Table 2.

Fluoride concentration in drinking water, according to Institute of Standards and Industrial Research of Iran [5], [6], [7], [8], [9], [10].

The annual average maximum	The maximum allowable	Desirable level (mg/l)	The minimum allowable
daily air temperatures (°C)	amount of fluoride (mg/l)		amount of fluoride (mg/l)
10–12	2.4	1.2	1.1
12–14.6	2.2	1.1	1
14.6–17.7	2	1	0.9
17.7–21.5	1.8	0.9	0.8
21.5–26.3	1.6	0.8	0.7
26.3–32.5*	1.4*	0.7*	0.6*

^*These target values accounts for Larestan region since the annual average maximum daily temperature is about 32.5 °C there.