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Why can the brightness and color of a totally eclipsed Moon vary from one eclipse to another?

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Solar eclipse — Eclipse Total solar eclipse as seen from Hopkinsville, Kentucky, August 21, 2017.

During a total lunar eclipse, the Moon is not completely obscured because some sunlight is refracted by Earth's atmosphere into the umbra, or darkest part of the shadow. This light reaches the lunar surface, typically giving the Moon a reddish-brown or coppery appearance.12

The brightness and specific color of the eclipsed Moon vary significantly from one event to another primarily due to meteorological conditions on Earth. These conditions dictate how much sunlight can penetrate the atmosphere and reach the Moon. For instance, the presence of increased dust or other particles in the atmosphere can scatter more light, causing the Moon to appear a deeper, more intense red. Because these atmospheric factors are constantly changing, the visual characteristics of each total lunar eclipse are unique.123