Emissions of regulated and non-regulated compounds were measured on nine gasoline light-duty vehicles according to the US FTP test. The measurements of non-regulated compounds comprised about 40 different VOC in the C2-C10 range, a large number of PAH determined both in the gas and particulate phase, and particulate number in different size fractions determined using an Electrical Low Pressure Impactor (ELPI). The vehicle sample consisted of both low-emitting and high-emitting vehicles of the two main categories catalyst and non-catalyst cars, recruited from on-road remote sensing measurements. For the high-emitters, measurements were carried out both before and after service and repair. The results show that there may be very large differences between individual vehicles as regards emissions of both regulated and non-regulated compounds. For certain non-regulated compounds differences of up to three orders of magnitude were observed. It was also found that the degree of maintenance in many cases had a large impact on emissions. The magnitude of this impact however, varied largely between individual and unregulated compounds. (A)
Abstract