This paper described the effect of the diesel cetane number on exhaust emissions characteristics according to various additives. In addition, the emission characteristics of test fuels blended with three additives (GTL, biodiesel and additive for improving CN) were analyzed and the potential for uses of these additives were evaluated in this study. To achieve this purpose, the test diesel vehicle with a two-thousand cubic centimeter displacement was used to analyze the emission characteristics according to the CN. Also, the NEDC (New European Driving Cycle) was applied as the test mode which is widely used as the test method for environmental certification of diesel vehicles. To analyze the characteristics of HAPs, the VOCs and PAHs were analyzed from the BTEX and the particulate matter, respectively. The analysis results revealed that the CO emissions show the largest reduction rate while the NOx+THC emissions are reduced at a low as the CN got higher. In the NEDC mode, the PM emissions in the EUDC mode were found to be at a lower level than those in the UDC mode. As for the VOCs and PAHs characteristics, the VOCs of the CN 58 show the lowest amounts. Also, the PAHs of diesel blended with GTL show the highest level, followed by those of diesel blended with biodiesel and diesel blended with cetane additive.

Severe PM 2.5 air pollution over the Asian continent is occasionally transported across the East China Sea by the westerly winds to Japan, continuing for long distances over the Pacific Ocean. Despite such polluted air masses causing health issues, conventional models tend to underestimate levels of organic aerosols (OA) and PM 2.5 . Here, PM 2.5 and its major components recorded during three field campaigns carried out at Fukue Island (32.75°N, 128.68°E), Japan (spring 2009), Rudong (32.25°N, 121.37°E), China (spring 2010), and Jeju (33.35°N, 126.39°E), Korea (autumn 2012) around the East China Sea were used to test the performance of the Weather Research and Forecasting-Chem/ATRAS-MOSAIC model. Overall, model performance was improved by introducing chemical aging represented by a volatility basis-set scheme, whereby median values of the model/observation ratio for OA were raised to 0.34-1.28 from 0.30-0.35 in the case of conventional settings. In particular, the levels of OA at the Fukue site and daytime buildup of the OA levels at all three sites were reproduced by the model. OA levels were still sometimes underestimated. This suggests that either emission rates of organic precursors are being underestimated or other pathways of OA formation are also important. Our analysis also indicates that this region is characterized by high OH concentrations, promoting chemical aging. The predictions of PM 2.5 levels in the model also improved, with median values of the model/observation ratio shifting from 0.67-0.91 to 0.68-0.95, when chemical aging of OA was taken into account.

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