  In this paper, so-called alternative mass balance equations for atmospheric
constituents published recently are assessed in comparison with the true local
mass balance equations deduced from exact integral formulations. It is shown
that these "alternative" expressions appreciably violate the physical law of
the conservation of mass as expressed by the equation of continuity. It is also
shown that terms of these "alternative" mass balance equations have different
physical units, a clear indication that these "alternative" expressions are
incorrect. Furthermore, it is argued that in the case of "alternative" mass
balance equations a real basis for Monin-Obukhov similarity laws does not
exist. These similarity laws are customarily used to determine the turbulent
fluxes of momentum, sensible heat and matter in the so-called atmospheric
surface layer over even terrain. Moreover, based on exact integral formulations
a globally averaged mass balance equation for trace species is derived. It is
applied to discuss the budget of carbon dioxide on the basis of the globally
averaged natural and anthropogenic emissions and the globally averaged uptake
caused by the terrestrial biosphere and the oceans.
