[en] The influence of charged impurities on the transport properties of graphene, including the diffusion coefficient at low and high electric fields, is investigated by means of an ensemble Monte Carlo simulator. Three different possible substrates are considered, h-BN, SiC and SiO_2. The results show the importance of impurity scattering in degrading the diffusion coefficient, electronic mobility and drift velocity, particularly at low and intermediate electric fields. The influence of the substrate dielectric constant in relation to impurities and surface polar phonon scattering is also evidenced; this turns SiC into the most suitable substrate of choice from this point of view. (paper)