ISO 19996:2024

Overview

ISO 19996:2024 - Charge conditioning of aerosol particles provides requirements and guidance for using charge conditioners to establish known electrical charge states on aerosol particles. It focuses on particle characterization and on generating calibration and test aerosols for electrical-mobility–based instruments. The standard defines a methodology to specify charge conditioner performance and implement adequate quality control for applications in differential mobility analysing systems (DMAS) and differential electrical mobility classifiers (DEMC).

Key topics and technical requirements

• Scope and limits
  • Particle sizes covered: approximately 1 nm to 1 µm.
  • Particle number concentrations at the inlet: up to approximately 1 × 10^7 cm⁻3.
  • Applies specifically to DMAS and DEMC use cases; does not cover radiation safety for radioactive or x‑ray ionizers or charge conditioner design details.
• Charge conditioning fundamentals
  • Principles of bipolar and unipolar charge conditioning and the physics of ion–particle interactions.
  • Role of diffusion charging vs. field charging (diffusion charging preferred for mobility-based sizing).
• Ionization sources
  • Coverage of common ion sources such as radioisotopes, soft X‑ray sources, and corona discharge, including differences in ion production and consequences for charge distribution.
• Charge distribution and influencing factors
  • Definition and use of charge distribution functions.
  • Factors affecting outcomes: particle size and morphology, pre‑charge, carrier gas composition/temperature/humidity, aerosol concentration, residence time, ion production rate, and particle losses.
• Performance specification & testing
  • Methodology for device specification, operational parameters, and quality control.
  • Test procedures and verification, including particle loss measurement, generation rates, and charge distribution characterization.
• Informative annexes
  • Practical guidance: implementation of bipolar steady‑state conditioning, test procedures, electrostatic precipitator for uncharged aerosols, concentration series tests, example test suites and ambient aerosol methods.

Practical applications and users

ISO 19996:2024 is intended for:

• Calibration and test laboratories that service DMAS/DEMC instruments.
• Instrument manufacturers and developers of aerosol charge conditioners.
• Metrology institutes and research labs performing aerosol size and concentration measurements.
• Quality managers implementing traceable calibration and performance verification of mobility‑based particle sizing/classification systems.

This standard supports accurate particle size distribution measurement, reliable mobility classification, and robust calibration practices for aerosol instrumentation.

Related standards

• ISO 15900 - Differential electrical mobility analysis for aerosol particles.
• ISO 27891 - Calibration of condensation particle counters.

Keywords: ISO 19996:2024, charge conditioning, aerosol particles, DMAS, DEMC, bipolar charge conditioner, unipolar charge conditioner, charge distribution, ionization sources, calibration aerosols, particle characterization.