  We explore the microwave anisotropies at large angular scales produced by the
emission from cold and large dust grains, expected to exist in the outer parts
of the Solar System, using a simple toy model for this diuse emission. Its
amplitude is constrained in the Far-IR by the COBE data and is compatible with
simulations found in the literature. We analyze the templates derived after
subtracting our model from the WMAP ILC 7 yr maps and investigate on the
cosmological implications of such a possible foreground. The anomalies related
to the low quadrupole of the angular power spectrum, the two-point correlation
function, the parity and the excess of signal found in the ecliptic plane are
significantly alleviated. An impact of this foreground for some cosmological
parameters characterizing the spectrum of primordial density perturbations,
relevant for on-going and future CMB anisotropy experiments, is found.
