  Bhatnagar-Gross-Krook (BGK) collision kernel is employed in the Boltzmann
equation to formulate relativistic dissipative hydrodynamics. In this
formulation, we find that there remains freedom of choosing a matching
condition that affects the scalar transport in the system. We also propose a
new collision kernel which, unlike BGK collision kernel, is valid in the limit
of zero chemical potential and derive relativistic first-order dissipative
hydrodynamics using it. We study the effects of this new formulation on the
coefficient of bulk viscosity.
