Mums for Lungs, the parents’ campaign group, said the high levels of nitrogen dioxide were recorded last year despite the pandemic causing an initial dramatic fall in road traffic.
Stencilled warning signs alerting Londoners to the dangerous levels of NO2 have been drawn on pavements in each of the locations.
The highest readings were in Brixton Road in Lambeth (60mg/m3), Putney High Street (58) and Hanger Lane (51). The legal level is 40.
Two of the 15 sites – Walbrook Wharf and Strand – are inside the central London Ulez, and eight will fall within the widened zone.
Five are in outer London or on the outer edge of the new boundary, such as Ikea at Brent and Crooked Billet in Waltham Forest, and roads in Kingston and Morden.
The pollution data has been gathered by Environmental Defense Fund Europe (EDF Europe) from air pollution monitors across the city.
It is estimated that about two-thirds of the NO2 pollution at these locations came from diesel vehicles, such as cars, taxis, vans and heavy goods vehicles.
Nine of the 15 locations are on or adjacent to the city’s Red Routes – a network of major roads managed by Transport for London.
Jemima Hartshorn, founder of Mums for Lungs, said, “Even during the pandemic when London’s roads felt empty for months, it’s astounding to see that so many areas were still illegally polluted in 2020.
“We are grateful for the Ultra Low Emission Zone and the October expansion is critical to protecting kids’ health. But initial data from 2021 indicates many of these sites will continue to exceed legal limits, highlighting the inadequacy of existing plans to reduce pollution. We need firm proposals for a diesel-free city.”
Elizabeth Fonseca, senior air quality manager for Environmental Defense Fund Europe, said: “London still fails to meet legal levels of NO2 air pollution, meaning children are continuing to grow up breathing toxic air.
“Data at these individual monitoring sites only provides a tiny part of the wider picture. Modelling clearly shows that many areas across London are continuing to exceed legal limits, including those outside the bounds of the Ulez expansion. Without further action, there is a great risk that some London communities will be left behind.”
The GLA Conservatives and Federation of Small Businesses today sent the Mayor a joint letter urging him to go further, saying this would boost the “green recovery” and speed up the removal of polluting vehicles.
Tory leader Susan Hall said: “Few Londoners and businesses have been able to prepare for Sadiq Khan’s Ulez expansion due to the pandemic. That’s why the Mayor needs to put extra support in place to help them switch to cleaner vehicles and avoid the charge.”
Michael Lloyd, FSB’s London infrastructure chair, said: “Small businesses have been faced with an unprecedented set of financial and emotional challenges in the last 15 months.
“We want to do the right thing by the environment and help improve the air quality, however, we must be understanding that in these current times many simply cannot afford to replace their business vehicles.”