No abstract

The transport sector is one of the main sources air pollutants. Different exhaust after-treatment systems have been implemented over the years to control the emissions of criteria pollutants. However, while reducing the emissions of the target compounds these systems can lead to the emissions of other pollutants and/or greenhouse gases such as NH 3 or N 2 O. Following the implementation of the Real Driving Emissions (RDE) test procedure in the EU, vehicles have been equipped with more complex after-treatment configurations. The impact that these technologies may have on the emissions of non-regulated pollutants during real-world driving have not been evaluated until now. In the current study we present the on-road emissions of a series of non-regulated pollutants, including NH 3 , N 2 O, CH 4 and HCHO, measured with a portable FTIR from a series of Euro 6d, Euro 6c and Euro 6d-TEMP, gasoline diesel and compressed natural gas (CNG) vehicles during real-world testing. The obtained results show that it is possible to measure N 2 O, NH 3 , CH 4 and HCHO during on-road operation. The results also highlight the importance of the measurement of the emissions of these pollutants during real-world driving, as the emissions of NH 3 (a particulate matter precursor) and those of N 2 O and CH 4 (green-house gases) can be high from some vehicle technologies. NH 3 emissions were up to 49 mg/km for gasoline passenger cars, up to 69 mg/km for the CNG light-commercial vehicle and up to 17 mg/km a diesel passenger car equipped with a selective catalytic reduction system (SCR). On the other hand, N 2 O and CH 4 emissions accounted for up to 9.8 g CO 2 eqv/km for a diesel passenger car equipped with a combination of diesel oxidation catalysts (DOC), lean NO x traps (LNT), SCR and possibly an ammonia slip catalyst ASC.Atmosphere 2020, 11, 204 2 of 18 organic compounds (NMVOCs) and CH 4 are the main precursors of ground-level (tropospheric) O 3 . Aiming at improving Europe's air quality, policy actions have increasingly been taken to address transport-related air pollution. At European Union (EU) level, this has included the regulation of emissions by setting emission standards (Euro 1 to Euro 6) or by setting requirements for fuel quality.To meet these standards, passenger cars have been equipped with different emission control systems. Thus, three-way catalytic converters (TWC) are commonly used to reduce the emissions of CO, hydrocarbons (HC) and NO x from gasoline cars. In the case of diesel cars, CO and HC emissions are reduced using diesel oxidation catalysts (DOC), and NO x emissions using selective catalytic reduction systems (SCR), lean NO x traps (LNT) or a combination of both. While reducing the emissions of the target compounds these systems can lead to the emissions of other pollutants that are not currently regulated for the passenger cars in the EU. The emitted pollutants include NH 3 [2,3] and N 2 O. In fact, several laboratory-based studies have indicated that vehicle emissions of NH 3 and N 2 O are linked to the use o...

SHRNUTÍ Měření výfukových emisí spalovacích motorů během reálného provozu přenosnými zařízeními umístěnými na palubě vozidla (PEMS) je důležitou součástí hodnocení dopadu nových paliv a technologií na životní prostředí a lidské zdraví. Znalost aktuálního toku výfukových plynů je jedním z nezbytných předpokladů pro takové provozní měření. Jedním z nejjednodušších způsobů je výpočet z toku nasáveného vzduchu, který je vypočten z měřených otáček motoru a tlaku a teploty náplně v sacím potrubí. V této práci byl obecný algoritmus využívající odhad dopravní účinnosti libovolného běžného čtyřdobého motoru aplikován na tři produkční evropské motory běžně využívané v ČR: těžký a automobilový přeplňovaný vznětový motor, a atmosférický zážehový motor. Vypočtené průtoky nasávaného vzduchu byly porovnány s různými referenčními metodami. Výsledky ukazují, že nejistota stanovení toku nasáveného vzduchu obecným algoritmem je v řádu 10% pro většinu provozních režimů motoru, kromě případů recirkulace velké části výfukových plynů, kdy nejistota vzrůstá na desítky procent. Desetiprocentní nejistota pro motory bez vysoké míry recirkulace výfukových plynů je přijatelná pro mnohá, zvláště průzkumná a orientační, měření emisí za provozu, a může být snížena kalibrací algoritmu pro daný motor.

Whether the spring season brings additional pollution to the urban environment remains questionable for a megacity. Aerosol sampling and characterization was performed in the urban background of the Moscow megacity in spring 2017, in a period of a significant impact of mass advection from surrounding fire regions. Parametrization of Angstrom absorption exponent (AAE) on low and high values provides periods dominated by fossil fuel (FF) combustion and affected by biomass burning (BB), respectively. The period identification is supported by air mass transportation from the south of Russia through the regions where a number of fires were observed. Functionalities in entire aerosol composition, assigned to classes of organic, ionic compounds, and dust, are inferred by diffusion refection infrared Fourier transmission (FTIR) spectroscopy. Functional markers of urban transport emissions relate to modern engine technology and driving cycles. Regional BB functionalities indicate the fire impacts to the spring aerosol composition. The development of the advanced source apportionment for a megacity is performed by means of combined ambient FTIR data and statistical PCA analysis. PCA of FTIR spectral data differentiate daily aerosol chemistry by low and high AAE values, related to FF- and BB-affected spectral features. PC loadings of 58%, 21%, and 11% of variability reveal the functional factors of transport, biomass burning, biogenic, dust, and secondary aerosol spring source impacts.