Normalized probability distribution functions of gas mass density, ρ (top row), temperature, T (middle row), and metallicity, Z_met (bottom row), as a function of the halo mass. The population of galaxies in filaments (1825), filament-void transition region (3434), and voids and walls (10 183) is shown in the first three columns, respectively. The last two columns show the ratios of the fil-voids transit_gal and the voids+wall_gal to the fil_gal population. The colour bars in the ratio panels indicate the relative suppression (blue) or enhancement (red) of the thermodynamic quantity of the filament galaxies with respect to transition or galaxy voids and walls. We find that the overdense intrafilamentary environments hosting the fil_gal population show up to a factor of 9× higher gas densities, 14× higher temperatures, and 14× higher metallicities compared to the void and wall populations.