  The dynamical transport properties near the integer quantum Hall transition
are investigated at zero temperature by means of the Dirac fermion approach.
These properties have been studied experimentally at low frequency omega and
low temperature near the nu=1 filling factor Hall transition, with the
observation of an anusual broadening and an overall increase of the
longitudinal conductivity Re sigma_{xx} as a function of omega. We find in our
approach that, unlike for normal metals, the longitudinal conductivity
increases as the frequency increases, whilst the width Delta B (or Delta nu) of
the conductivity peak near the Hall transition increases. These findings are in
reasonable quantitative agreement with recent experiments by Engel et al. as
well as with recent numerical work by Avishai and Luck.
