Dangerous bacteria in air-con: drivers urged to get theirs cleaned

Do you know what’s living in your car’s air-con? You may never have considered it but a car’s air-conditioning system is a haven for bacteria. Scientists have even discovered that some of the bugs can be dangerous, leading to meningitis, urinary tract infections and sceptic arthritis.

Our expert has already written this useful guide on why you can’t expect air-conditioning to work effectively if it’s not regularly serviced. But new research has found out exactly what inhabits our air-con. In America, where air-con has been common in more vehicles for longer, they even have a name for the effect that exposure to these bacteria can have: Sick Car Syndrome.

What is the most common bug in our air-con?

The micro-organism found most frequently when London Metropolitan University scientists tested in-car cooling systems was Bacillus Licheniformis. This bacterium lives in soil and in birds’ feathers. Although it sounds pretty revolting, it’s actually not that harmful to humans. Boffins have even been investigating whether it can be used to remove plaque from teeth.

What about the dangerous bacteria?

The next most common bugs found are from the Bacillus family. Bacillus Subtilis exists in soil. However, it is also lives in the gut (and therefore faeces) of humans. And it is very hard to kill: experiments have proved it’ll even survive in space!

It’s closely followed by other members of the Bacillus family. The spores of this regularly contaminate raw foods and in extreme cases can cause stomach ache, diarrhoea and vomiting. Bacillus bacteria have links to a wide range of infections including meningitis and septicaemia.

How was the research conducted?

Scientists from London Metropolitan University took 15 cars and examined their air-conditioning filters. They found micro-organisms in all of them. On average cars had 1.6 kinds of bacteria in their air-con. Drivers in Plymouth had the most contaminated cars followed by those in Dundee. Cardiff drivers had the cleanest.

Senior lecturer specialising in microbiology at London Metropolitan University, Dr Paul Matewele, said: “Some of the bacteria found has links to animals, the gastrointestinal tract of humans and some infections that could cause a lot of harm to individuals, especially those with a compromised immune system. The study highlights that air-conditioning systems are suitable breeding grounds for bacteria. I’m sure if car owners knew what they were blowing out of their air-conditioning’s vents they would think twice before switching it on this summer.”

What can drivers do?

It’s recommended that car air-con units are serviced every two years. That’s because air-con contains refrigerant which slowly leaks away, reducing the system’s ability to cool. In addition to what’s known as a re-gas, many garages will also perform a bacterial cleanse.

This is where they put a cleaner through the system to kill the bacteria. These build up over time because it’s a frequently warm, moist environment with lots of nooks and crannies to harbour germs. Some of these are odourless but some will cause the stale smell that sometimes comes out of a car’s vents.

Is there a DIY fix?

Garages will frequently charge around £20 to perform an air-con bacterial cleanse. However, from £5 upwards you can buy aerosol treatments that claim to clean cars’ air-con. With the engine and air-conditioning running, you place these in a closed car, set them off and leave them for 10 minutes so the gas can circulate through the car’s system. Some people swear by them, others speak less favourably.