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As the world tries to come together to slow down climate change and become as green as possible, it begs the question. What do airplanes emit?

Plane emissions will depend largely on what type of airplane it is and also what type of fuel is being burned. But for the most part, planes emit five things — carbon dioxide, nitrogen oxides (and ozone), contrails, sulfate and soot aerosols, and water vapor.

We all more or less know what cars emit (mainly carbon dioxide), and we know the potential harm that it can cause to the environment. But what about planes, what do they emit? In this article, we’ll take a deep dive into airplane emissions and how they can affect the environment. We’ll also dispel a common fear about contrails and even discuss the possibility of electric aircraft in the future.

When you come to this site, we want you to leave with the confidence that you have access to the best, most helpful content that you can find on the web. Everything we publish is thoroughly vetted for accuracy via extensive research and examination of other sources on the web. So that when you finish reading this article, you really do know the things that planes emit and you have a better sense of how air travel may be contributing to climate change.

Table of contents


What Do Airplanes Emit During Flight?

Emissions have been one of the hottest topics in transportation over the last decade or so. Just look at the automotive industry, for example. I’m sure that most of you reading this have a car or at least ride in a car commonly. Whether that’s to go to work, get to school, or to head somewhere to hang out with friends — cars are by far the most common form of transportation in the country. And the world for that matter.

And in recent years, more and more automakers have been heading towards more and more electric vehicles. Take Korean automotive giant Hyundai, which recently committed to being fully carbon neutral by 2045. The reason for this change in the ideology behind automotive manufacturing is the harmful effects that emissions have on the environment and the future of this world.

Cars, for the most part, release carbon dioxide into the environment, which has been shown to negatively affect the atmosphere over time. And let’s be honest, car engines are a heck of a lot smaller than aircraft engines, especially when we’re talking about commercial aircraft. These engines also typically operate differently than automobile engines. All that said, it’s time to take a look — what do planes emit?

Like cars, airplane engines burn fuel to create power (thrust) which enables the aircraft to effortlessly fly through the air at incredible speeds. But these engines burn significantly more fuel than cars do, and the type of fuel that planes use is entirely different from that of automobiles. So the emissions are a bit different. According to the Climate Change Connection, airplanes typically emit the following five things:

  • Carbon dioxide — This is the same thing that passenger vehicles emit when the combustion engines burn fuel. It’s estimated that commercial planes produce roughly the same amount of carbon dioxide per passenger per mile as a single occupant driving a car the same distance.
  • Nitrogen oxides (and ozone) — This greenhouse gas is what contributes to heavier concentrations of ozone in the ozone layer.
  • Contrails — The vapor contrails that planes leave behind are mostly made entirely of water vapor, but there are some other small concentrations of chemicals within.
  • Sulfate and soot — With airplanes, sulfates and soot will be released in the form of aerosols.
  • Water vapor — Mostly formed naturally by the condensation due to the hot exhaust gases mixing with the cold outside air, water vapor and water droplets are typically the least harmful thing that planes emit.

Now that you have a bit of an idea about what planes emit, it’s time to think about why it really matters. After all, the importance of examining vehicular emissions is almost entirely about the ways that they can contribute to climate change and the health of our environment, so let’s take a look at how these substances that planes emit can affect the environment.

Air Airplane Emissions Harmful To The Environment?

Unfortunately, the truth is that all of the things that planes emit can potentially have negative effects on the atmosphere and the environment. And with climate change becoming more and more of a reality every year, it’s important to know how exactly air travel is contributing to the issue.

As you might have guessed, the two most harmful things from above that planes emit are carbon dioxide and nitrogen oxides. These emissions are typically the ones that lead to the destruction of the ozone layer and are major contributors to the greenhouse effect that leads to warmer temperatures down here on the surface. Since these two things are the most harmful and released in the biggest quantities, it’s important to keep them in mind.

The other three — water vapor, contrails, and sulfate/soot — are not quite as bad. Contrails are made mostly of water vapor, as you’ll shortly read. And those, combined with the soot and sulfate, can lead to enhanced cloud formation. The properties of clouds can also be affected by these emissions, and the results can lead to more warming of the planet.

So in the end, it’s true that air travel and airplane emissions are, in fact, harmful to the environment and it’s an issue that might not be very easy to solve. At least not very quickly.

What Are The White Vapor Trails That Come Out Of Airplanes?

If you ever look up on a clear day and see long, narrow white streaks of clouds across the sky, then you’ve likely seen what is known as vapor contrails. If you follow those vapor trails all the way to their source, you might be able to see a small speck of an airplane leaving them behind as it flies.

A common misconception about these vapor trails is that they are chemicals released by the government for various purposes. Or that they are harmful chemicals designed to control the weather, affect the population, or one of a hundred other conspiracies about them. But the truth is, these vapor trails are almost entirely harmless.

So what exactly are these trails that planes leave behind while flying?

In short, the white contrails that you can see behind a plane is basically just water vapor that naturally forms due to temperature differences and the presence of gases. When the hot exhaust air from an airplane leaves the engine, condensation forms as it enters the cold temperatures at the extreme heights that planes fly at. As this water vapor forms, the cold temperatures freeze the droplets in place, where they remain as contrails that look like clouds.

For more information about the contrails that planes leave behind, check out our full article on the topic. But suffice it to say that they’re mainly just naturally occurring water vapor and they aren’t really too harmful to people or the environment.

Will Electric Planes Ever Be Possible?

While the automotive industry goes in the direction of more and more electric vehicles, it brings into question whether other forms of transportation — especially airplanes — can ever go in that same direction. After all, it would make sense to head that way considering how much the aviation industry affects the environment, releasing upwards of 1 billion pounds of carbon dioxide alone annually.

The truth is that electric airplanes have been around for a long time, going all the way back to the late 19th-century. But even over the last 140 years, the battery technology that we have access to has not gotten to a point yet where they’re suitable for sustained flight that can actually compete with fuel-powered jet engines of today.

Sure, battery technology has improved immensely in relatively recent years, largely due to the push of the automotive industry to go electric. But the batteries needed for actual commercial flight just have not been created yet. The biggest issue currently is a combination of needing more powerful batteries without simultaneously vastly increasing the size and weight of the battery.

It will also be an issue for airplane manufacturers and airlines alike to make the switch from fuel-powered aircraft to electric ones. So even though it’s likely that electric-powered smaller aircraft will be available in the next decade or two, a fully electric aviation industry is still quite a long time away. But every little bit helps, and it’s going to be exciting to see how batteries and electric-powered planes start changing everything we know about aviation moving forward.