in 1986, green began her 20-year landmark study in the rural queensland town of nambour of sunscreen usage, where half of 1621 participants applied sunscreen daily and the rest maintained previous sporadic sunscreen application habits. these participants were followed initially for 10 years, with the results showing the application of sunscreen halved the chance of getting melanoma. this was perceived as a breakthrough in skin cancer research due to it demonstrating the application of sunscreen can prevent melanoma.