Improving inner city air quality

Challenge

In our cities, small airborne soot particles form a serious health risk, generating an estimated 492,000 premature deaths per year from respiratory and cardiovascular problems in Europe. The EU’s Air Quality Directive requires Member States to limit exposure to these particles, many of which are produced by vehicle engines. Cities are implementing their own strategies to combat this problem, such as London’s ultra-low emission zone and other German and French initiatives. For reliable enforcement, accurate measurements of the particle size, mass and number in a volume of air are required.

The United Nations Economic Commission for Europe Particle Measurement Programme (UNECE PMP), brings together NMIs with instrumentation and vehicle manufacturers, and vehicle testing laboratories. It is responsible for devising workable and acceptable methods for measuring engine emissions. Recently their efforts have been augmented by the European and international standards organisation, CEN and ISO, to produce documented methods for characterising vehicle exhaust emissions and airborne concentrations, for example CEN 16976 and CEN/TS 17434. This places increased importance on the accurate calibration of relevant instruments.

The automotive industry is required to reliably demonstrate that vehicle emissions conform to environmental regulations and to do this emission testing is performed on a test bench. The reduction of permitted emissions and requirements to measure smaller and smaller particle sizes mean that instruments must achieve greater sensitivity than previously possible. Testing this relies on the use of well-characterised aerosols that conform to documented test procedures to ensure measurements provide reliable data that matches real-world requirements.