Safety is the state of being "safe" (from French sauf), the condition of being protected from harm or other non-desirable outcomes. Safety can also refer to the control of recognized hazards in order to achieve an acceptable level of risk.
To understand changes observed in the aerosol layer of the stratosphere, scientists use remote sensing to collect relevant data. EU funded scientists are now 4D modelling aerosol formation and transport, in particular after volcanic eruptions.