Environmental Engineering Reference
In-Depth Information
The effectiveness spectrum (ES(O)) is the product of an action spectrum (AS(O))
for a biological effect with a given solar irradiance spectrum E(O), originated by a
particular ozone-depletion scenario; it gives indication on the biological significance of
the change in solar UV-B.
ES(O) = AS(O)E(O)
1.E+01
1.E+01
Action spectrum
Solar spectra
1.E+00
1.E+00
1.E-01
1.E-01
1.E-02
Effectiveness spectra
1.E-03
1.E-02
295
300
305
310
315
320
Wave le ngth [nm]
Figure 1. Effectiveness spectra. Two different solar spectra multiplied by an action spectrum (in
which the biological weight is expressed in reciprocal units of irradiance) give two different
effectiveness spectra. The areas under the two effectiveness spectrum curves are an useful measure of
the overall effect of the two different irradiation conditions.
The overall effect of a particular irradiation condition can be estimated by means
of the biologically active irradiance (E BA ), defined as the area under the ES curve:
E BA = ³ AS(O)E(O)dO
Ecologically relevant studies, performed in order to determine action spectra,
require the careful consideration of various experimental features. Treatment duration
should be adequate, because short exposures may not allow to observe the overall
 
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