Ultraviolet solar radiation that reaches the surface of the Earth has a very important role in the energy budget of our planet, although at certain amounts of exposure it can be harmful not only for human health, but animals and plants. Brazil is a tropical country receiving high intensity of UV radiation mostly of the year. UV radiation, specially UV-B is mainly absorbed in the ozone layer, changes in ozone content or ozone distribution directly affects UV radiation attenuation, so that surface UV. Ozone hole is characterized by an intense ozone depletion in the stratosphere in Antarctic region, happening during spring in the south hemisphere. There is evidence of poor-ozone air masses detachment from polar vortex and reaching mid-latitude regions, such as South of Brazil. Those air masses cause impact on the regions which they act due to low ozone content, allowing more radiation to reach the surface. UV index data from a Brewer Spectrophotometer (MKIII #167), located in south of Brazil, in the Southern Space Observatory (29.42° S, 53.87° W) was analysed with data collected between 2005 and 2017. Ground data was compared to satellite-derived from OMI/Aura, resulting in a correlation coefficient of 0.95 %. The climatology of Brewer data was done, analysing seasonal and interannual variability. Wavelet analysis showed the influence of ENSO, QBO and solar cycle on the variability of UV index. The results show a typical seasonal behaviour of UV Index, reaching extreme during summer season. Events of secondary effects of Antarctic ozone hole, identified between 2005 and 2016 (Bittencourt, 2018), were selected and the behavior of UV index and UV-B non-weighted during those events were studied. All ten events studied showed a significant increase in UV radiation at the days of events, the majority resulted in an increase of 4 % of UV index for each 1 % ozone total column decrease. One specific event was described in detail due to the major ozone depletion. Occurred in October 2016, ozone depletion was of almost 20 % while UV index increased 88 % in relation to the climatological mean, raising the concern with public health regarding excess exposure to UV radiation.