Marques Baptiste, Kostenidou Evangelia, Valiente Alvaro Martinez, Vansevenant Boris, Sarica Thibaud, Fine Ludovic, Temime-Roussel Brice, Tassel Patrick, Perret Pascal, Liu Yao, Sartelet Karine, Ferronato Corinne, D'Anna Barbara
Aix Marseille Univ, CNRS, LCE, UMR 7376, 13331 Marseille, France.
French Agency for Ecological Transition, ADEME, 49000 Angers, France.
Toxics. 2022 Apr 8;10(4):184. doi: 10.3390/toxics10040184.
The characterization of vehicle exhaust emissions of volatile organic compounds (VOCs) is essential to estimate their impact on the formation of secondary organic aerosol (SOA) and, more generally, air quality. This paper revises and updates non-methane volatile organic compounds (NMVOCs) tailpipe emissions of three Euro 5 vehicles during Artemis cold urban (CU) and motorway (MW) cycles. Positive matrix factorization (PMF) analysis is carried out for the first time on proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS) datasets of vehicular emission. Statistical analysis helped to associate the emitted VOCs to specific driving conditions, such as the start of the vehicles, the activation of the catalysts, or to specific engine combustion regimes. Merged PTR-ToF-MS and automated thermal desorption gas chromatography mass spectrometer (ATD-GC-MS) datasets provided an exhaustive description of the NMVOC emission factors (EFs) of the vehicles, thus helping to identify and quantify up to 147 individual compounds. In general, emissions during the CU cycle exceed those during the MW cycle. The gasoline direct injection (GDI) vehicle exhibits the highest EF during both CU and MW cycles (252 and 15 mg/km), followed by the port-fuel injection (PFI) vehicle (24 and 0.4 mg/km), and finally the diesel vehicle (15 and 3 mg/km). For all vehicles, emissions are dominated by unburnt fuel and incomplete combustion products. Diesel emissions are mostly represented by oxygenated compounds (65%) and aliphatic hydrocarbons (23%) up to C, while GDI and PFI exhaust emissions are composed of monoaromatics (68%) and alkanes (15%). Intermediate volatility organic compounds (IVOCs) range from 2.7 to 13% of the emissions, comprising essentially linear alkanes for the diesel vehicle, while naphthalene accounts up to 42% of the IVOC fraction for the gasoline vehicles. This work demonstrates that PMF analysis of PTR-ToF-MS datasets and GC-MS analysis of vehicular emissions provide a revised and deep characterization of vehicular emissions to enrich current emission inventories.
挥发性有机化合物（VOCs）车辆尾气排放特征对于评估其对二次有机气溶胶（SOA）形成以及更广泛空气质量的影响至关重要。本文修订并更新了三辆欧5车辆在阿尔忒弥斯寒冷城市（CU）和高速公路（MW）循环期间的非甲烷挥发性有机化合物（NMVOCs）排气管排放。首次对车辆排放的质子转移反应飞行时间质谱仪（PTR-ToF-MS）数据集进行了正定矩阵因子分解（PMF）分析。统计分析有助于将排放的VOCs与特定驾驶条件相关联，例如车辆启动、催化剂激活或特定发动机燃烧工况。合并后的PTR-ToF-MS和自动热解吸气相色谱质谱仪（ATD-GC-MS）数据集对车辆的NMVOC排放因子（EFs）进行了详尽描述，从而有助于识别和量化多达147种单个化合物。一般来说，CU循环期间的排放量超过MW循环期间的排放量。汽油直喷（GDI）车辆在CU和MW循环期间均表现出最高的EF（分别为252和15 mg/km），其次是进气道燃油喷射（PFI）车辆（24和0.4 mg/km），最后是柴油车辆（15和3 mg/km）。对于所有车辆，排放主要由未燃烧燃料和不完全燃烧产物主导。柴油排放主要由含氧化合物（65%）和碳数高达C的脂肪烃（23%）组成，而GDI和PFI尾气排放由单环芳烃（68%）和烷烃（15%）组成。中等挥发性有机化合物（IVOCs）占排放量的2.7%至13%，柴油车辆主要为直链烷烃，而汽油车辆中萘占IVOC组分的比例高达42%。这项工作表明，对PTR-ToF-MS数据集进行PMF分析以及对车辆排放进行GC-MS分析，可为车辆排放提供修订后的深入特征描述，以丰富当前的排放清单。
