Solar ultraviolet (UV) radiation exposure in outdoor working environment during cold months

Abstract

Professions that are predominantly based outdoors have the risk of workers being exposed to solar ultraviolet (UV) radiation every day and during every season. Multiple studies have been conducted on outdoor workers' UV exposure during spring and summer months, but studies detailing their exposure during winter months are rare. The purpose of this study was to assess the UV exposure of groundskeepers employed at East Carolina University (ECU) during cold seasons (fall, winter, spring) compared to the summer season and to determine if UV exposure during cold seasons exceeded the Threshold Limit Values (TLVs) set by the American Conference of Governmental Industrial Hygienists (ACGIH) as occupational exposure limits. Area monitoring of UV radiation was conducted to measure the UV effective irradiance (UVeff) using a weatherproof erythema UV detector and a digital data-logging radiometer. Ambient temperature was also collected using the OSHA-NIOSH Heat Safety Tool app. Data were collected for one year in order to have data for every season. Data analysis was conducted using analysis of variance (ANOVA) to compare UVeff by month and season, and using Pearson correlation coefficient to analyze the strength and direction between UVeff and ambient temperature. Results showed that hourly and daily UV exposures exceeded the 1-hr and 8-hr TLVs, respectively, during cold months. The hourly TLV exceedance percentages for November, December, January and February were 78.0%, 62.7%, 73.4% and 74.3%, respectively. December had the lowest hourly (0.0020 ± 0.0018 mW/cm2) and daily (0.0020 ± 0.0006 mW/cm2) mean UVeff but 62.7% and 100% of the hourly and daily data still exceeded the 1-hr and 8-hr TLVs. The seasonal average UVeff for summer (0.0095 ± 0.0025 mW/cm2) was significantly higher than winter (0.0034 ± 0.0017 mW/cm2). The seasonal average UVeff for fall (0.0044 ± 0.0017 mW/cm2) compared to the summer is much lower and is closer to the winter average. The seasonal average UVeff for spring (0.0096 ± 0.0026 mW/cm2) compared to the summer is slightly higher and is also higher than the winter and fall averages. Overall, the UVeff positively correlates with the ambient temperature, as expected. Study findings demonstrate that groundskeepers and other outdoor workers, as well as the general public, should continue to use preventive measures to reduce UV exposures during the cold months to reduce risk to UV-related adverse health effects.