Tropospheric ozone concentration at the tropopause. About 90% of total ozone in the atmosphere is in the stratosphere, and 10% is in the troposphere. Although tropospheric ozone is less concentrated than stratospheric ozone, it is of concern because of its health effects. Ozone in the troposphere is considered a greenhouse gas, and may contribute to global warming. Photo-chemical and chemical reactions involving ozone drive many of the chemical processes that occur in the troposphere by day and by night. At abnormally high concentrations (the largest source being emissions from combustion of fossil fuels), it is a pollutant, and a constituent of smog.
Dobson ozone spectrophotometer and comparing it to that of UVA radiation at ground level. If all of the ozone were removed from the atmosphere, the amount of UVB radiation would equal the amount of UVA radiation on the ground. As ozone does exist in the atmosphere, the Dobson Spectrometer can use the ratio between UVA and UVB radiation on the ground to determine how much ozone is present in the upper atmosphere to absorb the UVC radiation. The ratio is determined by turning the R-dial, which can be rotated a full 300°, on the instrument. The spectrometer compares two different wavelength intensities, UVB