New particle number measurement method equivalent to particle measurement programme methodology

Abstract

A nano-aerosol monitor, which is a newly developed particle number (PN) measurement system having no volatile particle remover, was evaluated as an alternative to the particle measurement programme (PMP) methodology. The nano-aerosol monitor is a combination of a newly developed sheathless classifier and an electrometer. The nano-aerosol monitor is quite compact compared with other conventional PMP systems and can be used under vibrating conditions. Furthermore, omitting the volatile particle remover results in lower electricity usage. These features will allow the nano-aerosol monitor to be applied to PN portable emission measurement system. It was confirmed that the nano-aerosol monitor classified particles as expected, using 23-nm sodium chloride particles. The exhaust measurements from a gasoline direct injection passenger car and diesel trucks equipped with a diesel particulate filter were conducted using the nano-aerosol monitor and the PMP methodology. The results obtained with the nano-aerosol monitor were similar to those obtained with the PMP methodology for all vehicles and in all test modes, despite the fact that the nano-aerosol monitor does not have a volatile particle remover and hence detects both solid and volatile particles. These results indicated that the nano-aerosol monitor has a performance comparable to the PMP methodology. Simultaneously, the results suggested the possibility that the ratio of volatile particles in the exhausts from modern vehicles is constant. If this feature is applied to various conditions, it will be possible to obtain data comparable to those from the PMP methodology, using a particle measurement system without a volatile particle remover.