by Wm. Robert Johnston
last updated 26 December 2002
Description: In blue, the graph shows atmospheric ozone (O3) levels in Dobson units (left scale). In red, the graph shows annual average UV-B measured at the Earth's surface in the United States in units of Robertson-Berger meter counts per 10,000/year (right scale). The UV-B measurements specifically are averaged from 8 measuring stations in the lower 48 states as reported by Scotto et ali. (1988).
Comments: Note that when ozone amounts decreased from 1980 to 1986, measured UV-B decreased--the opposite of what the ozone depletion hypothesis predicted. (End of UV-B data in 1985 corresponds to end of federal funding for the measuring program.) Much subsequent data on UV-B exposure (such as that available from U.S. government web sites) are not actual measurements but are calculated from measured ozone quantities--and assumed relations between UV-B and ozone. (One particular exception in the U.S. is data from the USDA monitoring program.)
Further note that atmospheric ozone increased from 1974 to 1980--in spite of a more than 25% increase in atmospheric chlorine from man-made chemicals. This also contradicts the ozone depletion hypothesis.
Sources: Scotto, Joseph, et ali., "Biologically effective ultraviolet radiation: surface measurements in the United States, 1974-1985," Science, 12 Feb. 1988; Maduro, Rogelio A., and Ralf Schauerhammer, The Holes in the Ozone Scare, 1992, 21st Century Science Associates (Washington, DC).
© 2001, 2002 by Wm. Robert Johnston.
Last modified 26 December 2002.
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