The time of ignition tau(r), the time of burning tau(h), and the time of burning-out tau(d) at the definite wave length of radiation being attenuated can be determined reliably from time course of attenuation of radiation caused by aerodispersions generated from the smoke protection grenades. In case of grenades being tested containing the smoke mixtures with red phosphorus, the first mentioned time characteristics at the wave length of radiation 10.6 mu m were typical by longer values than at the wave length 0.82 mu m. With the grenades containing charges of smoke mixture in pressings the maximum attenuation values 0.82 mu m were reached at the time of ignition tau(r) = 3 s, at the wave length 10.6 mu m approximately up to tau(r) = 5 s. The mentioned values of ignition tau(r) and the time of burning tau(h) make exact the technical data of screening smokes created from the smoke grenades mentioned.