Minutes for Vitamin-D Sufficiency Anytime Anywhere
Now available on the GlobalUV App ...
A recent study drew attention to breathing difficulty in New Zealand infants arising from their sub-optimal levels of vitamin D, with the infants inheriting those low levels from their mothers. The authors argue that their sub-optimal levels arise partly because of the conflicting sun-safe messaging. My recent posting showed that the solution to those conflicts is already at hand for Kiwis. Thanks to my friend Jerry, it’s now available for everyone, anywhere in the world at any time ...
It took a while, but we got there! Just in time for the winter lows down-under.
Jerry has just updated our GlobalUV smartphone app. In addition to providing the UVI and corresponding personalised sun-safe advice, it now includes the exposure times needed for vitamin-D sufficiency (and a few other improvements). It works anywhere, any time, and for any skin type and exposure. The calculation method is as described previously.
This new version of the app is available for both iPhone (OS version 12.3 or later) and Android (OS 10 or later), but unfortunately not for earlier versions or tablets. The screen shots below (from an iPhone SE) are for Beijing, China on April 21.
As with the NZUV app (which has more detailed cloud forecasts), the main focus is on sun-safe protection messaging. To see how many minutes of exposure are needed for vitamin-D sufficiency at solar noon or the current time, you need to touch the relevant coloured bar in the first screen shot below. Note that in this screen the times shown are for your local time zone.
For other times of the day, you can access the Graph screen. The exposure times (in minutes) required to meet you daily needs for vitamin D are shown below the dots in the screen for solar noon - the time when the sun is highest in the sky - and for the ‘current' time, about 10 am. Other times an be selected by touching the screen at different points. In this example, the times shown are for pale skin (skin type 2), with 35 percent of the skin area exposed to sunlight. Other skin types and coverage can also be selected.
Some final caveats. The calculated times don’t take account of body posture and assume the sky is unobscured from horizon to horizon. If nearby buildings or trees obscure some of the sky, then the number of minutes required for vitamin-D sufficiency has to be scaled up commensurately. For example, if one quarter of the sky is visible, then it will take about four times as long. Read the info screen for more details.
There’s also a ‘Geeks’ button that takes you to improved tools to explore how the UVI and associated health messages vary for other months, for other ozone amounts, and more ….
That’s it. Yours for free at your app store.
Thanks for reading this. Previous posts on the intersection between Ozone, UV, Climate, and Health can be found at UV & You on Substack. Click below to subscribe for occasional free updates.