  This paper is concerned with the stability issue in determining absorption
and diffusion coefficients in quantitative photoacoustic imaging. Assuming that
the optical wave is generated by point sources in a region where the optical
coefficients are known, we derive pointwise H{\"o}lder stability estimate of
the inversion. This result shows that the reconstruction of the optical
coefficients is stable in the region close to the optical illumination sources
and deteriorate exponentially far away. Our stability estimate is therefore in
accordance with known experimental observations. Mathematics subject
classification : 35R30.
