Wavelength trends of photoproduction of reactive transient species by chromophoric dissolved organic matter (CDOM), under steady-state polychromatic irradiation.

The formation quantum yields of photochemically produced reactive intermediates (PPRIs) by irradiated CDOM (in this study, Suwannee River Natural Organic Matter and Upper Mississippi River Natural Organic Matter) decrease with increasing irradiation wavelength. In particular, the formation quantum yields of the excited triplet states of CDOM (CDOM*) and of singlet oxygen (O) have an exponentially decreasing trend with wavelength. The OH wavelength trend is different, because more effective OH production occurs under UVB irradiation than foreseen by a purely exponential function.