This document gives guidelines on the use, calibration and evaluation of low-cost optical particulate matter sensor modules and systems for workplace exposure assessments. This document is based on extensive laboratory and workplace tests for airborne NOAA. This document is particularly aimed at engineered NOAA at workplaces and the sensors applicability for process control of NOAA-producing plants via airborne particle concentration measurements in workplace air. NOTE This document is also applicable to other airborne particles included in some of the tests during the prenormative research.