Projects

Project P1 - Accurate particulate size, number and surface area

The aim of this project is to provide the capability for measurement methodologies, standards and facilities required for robust measurements of airborne particle size, number density and surface area.

The objectives of the project are:

• To quantify factors affecting instrument sampling.
• To compare particle counting methods (such as condensation particle counting and electrometry) and size selection techniques (such as impactors and electrical mobility).
• To construct a particle generation mixing chamber for assessing particle monitoring instruments with a variety of size and composition distributions of particles.
• To investigate the influence of particle charge and size on the performance of Differential Mobility Analysers (DMAs) to assess the validity of physical
  assumptions and software used in determining size distributions with this method.
• To review and investigate methods for measuring the surface area of ambient nanoparticles.
• To develop a prototype device for diluting flows of nanoparticles using NPL’s patented ‘time division dilution’ method.