Neutrino and axion hot dark matter bounds after WMAP-7

We update cosmological hot dark matter constraints on neutrinos and hadronic axions. Our most restrictive limits use 7-year data from the Wilkinson Microwave Anisotropy Probe for the cosmic microwave background anisotropies, the halo power spectrum (HPS) from the 7th data release of the Sloan Digital Sky Survey, and the Hubble constant from Hubble Space Telescope observations. We find 95% C. L. upper limits of \ m_\<0. 44 eV (no axions), mₐ<0. 91 eV (assuming \ m_\=0), and \ m_\<0. 41 eV and mₐ<0. 72 eV for two hot dark matter components after marginalising over the respective other mass. CMB data alone yield \ m_\<1. 19 eV (no axions), while for axions the HPS is crucial for deriving mₐ constraints. This difference can be traced to the fact that for a given hot dark matter fraction axions are much more massive than neutrinos.