A MULTIVARIATE STATISTICAL-ANALYSIS OF FUEL-RELATED POLYCYCLIC AROMATIC HYDROCARBON EMISSIONS FROM HEAVY-DUTY DIESEL VEHICLES

The fuel-dependent emissions of polycyclic aromatic hydrocarbons (PAH) were studied in diluted exhaust from two heavy-duty diesel vehicles during transient driving conditions. Principal component analysis (PCA) was used to investigate the relationship between fuel parameters and PAH contents in fuels. The PCA model shows that certain fuel parameters are related to PAH contents in diesel fuels. Linear regression analysis, PCA, and partial least-squares regression to latent structures (PLS) were used to study the correlation of PAH in fuels and PAH in exhaust emissions. The statistical methods used support the fact that there is a relationship between PAH contents in the diesel fuel and PAH contents emitted in the exhaust emissions. The PLS model resulted in correlation coefficients of r = 0.97 and r = 0.93 for vehicles 1 and 2, respectively. The PAH emission emitted in the exhaust consists of uncombusted through fuel input PAH and PAH formed in the combustion process. This investigation shows that it is possible to reduce PAH emissions in exhaust originating from uncombusted fuel PAH by using diesel fuels with PAH contents less than 4 mg/L.