Seasonal Variation in Exposure Level of Types A and B Ultraviolet Radiation: An Environmental Skin Carcinogen

BACKGROUND: The main source of ultraviolet radiation (UVR) is the sun, affecting organs such as the skin, eyes, and immune system. According to American Conference of Governmental Industrial Hygienist (ACGIH) reports, the amount of UVR reaching the Earth's surface is increasing yearly and is responsible for an increase in solar radiation-related diseases. AIMS: To investigate the amount of UVR reaching the Earth's surface and understand the risk of UVR on disease among outdoor laborers in one of the central provinces of Iran. MATERIALS AND METHODS: Arak city was divided into two geographic areas, and the weekly measurement of UVR was done in three locations) asphalt, grass and rooftop). To measure UVR, Hanger UV spectrometer, standard deviation (SD8-A), and SD8-B detectors were used. Amounts of UVR for a consecutive year and varying weather conditions were measured. Finally, values obtained were compared to ACGIH standards. RESULTS: The minimum and maximum levels of UV type A radiation occurred in April 1.27 (0.724) W/m(2) and September 7.147 (4.128) W/m(2), these figures for UV type B were in March–April 0.005 (0.003) and September 0.083 (0.077). The maximum UVR is received between 11 and 15 o’clock. CONCLUSIONS: In the central cities of Iran, the minimum and maximum UV type A and B is received in March–April and in September, respectively. Based on the results, the angular position of the sun in the sky, cloud cover, and height from ground level affected the amount of UVR received, but the geographic locations studied did not.