In Landmark Ruling, Air Pollution Recorded as a Cause of Death for British Girl

Countless studies have shown that polluted air, whether caused by car traffic, coal-fired plants or oil refineries, harms billions of people across the world. In California, wildfire smoke has been poisoning children, some paying a higher price than others; in Southeast Asian countries, more than 200 million children breathe highly toxic air; and scientists have found that children living near highways faced developmental delays.

“Children have one major vulnerability: their lungs are developing, so that makes them more vulnerable to diseases or dysfunctional growth,” said Professor Grigg. “Yet when we talk about air pollution, we shouldn’t lose sight of the effects across the whole life course.”

In 2014, a first inquest ruling on Ella’s death found that she had died of acute respiratory syndrome. But a court overturned the ruling last year, and Mr. Barlow on Wednesday, concluding a second inquest, ruled that she “died of asthma contributed to by exposure to excessive air pollution.”

During the weekslong inquest, Ella’s family described her as a lively and well-liked child, who played more than 10 instruments and dreamed of becoming a pilot.

“I had printed off Beethoven’s love letters that day, so that was the last thing I read to her,” her mother, Rosamund Adoo-Kissi-Debrah, said of Ella’s final asthma attack, on Feb. 14, 2013. Ella was pronounced dead in the early hours of the 15th.

“Air pollution is the biggest environmental threat to health in the U.K.,” according to Public health England, with up to 36,000 people deaths a year “attributed to long-term exposure.” But British authorities have repeatedly failed to comply with guidelines set up by the W.H.O. on levels of nitrogen dioxide and particulate matter — the very small particles most dangerous to human tissues — as well as other legally binding obligations, according to Rose Grogan, a lawyer at 39 Barrister Essex Chambers who specializes on environmental law.

“Today’s ruling comes in the long running context of Britain being in breach of European directives on air pollution,” she said. “The findings per se aren’t legally binding, yet that conclusion could likely pave the way for claims to be brought against the government in civil jurisdictions.”