Solar photolysis of ozone to singlet D oxygen atoms

The ground level photolysis frequency of ozone J (O 3 ) to produce metastable singlet D oxygen atoms (O ( 1 D )) has been measured using a novel instrumental technique involving electrical conductivity. The O( 1 D ) atoms produced react with nitrous oxide (N 2 O) carrier gas to form higher oxides of nitrogen (NO x ). These oxides (NO x ) were detected by mixing with methanol and determining the increase in electrical conductivity with a continuous flow dual conductivity cell. Over 70 days of data were collected under varying sky conditions. The effect of temperature on J (O 3 ) was measured. The results agree with model predictions. The effects of atmospheric aerosols, changes in overhead ozone column, and local cloudiness are discussed.