POLYCYCLIC AROMATIC HYDROCARBONS IN EXHAUST EMISSIONS FROM MOBILE SOURCES – Sampling and Determination –

Sweden Front cover: Electrone microscope image of a diesel exhaust particle agglomerate.Till Cicci, Erica och Arvid " Every animal is naturally made for the use of pure, natural and free air " Tests of the effects of air on the human body, John Arbuthnot.ABSTRACT Exhaust emissions from mobile sources is one of the major sources to air pollution. Thus, it is important to identify and quantify chemical compounds in these emissions that are potential hazards to the environment and to human health. This thesis discuss the measurements of exhaust emissions from mobile sources, with regard to polycyclic aromatic hydrocarbons (PAHs), a group of compounds that are suspected to have adverse health effects. Gasoline and diesel fuelled light-duty vehicles, a heavy-duty diesel vehicle and a small engine, i.e. a lawnmower, with and without an oxidizing catalyst has been investigated. The impact of fuel, catalyst and driving cycle on the emissions of PAH and particulate matter has been investigated. It is concluded that a major part, 50-80%, of the pollutants in gasoline light duty exhaust emissions are emitted during the cold start phase, Further the properties of the fuel, especially aromatic and sulphur content, has a strong influence on the emissions of PAHs and/or particulate matter. The Swedish environmentally classified diesel fuel (MK1) gives significantly lower emissions of both PAHs and particulate matter compared to an European diesel fuel. As for small engines, the emissions of PAHs is strongly affected by the fuel used, i.e. alkylate or regular gasoline.m The use of a catalyst affects the emissions of both the PAHs and particulate matter, as expected. The lowest PAH emissions was obtained using a catalyst together with an alkylate fuel. The size distribution of particulate matter has been measured by the use of a cascade impactor. The size distributed particule samples were also analysed with respect to PAHs. It was concluded that there was a need to develop a more suitable analytical method with high sample throughput and low limits of detection. A fast and relatively simple analytical method for analysis of PAH in ambient air particulate matter as well as diesel exhaust particulates has been developed. The method is based on hyphenated LC-GC-MS and is validated for the PAH analysis of ambient air particulate matter and diesel particulate matter. The major advantages of the method are the high sample throughput and low sample based limit of detection, Thus, it is well …