Switch off your engine: how reducing vehicle idling can help improve air quality

Leaving your engine running while you’re waiting, also known as vehicle idling, might not feel like a big deal. But switching it off is one of the simplest things you can do to reduce unnecessary air pollution where you live.

From 30 September 2026, drivers in Wales who leave their engine running unnecessarily while parked on a public road could face a fine of between £75 and £150, up from £20.

Switching off your engine when parked is a simple way to help reduce unnecessary pollution and improve the quality of the air we breathe.

Why does switching your engine off matter?

When a vehicle is sitting still with its engine running, it's still producing pollution.

Vehicle emissions release pollutants such as nitrogen dioxide and tiny particles called particulate matter into the air. Breathing in these pollutants can affect our heart and lungs, and long-term exposure can increase the risk of heart and lung disease, as well as lung cancer.

In Wales, around 33,000 healthy life-years were estimated to be lost in 2023 due to air pollution.

And some people are more affected than others.

Children are particularly vulnerable because their lungs are still developing. Older people and people living with heart or lung conditions can also be more sensitive to poor air quality.

That makes switching off particularly important in places where people regularly gather, such as outside schools, nurseries, healthcare settings, shops and train stations.

How does vehicle idling affect our health?

We’ve probably all done it.

You arrive a few minutes early for school pick-up. You’re waiting for somebody outside the shops. You’re sitting in the car checking your phone. Keeping the engine running can easily become a habit without us really thinking about it.

But if your vehicle is parked and you don’t need the engine on, switching it off means you’re not producing unnecessary emissions.

Research reviewed by the UK Health Security Agency shows that children are particularly exposed to traffic-related air pollution, especially on their journeys to and from school.

So a simple change made by lots of us can help reduce pollution in the places where children and other vulnerable groups spend time.

When is it ok to keep your engine running?

There are situations where switching off may not be safe or practical. Know your Highway Code.

For example, you may need your engine running when:

• You’re stopped because of traffic

• The engine is needed to power essential equipment, such as emergency vehicle systems, hydraulic doors or refrigeration units on lorries or vans

• A vehicle fault is being diagnosed or repaired

The rules on engine idling apply to public roads, not private land where public access is restricted. However, switching off your engine whenever it's safe and practical to do so can still help reduce unnecessary emissions.

Warming up your car, de-icing your windscreen or clearing it of mist aren't exemptions to the idling rules. However, the Highway Code still requires you to make sure your windscreen is clear of ice, snow and mist before setting off. Where possible, use alternative methods to clear it without leaving your engine running.

Waiting for someone, charging your phone, listening to music or keeping the heating or air conditioning on for comfort aren't considered necessary reasons to leave your engine running.

How to reduce vehicle emissions

The easiest place to start is to make “park up, switch off” a habit.

If you’re waiting outside school, picking somebody up from the station or sitting outside the shops, switch the engine off when it’s safe to do so.

You can also think about other ways to reduce pollution from everyday journeys. Walking, wheeling or cycling shorter journeys where possible, combining trips and using public transport can all help reduce the number of vehicle journeys we make.

How can I check air quality in Wales?

Air pollution isn’t always something you can see or smell.

The Air Quality in Wales website lets you check monitored air pollution levels across Wales, including nitrogen dioxide, particulate matter and ozone.

You can use it to see current air quality information where monitoring is available and learn more about the pollutants in the air around us.