Fraction of the diffuse (cirrus) emission in the WISE 22 μm image shows a large contribution from the diffuse emission to the total flux in low surface brightness regions. Each data point and the error bar represent a median and a standard deviation of the diffuse emission over total emission inside a bin of log(I_ν(22 μm)) with a bin size of 0.1. The color contours represent pixel number density contours.