Ice cream truck owners said that Britons’ penchant for soft-serve ice cream is one of the drivers of the diesel pollution problem. The trucks’ freezers can operate with the engine turned off, but the machines that pump out soft-serve ice creams such as Mr. Whippy — the British equivalent of Mister Softee — need engine power to run.

“We have got to be conscious of the impact of diesel,” Amy Rudgley, 25, who worked in ice cream trucks in London for eight years before starting her own business, Fat Cows Ice Cream, said in a phone interview on Thursday.

“But it has to be seen as a bigger picture than just ice cream vans,” she added.

As he sat in his truck on a central London street on Friday, taking a break from serving hungry tourists and Londoners who had been enjoying some fleeting sunshine, Ndue Meli, 45, echoed the complaint. His truck, which cost him 100,000 pounds (about $130,000), meets the latest European Union standard on emissions, he said.

“My van does not burn a lot of fuel,” Mr. Meli said. “I see black cabs, tourist buses and coaches which are all pumping out fuel. But the councils are putting everybody in the same boat.”

As London explores ways to reduce air pollution caused by all diesel vehicles, one solution offered is to install electric power points in parks and popular spots, which would allow ice cream trucks to turn off their engines and run their machines on electricity instead.

That strategy is favored by Britain’s ice cream industry trade body, the Ice Cream Alliance, over an outright ban.