Fig 2. Infuence of airborne gaseous fluoride on the yield of beans, strawberries, and oranges, as plotted from the data of several authors. For further details, consult Notes 2, 8, and 11 in our Table 9. Where necessary, the concentration of atmospheric gaseous fluoride has been converted to ug/m3, according to the formula: 1.0 ppb F = 0.8 ug F/m3 (Nat. Acad. Sci. 1971, p.34).