How does the sun's height above the horizon from morning to midday change how milky a humid sky looks at one spot?

The verified facts do not directly show how the sun's height from morning to midday changes the milkiness of a humid sky at one spot ¹²³. A 1981 study reports that during morning twilight the sky brightness ratio at two wavelengths is sometimes close to the value expected for pure Rayleigh molecular scattering ¹. The same record links a red shift in the sky background to aerosols, observed during eclipse mid-totality, not to sun height ². A separate undated note says visibility drops sharply once humidity rises above 80%, even when the pollutant particle count stays the same ³. The newest dated fact is from 1981, so the evidence is old and does not address the sun-height question.

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