(Nano) Particles from 2-S Scooters: SOF / INSOF; Improvements of Aftertreatment; Toxicity 2007-01-1089
Limited and non-regulated emissions of scooters were analysed during several annual research programs of the Swiss Federal Office of Environment (BAFU) *).
Small scooters, which are very much used in the congested centers of several cities, are a remarkable source of air pollution. Therefore every effort to reduce the emissions is an important contribution to improve the air quality in urban centers.
In the present work detailed investigations of particle emissions of different 2-stroke scooters with direct injection and with carburettor were performed.
The nanoparticulate emissions were measured by means of SMPS, (CPC) and NanoMet. Also the particle mass emission (PM) was measured with the same method as for Diesel engines.
Extensive analyses of PM-residuum for SOF/INSOF, PAH and toxicity equivalence (TEQ), were carried out in an international project network.
Particle mass emission (PM) of 2-S Scooters consists mostly of SOF. The standard coulometric EC/OC-analysis, as well as the analyzer MEXA 1370 PM overestimate the amount of soot due to the effect of “charring”, which provokes the heaviest VOC to stay in the sample during the thermal extraction and to be indicated as EC. A solution for this analytical problem is demonstrated.
Wiremash Filter Catalyst (WFC) is en efficient measure to intensify the oxidation of the exhaust gas components and to reduce PM, PC, PAH, TEQ & VOC. The presented WFC needs a further development for durability and product integration.
The amount of total PAH, as well as the toxicity equivalence factor TEQ correlate roughly with the total particle mass PM.
WFC is an efficient aftertreatment measure to substancially lower the toxicity of 2-S exhaust gases.