Inexpensive instruments that measure concentrations of airborne particles in workplaces have grown to become an efficient way to estimate personal aerosol exposure of workers. This study evaluates the performance of two types of inexpensive instruments: an “active” version which pulls particle-laden air into a sensing zone for measurement, and a “passive” version which does not. The response of these instruments to clean air over time was evaluated as an indicator of contamination in laboratory and factory settings. Additionally, the effect cleaning of the instruments had on performance was evaluated.
After exposure to high concentrations of particles in the laboratory, the active and passive versions of the instruments lost partial to full ability to detect particle concentrations. In the factory, this change was only seen in the active version, and occurred over a longer amount of time. Cleaning of the instruments returned some ability to detect particles, but not to the ability a new instrument.
The accumulation of particles within instruments used to estimate aerosol exposures can affect the output of and overall performance of the instruments. Cleaning of the instruments after accumulation results a lessening of the effect, but not completely. Cleaning can be a way to extend the lifetime of these instruments. However, the time and financial costs related to cleaning several sensors within a workplace should be considered.