Ella Kissi-Debrah, who lived close to the busy South Circular road in Lewisham, south London, died in February 2013.
She had suffered numerous seizures – making 27 visits to hospital with breathing problems in the three years before her death.
An inquest ruling from 2014, which found Ella died of acute respiratory failure, was quashed in light of new evidence that suggested illegal levels of pollution contributed to her fatal asthma attack.
Her mother Rosamund Kissi-Debrah told a new inquest on Monday: “She was lively bubbly and intelligent. She loved family. She was a joy. She was the centre of our world.”
The teacher described how her daughter had dreamed of being a pilot. She played nine or ten instruments and had a reading age of 14 when she was nine.
Mrs Kissi-Debrah described how her daughter had walked to school near the South Circular, and how her health deteriorated from 2010.
She was admitted to hospital multiple times before her death after suffering seizures and a cardiac arrest.
On one occasion she said she “went stiff and blue”.
Coroner Philip Barlow asked Mrs Kissi-Debrah what action she would have taken if a connection had been made between air pollution and her daughter’s condition before she died.
She replied: “As a mother definitely we would have moved. She was desperate, I was desperate we would have moved.”
Ella’s family have accused the London Borough of Lewisham of acting at a “glacial pace” over illegal levels of air pollution which they believe caused Ella’s death.
A 2018 report by Professor Stephen Holgate found that pollutant levels at the Catford monitoring station, one mile from Ella’s home, “consistently” exceeded lawful EU limits over the three years prior to her death.
On the first day of the inquest into Ella’s death, Lewisham Council’s head of environmental health said the borough struggles with pollution caused by transient traffic on the South Circular and A21.
David Edwards, who took on the role in the months after Ella died, told the court that the local authority has a number of “diffusion tubes” set up around the borough to monitor air quality.
He said it also has a number of Air Quality Management Areas (Aqmas) where air pollutant levels are of particular concern, with the first set up in 2001.
Mr Edwards said that once an Aqma has been set up, it has to be followed by an Air Quality Action Plan with input from several local authority departments.
He said the local authority can encourage cleaner vehicles and alternative forms of transport among its residents, and has implemented a banded system of parking permits based on emissions.
But he said the main source of pollution, particularly nitrogen dioxide and particulate matter, is from road traffic over which Lewisham has little control.
Richard Hermer QC, for Ella’s family, accused the London Borough of Lewisham of failing to treat air pollution as a priority despite knowing how dangerous it is.
The barrister pointed out that it had taken seven years for the first strategic needs assessment to be produced once studies indicated soaring pollution levels.
He added that once Lewisham had designated its first Aqma, it had taken three years to create a draft action plan and another four years for it to be formally adopted.
“That’s a glacial pace in the context of a public health emergency, isn’t it?” Mr Hermer said.
Mr Edwards replied: “Certainly when you look at it in the context of today, yes.”
Ella’s inquest has been listed under Article 2, the right to life, of the Human Rights Act, which scrutinises the role of public bodies in a person’s death.
The inquest, which is listed for 10 days, will consider whether air pollution caused or contributed to Ella’s death and how levels were monitored at the time.
Other issues to be addressed at the inquest include the steps taken to reduce air pollution, and the information provided to the public about the levels, its dangers and ways to reduce exposure.
Ella may become the first person in the UK for whom air pollution is listed as the cause of death.
The inquest continues.