DIY Workshop: Build your own Particulate Matter ("Feinstaub") Sensor! The air quality in urban centers is often not as good as it could be or as it's supposed to be. The City of Vienna, for instance, believes that their air quality is "good" based on the data of 17 official measuring stations. But does this really eflect the real situation? Luftdaten.at is a citizen science project that encour ages citizens to do their own measurements. We found out that the situation in certain Vienniese districts is much more grave than the official data suggests. In this hands-on workshop we build our own measuring station that can be easily integrated in the luftdaten.at network and allows you to assess the air quality in your neighbourhood - wherever you live. We will also explain which air pollutants exist and what role they play. All parts of the measuring station will be provided on a free donation basis. The current situation in Vienna and other places can be looked up on our live map: https://wien.luftdaten.at luftdaten.at is part of an international network to assess air quality. As you can see on the live map, data is provided for many places around Europe and the W orld. We especially encourage internationals to participate in the workshop to s pread the idea further.