  Contemporary data are analyzed concerning the half-lives of the $^{229m}$Th
isomer in neutral atoms and various ions. It is explicitly shown that the
isomer lifetime may strongly depend on the plain environmental physical
conditions like pressure and temperature. Calculation is performed on the
united platform of interplay of traditional and subthreshold resonance
conversion. General agreement with experiment is obtained in the cases of
Th$^I$ and Th$^{III}$, a prediction is made concerning Th$^{IV}$. Disagreement
with the experiment in the case of Th$^{II}$ may be a consequence of a random
very sharp resonance with an electronic level. Account of the influence of the
environment on the decay rate helps one to loose the resonance condition, which
may lead to agreement with experiment. This will mean the first experimental
observation of strong dependence of the nuclear decay rate on the environment.
