Direct Numerical Simulation (DNS) is used to compute a horizontal gas channel flow at Re-b = 2800 (based on bulk velocity and half channel width), and to investigate the motion and dispersion of solid particles under external influences such as gravity and/or electrostatic field. Other forces such as non-linear drag corrected for wall proximity and shear-induced lift are also implemented. Emphasis is put on the time correlations of the fluid velocity along the discrete particle path in order to investigate the integral time scales of the fluid seen by the particles in the near wall region. The effect of parameters such as wall distance or external field intensity is highlighted.