  We estimate the effects of viscosity on the phase space distribution
appearing in the Cooper-Frye formula within the framework of the Grad's
fourteen moment method and find that there are non-trivialities in the
discussion of a multi-component system. We calculate the viscous corrections of
particle spectra and elliptic flow coefficients from the distortion of the
distribution using the flow and the hypersurface taken from a (3+1)-dimensional
ideal hydrodynamic simulation. We see that the bulk viscosity have visible
effects on particle spectra. The results suggest we should treat both shear and
bulk viscosity carefully when constraining the transport coefficients from
experimental data.
