PM2.5 measurement protocol for offices

People are more than 80% of their time indoors. However, in contrast to ambient air, no (legal) limits for indoor particulate matter exist. This paper describes a measurement protocol to determine the yearly averaged indoor PM2,5 concentration and gives reference values for five quality classes: <2,5 μg/m3 (A+), <10 μg/m3 (A: WHO annual advisory value), <17,5 μg/m3 (B),