Clean Air Day has today sparked a raft of announcements designed to tackle poor air quality across the UK, including plans for London's largest ever Car Free Day and the unveiling of one of the world's first all-electric ice cream vans.

London Mayor Sadiq Khan marked the annual event today with confirmation that Sunday September 22 has been designated a Car Free Day, with plans underway to close up to 20km of streets across central London.

The closures, which will include Tower Bridge and much of the City of London, will be accompanied by a series of events across 18 boroughs designed to highlight air pollution risks and ask residents to 'reimagine' how the city could operate to avoid emissions.

Khan hopes over 150,000 Londoners will join in London's 'Reimagine' events, which will aim to encourage the changes in behaviour needed to meet the Mayor's ambitious target of 80 per cent of all journeys to be taken via sustainable modes of transport by 2041, compared to 63 per cent today.

"London is leading the way in innovative measures to improve air pollution and I want this year's Car Free Day events to be the best of any world city," Khan said. "This will be a great opportunity for us all to leave our cars behind and explore our streets by foot, or by bike. We've called our range of events 'Reimagine' so that Londoners get an idea of what some of the busiest parts of our city would be like without cars and traffic."

He also stepped up pressure on London Boroughs and planners to accelerate efforts to encourage cleaner forms of transport. "I will continue to work with those boroughs who are forward-looking and want to think differently about how to use road space," he said. "Hopefully this will shame into life those boroughs with outdated views who are dragging their feet."

The move comes just days after plans for new cycling infrastructure in West London were blocked by Kensington and Chelsea Council.

The annual Clean Air Day event, which is co-ordinated by environmental charity Global Action Plan, will involve around 300 events across the country ranging from walking buses and cycling initiatives to no-idling events and street takeovers.

It has also prompted a flurry of corporate announcements. For example, leading clean cooling technology specialist Dearman announced an agreement with two major Chinese organisations, the China Energy Conservation and Environmental Protection Group (CECEP) and the Chengdu Industrial Asset Management Group (CIAM), to collaborate to bring its Dearman technology to China.

The company's zero-emission engine is powered by liquid nitrogen and has already been successfully deployed in Europe by Sainsbury's, Marks & Spencer and Unilever, slashing emissions from refrigerated vans.

Meanwhile, electric vehicle technology specialist Spark EV Technology today announced it has successfully collaborated with BP to undertake real-world trials that have validated its advanced range prediction system for electric vehicles (EVs).

The project saw BP employees based at five locations drive 10,000 km in two types of EVs equipped with Spark's AI-based journey prediction solution. The system successfully used algorithms to learn from each journey, enabling more accurate range predictions and better guidance for drivers to help them maximise their range.

Finally, Nissan unveiled a new concept vehicle design that could help tackle a common source of summer air pollution: ice cream vans.

Ice cream vans typically run their engines for long periods to provide power for their cooling equipment, leading to air pollution at locations typically close to children's play areas.

Nissan today announced it has partnered with Mackie's of Scotland, an ice cream producer powering its family-owned dairy farm by renewable wind and solar energy, to develop an all-electric ice cream van based on the auto giant's existing e-NV200 electric van.

"Ice cream is enjoyed the world over, but consumers are increasingly mindful of the environmental impact of how we produce such treats, and the 'last mile' of how they reach us," said Kalyana Sivagnanam, managing director of Nissan Motor (GB). "This project is a perfect demonstration of Nissan's Intelligent Mobility strategy, applying more than a decade of EV experience and progress in battery technology to create cleaner solutions for power on the go - in ways customers might not expect. By eliminating harmful tailpipe emissions, and increasing our use of renewable energy, we can help make this a better world for everyone."