NA 134

VDI/DIN-Commission on Air Pollution Prevention (KRdL) - Standards Committee


Indoor air - Part 42: Measurement of the particle number concentration by Condensation Particle Counters (ISO/DIS 16000-42:2021); Text in German and English


total number of airborne particles per unit volume of air, using a Condensation Particle Counter (CPC). This instrument counts all particles roughly between 10 nm to approximately 3 μm. As the particle number concentration is often dominated by the UFP fraction, obtained result can be used as an approximation of the UFP concentration. Quality assurance, determination of the measurement uncertainty and minimal reporting information are also part of this document. This document is applicable to indoor environments as defined in ISO 16000-1. This document does not address the determination of bioaerosols or the chemical characterization of particles. Nevertheless, some bioaerosols can be detected by the CPC and will then contribute to the measured count of particles. For the measurement and assessment of dust composition, see the relevant technical rules in the ISO 16000 International Standards series.



Planned document number

DIN ISO 16000-42

Project number


Responsible national committee

NA 134-04-04-04 UA - Measurement of airborne particles (UFP, PM 2,5, PM 10) 

Responsible international committee

ISO/TC 146/SC 6/WG 21 - Strategies for the measurement of airborne particles 

draft standard

Indoor air - Part 42: Measurement of the particle number concentration by Condensation Particle Counters (ISO/DIS 16000-42:2021); Text in German and English
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