How Much Do Diesel Trains Pollute?

Diesel trains are a major contributor to air pollution. While railway travel is considered one of the greenest modes of transportation, diesel trains emit pollutants such as nitrogen oxide (NOx) and sulphur dioxide (SO2), which have detrimental effects on both health and the environment. The emissions produced by diesel trains are similar to those of large trucks, and the use of diesel engines in enclosed stations can lead to poor air quality, posing risks to travellers and workers. In the UK, where air pollution causes approximately 29,000 deaths annually, the government is facing mounting pressure to improve air quality, with only 41% of train tracks electrified.

Electric trains are emission-free at the point of use

Diesel trains are a major contributor to air pollution. The pollutants emitted by trains are similar to those emitted by large trucks. Railway locomotives produce a relatively higher proportion of sulphur dioxide (SO2) emissions than on-road diesel engines as the diesel fuel used by locomotives has a higher sulphur content. Sulphur dioxide wreaks havoc on fragile ecosystems by causing acid rain. Diesel locomotive engines also emit nitrogen oxide (NOx), which is extremely harmful to the ozone layer and is a primary contributor to climate change.

Electric trains, on the other hand, are emission-free at the point of use. They emit between 20% and 35% less carbon per passenger mile than diesel trains. This benefit will only improve as the electricity generation industry reduces its carbon levels. Electric trains improve air quality by reducing fossil fuel combustion. As electricity production shifts to renewables, electric trains can provide nearly emissions-free transport.

The EU-funded ENSPIRIT project is developing an innovative emission abatement system capable of reducing nitrogen oxide and sulphur dioxide pollution levels. The system uses extremely fine water sprays in a special reactor to capture particle matters that are then removed downstream. This system can be integrated with other devices to provide a complete, cost-effective, and energy-efficient way of making new and older diesel trains more efficient.

The UK government has announced a package of railway spending across England and Wales worth £9.4 billion, of which £4.2 billion will be spent on previously unannounced projects, including the electrification of more railway lines. This electrification of freight train tracks will reduce energy consumption and replace the use of diesel freight trains.

Diesel trains emit large quantities of pollutants in enclosed stations

Diesel locomotive engines are a major contributor to air pollution. They produce nitrogen oxide (NOx) and sulphur dioxide (SO2), which cause a range of health and environmental problems. Nitrogen dioxide (NO2), a type of NOx, is particularly harmful as it is 240 times more destructive to the ozone layer than carbon dioxide, making it a primary contributor to climate change. The diesel fuel used by locomotives has a higher sulphur content, resulting in relatively higher emissions of SO2. These emissions have various health impacts, including reduced lung function and increased levels of DNA strand breaks.

To address this issue, the EU-funded ENSPIRIT project aims to develop an innovative emission abatement system capable of reducing NOx and SO2 pollution levels. This system uses fine water sprays in a special reactor to capture particulate matter, which can then be removed downstream. While the ENSPIRIT solution focuses on new locomotives, it also allows older locomotives to meet emission regulations through remanufacturing.

Despite these efforts, replacing or retrofitting older diesel locomotives to meet tighter emission limits can be economically and technically challenging. As a result, the renewal of the fleet is suggested as the most feasible approach to reducing emissions by 2030. Additionally, converting diesel trains to battery-electric propulsion is another potential solution, offering environmental, health, and economic benefits.

EU-funded ENSPIRIT project aims to reduce nitrogen oxide and sulphur dioxide pollution

Diesel trains contribute significantly to air pollution, particularly nitrogen oxide (NOx) and sulphur dioxide (SO2) emissions. NOx is especially harmful, being 240 times more destructive to the ozone layer than carbon dioxide, and a primary contributor to climate change, smog, and acid rain. Sulphur dioxide emissions from trains are also a concern, as locomotive diesel fuel has a higher sulphur content than on-road diesel fuel.

To address this issue, the EU-funded ENSPIRIT project aims to develop an innovative emission abatement system to reduce NOx and SO2 pollution levels from diesel trains. ENSPIRIT's low-temperature activated carbon oxidative catalytic device is designed to be used by train operators without the need for external service providers, except for periodic function checks. The system employs fine water sprays in a special reactor to capture particulate matter, which is then removed downstream. This technology can be applied to new and old diesel trains, ensuring that they meet stringent global regulations on emissions.

