Table 2: Recommended amounts of fluoride in drinking water depending on climate.

Average annual temperature (℃) Fluorides concentration (ppm)
Minimal Optimal Maximal
10-12 0.9 1.2 1.7
12-14.5 0.8 1.1 1.5
14.6-17.5 0.8 1.0 1.3
17.6-21.4 0.7 0.9 1.2
21.5-26.2 0.7 0.8 1.1
26.3-32.5 0.6 0.7 0.8

Source: Voinovic J., Tatic E., Andelic P., Pintaric J. Preventive program in dentistry. Scientific book, Beograd, 1990 [26].