Courtney Partridge-McLennan was found dead on the morning of 29 November after going to sleep in her family home in the town of Glen Innes, New South Wales.
The town has been one of the worst hit areas during Australia’s ongoing wildfires crisis, which saw New South Wales’ government declare a state of emergency in December.
“She had no symptoms before she went to bed,” her sister Cherylleigh told the BBC.
“She was healthy and that's what made it the biggest shock for us. It was so out of nowhere.”
Although Courtney was diagnosed with asthma as a child, her sister added that it was not usually severe but could flare up around dust and air pollutants.
Her death was listed as “unconfirmed” in a preliminary autopsy report but she was found to have a “hyper-extension of the lungs”, Cherylleigh said, which is an indicator of an asthma attack.
Earlier this month, Asthma Australia called on all states to provide real-time air quality reporting for small particle pollution to help those who have respiratory diseases.
In a statement to the Australian website 7NEWS, the family said they were “overwhelmed” by the support they had received following their daughter’s sudden death
“Our family have been overwhelmed today with the outpouring of love and condolences and personal experiences of others tragically affected by asthma and smoke-induced illnesses,” the statement said.
“When you get to the hazardous range, anyone can develop symptoms,” Brett Sutton said in a statement on the city's air quality.
“There is eye and throat and nose irritation, people can have a cough develop or worsening of cough or wheezing.”
He said authorities were particularly concerned for children aged 14 or younger, adults aged 65 or older, pregnant women and those with pre-existing medical conditions.