Evaluation of UV Radiation Levels and Sun Protection Factor of Selected Sunscreen Products in Ibadan

Ultraviolet radiation from solar irradiance constitutes a significant occupational and public health concern for outdoor workers and the general population in tropical Nigeria. The Sun Protection Factor of commercial sunscreen products determines their effectiveness in attenuating UVB radiation reaching the skin. This study evaluates ambient UV radiation levels in Ibadan, Oyo State, South West Nigeria, and tests the SPF of five commercially available sunscreen products sold in Dugbe and Bodija markets. Ambient UVA and UVB irradiance is measured hourly from 7:00 am to 6:00 pm on clear sky days in January and July using a calibrated ultraviolet radiometer. SPF determination follows the ISO 24444 in vitro method using a UV-Vis spectrophotometer and quartz plates coated with sunscreen films. Measured ambient UVB levels peak at 12.4 mW per square centimetre between 12:00 and 1:00 pm in July. SPF values of tested products range from 8.2 to 27.4, compared to manufacturer-claimed values of 15 to 50. Three of the five products show SPF values significantly below their labelled claims. The study highlights consumer protection concerns regarding sunscreen efficacy labelling and recommends strengthening the National Agency for Food and Drug Administration and Control's quality assurance testing of photoprotective cosmetics. Keywords: UV radiation, sun protection factor, sunscreen, Ibadan, public health