In 2019, London Mayor Sadiq Khan established the world’s first 24-hour Ultra Low Emission Zone (ULEZ) in central London to protect the city’s residents from air pollution. The ULEZ imposed daily £12.50 ($15) charges on vehicles whose emissions exceeded certain standards. Two years later, Khan expanded the zone to include inner London within the boundaries of the North and South Circular roads.
Now, a new peer-reviewed report from the mayor’s office finds the policy has been a success. It's good timing for Khan, as he intends to expand it once again.
“As a former lawyer, I just love looking at the evidence.The evidence today is game, set and match unequivocal,” Khan told the Evening Standard. “The Ulez is the most effective policy to clean up the air in our city there has ever been.”
Among its key findings, the report revealed that:
The number of older, highly polluting, non-compliant vehicles in the zone fell by nearly 60 percent since the ULEZ was expanded.
Nitrogen oxide (NOX) emissions fell by 23 percent across all of London since 2019 compared to what they would have been without the ULEZ. Within the ULEZ, NOX emissions fell by 26 percent.
Fine particulate matter (PM2.5) emissions fell by seven percent over the four years across all of London compared to what they would have been without the ULEZ. PM2.5 emissions fell by 19 percent within the ULEZ itself.
Carbon dioxide emissions fell by three percent across London since 2019 and four percent within the ULEZ.
NOX concentrations were 21 percent lower than they would have been without the ULEZ in inner London and 46 percent lower in central London.
Nitrogen dioxide (NO2) emissions did not return to pre-pandemic levels when traffic increased, suggesting the impact of the ULEZ.
Average PM2.5 levels have fallen by 41 percent in inner and central London since 2017.
The ULEZ is not the only thing that has helped reduce pollution. Prior to the ULEZ, London launched a Low Emission Zone (LEZ) in 2008 applying to larger vehicles, and standards for this were updated in 2021. Vehicles are also becoming cleaner in general.