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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.

Innovation Summary

Innovation Overview

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?

Innovation Description

What Makes Your Project Innovative?

The iSPEX is an innovative product. Its big brother, the SPEX, will be used for an earth observation mission by NASA. The iSPEX uses the same technology on a smaller scale and cheaper materials to create new possibilities. What is new is that the SPEX, and potentially the iSPEX as well, not only measures how much particulate matter there is in the air but also the composition of the particulate matter. And the fact that the iSPEX is used by so many people creates a highly detailed picture.

What is the current status of your innovation?

Over the past 2.5 years, the program has grown considerably. The focus has shifted from iSPEX to various other sensors that allow citizens to help monitor air quality. The National Institute of Public Health and Environmental Protection is now at a stage where crowd-based monitoring is implemented in the regular process, whereby the data obtained is also made available to citizens. The institute is scaling up in the Netherlands. Meanwhile, it is focusing on developing and supporting communities of citizens who are jointly engaging in particulate matter monitoring. This sees residents make a measuring plan for their neighborhood, while carefully considering what the community needs.

Embracing citizen science has yielded valuable data and created a new network of partners. In this network, the institute fulfills the role of an independent and expert adjudicators, facilitating measuring done by citizens and putting openness and transparency first.

Innovation Development

Collaborations & Partnerships

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). With regard to developing communities of citizens, the institute draws on methods used by, a German citizen science project.

Users, Stakeholders & Beneficiaries

Ultimately, the citizens measuring particulate matter are at the core of this innovation. They are both user and collaborator in this project. Putting trust in citizens and communities is an important development that the National Institute of Public Health and Environmental Protection has gone through over the past years.

Innovation Reflections

Results, Outcomes & Impacts

In 2013, 9,997 measurements were performed over a period of three days. Based on the resulting data, two articles were published confirming the effectiveness of the measurements and the power of citizen science. This experiment was repeated on a European level in 2015 (5,368 measurements in eleven European cities). These experiments have generated great exposure, as the iSPEX shows that citizen science works, that people are willing to get involved, and that this is a good and efficient way to conduct science experiments.

But above all, the experiment has produced a learning effect. Citizen science will fundamentally change the role of the National Institute of Public Health and Environmental Protection, because the organisation will no longer do all the measuring itself, and become more of a facilitator enabling others to perform the measurements, using its expertise to ensure reliable measurements and provide open access to data.

Challenges and Failures

During the innovation process, not all of the institute’s employees backed the new way of working, because the measurements using iSPEX differed from their own official measurements. They questioned the quality of the data collected by citizens. And they were afraid of losing their jobs, as they saw citizens do what they used to do. As it turned out, data collection helped shape a new role for the institute, changing from that of an institute that performs measurements detached from society, where virtually no one took any notice of the outcomes, to that of a service provider to other parties. What was also interesting to see was that measurements by citizens actually led to an increase in the number of official monitoring stations.

Conditions for Success

The institute simply started with a number of projects. The results brought success. Internally, support grew, and the innovation became ever more important, in part because management was open to it. The institute has always been an organisation that has allowed its employees to work on innovations, such as the iSPEX in this case.

One of the institute’s core tasks is to conduct independent research. In this citizen science project, they had the courage to outsource monitoring, showing faith in the citizens who, thanks to the iSPEX device, became co-researchers. This was a key success factor, as was the institute’s consistency in providing open access to data.

On top of that, the institute turned out to be able to strike up successful partnerships with parties that did not work according to traditional structures but were structured differently, such as networks and communities. This is important when, for example, you need to submit a subsidy application together.


The institute teamed up with the German citizen science project. This project is a network that works based on communities. It inspired the institute to also start harnessing the power of communities in the Netherlands. What is interesting about this way of working is that it can be effective both in countries where the public sector has a very independent role, such as in the Netherlands and in countries where this is not the case and where citizens take the initiative, filling the void left by an ineffective public sector.

On the one hand, customisation is key. Within the communities, the institute tries to tap into what the people of the region find important and how they would like to shape the monitoring of airborne particulate matter. On the other hand, it is important that the same technology is used everywhere, so as to ensure the data can be compared across national borders. After all, particulate matter does not take any notice of borders.

Lessons Learned

The National Institute of Public Health and Environmental Protection has learnt that partnering with citizens in monitoring particulate matter yields valuable data. Citizen science requires a different approach to data collection and the institute’s role in that. A new network is created, a network of partners with whom they work together. In this network, the institute’s role is that of an independent party that facilitates monitoring by citizens and puts openness and transparency first. The institute has learnt how important it is to tie in with the broader system by working together with communities.

Citizen science is based on a philosophy of transparency and data sharing. Collaborating with other parties that do not work based on this philosophy sometimes creates tricky situations for the Dutch National Institute of Public Health and Environmental Protection. As a research institute, the Dutch National Institute of Public Health and Environmental Protection is used to only publishing data when they are 100% sure it is accurate. But now they are publishing data without certainty on its accuracy. For citizens, this is important because it confirms to them that data is shared with maximum openness. The institute does, however, still provide an indication of the quality of the data. This independent assessment is crucial, and legitimises the institute’s role. For the institute, it is crucial that they consistently provide that openness, and keep independently assessing data, because if they do not, they will lose citizens’ trust.

And the institute has furthermore learnt that the best approach to innovation is sometimes to just get started and get stuck into one specific project. In doing so, however, the internal organisation needs to be geared towards this, and internal and external communications about the innovation need to be consistent.

Year: 2013
Level of Government: National/Federal government


  • Diffusing Lessons - using what was learnt to inform other projects and understanding how the innovation can be applied in other ways

Innovation provided by:

Date Published:

18 November 2019

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