In 2024, IEC 63086-2-1 was published as the first international testing standard for measuring the performance of air cleaners with particulate pollutants. For measuring particles in the size range from 0.1 – 1 µm, the standard requires the use of Optical Particle Size Spectrometers (OPSS), whereas the total number concentration including also ultrafine particles <0.1 µm is measured with Condensation Particles Counters (CPC). However, the standard deliberately refrains from prescribing specific models. Moreover, it allows either cigarette smoke or potassium chloride (KCl) as two interchangeable test aerosols and leaves for the latter the flexibility to neutralize the particles or not. So far, there has been no systematic study on the effect of these flexibilities in the choice of the measurement instrument, test aerosol and neutralization on the measurement results.

To address these questions, they were tackled in a detailed investigation using three different air cleaners. The filter types of the air cleaners were an H13 filter in accordance with EN 1822-1 (negligible particle size dependence), a commonly used electret filter (moderate particle size dependence), and a completely discharged electret filter (pronounced particle size dependence). The air cleaners were tested using the methods of IEC 63086-2-1 with ten different measurement instruments in parallel. Besides a CPC and five different OPSS models, also a Mobility Particle Size Spectrometer (MPSS), a Fast Mobility Particle Sizer (FMPS), and two appliances based on the principle of unipolar diffusion charging were used. The tests were performed with cigarette smoke as well as either neutralized or not neutralized KCl particles. From fitting the exponential decay curves with and without air cleaner, the size-dependent Clean Air Delivery Rate (CADR) was derived and compared between the different instruments, test aerosols, and neutralization stages.

For the integrated size range from 0.3 µm to 1 µm, all OPSS showed

In 2024, IEC 63086-2-1 was published as the first international testing standard for measuring the performance of air cleaners with particulate pollutants. For measuring particles in the size range from 0.1 – 1 µm, the standard requires the use of Optical Particle Size Spectrometers (OPSS), whereas the total number concentration including also ultrafine particles <0.1 µm is measured with Condensation Particles Counters (CPC). However, the standard deliberately refrains from prescribing specific models. Moreover, it allows either cigarette smoke or potassium chloride (KCl) as two interchangeable test aerosols and leaves for the latter the flexibility to neutralize the particles or not. So far, there has been no systematic study on the effect of these flexibilities in the choice of the measurement instrument, test aerosol and neutralization on the measurement results.

To address these questions, they were tackled in a detailed investigation using three different air cleaners. The filter types of the air cleaners were an H13 filter in accordance with EN 1822-1 (negligible particle size dependence), a commonly used electret filter (moderate particle size dependence), and a completely discharged electret filter (pronounced particle size dependence). The air cleaners were tested using the methods of IEC 63086-2-1 with ten different measurement instruments in parallel. Besides a CPC and five different OPSS models, also a Mobility Particle Size Spectrometer (MPSS), a Fast Mobility Particle Sizer (FMPS), and two appliances based on the principle of unipolar diffusion charging were used. The tests were performed with cigarette smoke as well as either neutralized or not neutralized KCl particles. From fitting the exponential decay curves with and without air cleaner, the size-dependent Clean Air Delivery Rate (CADR) was derived and compared between the different instruments, test aerosols, and neutralization stages.

For the integrated size range from 0.3 µm to 1 µm, all OPSS showed ...