Validating an advanced smartphone application for thermal advising in cold environments.

Area of Science:

• Environmental Health
• Human Physiology
• Biometeorology

Background:

• Heat and cold stress pose significant health risks, necessitating accurate personal thermal exposure assessment.
• Existing thermal indices often lack personalization, limiting their effectiveness for individual risk management.

Purpose of the Study:

• To validate the ClimApp application's individualized thermal index against direct measurements and compare its performance with the Universal Temperature Climate Index (UTCI).
• To assess the efficacy of ClimApp in predicting personal thermal stress and strain in cold outdoor conditions.

Main Methods:

• 55 participants were exposed to outdoor temperatures ≤10°C, providing activity level and clothing insulation data to the ClimApp application.
• ClimApp and UTCI indices were calculated and compared with participants' perceived thermal sensation.
• Root Mean Square Deviation (RMSD) was used to evaluate prediction accuracy against perceived thermal sensation.

Main Results:

• The ClimApp index demonstrated a lower RMSD than the standard deviation of perceived thermal sensation, indicating a valid prediction.
• The UTCI index's RMSD exceeded the standard deviation of perceived thermal sensation, suggesting an invalid prediction.
• Both ClimApp and UTCI showed statistically significant correlations with perceived thermal sensation, but ClimApp was more accurate.

Conclusions:

• The ClimApp application provides a valid and personalized method for assessing thermal stress in cold environments.
• ClimApp offers a superior alternative to the UTCI for individualized thermal warning systems, enhancing user safety and comfort.