  Under the assumption of a simple and time-invariant gravitational potential,
many Galactic dynamics techniques infer the Milky Way's mass and dark matter
distribution from stellar kinematic observations. These methods typically rely
on parameterized potential models of the Galaxy and must take into account
non-trivial survey selection effects, because they make use of the density of
stars in phase space. Large-scale spectroscopic surveys now supply information
beyond kinematics in the form of precise stellar label measurements (especially
element abundances). These element abundances are known to correlate with
orbital actions or other dynamical invariants. Here, we use the Orbital Torus
Imaging (OTI) framework that uses abundance gradients in phase space to map
orbits. In many cases these gradients can be measured without detailed
knowledge of the selection function. We use stellar surface abundances from the
APOGEE survey combined with kinematic data from the Gaia mission. Our method
reveals the vertical ($z$-direction) orbit structure in the Galaxy and enables
empirical measurements of the vertical acceleration field and orbital
frequencies in the disk. From these measurements, we infer the total surface
mass density, $\Sigma$, and midplane volume density, $\rho_0$, as a function of
Galactocentric radius and height. Around the Sun, we find
$\Sigma_{\odot}(z=1.1$ kpc)$=72^{+6}_{-9}$M$_{\odot}$pc$^{-2}$ and
$\rho_{\odot}(z=0)=0.081^{+0.015}_{-0.009}$ M$_{\odot}$pc$^{-3}$ using the most
constraining abundance ratio, [Mg/Fe]. This corresponds to a dark matter
contribution in surface density of $\Sigma_{\odot,\mathrm{DM}}(z=1.1$
kpc)$=24\pm4$ M$_{\odot}$pc$^{-2}$, and in total volume mass density of
$\rho_{\odot,\mathrm{DM}}(z=0)=0.011\pm0.002$ M$_{\odot}$pc$^{-3}$. Moreover,
using these mass density values we estimate the scale length of the
low-$\alpha$ disc to be $h_R=2.24\pm0.06$kpc.
