  Observations of protoplanetary disks have revealed them to be complex and
dynamic, with vertical and radial transport of gas and dust occurring
simultaneously with chemistry and planet formation. Previous models of
protoplanetary disks focused primarily on chemical evolution of gas and dust in
a static disk, or dynamical evolution of solids in a chemically passive disk.
In this paper, we present a new 1D method for modelling pebble growth and
chemistry simultaneously. Gas and small dust particles are allowed to diffuse
vertically, connecting chemistry at all elevations of the disk. Pebbles are
assumed to form from the dust present around the midplane, inheriting the
composition of ices at this location. We present the results of this model
after 1 Myr of disk evolution around a 1$M_\odot$ star at various locations
both inside and outside of the CO snowline. We find that for a turbulent disk
($\alpha = 10^{-3}$), CO is depleted from the surface layers of the disk by
roughly 1-2 orders of magnitude, consistent with observations of protoplanetary
disks. This is achieved by a combination of ice sequestration and decreasing UV
opacity, both driven by pebble growth. Further, we find the selective removal
of ice species via pebble growth and sequestration can increase gas phase C/O
ratios to values of approximately unity. However, our model is unable to
produce C/O values of $\sim$1.5-2.0 inferred from protoplanetary disk
observations, implying selective sequestration of ice is not sufficient to
explain C/O ratios $>1$.
