| We present a LO evaluation of helicity densities of valence, $\\Delta u_v+\\Delta d_v$, non-strange sea, $\\Delta \\bar u+ \\Delta \\bar d$,
and strange quarks, $\\Delta s$ (assumed to be equal to $\\Delta \\bar s$). They have been obtained from the inclusive
asymmetry $_{A1}$,d and the semi-inclusive asymmetries $A{\\pi +}_{1,d}, A{\\pi -}_{1,d}, A{K +}_{1,d}, A{K -}_{1,d}$ measured in polarised
deep inelastic muon-deuteron scattering. The full deuteron statistics of COMPASS (years 2002–2004 and 2006) has been used. The data cover the range Q2 > 1 (GeV/c)2 and 0.004 < x < 0.3. Both nonstrange
densities are found to be in a good agreement with previous measurements. The distribution of $\\Delta s(x)$ is compatible with zero in the whole measured range, in contrast to the shape of the strange
quark helicity distribution obtained in most LO and NLO QCD fits. The sensitivity of the values of $\\Delta s(x)$ upon the choice of fragmentation functions used in the derivation is discussed.
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