As a government-ordered review of the disaster begins, state opposition health spokeswoman Mary Wooldridge called for the inquiry to be expedited so Victorians can trust emergency services heading into the bushfire season. Ranjith Peiris became the eighth victim of last week's thunderstorm asthma. Ms Wooldridge also called for Ambulance Victoria to explain why some people were given information about how long they would wait for paramedics on the night, while others did not receive estimates. The family of Roxburgh Park man Ranjith Peiris​ who died at Northern Hospital on Tuesday, have questioned why they were not told to drive him to hospital. The family claims they waited more than an hour for paramedics to arrive but Ambulance Victoria said it took 28 minutes. "Mum just keeps saying, 'if only they told me, if only they told me. If only I knew I would have brought you here earlier', Mr Peiris' son Roshan​ said on Tuesday.

"How will the state react if there was a real disaster?" Asthma sufferer Palli Zamani with his mother Rayann Zamani. Credit:Justin McManus Dr Michael Sutherland, a respiratory physician and allergist at the Epworth Hospital, said the event was "by far the worst" in world history, and could prompt doctors to prescribe preventative medication to people with severe hay fever who are not asthmatic during spring. He said anybody who experienced wheezing, coughing or shortness of breath during the outbreak should discuss it with their GP because they may be asthmatic, or want allergy testing to explore better treatments for symptoms that put them at risk. Asthma sufferer Angelique Harkins uses a spacer with her puffer, overseen by Dr Mark Hotu. Credit:Jason South

Health authorities, meteorologists, botanists, and doctors are now trying to understand the causes of last week's epidemic so they can try to predict future events, and warn the public. A working group has been established by the state government to explore whether other pollens, such as fungal spores, and pollutants contributed to the event, and to set up a warning system for next year. Fairfax Media understands doctors are also testing victims who were hospitalised to see if they share common histories and allergies. Ed Newbigin, a botanist from University of Melbourne, said there were "noticeable levels of fungal spores" in the air last Monday and Tuesday, in addition to the high grass pollen levels, that were being studied. Fungal spores have been implicated in thunderstorm events in Queensland. Associate Professor Newbigin said while experts can broadly predict the chance of thunderstorm asthma by looking at the weather and pollen forecasts, they can't accurately predict the likelihood of it being catastrophic.

"We don't know what it is that causes a major event because in Melbourne we might get thunderstorm asthma events once every four or five years but not all of them are major catastrophic events like the one from Monday," he said. "Is it something about the nature of the storm or the type of the storm, or the humidity? Or is it a particular type of wind that is produced by the thunderstorm?" Associate Professor Newbigin said he and others were now studying past events for common threads. "We've got data from the Bureau about storms and types of storms, we just need to sit down and crunch that data and figure it out." A spokesman for Ambulance Victoria would not comment on what protocols applied last week during the crisis, and whether all callers were given estimates of response times.

"The Inspector-General for Emergency Management will conduct a comprehensive review into the circumstances surrounding the response," he said. "This independent review will consider the appropriateness of actions taken and any opportunities for improvement." Asthma Australia is now surveying people who felt symptoms during last week's outbreak to better understand what can be done to protect them in future. "Although these events are rare we need to think about how we can be best prepared in future," CEO of Asthma Australia Michele Goldman said. The survey can be accessed here.

An earlier version of this story said it took more than an hour for an ambulance to arrive at the Peiris' home. Ambulance Victoria has since said it took 28 minutes.