The Ultraviolet Index is well estimated by the terrestrial irradiance at 310nm

TL;DR

This study demonstrates that the UV Index can be accurately estimated using the irradiance at 310nm, simplifying UV exposure assessment for health-related applications.

Contribution

The paper shows that the UV Index is well approximated by a simple linear relation with irradiance at 310nm, supported by analysis of extensive spectral data and atmospheric modeling.

Findings

UVI correlates strongly with 310nm irradiance

Linear model UVI = 77 * I(310nm) fits data well

Model applies across diverse atmospheric conditions

Abstract

Ultraviolet (UV) exposure significantly contributes to non-melanoma skin cancer. In the context of health, UV exposure is the product of time and the UV Index (UVI), a weighted sum of the irradiance I(lambda) over all wavelengths from lambda = 250 to 400nm. In our analysis of the United States Environmental Protection Agency's UV-Net database of over four-hundred thousand spectral irradiance measurements taken over several years, we found that the UVI is well estimated by UVI = 77 I(310nm). To better understand this result, we applied an optical atmospheric model of the terrestrial irradiance spectra and found that it applies across a wide range of conditions.