INTRODUCTION: Understanding UV exposure is essential for the assessment of its contribution to the occupational risk of pilots developing ocular and skin pathologies. The objective of this observational study was to measure the UV exposure of pilots flying between the United Kingdom and a range of destinations at three different seasons.METHODS: The in-flight UV exposure of pilots was measured on 322 Monarch Airlines short-haul flights on the Airbus A321-231 and Airbus A320-214 to 31 destinations, mostly in Europe, from 4 UK airports in September 2016-August 2017. The erythema effective and UV-A doses were compared with the ICNIRP guidance and typical recreational weekend exposure of UK office workers.RESULTS: The erythema effective radiant doses did not exceed 0.1 SED. For most of the flights, the UV-A exposure was also low. On 27 single sector flights, UV-A exposure could have exceeded the ICNIRP guidance if eye protection was not used.DISCUSSION: The UV exposure in a cockpit is mostly governed by the presence of direct sunlight and the duration of a flight. The average monthly exposures were low and significantly below weekend recreational exposures of UK office workers over a similar period. To assess the contribution of occupational UV exposure to the risk of developing sun-related ocular and cutaneous pathologies, it is important to consider the accumulative flight time, destinations, and UV attenuation of aircraft windshields. Additionally, leisure and recreational outdoor time needs to be considered before meaningful overall risk analysis can be undertaken.Baczynska KA, Brown S, Chorley AC, O'Hagan JB, Khazova M, Lyachev A, Wittlich M. In-flight UV-A exposure of commercial airline pilots. Aerosp Med Hum Perform. 2020; 91(6):501-510.