What Is Dirty Air and Clean Air in F1?

Many variables are constantly running through the mind of a Formula 1 driver during a race, and one of the most important ones is understanding how their car behaves in different situations of airflow, i.e., clean air and dirty air. For example, a driver can push harder when he is in clean air.

However, if he does so when in dirty air, the temperature in the tires and other crucial components like brakes can shoot up very quickly, in which case the driver has to back out and get some clean air around the car. Even strategic decisions like when to pit are often made by considering whether the driver will come out after the stop in traffic or an empty portion of the track.

This has become even more pertinent in the current generation of ground-effect cars which are aerodynamically very sensitive. So, here’s a look at what both clean and dirty air actually mean in F1.

What is clean air in F1?

Clean air refers to the undisturbed airflow that a car experiences when it’s at the front of the pack or driving in an open space without another car directly ahead. This is important because, in clean air, the car can generate the maximum possible downforce, thereby improving the overall grip.

This makes the car faster and easier to control, especially through corners and that’s why being in clean air is a huge advantage for a driver. With clear airflow, the car can operate at its peak, giving the driver better control, faster lap times, and more tire life due to less wear.

The phrase “clean air is king” is often used in F1, and Oscar Piastri recently used it at the 2024 Belgian Grand Prix when he found himself at the front of the pack after spending much of his opening stint in the dirty air of the Ferrari.

At the 2024 Azerbaijan Grand Prix, Piastri again showed the value of clean air when he took the lead from Charles Leclerc after a pit stop and then managed to stay ahead for 31 laps, keeping the Monagasque behind him.

Despite Leclerc staying close behind for most of the second stint, he couldn’t pass Piastri as he was stuck in the dirty air. Being in clean air allowed Piastri to maintain his pace and keep his tires in better condition, while Leclerc struggled and eventually wore his tires out, losing any chance to challenge for the win.

What is dirty air in F1?

Dirty air is the turbulent, disrupted airflow that follows a car as it speeds along the track. When a car is directly behind another, the airflow it receives is disturbed, reducing the effectiveness of its various aerodynamic components. In dirty air, a Formula 1 car generates less downforce, making it harder to control.

Especially in corners, the drivers have to work harder to keep their cars stable, and their tires wear out faster as a result. However, sometimes it becomes confusing to differentiate between dirty air and slipstream because both these phenomena occur when a car is close behind another.

A slipstream helps a driver by reducing the overall drag on the car, allowing them to go faster down a straight and potentially overtake. However, when a car follows another too closely for too long, the slipstream can become counterproductive, turning into dirty air.

This happens when the car behind moves into the wake of turbulent air coming from the car in front. Instead of gaining speed due to less drag, the car behind loses grip and suffers from increased tire degradation.

A good example of this is George Russell’s scary accident during the Australian Grand Prix when he suddenly got too close to the Aston Martin of Fernando Alonso ahead on the last lap of the race. As a result, he lost significant downforce and slid into the wall through the gravel.

In the current era of F1, with cars relying heavily on ground-effect aerodynamics, which was originally introduced to create more wheel-to-wheel action and close racing, dirty air has become an even bigger issue. Even back in 2023, several drivers pointed out that the current generation of cars would make overtaking more difficult than ever due to the higher levels of downforce they produce.

Following a rather action-less 2023 Azerbaijan Grand Prix on the Baku City Circuit, a track with one of the longest straights on the calendar, Sergio Perez and Max Verstappen explained why these cars are more prone to dirty air than before.

Perez explained as quoted by Motorsport.com, “These cars are generating a bit more downforce, and by generating that little more downforce, the car behind [in the dirty air] struggles a little bit more to follow.”

Verstappen agreed to this by saying, “Like Checo said, I think the more downforce we generate — and that, of course, will always be every year — if you keep the rules the same it will be harder to pass.”