Many Sibata digital dust indicators are used to measure airborne particles at worksites. These are relative concentration meters based on the light scattering method, and provide data faster than with the filtration collection method, which gives them an advantage when assessing sudden concentration changes. On the other hand, given the characteristics of the relative concentration obtained, the measurements must be corrected to mass concentration by determining a mass concentration conversion factor with the filtration collection method as the standard. Entering a mass concentration conversion factor (K value) makes it easy to convert the measured value to mass concentration. The LD-5R is a relative concentration meter that uses the light scattering method, and is capable of displaying the measurement results in a variety of styles.