iSPEX-EU at a Glance

Information about the iSPEX-EU campaign.

Campaign Goals

iSPEX-EU is the first Europe-wide citizen campaign of the iSPEX project.

The iSPEX project actively involves citizens in the scientific measurement of air pollution. With the iSPEX add-on you can transform your smartphone into an optical sensor that is suited to measure tiny atmospheric particles, also called aerosols. Atmospheric aerosols play an important but as-yet poorly understood role in climate and air quality, with significant impacts on our environment, health, and air traffic. To asses their role and consequential implications, aerosols need to be measured with high spatio-temporal resolution.

Present ground-based aerosol monitoring networks are limited in spatial coverage. Satellite-based aerosol monitoring is, despite its global coverage, limited in spatial and temporal resolution (with global coverage up to once a day with a ground resolution of a few kilometers only), and lacks sufficient information on aerosol particle characteristics. Therefore, a different strategy is needed to overcome these current limitations.

Following an initial citizen campaign in the Netherlands in 2013, the iSPEX project is now crossing borders with a first Europe-wide citizen campaign: iSPEX-EU. This campaign will run from 1 September to 15 October 2015 in major cities in Europe.

iSPEX-EU aims to:

  • make atmospheric science accessible to everyone, by active participation in scientific measurements.
  • form a network of thousands of people all over Europe that perform iSPEX measurements and provide information at locations and times that are not covered by current air pollution monitoring efforts.

With your help and that of thousands of others iSPEX-EU will be a first effort largest-ever citizen campaign for air pollution. By joining iSPEX-EU you can be part of a major project to help understand our atmosphere and make an important scientific contribution.

Join iSPEX-EU and become an iSPEX scientist in your city!

How to join?

Interested in joining iSPEX-EU in one of the participating cities?


Please click on one of the cities for details on each local city campaign and find all information needed to register to join:

After registration you will receive your own iSPEX add-on and you are about ready to start your own measurements.

This is how to get started: 1) Download the iSPEX app from the App Store and install it on your iPhone. 2) Read our measurement guidelines below. 3) Follow us on twitter and visit the iSPEX-EU website for all latest campaign news.

Become an iSPEX scientist and join us in this campaign!

Measurement Guidelines


Please follow the measurement guidelines outlined below:

All iSPEX measurements are done on cloud-free days and in daylight. Before you start, make sure you have the iSPEX add-on and your iPhone – with the iSPEX app installed – at hand. To perform an iSPEX measurement, go outdoors and proceed as follows:

  1. Find an open space such as a square, park, or similar location where there are no objects – e.g. buildings, trees or otherwise – obstructing your view on the sky.
  2. Place the add-on onto your phone, in front of the main camera. Start the app.
  3. Make sure the sun is behind you. Hold your iPhone with iSPEX in front of you, with your arm fully extended and in-line with your shadow. The iPhone should be held vertically, such that you can see the screen and iSPEX points at the horizon. Click ‘Proceed’ to start.
  4. Slowly move your arm upwards to scan the sky, until your arm is in a vertical position.
  5. Repeat this last step to take a second measurement. This second measurement is needed.
  6. Your preliminary result, a color-coded representation of your sky condition based upon your measurements, is now shown.
  7. Press ‘Share’ to upload your measurements to the iSPEX database. Note: this may take few minutes depending upon your Internet connection (Wifi or 3/4G). No connection available? Keep the app activated and get to a location with connection within 10 minutes to submit your measurements.
  8. Once your measurement is submitted, a map with all preliminary iSPEX measurement results is shown. You can also view this map on

Note: The polarizer that comes with the iSPEX add-on is not needed to take an iSPEX measurement.

Although iSPEX measurements can be made at all times during the day provided there is daylight, most useful times for measurements with iSPEX are the first part of the morning and late afternoon, at  7-11 am and 4-8 pm local summer time.