Unlike congestion charge, ULEZ operates 24 hours a day, seven days a week, 365 days a year in the central London congestion charging zone. Motorists who drive in the zone in a vehicle that does not meet the new emission standard (petrol vehicles that do not meet Euro 4 standards and diesel vehicles that do not meet Euro 6) have to pay the daily charge.

The report launched this week examines the initial impact of the ULEZ throughout April, the first month since its launch. Its key findings include: In the first month of operation (excluding non-typical days) the compliance rate with the ULEZ standards was around 74 per cent in a 24-hour period, and 71 per cent in congestion charging hours – a huge increase from 39 per cent in February 2017, and 61 per cent in March 2019 (congestion charging hours). There were around 9,400 fewer older, more polluting, non-compliant vehicles seen in the zone on an average day (excluding non-typical days), a reduction of over a quarter (26 per cent).

In addition to examining the first month after launch, the report also outlines how the ‘preparation period’ for the ULEZ affected the numbers and types of vehicles driving into central London. The Mayor has also led by example by ensuring every bus operating in central London meets or exceeds the ULEZ standards.

The report highlights how compliance has been improving since February 2017, when the Mayor confirmed the introduction of the Toxicity Charge (T-Charge) as a stepping stone towards the ULEZ and Londoners and businesses began preparing for the new schemes. The report compares the number of vehicles detected in the ULEZ and compliance rates for February 2017, March 2019 (the month before launch) and April 2019, and found that over the period as a whole:

There were around 36,100 fewer older, more polluting, non-compliant vehicles seen in the zone on an average day (excluding non-typical days), a reduction of around 58 per cent, from February 2017 to April 2019.

There was an 80 per cent increase in the proportion of vehicles in the central zone that were compliant from February 2017 to April 2019 (excluding non-typical days).

This has already started translating into real-world improvements in air quality, including a reduction of approximately 20 per cent in NO2 concentrations measured at roadside monitoring sites in the zone since February 2017.

The Mayor of London, Sadiq Khan, said:

Today’s report shows how bold action reaps rewards – just one month after launching the world’s first ULEZ, leading the way for cities around the globe, we have already seen a significant impact on the types of vehicles driving in the centre of our capital and polluting our air. These were big changes, and vital ones - our toxic air is an invisible killer responsible for one of the biggest national health emergencies of our generation.

It’s early days, but it’s great to see Londoners and businesses are doing their bit to make a difference, with nearly three quarters of the vehicles driving into central London each day now meeting the standards required to turn around this public health crisis. It’s vital this compliance is sustained to truly make a difference to our air quality, and as time goes on we will publish more research into the impact of the ULEZ, progressing this ground-breaking, life-saving work even further.

It is not yet possible to determine the full impact of the ULEZ on air quality concentrations and emissions, because of the short time since its launch and other factors that may have affected traffic and concentrations, such as Easter holidays and the weather, in the central zone during this time. The best interim measures of success is vehicle compliance, with more research to come as the scheme progresses.

Alex Williams, Transport for London's Director of City Planning, said:

Everyone benefits from clean air, which is why it is great to see that so many people have responded to the Ultra-Low Emission Zone, which has resulted in a reduction in the number of polluting vehicles in the capital. The ULEZ will nearly halve road-based NOx emissions in central London, and in addition to our work to green up the bus fleet and encourage the taxi industry to switch to cleaner vehicles, together we will help to tackle this public health crisis.

Petrol vehicles that meet the new standards have been widely available since 2006. There are two ULEZ charge levels for vehicles driving into the zone which do not meet these standards: £12.50 a day for cars, vans and motorbikes and £100 a day for lorries, buses and coaches. Non-compliant vehicles which have failed to pay the charge when driving into the zone during the launch period and are not exempt from the scheme have been issued warning letters from TfL. This has been done for the first contravention to ensure the correct action is taken in the future and to allow for any genuine mistakes that may have occurred.

On an average day (24 hour period) in the scheme’s first month of operation around 32,100 non-compliant vehicles were detected in the zone. Of these:

Around 17,400 (54 per cent) paid the charge 4,300 ULEZ web or call centre payments, 8,200 Auto Pay payments and 4,900 ULEZ Fleet charge payments).

Around 3,000 (9 per cent) were in contravention of the scheme and issued with a warning notice on the first offence.

Around 11,700 (37 per cent) were not required to pay the daily ULEZ charge as they are eligible for a 100 per cent discount or exemption.

Dr Penny Woods, British Lung Foundation Chief Executive, said:

It’s early days for the ULEZ but the evidence suggests it’s having the effect we hoped for. Fewer older, more polluting vehicles on London’s streets and a 20 per cent reduction in health harming nitrogen dioxide will literally be a breath of fresh air for those living in, working in or visiting the zone. “Air pollution can make life more difficult for people with lung conditions. It can cause their symptoms to flare up, often so badly they need to be admitted to hospital. Parents should also know polluted air is especially dangerous for children’s lungs – as well as stunting lung growth it can set them up for host of health problems in their future. “What’s needed now is the ULEZ’s expansion and for the rest of the UK to introduce similar measures. It’s terribly wrong your postcode dictates how clean the air you breathe is. After all, clean air should be as easy to access as clean water.