We construct realizations for
the 2-toroidal Lie algebra associated with the Lie algebra A1 using vertex operators
based on bosonic fields. In particular our construction realizes higher-level
representations of the 2-toroidal algebra for any given pair of levels (k0,k1) with
k0≠0. We also construct a smaller module of level (k0,0) for the toroidal algebra
from the Fock space using certain screening vertex operator, and this later
representation generalizes the higher-level construction of the affine Lie algebra
sl2.