The original plan for ENSPIRIT placed the emission abatement system behind the locomotive, treating emissions from multiple trains. However, research indicated that the system is more effective when applied to trains at railway sidings, depots, and stations when they are not in use. ENSPIRIT is expected to provide a cost-effective and energy-efficient solution for reducing emissions, and its device will be integrated into a broader system for the removal of heat, moisture, sulphur oxides, ultrafine particulate matter, and nitrogen oxides.

The project's impact is significant, as approximately 20% of Europe's rail traffic is hauled by diesel locomotives, and air pollution within train stations poses a potential risk to the health of travellers and workers. While rail transport is considered one of the greenest modes of transportation, the electrification of train lines varies across Europe, with about half remaining non-electrified. Thus, initiatives like ENSPIRIT are crucial to reducing harmful emissions from diesel trains and improving air quality.

Exposure to diesel exhaust has been linked to reduced lung function and DNA strand breaks

Diesel locomotive engines are a major contributor to air pollution. They produce nitrogen oxide (NOx) and sulphur dioxide (SO2), which cause a range of health and environmental problems. Nitrogen dioxide (NO2), a type of NOx, is particularly harmful to the ozone layer, making it a primary contributor to climate change. Railway locomotives produce higher levels of SO2 emissions than on-road diesel engines due to the higher sulphur content of their fuel.

Diesel exhaust particles (DEP) are an air pollutant consisting of a mixture of a carbonaceous core and various compounds such as aldehydes and polycyclic aromatic hydrocarbons. Long-term exposure to DEP is associated with airway hyperresponsiveness, pulmonary fibrosis, and inflammation. Studies have shown that DEP exposure can lead to oxidative stress, pro-inflammatory responses, and reduced lung function. Specifically, mice exposed to DEP for eight weeks exhibited fibrotic foci and significantly higher levels of α-smooth muscle actin and fibronectin in their lungs, indicating the rapid progression of pulmonary fibrosis.

In addition to the respiratory tract effects, DEP exposure has also been linked to DNA damage. Studies in mono-cultures of cells have shown that DEP exposure increases the production of reactive oxygen species (ROS) and causes oxidative stress-related damage to DNA, including DNA strand breaks. Furthermore, in studies of cells in lab dishes, diesel exhaust has been found to cause changes in the cells' DNA, which are usually needed for cancer to develop. Long-term, heavy exposure to diesel exhaust has been linked to lung cancer in lab animals, and several studies of workers exposed to diesel exhaust have shown small but significant increases in lung cancer risk.

The health risks associated with diesel exhaust exposure have led to increasing pressures for improvement in reducing emissions. Various initiatives and regulations have been implemented to address this issue, such as the EU-funded ENSPIRIT project, which aims to develop an innovative emission abatement system to reduce NOx and SO2 pollution levels. While advancements have been made, challenges remain in retrofitting older diesel locomotives to meet tighter emission limits.

Switching to battery-electric propulsion could save the US freight rail sector billions

Diesel trains contribute significantly to air pollution. Railway locomotives produce a relatively higher proportion of sulphur dioxide (SO2) emissions than on-road diesel engines since the diesel fuel used by locomotives has a higher sulphur content. Diesel locomotive engines also emit nitrogen oxide (NOx), which is extremely harmful to the ozone layer and contributes to climate change.

In the US, diesel freight trains emit 35 million metric tons of carbon dioxide annually, causing $6.5 billion in health costs and leading to approximately 1,000 premature deaths each year. These adverse health impacts disproportionately affect disadvantaged and low-income communities, which are often located near freight rail yards and railways.

However, there is a growing movement towards battery-electric propulsion for trains, which could offer a more sustainable and cost-effective alternative to diesel engines. Researchers from the US Department of Energy's Lawrence Berkeley National Laboratory, in collaboration with UCLA and UC Berkeley researchers, have found that retrofitting existing diesel-electric trains with batteries is a cost-competitive option.

Battery-electric trains have several advantages. Firstly, they can use half the energy required by diesel-electric trains, and with falling battery prices, they are becoming increasingly economically viable. Secondly, they provide a dual-fuel capability, allowing for either battery or diesel usage, which is a unique benefit compared to fully electrifying the rail system. Thirdly, they can be deployed during extreme weather events, such as wildfires or storms, to provide backup power and avoid blackouts.

By switching to battery-electric propulsion, the US freight rail sector could save billions. The researchers estimate that over 20 years, the savings from reduced air pollution and carbon dioxide emissions could amount to \$94 billion. This includes the health and climate damages avoided by reducing pollution and emissions. Therefore, not only would battery-electric propulsion bring environmental benefits, but it would also result in significant cost savings for the US freight rail sector.

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