The Dobson Spectrophotometer is an instrument used to measure the concentration of ozone in the Earth's atmosphere. It works by analyzing the intensity of ultraviolet light absorbed by ozone at specific wavelengths. This allows scientists to monitor changes in ozone levels over time, which is crucial for understanding atmospheric chemistry and environmental health. Developed by G.M.B. Dobson in the 1920s, the spectrophotometer has become a standard tool in atmospheric research. It is often used in conjunction with other instruments to provide a comprehensive view of air quality and the effects of pollutants, contributing to global efforts in climate change research and environmental protection.