Solar ultraviolet radiation is a significant factor in environmental biology. It can be measured spectrally by a spectroradiometer, or non-spectrally by a broadband radiometer. The characteristics of these instruments determine the reliability and suitability of the results. The radiation data should be accompanied by detailed documentation on the calibration and operating procedures, sufficient to assure the data user that the measurements are accurate enough for the intended purpose. A description of the observing site and conditions should also be supplied, so that the user can determine whether the observing conditions meet the requirements of the environmental investigations.