title: Size-resolved particle number emission patterns under real-world driving conditions using positive matrix factorization.
abstract: A novel on-board system was tested to characterize size-resolved particle number emission patterns under real-world driving conditions, running in a EURO4 diesel vehicle and in a typical urban circuit in Madrid (Spain). Emission profiles were determined as a function of driving conditions. Source apportionment by Positive Matrix Factorization (PMF) was carried out to interpret the real-world driving conditions. Three emission patterns were identified: (F1) cruise conditions, with medium-high speeds, contributing in this circuit with 60% of total particle number and a particle size distribution dominated by particles >52 nm and around 60 nm; (F2) transient conditions, stop-and-go conditions at medium-high speed, contributing with 25% of the particle number and mainly emitting particles in the nucleation mode; and (F3) creep-idle conditions, representing traffic congestion and frequent idling periods, contributing with 14% to the total particle number and with particles in the nucleation mode (<29.4 nm) and around 98 nm. We suggest potential approaches to reduce particle number emissions depending on particle size and driving conditions. Differences between real-world emission patterns and regulatory cycles (NEDC) are also presented, which evidence that detecting particle number emissions <40 nm is only possible under real-world driving conditions.
authors.affiliation: Environmental Department, Pollutant Emissions from Motor Vehicles, CIEMAT, Avda. Complutense, 40, Madrid, 28040, Spain. aida.dominguez@ciemat.es
authors.forename: Aida
authors.initials: A
authors.lastname: Domínguez-Sáez
authors.forename: Mar
authors.initials: M
authors.lastname: Viana
authors.forename: Carmen C
authors.initials: CC
authors.lastname: Barrios
authors.forename: Jose R
authors.initials: JR
authors.lastname: Rubio
authors.forename: Fulvio
authors.initials: F
authors.lastname: Amato
authors.forename: Manuel
authors.initials: M
authors.lastname: Pujadas
authors.forename: Xavier
authors.initials: X
authors.lastname: Querol
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data; D001334:Automobile Driving / Q000706:statistics & numerical data*; D004784:Environmental Monitoring / Q000379:methods*; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D013030:Spain; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions