Apps on chemical and biological risks are mainly a consultative and didactic, while the app on radioactive risk contains an application that allows you to calculate - in connection with an intensity of any source placed at a certain distance, the values of which are measured on field - the safety distance or the time or the exposure dose for operators and for the population as compared with the levels established by law. These are estimates made by comparison, ie on the basis of the physical properties of proportionality between the intensity and the squares of the distances, you do not know the type of radioactive source, but the evaluation is based only on reading the supplied instrumentation (radiametro and rangefinder) .