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The Variation of Time to Exceed the TLVs of the ACGIH and ICNIRP Guidelines, the Time to Achieve Erythema, and the Equivalent SEDs/hr for Solar UVR of Various UV Indices
| UV Index | Time to exceed TLV (min) | Time to achieve erythema (min) | Ambient UVR (SEDs/hr) |
|---|---|---|---|
| 3 | 26.4 | 44.4 | 2.7 |
| 4 | 19.8 | 33.3 | 3.6 |
| 6 | 13.2 | 22.2 | 5.4 |
| 8 | 9.9 | 16.7 | 7.2 |
| 10 | 7.9 | 13.3 | 9.0 |
| 12 | 6.6 | 11.1 | 10.8 |
| 14 | 5.7 | 9.5 | 12.6 |
Note that WHO recommend that protection against solar UVR be used when the UV Index is 3 or greater [WHO, 2002].
