Physical characteristics and sources of exposure to artificial UV radiation

UV radiation belongs to the non-ionizing part of the electromagnetic spectrum and ranges between 100 nm and 400 nm; 100 nm has been chosen arbitrarily as the boundary between nonionizing and ionizing radiation. UV radiation is conventionally categorized into 3 regions: UVA (>315–400 nm), UVB (>280–315 nm) and UVC (>100–280 nm) (Figure 1). These categories have been confirmed by the Commission Internationale de l’Eclairage (CIE, 1987), although there is variation in usage. In the medical and biological fields, for example, 320 nm is used as the limit between UVA and UVB. More recently, it was proposed to distinguish between UVA-1 (>340–400 nm) and UVA-2 (320–340 nm). Units and measurements of UV radiation Measurement of ambient solar UV radiation