This project addressed a major source of air pollution. Of particular concern are the fine particles emitted by diesel engine exhausts that are classified by the World Health Organization as carcinogenic to humans, as well as platinum group elements (PGE) and mercury released from cars and industrial processes. This project provided the underpinning metrology infrastructure and research to better understand and measure, and therefore control, such emissions.
The project developed:
- A new validated aerosol to enable the traceable calibration of condensation particle counting instruments used to measure particulates during the type approval and certification of new automotive engines against European regulation (the Euro 6c regulation).
- A simulated comparison exercise between existing particle emission meters (based on opacity measurements) and novel prototype instruments based on diffusion chargers and optical methods, providing instrument validation at the low particle levels present in Euro 6 compliant diesel vehicle exhausts.
- Improved analysis methods and the associated uncertainties for measurements of small concentrations of PGE present in sample matrices using two mass spectrometry techniques.
- The foundations for an improved SI traceable metrological infrastructure for mercury-in-air measurements (≤15 ng Hg m-3) which is closer to realistic ambient air concentrations (1–2 ng Hg m-3) than was previously possible.
This project is supporting the introduction of effective particulate assessment methods to meet the updated Euro 6c regulation, which will cover type approval of new engines and mandatory periodic testing of diesel engine exhausts in both static and on-road conditions. Methods developed in the project are expected to be incorporated in the UN Particle Measurement Programme documentation (a key reference for the Euro 6 regulation) when it is updated in 2016. The new NMI capabilities are being used by manufacturers of particulate measuring instrumentation to provide traceable measurements and develop products for the new on-road testing requirements.