Here are the answers to PS2.

The following assumptions have been made:

-Zenith angle = 45 deg;
-Only Rayleigh scattering and absorption by O3 and O2 are considered;
-O3 mixing ratio is averaged over each 5km slab;
-Both O3 and O2 column number density are based on the exact solution 
 for atmospheric column density;
-Attenuation of the solar flux above 50km by O2, Rayleigh scattering, 
 and O3(2.0e16).

                                I/Io
    km   200nm       250nm      350nm      450nm      550nm      650nm
    50  9.45E-01   7.30E-01   9.99E-01   1.00E+00   1.00E+00   1.00E+00
    45  8.90E-01   3.89E-01   9.99E-01   1.00E+00   1.00E+00   1.00E+00
    40  7.74E-01   5.70E-02   9.97E-01   9.99E-01   9.99E-01   9.99E-01
    35  5.42E-01   1.10E-04   9.95E-01   9.98E-01   9.97E-01   9.98E-01
    30  2.28E-01   6.33E-12   9.89E-01   9.96E-01   9.91E-01   9.94E-01
    25  3.95E-02   1.29E-25   9.77E-01   9.92E-01   9.80E-01   9.86E-01
    20  1.86E-03   7.20E-44   9.50E-01   9.82E-01   9.65E-01   9.75E-01
    15  1.22E-05   4.82E-59   8.97E-01   9.62E-01   9.47E-01   9.63E-01
    10  1.59E-09   2.07E-65   7.93E-01   9.21E-01   9.25E-01   9.51E-01
     5  1.14E-16   1.40E-68   6.25E-01   8.48E-01   8.90E-01   9.32E-01
     0  8.07E-29   4.81E-72   4.17E-01   7.35E-01   8.35E-01   9.02E-01
~

These calculations are the same as the first ACCEPT that the O3 
number density is averaged over each 5km slab.

                                 I/Io
    km   200nm       250nm      350nm      450nm      550nm      650nm
    50  9.45E-01   7.30E-01   9.99E-01   1.00E+00   1.00E+00   1.00E+00
    45  8.88E-01   3.64E-01   9.99E-01   1.00E+00   1.00E+00   1.00E+00
    40  7.67E-01   4.22E-02   9.97E-01   9.99E-01   9.99E-01   9.99E-01
    35  5.24E-01   3.55E-05   9.95E-01   9.98E-01   9.96E-01   9.97E-01
    30  2.14E-01   7.61E-13   9.89E-01   9.96E-01   9.91E-01   9.93E-01
    25  3.77E-02   2.49E-26   9.77E-01   9.91E-01   9.80E-01   9.85E-01
    20  1.99E-03   7.50E-43   9.51E-01   9.82E-01   9.65E-01   9.75E-01
    15  1.62E-05   8.90E-55   8.97E-01   9.62E-01   9.49E-01   9.65E-01
    10  2.33E-09   8.55E-60   7.93E-01   9.21E-01   9.29E-01   9.53E-01
     5  1.68E-16   8.24E-63   6.26E-01   8.48E-01   8.94E-01   9.35E-01
     0  1.20E-28   3.81E-66   4.17E-01   7.35E-01   8.38E-01   9.04E-01