School of Environmental Science and Engineering, Huazhong University of Science & Technology, Wuhan, 430074, PR China.
School of Environmental Science and Engineering, Huazhong University of Science & Technology, Wuhan, 430074, PR China.
Environ Res. 2020 Sep;188:109802. doi: 10.1016/j.envres.2020.109802. Epub 2020 Jun 21.
VOCs emissions from motor vehicles have become a main source of air pollution in many cities. However, the characteristics of VOCs emissions have not been fully elucidated. Ten representative vehicles were selected in Wuhan, China, and the VOCs emitted by these vehicles under actual working conditions were collected and analyzed through on-road tests. Results showed that the average concentrations of total VOCs emitted by gasoline and diesel vehicles were 5.9 ± 2.4 mg/m and 6.8 ± 3.0 mg/m, while the average emission factors were 5.3 ± 2.2 mg/km and 33.9 ± 22.7 mg/km, respectively. The five compounds emitted at the highest levels by gasoline and diesel vehicles were hexanal, acetone, toluene, p-xylene and iso-pentane. Emission concentration of diesel vehicles was slightly higher than that of gasoline vehicles. Emission factor of diesel vehicles was much higher, because they consumed more fuel and produced more power than gasoline vehicles. The average concentrations of total VOCs emitted by China III, IV and V vehicles were 8.4 ± 1.4 mg/m, 5.8 ± 3.4 mg/m and 5.3 ± 1.9 mg/m, and their average emission factors were 21.7 ± 18.6 mg/km, 19.4 ± 28.9 mg/km and 9.1 ± 7.2 mg/km, respectively. Vehicle emissions decreased obviously as the emission standards increased. The average concentrations of total VOCs emitted under low-speed and high-speed conditions were 9.4 ± 3.5 mg/m and 5.5 ± 1.8 mg/m. Concentrations of acetone, hexanal, toluene and p-xylene were the highest four VOCs under both conditions. The average emission factor of VOCs under high-speed conditions (24.0 ± 13.6 mg/km) was substantially lower than under low-speed conditions (54.0 ± 41.5 mg/km). Thus, tightening emission standards and reducing traffic congestion would help reduce VOCs emissions.
机动车排放的挥发性有机化合物已成为许多城市空气污染的主要来源。然而，挥发性有机化合物排放的特征尚未得到充分阐明。本研究在中国武汉选择了 10 辆有代表性的车辆，通过道路测试收集和分析了这些车辆在实际工作条件下排放的挥发性有机化合物。结果表明，汽油车和柴油车排放的总挥发性有机化合物的平均浓度分别为 5.9±2.4mg/m 和 6.8±3.0mg/m，排放因子分别为 5.3±2.2mg/km 和 33.9±22.7mg/km。汽油车和柴油车排放浓度最高的 5 种化合物分别为正己醛、丙酮、甲苯、对二甲苯和异戊烷。柴油车的排放浓度略高于汽油车，而柴油车的排放因子则要高得多，因为它们比汽油车消耗更多的燃料并产生更多的动力。中国 III、IV 和 V 车辆排放的总挥发性有机化合物的平均浓度分别为 8.4±1.4mg/m、5.8±3.4mg/m 和 5.3±1.9mg/m，排放因子分别为 21.7±18.6mg/km、19.4±28.9mg/km 和 9.1±7.2mg/km。随着排放标准的提高，车辆排放明显下降。低速和高速条件下总挥发性有机化合物的平均排放浓度分别为 9.4±3.5mg/m 和 5.5±1.8mg/m。在这两种条件下，丙酮、正己醛、甲苯和对二甲苯的浓度均为最高的四种挥发性有机化合物。高速条件下挥发性有机化合物的平均排放因子（24.0±13.6mg/km）明显低于低速条件下（54.0±41.5mg/km）。因此，收紧排放标准和减少交通拥堵将有助于减少挥发性有机化合物的排放。
