Emission factors of unregulated atmospheric pollutants for passenger cars:Task 322 of the EU Artemis project

EU ARTEMIS project focused on the assessment and reliability of transport emission models and inventory system, and the sub-task 322 entailed measurements of unregulated pollutants from passenger cars. As the result of this work a database of unregulated exhaust pollutants was developed, providing a unique and extensive set of data to study and define emission factors for several non-regulated pollutants. Based on the current knowledge on the atmospheric pollutants from mobile sources, and taking into account limitations of Artemis data on unregulated pollutants, the following "Priority Toxics" were selected for determination of emission factors: benzene, 1,3-butadiene, ethylbenzene, toluene, xylenes, n-hexane, formaldehyde, acetaldehyde, acrolein, benzo[a]pyrene and sum of six most carcinogenic PAHs from the combined "semivolatile+ particulate" phase. For major part of unregulated pollutants, the emissions level decreased step by step, when advancing from pre-Euro-1 cars towards Euro-4 emission class cars. In some cases, like 1,3-butadiene emission, emissions were close to zero with cars from Euro-1 to Euro-4 emission class. Generally, emissions of individual hydrocarbons from diesel cars were at lower level than those from petrol fuelled cars, whereas aldehyde emissions on the other way around.