Higher solar zenith angles reduce the penetration of UVB photons to the earth's surface, which decreases the production of cutaneous pre-vitamin D3.

Is it true that higher solar zenith angles reduce the penetration of UVB photons to the earth's surface, which decreases the production of cutaneous pre-vitamin D3?

Yes. Higher solar zenith angles increase the atmospheric path length for incoming sunlight, which attenuates UVB photon penetration to the Earth's surface and subsequently reduces cutaneous pre-vitamin D3 production.

Verdict: SUPPORTED · 3 sources for, 0 against · Last checked 4 Oct 2026

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W, C., RD, B., & G, N. (2025). Assessing playgrounds ultraviolet radiation (UVR) environments in College Station, Texas: Creating UVR-safe environments for children.. doi.org. https://doi.org/10.1016/j.envres.2025.121803