Every light source produces some UV, and UV is inherent to the operation of most discharge light sources. The former is a measure of the amount of UV impinging on a surface, while the latter is a measure of the amount of UV per unit of visible light. Lamps emit a mix of wavelengths, so to estimate the impact requires that each wavelength's intensity be multiplied by a factor that adjusts for its damage potential. Standard acrylic lenses can reduce UV exposure to levels safe even for sensitive individuals. Halogen lamps produce both high UV and visible light levels in the center of their beams, but the concentration of UV from bare lamps is not much higher than that produced by other incandescents.
Lenses reduce all UV to safe levels.
However, closer examination has shown that some of these data are erroneous. According to the report, a British UV-meter produced most of the faulty results. For comments see letters . Lindsay Audin, author of the E Source report, kindly provided background material for part of this article.