Validation of UV warning devices by comparative measurements with data logger dosimeters

Status:

completed

Aims:

Preventing UV radiation-induced skin cancer by means of appropriate protective measures presents itself as one of the greatest challenges within practical occupations. Certainly, the measures to be taken – such as wearing long clothing and headgear and using sun protection products – are well known. However, until now these measures have been used only rarely or not at all and, most importantly, not on a regular basis as they are often not accepted by employees.

It is also very clear that many people are insufficiently informed about sun protection and its connection to the increased risk of developing skin cancer. One of the main issues here is that people are not usually able to adequately assess and evaluate the risk posed by UV radiation in everyday life. An increased use of UV warning devices is now starting to close this gap, predominantly in private spheres.

Accident insurance institutions that are particularly affected by this issue, whose employees mainly work in outdoor occupations, also see devices such as these as a way to promote prevention in this area. Since UV warning devices were introduced, the question of their suitability for prevention purposes in occupational settings has been raised with increasing frequency. In principle, UV warning devices could be a suitable tool to increase awareness or for prevention purposes. However, the accuracy of the data provided by the devices is uncertain. For this reason, a selected UV warning device will be tested in direct comparison with the personal dosimeters used for the GENESIS-UV measurements. The incident UV radiation is measured directly by the UV warning device chosen for the test. All further data processing is carried out on a mobile end device (smartphone or tablet PC). Using a corresponding app, this measurement data will be combined with the site-specific ozone value (which is provided by a remote server) to form a UV exposure value based on the UV index. This will then be displayed in the app together with further information about personal UV exposure.

Activities/Methods:

Using several comparative measurements, the UV warning device was tested against the UV data logging dosimeters from the GENESIS-UV project. A variety of measurements were necessary for this purpose. In the laboratory measurements, an initial comparison was conducted using artificial UV radiation. This was followed by static measurements of solar UV radiation on the roof of the IFA building (IFA: Institute for Occupational Safety and Health of the German Social Accident Insurance). The devices were mounted on a tripod, ensuring a fixed angle of incidence of the sun's rays on the dosimeters. Finally, measurements were to be conducted on people moving around outdoors, measuring different movements and different parts of the body.

Within the scope of these measurements, a comparison should be carried out to establish whether the measured values of the two UV measuring devices (warning device and data logging dosimeter) differ and to determine the difference in order of magnitude. This is also interesting in terms of the person-borne measurements, as these measurements reflect how the devices are used in everyday life. It is therefore important to compare how the different measurement positions on different parts of the body affect the validity and accuracy of the readings from the UV warning device. In addition to the exposure values, important insights may also be gained regarding the device’s suitability for occupational use. Any strengths and weaknesses of the UV warning devices can be identified at this point.

As the accident insurance institution commissioning the project planned to equip approx. 100 people with these warning devices in a pilot project from spring 2022, plans were made to carry out further comparisons involving direct measurements on test persons in the field. To this end, the UV warning device and the data logging dosimeter would be worn simultaneously on the left upper arm during a work shift. The measurement data acquired in this way would then be compared against each other.

Results:

The measurements taken both in the laboratory and outdoors have, in principle, yielded comparable results to each other and to the dosimeters from the GENESIS-UV project. Reliability proved to be problematic. The devices themselves have no displays or status LEDs. The only way to view all the information is via the corresponding app on a smartphone. However, the app often encountered problems when recording the measurements. In some cases, no measured values were recorded at all. There were also cases where the measurements were recorded but not attributed to the personal dose, meaning that no warning appeared once a specific dose was reached.

It was not possible to resolve any of these problems as the app does not have any adjustable setting options. Overall, the issues occurred in over 50% of the measurements taken across all the dosimeters tested. The same dosimeter could fail to display any readings one day but was fully functional again the next.

Due to the dosimeters’ unreliable performance, it was decided against taking measurements with people. A larger project involving many test persons would be particularly frustrating if the measuring devices functioned less than 50% of the time.

Owing to the high error rate it is not recommended to use these devices in a professional setting at this time. However, this assessment may change in the future should the manufacturer improve the stability of the software.

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