Europe is seeing 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.

This pollution comes from industry, as well as both petrol and diesel cars.

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

Pollution levels are likely to rise in the coming months and years.

Traffic emissions are a big and growing problem in Europe 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, diesel cars accounted for 49.8 percent of all cars sold last year, compared with petrol’s 48.8 percent.

In 2002, just 14 percent 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) gases emitted by diesel cars are at least as harmful as CO2 due to the smog they create in congested areas.