The article by R. B. Setlow, published in 1974, focuses on the theoretical analysis of the wavelengths in sunlight that are effective in producing skin cancer. The study assumes DNA as the primary target for UV-induced carcinogenesis and uses the known data on DNA sensitivity as a function of wavelength to calculate the carcinogenic effectiveness. The most effective wavelengths for skin cancer induction are below 305 nm, and a 1% change in atmospheric ozone results in a 2% change in the effective dose of UV light. The author emphasizes the importance of better epidemiological data to compare with animal models for a quantitative evaluation of the dose-response relationship for UV-induced skin cancer in humans. The study also discusses the theoretical framework for the dose-response relation, including the impact of different wavelengths and atmospheric conditions on DNA damage and skin cancer incidence. The results highlight that changes in ozone levels significantly affect the effective dose of UV light, with black skin being less affected due to its low transmission at effective wavelengths. The article concludes that more careful epidemiological studies are needed to understand the complex relationship between UV exposure and skin cancer incidence.The article by R. B. Setlow, published in 1974, focuses on the theoretical analysis of the wavelengths in sunlight that are effective in producing skin cancer. The study assumes DNA as the primary target for UV-induced carcinogenesis and uses the known data on DNA sensitivity as a function of wavelength to calculate the carcinogenic effectiveness. The most effective wavelengths for skin cancer induction are below 305 nm, and a 1% change in atmospheric ozone results in a 2% change in the effective dose of UV light. The author emphasizes the importance of better epidemiological data to compare with animal models for a quantitative evaluation of the dose-response relationship for UV-induced skin cancer in humans. The study also discusses the theoretical framework for the dose-response relation, including the impact of different wavelengths and atmospheric conditions on DNA damage and skin cancer incidence. The results highlight that changes in ozone levels significantly affect the effective dose of UV light, with black skin being less affected due to its low transmission at effective wavelengths. The article concludes that more careful epidemiological studies are needed to understand the complex relationship between UV exposure and skin cancer incidence.