Search

The use of diesel locomotives in transport is gradually decreasing due to electrification and the introduction of high-speed electric rails. However, in Korea, up to 30% of passenger and cargo transport still relies on diesel locomotives and vehicles. Many studies have shown that the exhaust gas from diesel locomotives poses a threat to human health. This study examined the characteristics of particulate matter (PM) in diesel locomotive engine exhaust. In a previous study, PM emissions were found to increase as the throttle was moved to a higher notch. The use of a portable emission measurement system (PEMS) in this study did not detect the highest emissions at notch 5, as is commonly found in gravimetric analyses. When comparing the mass concentrations, the notch 1 and 5 results were similar. However, at notch 8, there was a large difference between the mass concentrations collected on the filters. Further, to reduce the fine PM emitted from diesel locomotives, the ionic components, which account for the largest proportion of the total materials in fine PM, should be clearly identified. Therefore, in this study, an analysis of the weight, ionic composition, and metal components of fine PM discharged from a diesel locomotive was performed. Based on the results, Na+ (31%), Ca2+ (27%), NO3&minus, (24%), and SO42&minus, (13%), were the main ionic components, and the most abundant metal components being Ca (45%) and S (20%). In this study, the chemical components generated in diesel engines of other sources were compared, and as a result, different results were shown depending on the engine load and material ingredients. For the first time, a PEMS was used to measure PM from diesel vehicles, and a comparison was made with the results obtained by a gravimetric method. This is the first report of measuring PM concentrations by connecting a PEMS to a diesel locomotive, and of the distribution and characteristics of ions and heavy metals contained in the particles collected in the filter analyzed. The results indicate the importance of identifying the characteristics of fine PM emitted from a diesel locomotive and establishing an effective reduction measurement.

Use of diesel locomotives in transport is gradually decreasing due to electrification and the introduction of high-speed electric rail. However, in Korea, up to 30% of the transportation of passengers and cargo still uses diesel locomotives and diesel vehicles. Many studies have shown that exhaust gas from diesel locomotives poses a threat to human health. This study examined the characteristics of particulate matter (PM), nitrogen oxides (NOx), carbon monoxide (CO), and hydrocarbons in diesel locomotive engine exhaust. Emission concentrations were evaluated and compared with the existing regulations. In the case of PM and NOx, emission concentrations increased as engine output increased. High concentrations of CO were detected at engine start and acceleration, while hydrocarbons showed weakly increased concentrations regardless of engine power. Based on fuel consumption and engine power, the emission patterns of PM and gaseous substances observed in this study were slightly higher than the U.S. Environmental Protection Agency Tier standard and the Korean emission standard. Continuous monitoring and management of emissions from diesel locomotives are required to comply with emission standards. The findings of this study revealed that emission factors varied based on fuel consumption, engine power, and actual driving patterns. For the first time, a portable emission measurement system (PEMS), normally used to measure exhaust gas from diesel vehicles, was used to measure exhaust gas from diesel locomotives, and the data acquired were compared with previous results. This study is meaningful as the first example of measuring the exhaust gas concentration by connecting a PEMS to a diesel locomotive, and in the future, a study to measure driving characteristics and exhaust gas using a PEMS should be conducted.

Contributions of exhaust and non-exhaust sources to traffic-related particulate matter (PM) pollution in the atmosphere are almost identical and the most important non-exhaust source is known to be brake wear particles. In order to understand the properties and harmful effects of wear particles on people, accurate information on size distribution of brake wear particles is needed. Our previous study investigated the measured changes in size distribution of nanoparticles of 500 nm or smaller to understand the origin of nanoparticles due to temperature increases on the friction surface. The present study was intended to investigate the characteristics of size distribution (5.6 nm–32 μm) of PM released under different braking conditions by using different instruments. The measurement results under 9 braking conditions using 3 different instruments showed that the size distribution characteristics of particles can be divided into two main types according to braking energy. The first type is of PM up to 10 μm in size and with a peak number concentration at 0.2–0.75 μm regardless of braking energy, while the second type is of PM around 10 nm in size generated only when braking energy increased and particles that increased up to 100 nm. In addition, we found that the size distributions measured by the optical particle counter (OPC) and the aerodynamic particle sizer (APS) were consistent by assuming a mean diameter ratio of two instruments.

Exposure to airborne particulate matter (PM) causes several diseases in the human body. The smaller particles, which have relatively large surface areas, are actually more harmful to the human body since they can penetrate deeper parts of the lungs or become secondary pollutants by bonding with other atmospheric pollutants, such as nitrogen oxides. The purpose of this study is to present the number of PM inhaled by subway users as a possible reference material for any analysis of the hazards to the human body arising from the inhalation of such PM. Two transfer stations in Seoul, Korea, which have the greatest number of users, were selected for this study. For 0.3–0.422 μm PM, particle number concentration (PNC) was highest outdoors but decreased as the tester moved deeper underground. On the other hand, the PNC between 1 and 10 μm increased as the tester moved deeper underground and showed a high number concentration inside the subway train as well. An analysis of the particles to which subway users are actually exposed to (inhaled particle number), using particle concentration at each measurement location, the average inhalation rate of an adult, and the average stay time at each location, all showed that particles sized 0.01–0.422 μm are mostly inhaled from the outdoor air whereas particles sized 1–10 μm are inhaled as the passengers move deeper underground. Based on these findings, we expect that the inhaled particle number of subway users can be used as reference data for an evaluation of the hazards to health caused by PM inhalation.