The analysis found that London, San Francisco and Beijing were among 19 cities worldwide to achieve “significant reductions” in air pollution, reducing levels of two pollutants that worsen airways by more than 20% since 2010.
The analysis found that interventions such as bike lanes, increased use of electric vehicles and restrictions on polluting vehicles were helping to drive improvements.
Beijing and Warsaw topped the rankings for cleaning up particulate pollution (PM2.5), reducing levels by more than 45%, while Amsterdam and Rotterdam saw the most significant improvements, with nitrogen dioxide (NO2) reduced by more than 40%.
San Francisco was the only U.S. city to reduce levels of both pollutants by more than 20%, according to an analysis of about 100 cities around the world. Nine of the 19 cities are in China and Hong Kong, with the rest in Europe.
“This report shows that cities can do what was once thought impossible: reduce harmful air pollution by 20 to 45 percent in just over a decade,” said Cecilia Vaca Jones, executive director of Breeze Cities, one of the report’s authors. “This is not just happening in one corner of the world. From Warsaw to Bangkok, cities are proving they now have the tools to solve this crisis.”
Burning fossil fuels releases toxic gases and harmful particles that pose the greatest threat to human health.
The smallest of these particles can enter the bloodstream and spread throughout the body, damaging organs from the brain to the reproductive organs, while nitrogen dioxide damages the airways and reacts with water to form acid rain.
The report, shared exclusively with the Guardian, looked at air quality in cities in the C40 and Breeze Cities networks – primarily large cities, but also smaller cities such as Heidelberg in Germany – and found that with deliberate action “significant reductions” could be achieved within 15 years.
The report highlighted examples of actions that have helped clean the air, including China’s rapid switch from internal combustion engine cars to electric vehicles, expanding cycle lanes in Europe’s densely populated cities, regulating dirty vehicles in London and Warsaw’s move away from home heating with coal and wood. It did not examine the causal chain that distinguishes air quality improvements due to local policies from air quality improvements due to national policies.
“Air pollution is often treated as a difficult and politically unpopular problem to solve,” said Dr Gary Fuller, an air pollution scientist at Imperial College London who was not involved in the report. “This report shows that bold policies can improve the air we breathe.”
A report last year found that nearly every country on earth has polluted air more than doctors recommend. According to Swiss air quality technology company IQAir, only seven countries met the World Health Organization’s guidelines for PM2.5 last year.
Although there is no safe level of PM2.5, doctors estimate that millions of lives could be saved each year if guidelines are followed.
Breathing polluted air affects our health at every stage of life, from low birth weight and childhood asthma to cancer and heart disease in adulthood, Fuller said.
“Over the past decade, we have found that air pollution is associated with cognitive decline and dementia in older adults,” he added. “All of these illnesses place a huge burden on families, hamper our economy as people miss work or care for others when they are sick, and create direct costs to our health services. All of these illnesses are preventable.”
