“Why does petrol pollute in cars and planes?” Asks Pauline (8 years)

Gasoline is obtained by separating the crude oil components in specialized plants called refineries. Gasoline mixed with air is a flammable and explosive product that makes it possible to operate a car or aircraft engine. The explosion is controlled and it makes it possible to start parts of the engine to make the wheels of the cars move. For aircraft, we use a special gasoline called kerosene, which does not freeze even when it is very cold at high altitudes.

Although gasoline is dangerous, we rarely break down and everything generally works very well. But there is a problem: air pollution. When you burn gasoline or kerosene, the engine releases carbon dioxide (the CO₂ you often hear about) and products that did not burn well. And there it gets complicated, because air pollution disrupts the climate with more heat, more drought and floods and causes more diseases …

We know what goes into an engine: air and fuel. We know what happens there: Combustion makes it possible to move the car or plane forward by activating the engine. But what comes out of the exhaust pipe or reactor?

First problem: carbon dioxide (CO₂)

The oxygen in the air (O) enables combustion. It then becomes carbon dioxide, which combines 1 carbon atom and 2 oxygen atoms (CO₂). CO₂, however, is a greenhouse gas. It keeps the heat in the atmosphere. The more there are, the warmer it gets on Earth. And precisely its quantity is increasing at full speed. We have never found so many in the atmosphere!

Changes in temperature on the Earth’s surface in 2000 years – R. Woessner? changed from IPCC 2021 report (via The Conversation)

Second problem: particles that did not burn

Afterwards, there are also emissions of other molecules, which it is better to avoid breathing. The finest of them are less than 10 microns; we are talking about ultrafine particles (UFP). 1 micron is a thousand times smaller than a millimeter! UFPs can settle to the base of the lungs without coming out. In addition, the molecules can associate with each other, for example with pollen or dust in the air we breathe. All this can cause many diseases … It is in our interest to live far from airports and busy roads.

How to remove gasoline pollution?

The best solution would be to remove gasoline … “I imagine workers closing hundreds of thousands of abandoned oil and gas wells that need to be cleaned up,” said Joe Biden, President of the United States. Yes, but when do we do it? Most car manufacturers announce that they will switch to all-electric between 2030 and 2050. Airbus announces its first hydrogen-electric aircraft in 2035.

Amazon rainforest from the sky
Amazon rainforest from the sky – Neil Palmer – CIAT / Flickr CC BY-SA 2.0

We can also tinker with saying that if we have more forests, then the trees will capture CO₂ to keep the carbon from growing and releasing oxygen. Magical! But alas, all over the world, forests are being removed. Today, even the Amazon emits more CO₂ than it absorbs because we replace the forest with fields after burning it.

There is another idea with biofuels: We grow plants that are converted into fuel. When we burn it, we still release pollution, but the following plants trap the carbon in the air. And then there is a fuel / pollution / pollution collection / fuel circuit and so on. Then we limit the damage. But problem: where do we find enough fields when we need them for humans and livestock?

One day there will inevitably be no more oil or gas because these are natural reserves that will eventually be depleted. We have had wars for oil and gas, and we will continue to do so. So you might as well start right away with other solutions, even if it’s complicated and expensive!

This analysis is written by Raymond Woessner, Honorary Professor of Geography at the Sorbonne University.
The original article was published on the site of The conversation.

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