مقاله انگلیسی رایگان در مورد تاثیر دمای سرد در صدور ماشین مسافربری – الزویر 2018

Winter season is associated with high pollution episodes (Custodio et al., 2016; Wang et al., 2017
). Recent seasonal studies have shown that in some urban areas the highest levels of NOx, NH3, CO and PM occur in the cold season (Hofman et al., 2016; Hama et al., 2017). Those studies, as well as the recent report presented by the European Environment Agency (EEA, 2014), indicate that transport sector is one of the main sources of these air pollutants. Moreover, they are (themselves or as precursors) among the most problematic pollutants in terms of harm to human health in Europe: PM, ground-level O3 and nitrogen dioxide (NO2) (EEA, 2015). Urban PM composition is strongly influenced by vehicle exhaust (Custodio et al., 2016; Giorio et al., 2015; Jeong et al., 2016; Pey et al.,
2010). Vehicles contribute to both organic and inorganic fraction of the PM via: i) primary PM emissions and ii) emission of precursors of secondary organic aerosols (SOA) and secondary inorganic aerosols, such as volatile organic compounds (VOCs), NOx or NH3 (Amanatidis et al., 2014; Gordon et al., 2014; Link et al., 2017; Platt et al., 2014, 2017). Moreover, transport sector is one of the dominant sources of NOx, CO and non-methane volatile organic compounds (NMVOC) in Europe; pollutants that together with methane are the main ground-level ozone precursors (EEA 2014). Road transport emissions account for 40.5% NOx, 26.5% CO and 14.6% NMVOC of the total emissions in EEA-33. European vehicle emissions regulation has become more stringent over the years aiming at improving Europe’s air quality. Emissions of THC, NMHC, CO, NOx, solid particle number (SPN; solid particles with a diameter >23 nm) and particle mass (PM) are now a days regulated under the Type 1 test for Euro 6 vehicles. Furthermore, with the implementation of the new regulation in EU (EC, 692/2008), this test will be performed following the WLTP, where tests must be performed at 23 ± 5 C using the worldwide harmonized light-duty driving test cycle (WLTC) (UNECE, GTR 15). However, emission limits and testing procedure at cold ambient temperature have not seen significant changes since it first introduction in 1998 (EC, 98/69). The Type 6 test (name commonly used in EU to refer to the cold temperature test) was introduced “as a measure against air pollution by emissions from motor vehicles at cold ambient temperatures”. The test is carried out only on positive-ignition light-duty vehicles on a chassis dynamometer at
7 ±3 C over the Urban Driving Cycle (UDC; first of the two phases constituting the New European Driving Cycle, NEDC), and only foresees the analysis of CO and THC. It is worth noticing that CO and THC emissions must be, respectively, lower than 15 g km
1 and 1.8 g km
1 , which are more than 15 times higher than those allowed during Type 1 test performed at 23 ± 5 C. Similar procedures are applied at cold temperature in the USA (CFR 1066 Subpart H) (US. EPA), South Korea (MOE, 2014) and China (China 6, 2017). They present a number of similarities with the European Type 6 test, including the temperature at which the test is performed (-7 C) and the determination of the road-load (which can be either determined at
7 C or adjusting the driving resistance by decreasing 10% the coast-down time), but there are important differences as well. For instance, while the procedures applied in USA and China require petrol and diesel vehicles to be tested al low temperature, those in force in EU and Korea only apply to positive-ignition vehicles. Moreover, China has been the first country to include NOx measurements and emission limits at cold temperature (China 6, 2017).