The repeated hospital admissions of a girl who died in an asthma attack at the age of nine show a “striking association” with spikes in illegal levels of air pollution around her home in London, legal documents have revealed.

Ella Kissi-Debrah, from Hither Green, near the capital’s busy South Circular Road, experienced seizures for three years prior to her death in February 2013. Her family are calling for a new inquest into her death following fresh evidence that air pollution was a contributory factor.

Documents submitted to the attorney general by the family’s lawyers show that Ella’s increasingly frequent hospital admissions from asthma attacks in her last three years coincided with spikes in illegal levels of air pollution, primarily from diesel cars and vans. Ella’s home was 25 metres from the South Circular, one of London’s hotspots for high levels of air pollution.

“There was a striking association with air pollution episodes,” the legal papers state. Ella’s last hospital admission took place on 7 February 2013, just eight days before her death and during one of the worst air pollution episodes in her local area.

“The dramatic worsening of her asthma in relation to air pollution episodes would go a long way to explain the timing of her exacerbations across her last four years,” the documents say.

The government has been breaching the law since 2010 by failing to put in place plans to reduce air pollution and reduce the public’s exposure to it.

Air pollution, labelled a public health emergency by the World Health Organization, leads to the premature deaths of at least 40,000 people a year in the UK alone. It is known to be a major risk factor for childhood asthma.

New evidence submitted to the attorney general in support of a new inquest from Stephen Holgate, professor of immunopharmacology at the University of Southampton, states there was a “real prospect that without illegal levels of air pollution Ella would not have died”. He said nitrogen dioxide levels – primarily from diesel vehicles – around the child’s home were consistently above the legal limit of 40 µg/m3. He gave his “firm view” that Ella’s death certificate should reflect air pollution as a causative factor.

Human rights lawyer Jocelyn Cockburn, who is representing Ella’s family in their application for a new inquest, said the government “had willingly presided” over illegal air quality and its failure to act was costing lives.

“There are strong grounds for Ella’s inquest to be quashed on the basis that her right to life (Article 2 of the Human Rights Act) may have been breached by the government’s failure to act in relation to unlawful air pollution levels,” said Cockburn.

“There is a clear need for a fresh inquest to investigate the link between air pollution and Ella’s death so that the family can properly understand the circumstances that led to her untimely and tragic death, and that lessons can be learned to prevent future deaths ... Ella’s case illustrates the hard-hitting human impact of air pollution.”

A cause of death linked to air pollution in Ella’s case would be a legal first. As concern over the threat from toxic air and the government’s failure to act grows, increasing numbers of people are considering legal action both in the workplace and against the state.

A spokesperson for the attorney general’s office said: “The attorney general expresses his sincere sympathies to Ella Kissi-Debrah’s family. I can confirm that an application for approval to apply for a fresh inquest has been received by the attorney general’s office regarding Ella’s case and we will review the evidence.”