State Environmental Protection Key Laboratory of Food Chain Pollution Control, Beijing Technology and Business University, Beijing 100048, China; Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry, Beijing Technology and Business University, Beijing 100048, China.
State Environmental Protection Key Laboratory of Food Chain Pollution Control, Beijing Technology and Business University, Beijing 100048, China.
Sci Total Environ. 2021 Jun 15;773:145663. doi: 10.1016/j.scitotenv.2021.145663. Epub 2021 Feb 6.
Humans are more likely to be exposed to ultrafine particles (UFPs) emitted by light-duty gasoline vehicles (LDGVs) in urban road traffic, which can cause serious bodily harm. In this study, we conducted on-road measurement of the Particle Number (PN) emissions from 18 China-3, China-4, and China-5 LDGVs on representative roads in Beijing. To clarify the impact of key parameters (standards, driving conditions, and technology) on the PN emissions, we conducted a comprehensive analysis of the emission results. We found the PN emission factors (EFs) of port fuel injection (PFI) vehicles have declined considerably under stricter standards. Furthermore, we found the average EF of China-5 LDGVs with gasoline direct injection (GDI) was 10 times that of PFI vehicles, and the PN EFs of PFI vehicles increase as the age of the engine increases (R = 0.59). In different operating conditions, the PN EFs of all test vehicles under highway driving conditions were lower than those under non-highway driving conditions (6.5%-82.0%). The PN EFs of PFI LDGVs going uphill are 1.4-2.8 times those when going downhill. The PN EFs of LDGVs under start-up were 18-47% higher than under hot-running. PN emissions were high under positive engine power and increased with vehicle specific power. The dilution ratio has a significant impact on the test results, especially in a higher vehicle specific power interval, indicating that a high dilution ratio may lead to deviation of test values. Further research needs to determine the optimal dilution ratio to minimize test deviation. This study provides important data support for PN emission control. The optimal upper limit of the primary dilution ratio should be further studied and specified as a standard.
人类在城市道路交通中更有可能接触到轻型汽油车（LDGV）排放的超细颗粒（UFPs），这可能会对人体造成严重伤害。在这项研究中，我们对北京代表性道路上的 18 辆中国 3 号、中国 4 号和中国 5 号 LDGV 进行了车载测量，以了解其粒子数（PN）排放情况。为了阐明关键参数（标准、驾驶条件和技术）对 PN 排放的影响，我们对排放结果进行了全面分析。我们发现，在更严格的标准下，进气道燃油喷射（PFI）车辆的 PN 排放因子（EF）已经显著下降。此外，我们发现，采用汽油直喷（GDI）的中国 5 号 LDGV 的平均 EF 是 PFI 车辆的 10 倍，且随着发动机年龄的增长，PFI 车辆的 PN EF 也会增加（R=0.59）。在不同的运行条件下，所有测试车辆在高速公路行驶条件下的 PN EF 均低于非高速公路行驶条件下的 PN EF（6.5%-82.0%）。PFI LDGV 上坡行驶的 PN EF 是下坡行驶的 1.4-2.8 倍。LDGV 冷启动时的 PN EF 比热机运转时高 18%-47%。在发动机功率为正的情况下，PN 排放量较高，且随车辆比功率的增加而增加。稀释比会对测试结果产生显著影响，特别是在车辆比功率较高的区间内，表明高稀释比可能会导致测试值的偏差。需要进一步的研究来确定最佳的稀释比，以最大限度地减少测试偏差。本研究为 PN 排放控制提供了重要的数据支持。应进一步研究并规定最佳的初级稀释比上限作为标准。
