Revisiting Total Particle Number Measurements for Vehicle Exhaust Regulations

Road transport significantly contributes to air pollution in cities. Particle emissions are controlled by a particulate matter (PM) mass and a solid particle number (SPN) limit. There are concerns that the SPN limit does not effectively control all relevant particulate species and there are instances of semi-volatile particle emissions that are order of magnitudes higher than the SPN emission levels. This overview discusses whether a new metric (total particles, i.e. solids and volatiles) should be introduced for the effective regulation of vehicle emissions. Initially, it summarizes recent findings on the contribution of road transport to particle number concentration levels in cities. Then, both solid and total particle emission levels from modern vehicles are presented. Shortly the adverse health effects of solid and volatile particles are discussed. Finally, the open issues regarding an appropriate methodology in order to achieve representative and reproducible results are summarized. With better understanding of the instances of formation of nucleation mode particles it will be possible to identify its culprits (e.g. fuel, lubricant, combustion or aftertreatment operation). Then the appropriate solutions can be enforced and the right decisions can be taken on the need for new regulatory initiatives, for example addition of total particles in the tailpipe, decrease of specific organic precursors, better control of inorganic precursors, or revision of fuel and lubricant specifications.

GIECHASKIEL Barouch;  MELAS Anastasios;  MARTINI Giorgio;  DILARA Panagiota;  NTZIACHRISTOS Leonidas; 

2022-01-28

MDPI

JRC127624

2073-4433 (online),   

https://www.mdpi.com/2073-4433/13/2/155,    https://publications.jrc.ec.europa.eu/repository/handle/JRC127624,   

10.3390/atmos13020155 (online),