Calculated Ultraviolet Exposure Levels for a Healthy Vitamin D Status and no sunburn

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Version 1.1, Copyright © 2008 Ola Engelsen
Norwegian Institute for Air Research, Email:

NOTE! version 1.2 is available here: an d olaeng/fastrt/VitD_quartMEDandMED_v2.html

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Solar Geometry for Irradiance Calculations

Month Day

Latitude (degs N) Longitude (degs E)

When checked, use degrees for Solar Zenith Angle directly and ignore Date, Time, and Location

Skin type: 1 2 3 4 5 6

Timing of exposure: Around midday Start time (hours UTC)

Body exposure: %.

Desired dietary equivalent dose of vitamin D: IU. (1000 IU widely recommended every other day)

Cloudless sky: Visibility of km, Range [5-350] km. Ångström β of , Range [0.0-0.4] (AOD = βλ-1.3).

Scattered clouds: Cloud fraction of %, Range [0-100]. Cloud liquid water column of g m-2, Range [0-5000].
Press here for total cloud fractions from the NOAA AVHRR Pathfinder products.

Broken clouds (radiation enhancement): Cloud liquid water column of g m-2, Range [0-5000].

Overcast sky: Cloud liquid water column of g m-2, Range [0-5000]. (= cloud optical depth @ 360 nm * 5000/1083)

Estimate cloud thickness from UV index assuming overcast sky: UV index [0-20]

Total ozone column: Dobson Units (1000 * cm atm), Range [100-600]
Press here for total ozone column measurements from the TOMS satellite instruments.

Surface altitude km. Range [0.0-6.0] km

Surface albedo of Range [0.0-1.0].

Surface type:

This work has been funded by the European Commission (EC) and the Norwegian Research Council ( NFR) through the projects UV Radiation in the Arctic: Past, Present and Future (UVRAPPF), European Database for UV Climatology and Evaluation (EDUCE) and Integrated Assessment of Health Risks of Environmental Stressors in Europe (INTARESE).

Ola Engelsen                                                                          NILU Phone: (+47) 77 75 03 75
Norwegian Institute for Air Research (NILU)                    NILU Fax no:(+47) 77 75 0376
N-9296 Tromsø                                                                     Office-Phone no:(+47) 77 75 03 89
Norway                                                                                  Email: