During summer of 2019/2020, Sydney, Australia, experienced several days of extreme air pollution and low visibility due to bushfires. This research presents a case study that investigates the erythemal UV irradiance and resulting 1 h erythemal and 8 h actinic exposures during the worst of these days. Air quality, meteorological and UV data used in the analysis were readily available online or by request from governmental agencies. Analysis showed that even for the lowest visibility day (which had a minimum visibility of less than a kilometer) on 10 December 2019, there was a cumulative 1 h erythemal UV exposure of over 4 SED (standard erythema dose) and a cumulative 8 h exposure of 17 SED by the late afternoon. The 1 h exposure exceeded that of a minimum erythemal dose. Even on this extremely hazy day, these cumulative exposures are enough to exceed the recommended daily exposure limit for actinic exposures weighted with the health sensitivity spectrum for the skin and eyes set by the International Commission of Non-Ionizing Radiation Protection.
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