Britain could see an increase in smog as the popularity of diesel cars increases, warns a leading pollution expert from King’s College London.

The smog-like conditions that have descended on the UK over the past week have been caused by dust blown across from the Sahara Desert mixing with harmful pollution in urban areas.

However, Timothy Baker of King’s College London warns that the increase in popularity of diesel-powered cars could see pollution rise.

He told the Independent:

“The way things are going, pollution levels are likely to rise in the coming months and years. Traffic emissions are a big and growing problem in the UK because of the dramatic increase in diesel cars in the last few years.

“This is one of the big challenges in the years to come for public health and, within the urban environment, it’s probably the biggest challenge.”

According to figures from the Society of Manufacturers and Traders (SMMT), diesel cars accounted for 49.8% of all cars sold last year, compared with petrol’s 48.8%. In 2002, just 14% of new cars were powered by diesel.

Not only are diesel cars generally cheaper to run because they use less fuel, but they also emit less CO2 so drivers don’t pay as much in vehicle excise duty or company car tax. However, the nitrogen oxide (NOx) gasses emitted by diesel cars are at least as harmful as CO2 due to the smog they create in congested areas.

Sooty deposits that contribute to smog are reduced by diesel particulate filters (DPFs) that have been a legal requirement on all new diesel cars since 2009. As of February 2014, all cars originally fitted with DPFs need to have them fitted to pass an MOT.

Many people have also reported the smog leaving their cars covered in a layer of sand. Wiping the sand off could be damaging to your paintwork, so why not treat your car to a spring clean this weekend?