What information can particle counters provide?

• A. Size and number
• B. The number of bacteria
• C. Qualitative measurement
• D. The number of particles smaller than can be counted by turbidity meters

Answer: (A)

Particle counters give you both the size of particles and how many there are in a sample. They detect each particle as it passes through a sensing region and use methods like light scattering or electrical impedance to estimate its size, then tally counts for each size range to produce a size distribution and a concentration. This means you get quantitative data on how many particles exist and how large they are, not just a yes/no or a qualitative assessment. They aren’t designed to identify whether a particle is bacteria, since many different particle types can look the same to a general counter, and turbidity meters measure overall cloudiness rather than provide discrete counts by size, so they don’t give precise size and number information.