Cumulative particle counts

Particle counters display readings in two columns: cumulative (often depicted by ∑ sigma) and differential (often depicted by ∆ delta).

The cumulative total shows the amount of particles that were found at that size and greater.

The differential total shows the counts which are at least that size in diameter and up to, but not including the next size.

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Last updated: 2 July 2024

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