The Model 2030 Portable Ozone Transfer provides an accurate and convenient means of measuring low levels of ozone in ambient air. Using the Beer-Lambert law, ozone is measured in a single photometric cell by detecting the absorption of ultraviolet (UV) radiation from ozone molecules at a wavelength of 254 nm. Real-time comparison of the UV light intensity for the sample gas to the reference gas yields a precise concentration of ozone. The single cell design reduces the complexity of the ozone measurement and automatically eliminates zero drift.