Unit sometimes used in the description of the total ozone in a column of air overhead. It is given as the thickness (in units of 10-3 cm or 10-5 m) of that layer which would be formed by the total ozone in a column reduced to the pressure of  and temperature of ., Ühik osooni kogusisalduse kirjeldamiseks õhusambas, mis on esitatud selle samba puhta osooni kihi paksusena normaalrõhul ja -temperatuuril ühikutes 10-3 cm.