Longitudinal multi-subject photobiological studies that require accurate monitoring of the participants’ solar exposure are currently challenging and limited. Dosimeters or wearable devices are expensive to acquire and maintain and compliance among users can be low.
Here an innovative digital solution that provides personal solar dosimetry data using only a smartphone (no light sensors or dosimeters) has been investigated. The smartphone app (ExpoDose®, siHealth Ltd) is used to track whole-body exposure to spectral solar radiation. It's based on a patented technology already validated scientifically [1] combining real-time satellite data, radiation transfer modelling and AI-enabled automatic assessment of indoor/outdoor position. The app seamlessly tracks the solar exposure of multiple users for any number of action spectra (e.g., erythema, vitamin D synthesis, UVA) and body sites (e.g. scalp, face), providing the collected data to study investigators via a web-portal.
The results of a 6-month study into the accuracy and practical use of the app will be presented. Solar erythemal irradiance (global horizontal) data collected by the app have been compared to ground station measurements and found to have an R2 correlation coefficient of 0.90 and a mean absolute error of 21%. The automatic indoor/outdoor detection component has been tested and its detection accuracy ranged from 84% (iOS) to 92% (Android). This demonstrates the accuracy of the app, which, when coupled with its convenience, makes it a tool that could significantly enrichen and diversify the possibilities for epidemiological and photobiological studies.
[1] Young A, Schalka S et al. (2022), Photochem. Photobiol. Sci. 21, 1853