In this paper the detection of haze using satellite imagery is compared with simultaneous aircraft measurements of haze parameters. The vertical optical depths of the effective pollutant layers are compared with results from the satellite data in order to gauge a threshold for the detection of haze from satellites. This comparison indicates that in terms of the optical depth this threshold is approximately equal to 0.065. Regression analysis indicates that a ground aerosol SO=4 concentration of ~3 &mgr;gm-3 may be typical of such a value of optical depth.