  This paper considers a single-population model with age structure and
psychological effects in a polluted environment. We divide the single
population into two stages of larval and adult structure. The model uses
Logistic input, and the larvae are converted into adult bodies by constant
ratio. We only consider adulthood. The role of psychological effects makes the
contact between adult and environmental toxins a functional form, while the
contact between larvae and environmental toxins is linear.
  For the deterministic model embodied as a nonlinear time-varying system, we
discuss the asymptotic stability of the system by Lyapunov one-time
approximation theory, and give a sufficient condition for stability to be
established.
  Considering that the contact rate between biological and environmental toxins
in nature is not always constant, we make the contact rate interfere with white
noise, and then modify the contact rate into a stochastic process, thus
establishing a corresponding random single-population model. According to It\^o
formula and Lyapunov in the function method, we first prove the existence of
globally unique positive solutions for stochastic models under arbitrary
initial conditions, and then give sufficient conditions for weak average
long-term survival and random long-term survival for single populations in the
expected sense.
