The intensity of direct solar radiation was measured at the surface of planet Earth when the solar zenith angle was 45 degrees. The ratio of the intensity measured at wavelengths 308 nm and 353 nm was found to be I(308)/I(353) = 0.7. Determine the column amount of ozone in units of molecules/m2 and in Dobson units Absorption cross sections: (308 nm) = 12 10^-24 m^2 and (353 nm) = 62 10^-28 m^2