London Clean Air Restrictions Improve Children’s Lung Health as Cities Globally Expand Zones

A study from Queen Mary University London shows that restricting polluting vehicles in London has led to measurable improvements in children’s lung health, providing fresh evidence on the effects of urban low emission policies.

The capital’s Ultra Low Emission Zone, introduced by Mayor Sadiq Khan in 2019 and expanded in 2021 and 2023, charges £12.50 per day for vehicles that do not meet strict emissions standards. Researchers found that the resulting decline in nitrogen dioxide levels allowed children’s lungs to grow larger and stronger compared to prior years.

The research addresses long-standing health concerns in London, where between 6,000 and 8,000 premature deaths annually were linked to air pollution during the late 2010s. In 2020, an inquest officially established that the 2013 death of Ella Adoo-Kissi-Debrah was directly caused by air pollution, marking the first such legal finding in the United Kingdom.

Health experts emphasize that the problem extends far beyond the UK. World Health Organization figures show that air pollution causes seven million premature deaths globally each year. In addition to impaired lung development in children, exposure to dirty air is associated with heart disease, stroke, cancer, dementia, autism, and cognitive difficulties.

Nick Hopkinson, a professor of respiratory medicine at Imperial College London, noted that there is “an absolute wealth of evidence” establishing air pollution as a primary driver of global ill health and early mortality.

While primary sources of pollution differ globally—ranging from coal-fired power stations in China and India to agricultural burning in Southeast Asia—road traffic remains a universal factor. Despite political opposition, misinformation, and commercial resistance, hundreds of municipalities worldwide are introducing targeted clean air zones.

In South America, Bogotá, Colombia, is launching its second “Zuma” clean air zone following an Earthshot prize win for its initial phase. The program expands cycle lanes, paves dirt roads to suppress dust, and plants trees. City environment secretary Adriana Soto explained that “residents helped shape the design” to preserve local access and mobility.

Cities in Europe, such as Paris and Barcelona, have similarly expanded cycling infrastructure, building on models established in Denmark and the Netherlands. In contrast, implementation faces hurdles in the United States due to limited public transport, high vehicle sizes, and federal policy shifts under President Donald Trump aimed at rolling back environmental rules.

In East Africa, Nairobi passed an air quality act in 2022 requiring a 50 percent reduction in harmful emissions by 2035, supported by an initial network of 50 monitoring stations. Advocates from the Breathe Cities initiative—backed by the Clean Air Fund and the C40 coalition of nearly 100 city leaders—are promoting similar strategies, asserting that “we have the means to make a difference” through shared urban policies.

Background

Low emission zones are designated urban areas where access by high-polluting vehicles is restricted or subject to daily charges to improve local air quality. London operates both a Low Emission Zone (LEZ) and an Ultra Low Emission Zone (ULEZ), which focus on reducing traffic-related pollutants such as nitrogen dioxide and particulate matter. Similar municipal initiatives have been adopted internationally as local leaders face growing medical evidence and legal pressure to reduce public exposure to ambient air pollution.