measurements made by satellites.

Measuring particulate matter is important because certain kinds of particulate matter have adverse health effects. Particulate matter is a catch-all for very small particles in the air that can penetrate deep into our lungs and even our bloodstream. These particles can be made up of things such as sea salt (harmless) or soot (harmful). To be able to make policy for particulate matter control, it is useful to have good information about, for example, the origin of particles. Are they emitted by motorways, factories, or pig farms?

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Year: 2013
Level of government: National/Federal government


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