Diesel Engines: Pollution And Health Risks

Diesel engines have been the subject of scrutiny due to their emissions, with some governments even planning to discourage their use or ban them from urban areas. Diesel vehicles produce more than four times the pollution of petrol cars, emitting fine particulate matter that is associated with poor heart health and can lead to acute respiratory issues and increased hospital admissions. They also produce more nitrogen dioxide, contributing to the formation of ground-level ozone, which damages crops, trees, and vegetation. However, diesel engines are more fuel-efficient and emit less carbon dioxide, which led to their promotion as a more environmentally friendly option in the past. Today, newer diesel engines are equipped with particle filters, reducing particulate emissions, but the high nitrogen oxide output remains an issue.

Diesel engines produce more than four times the pollution of petrol cars

Diesel engines have been criticised for the amount of emissions they produce, with some governments even planning to discourage their use or ban them from urban areas. Science has shown that diesel vehicles produce more than four times the pollution of petrol cars.

Diesel engines produce fine particulate matter, which is associated with poor heart health. Research has shown that increases in particulate matter in the air lead to more hospital admissions and deaths from heart attacks. Diesel engines also produce more nitrogen dioxide, making them one of the main sources of this toxic gas. The particulate filters in car exhausts can reduce these emissions by more than 90%, but only when they are well-maintained and in good operating condition.

Diesel engines are used in trucks and heavy equipment because they generate more torque and are more fuel-efficient than petrol engines. They are also cheaper to run, as diesel fuel is more energy-dense, and the engines are more durable. However, these benefits come at a cost to human health and the environment. Diesel emissions contribute to the production of ground-level ozone, which damages crops, trees, and other vegetation. They also produce acid rain, which affects soil, water, and ecosystems, entering the human food chain.

While newer diesel engines are cleaner than older ones, and diesel cars produce less CO2 than petrol cars, the high levels of other toxic emissions mean that diesel engines are still considerably more polluting overall.

Diesel particulate filters can reduce emissions by more than 90%

Diesel engines have been criticised for the amount of pollution they produce. The fine particulate matter emitted from diesel engines is associated with poor heart health and can cause acute respiratory issues and even cancer.

Diesel particulate filters (DPFs) are devices that capture and store diesel particulates, preventing their release into the atmosphere. DPFs have been fitted to diesel-fuelled cars for almost two decades. They are highly effective in controlling solid particulate emissions, including soot, and can reduce emissions by more than 90%.

DPFs work through a combination of filtration mechanisms, such as diffusional deposition, inertial deposition, or flow-line interception. The collected particulates are then removed from the filter through thermal regeneration, which burns off the excess soot deposited in the filter, reducing harmful exhaust emissions.

While DPFs are effective in reducing particulate emissions, they require good operating conditions and regular maintenance. If not maintained properly, DPFs can become blocked, increasing exhaust emissions and reducing engine performance. In some cases, the combustion of particulate matter can cause the filter material to exceed its structural integrity threshold, leading to catastrophic failure.

Despite the benefits of DPFs, the promotion of diesel as a more environmentally friendly fuel option has been controversial. While diesel fuel contains slightly more carbon per litre than petrol, overall CO2 emissions from a diesel car tend to be lower due to their "lean-burn" nature. However, diesel engines can produce more nitrogen dioxide, and the fine particulate matter they emit has been linked to negative health outcomes.

Diesel engines produce more nitrogen dioxide and nitric oxide

Diesel engines have received negative attention for the amount of toxic emissions they produce. While diesel engines produce less carbon dioxide than petrol engines, they emit more nitrogen dioxide and nitric oxide. These emissions have been regulated, as long-term exposure to nitric oxide can significantly increase the risk of respiratory problems, and the fine particulate matter (PM) that diesel engines produce is associated with poor heart health and can cause acute respiratory issues. Diesel engines are also responsible for the production of acid rain, which affects soil, lakes, streams, and the human food chain.

Diesel engines were once promoted as a more environmentally friendly fuel as part of the EU's response to the 1997 Kyoto Protocol, which aimed to reduce greenhouse gas emissions. However, the focus on carbon dioxide emissions has proven detrimental to human health, as the fine particulate matter emitted from diesel engines has resulted in more hospital admissions and deaths from heart attacks.

Newer diesel engines are equipped with diesel particle filters that can reduce PM emissions by over 90% when properly maintained. However, the amount of nitrogen oxide emitted from diesel engines remains an issue.

To address the negative health impacts of diesel emissions, the US Environmental Protection Agency (EPA) has implemented the Diesel Emissions Reduction Act Program, which provides grants and loans to promote diesel emission reductions. Despite these efforts, millions of older, dirtier diesel engines are still in use due to their longevity, and projects aimed at reducing diesel emissions from existing engines are crucial for mitigating their environmental and health impacts.

Diesel exhaust can cause asthma, heart issues, and respiratory illnesses

Diesel exhaust has been linked to asthma, heart issues, and respiratory illnesses. Several studies have found a causal link between diesel exhaust and asthma, indicating that it can trigger attacks and increase susceptibility to developing asthma. The exhaust contains particles that alter the ratios of key immune cells, T-lymphocytes, which are associated with airway inflammation and allergic responses. These particles also stimulate the production of cytokines and chemokines, chemical messengers that promote inflammation and mucus production, leading to airway constriction and irritation.

The impact of diesel exhaust on children is particularly concerning. Exposure to diesel exhaust and common allergens, such as pollen, can result in a magnified response to the allergen. This may explain the increasing prevalence of allergies among children. School buses, often powered by diesel fuel, contribute significantly to children's exposure to diesel exhaust, putting them at risk for asthma and other respiratory issues.

In addition to respiratory ailments, diesel exhaust has been linked to cardiac problems and cancer. Long-term, heavy exposure to diesel exhaust has been associated with an increased risk of lung cancer in lab animals and humans. The International Agency for Research on Cancer (IARC) classifies diesel engine exhaust as "carcinogenic to humans," based on evidence linking it to lung cancer.

To mitigate the health risks associated with diesel exhaust, individuals working around diesel-powered vehicles can take preventive measures. Limiting time spent near idling engines, using personal protective equipment, and implementing workplace ventilation improvements can reduce exposure to diesel fumes and potentially offer protection from other chemical hazards.

Diesel engines are more efficient and emit less carbon dioxide

Diesel vehicles can travel 20% to 35% farther on a single gallon of fuel than similarly-sized gasoline vehicles. They are also more fuel-efficient on highways and in cities. For example, a limited comparison of passenger vehicles by The Motley Fool showed that diesel is 29% more efficient on the highway and 24% more efficient in the city.

Diesel engines are also built to last a long time. They can handle high compression and hard work with less upkeep required by owners. Simplified aftertreatment systems, longer oil-drain intervals, and maintenance-free filters are some of the features that contribute to their longevity.

However, it is important to note that while diesel engines emit less carbon dioxide, they are well-known to pollute through fumes and soot. Additionally, newer models have been found to have higher emissions of nitrogen oxides, which have led to decreased sales in Europe and plans to ban diesel engines in some cities like Paris.

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