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Air pollution is associated with a number of negative health impacts. Air quality is recognised as a key public health consideration. This is because of the harmful effects it can have on the respiratory system and other organs – particularly in those among us who are more vulnerable.

Advice from Public Heath England (PHE) about improving outdoor air quality and health identifies a range of measures including tackling idling. The challenge has been taken up by several councils.

Air quality remains good in Somerset and we don’t have the pollutant levels experienced in many cities in the UK.

Why you should stop idling

Vehicle idling is unnecessary.

  • It’s bad for the environment - it emits harmful pollutants, greenhouse gases and particles into the air. Car idling produces up to 150 balloons of harmful exhaust emissions per minute.
  • It’s bad for your health – when you’re idling, you are emitting harmful gases into the air which are then drawn back into your car. Air pollution has been linked to a number of health risks.
  • It’s bad for your wallet - it wastes fuel and increases wear on your car. You could save money by switching off your engine.

Circumstances where it is justified

In all cases, we should try to limit the idling to less than 30 seconds, but the main justified reasons are:

  • when you are sat at traffic lights or waiting at roadworks to proceed onwards
  • when you are queuing in traffic that may move forward imminently
  • if a roadside repair means that the engine needs to be running to diagnose and put right the fault

Some myths and the facts    

Idling gets you nowhere. Here, we clear up some common misconceptions about engine idling.

Remember, as well as wasting fuel and money, unnecessary engine idling means harmful vehicle pollution is released into the atmosphere, which is bad for the environment and our health.

  1. The engine needs to stay on to keep the battery fully chargedmodern battery design has largely eliminated this threat.
  2. Turning the engine on and off wears it out - electronic ignitions in modern cars have eliminated this problem. Idling increases wear and tear.
  3. Catalytic converters need to be hot to work properly – true, but an idling engine does not keep a catalytic converter warm. They retain their heat for about 25 minutes after an engine is switched off.
  4. Idling keeps an engine in better condition - idling means incomplete combustion, leading to a build-up of residue in an engine, and increasing wear and tear.
  5. Starting an engine uses more fuel and produces more pollution than idling – for a majority, engines idling for more than 10 seconds use more fuel and cause less pollution than starting the motor. This is one of the reasons why newer vehicles are fitted with stop-start technology.
  6. The best way to warm up your vehicle is to leave the engine running for a few minutes – modern engines are designed so that you can commence driving straight after starting the car.
  7. Idling reduces wear and tear on your engine, particularly when cold – idling creates wear and tear on your engine because fuel does not combust completely, causing damage to engine components such as cylinders, piston rings and the exhaust system.

What you can do to reduce the harmful effects of vehicle idling

There are things that you can do to reduce idling emissions and their impact on health and the environment.

  • Keep vehicles maintained in a good working condition with a regular service.
  • Switch off the engine when you are likely to be stationary for more than 30 seconds.
  • Cover vehicle windscreens where cars are left overnight in cold frosty weather, and use the windscreen heaters on vehicles equipped with them.
  • Consider Investing in a 12 volt DC mini auto heater if you might be sat in the vehicle for periods of time in cold weather.
  • Avoid using a car for some short journeys by walking or cycling instead.

Last reviewed: October 19, 2023 by Qi

Next review due: April 19, 2024

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