The protection of the public against ionising radiation and radioactive contaminations caused by nuclear or other radiologically relevant incidents or accidents (i.e. events), including terrorist attacks, is of major importance and may affect thousands of people. Following a radiological event, radiation protection authorities and other decision makers need quick and credible information on affected and contaminated areas. Therefore, this project will develop reliable instrumentation and methods needed in the field of preparedness comprising strategies to gather relevant information, i.e. accurate and traceable data on contamination and dose rate levels, so that sound decisions on countermeasure are possible. In addition, new measuring devices and methods will be elaborated to quickly gather quantitative data on contaminated areas and dose rate levels by aerial measurements, and to analyse contaminations of the air by flexible transportable systems. However, this project will not only focus on fast measurements needed in emergency situations, but will also work on improved methods for long-term monitoring. This project will further investigate whether non-governmental networks could support official data or undermine them. The results of this project will enable an adequate response for the protection of the public and the environment against dangers arising from ionising radiation during and in the aftermath of a nuclear or radiological event.