The recent measurements of stratospheric H2SO4 vapor concentrations using passive chemoionisation mass spectrometry are continued. The work extends altitude range of the measurements from 23.8 to 38.9 km. The results indicate a low concentration below approximately 30 km, followed by a sharp rise to a maximum value of 1¿107 molecules cm-3 at 35 km. The concentration then decreases slowly with increasing height. The results are compared with previous measurements and theoretical models.