CEN/TC 264/WG 32 - Air quality - Determination of the particle number concentration

This document describes a standard method for determining particle number size distributions in ambient air in the size range from 10 nm to 800 nm at total concentrations up to approximately 10^5 cm^-3 with a time resolution of a few minutes. The standard method is based on a Mobility Particle Size Spectrometer (MPSS) used with a bipolar diffusion charger and a Condensation Particle Counter (CPC) as the detector. The document describes the performance characteristics and minimum requirements of the instruments and equipment to be used, and describes sampling, operation, data processing and QA/QC procedures, including calibration.

This Technical Specification describes a standard method for determining the particle number concentration in ambient air in a range up to about 107 cm–3 for averaging times equal to or larger than 1 min. The standard method is based on a Condensation Particle Counter (CPC) operated in the counting mode and an appropriate dilution system for concentrations exceeding the counting mode range. It also defines the performance characteristics and the minimum requirements of the instruments to be used. The lower and upper sizes considered within this document are 7 nm and a few micrometres, respectively. This document describes sampling, operation, data processing and QA/QC procedures including calibration parameters.

This document specifies a process for the electrical diffusion charging of aerosols with subsequent measurement of particle charge. With the aid of this method, it is possible to determine the lung-deposited surface area (LDSA) concentration of particles in ambient air. Depending on the design of the electrical diffusion charger, the LDSA of particles in the size range of approximately 20 nm to approximately 300 nm is measurable.
Furthermore, this document specifies design criteria for LDSA measuring aerosol monitors as well as performance criteria and the associated test procedures. The performance criteria depend on the application and they are more stringent when the instrument is operated in an air quality monitoring station.
In the determination of the LDSA concentration, the share of geometric particle surface area concentration is determined that can be deposited in the alveolar region of the human lung. Typical particle surface area concentrations with alveolar deposition measured in urban areas range from 5 µm2/cm3 to 50 µm2/cm3.
Instruments based on this measurement principle can be designed to be very compact with a low power consumption. This makes them ideally suited for handheld measurements, other forms of mobile application or to measure personal exposure. On the other hand, they can be easily adapted to serve as a stationary instrument in air quality monitoring stations.

This European Standard specifies a standard method for determining the particle number concentration in ambient air in a range up to about 107 cm–3 for averaging times equal to or larger than 1 min. The standard method is based on a Condensation Particle Counter (CPC) operated in the counting mode and an appropriate dilution system for concentrations exceeding the counting mode range. It also defines the performance characteristics and the minimum requirements of the instruments to be used. The lower and upper sizes considered within this document are 10 nm and a few micrometres, respectively. This document describes sampling, operation, data processing and QA/QC procedures including calibration parameters.