Diesel Or Gas: What Causes More Air Pollution?

Diesel or Gas

If you are planning to buy a car, the age-old question “which is better: diesel or gas” is sure to give you a riddle. Along with price and fuel efficiency, “which causes more air pollution” also adds to this continuously evolving debate.

Here, we’ll dig in deeper and understand what’s more environmentally friendly between diesel or gas.

Studies show modern diesel vehicles are better!

According to a new six-nation study published in Scientific Reports, modern diesel vehicles emit less pollution than those running on gasoline. And since diesel is much cleaner than before, environmental regulators are increasingly shifting their focus to tackle dirtier gasoline-powered automobiles.

Previously, diesel had a poor reputation as diesel-powered vehicles emit visible pollution. But it’s actually the invisible pollution that comes from gasoline in motor vehicles that is worse.

Professor Hayes at UdeM says it’s time to remove gasoline and old diesel vehicles from the roads. According to him, modern diesel vehicles are running on new standards and are comparatively good for the environment. So, now the government should pay attention to regulating on-road and off-road gasoline engines to meet their environmental targets.

Diesel or Gas

What Makes Modern Diesel-Powered Automobiles More Efficient?

Automobile manufacturers in Europe and North America are now manufacturing cars with an engine add-on – a diesel particle filter (DPFs).

As with any other filter, the DPF captures and stores exhaust soot to reduce emissions from diesel cars. Because of their finite capacity, the DPF needs to be regularly cleaned through a process called regeneration.

The accumulated soot is burnt and removed at a temperature around 600 degrees C, which produces only a residue of ash. This process effectively renews the filter and makes it ready to capture more pollutants from the engine.

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Why is gasoline more polluting than modern diesel vehicles?

In a lab study at the Paul Scherrer Institute in Switzerland, scientists examined the carbonaceous Particulate Matter (PM) emitted from 5 gasoline and 5 diesel cars with engine add-ons like DPF.

Carbonaceous PM contains Primary Organic Aerosol (POA), Secondary Organic Aerosol (SOA) and Black Carbon (BC). These components make PM a highly toxic substance that can damage lung tissues and lead to other major diseases.

The study concluded that modern gasoline cars emit much more carcinogenic primary soot than modern diesel cars. Gasoline cars also produce Volatile Organic Compounds (VOC) that form an extensive amount of SOA than modern diesel cars. Especially at the lower temperature, when we start the vehicle, the emission rate of gasoline cars is astonishingly high. Carbonaceous PM and SOA is markedly higher in gasoline than diesel particle filter and catalyst-equipped diesel vehicles. 

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It’s true that older diesel vehicles emit far more nitrogen oxides, which causes acid rains and smog. However, this is because these vehicles don’t have DPF associated with their engines.

Though gasoline cars are better concerning Nitrogen Oxides (NOX) emissions, toxins and carcinogenic carbonaceous emissions, modern diesel cars are favourable.

To sum up, diesel vehicles with DPF filter make a greener alternative to dangerous gasoline-powered automobiles.

Stay tuned for our next article where we’ll discuss electric cars and their effect on air!