The Suffocating City
To the north of Melbourne lies a deadly beast. In winter, it hibernates, but come spring the beast will stir, and if provoked, exhale its poison over the city. On the 21st of November, 2016, the beast brought its wrath down upon the people of Melbourne. They coughed and wheezed, unable to breathe and most of them had no idea why.
The city suffocated. Nine people died.
I’m not referring to a new Stephen King thriller, but the thunderstorm asthma event that brought the city to a spluttering halt. The beast I speak of is the rye grass fields north of Melbourne.The November, 2016, thunderstorm asthma outbreak was the largest in the world with 3270 additional hospitalisations of asthma sufferers. The previous record holder, London in 1994, had around 600 hospitalisations. Emergency services were inundated with 1 triple zero call every 4.5 seconds.
Thunderstorm asthma has inflicted Melbourne before, so why was this event so bad?
I spoke to atmospheric chemist, Dr. Jeremy Silver, from the University of Melbourne who has spent the last eight months researching the November, 2016, outbreak. ‘Excuse the cliché, but it really was the perfect storm,’ he explained. Before the cool change came through, grass pollen levels were ‘extreme’. During the cool change, which triggered the thunderstorms, a wave of coarse dust particles swept over Melbourne. We also had high levels of fungal spores in the air. In south-east Australia, grass pollen is the main culprit triggering asthma symptoms but if anyone was allergic to either of those three allergens, grass pollen, dust or fungal spores, they were at risk.
The pollen levels were extreme before the storm, so why did it take a thunderstorm to trigger the asthma?
Wild weather provokes Melbourne’s slumbering beast. Fierce thunderstorm updrafts carry the rye grass grains high into the clouds where they are saturated with water. Unable to cope with the pressure caused by the encasing moisture, the grains rupture into thousands of granules-this is called osmotic shock. The granules can be as small as 0.5 micrometres, which is one-sixth the width of the thinnest human hair, and turn the idle beast into a deadly predator. At 0.5 micrometres, rye grass granules can penetrate deep into our lungs causing serious problems for allergy sufferers. To add to the chaos, powerful downdrafts from the thunderstorm disperse the granules across the city.
Winter is fading into spring and the beast may stir again.
How can we defend ourselves?
- Asthma and hay fever sufferers can talk to their doctor about making an ‘Action Plan’ outlining the medication they should take during an asthma outbreak.
- Keep an eye on the pollen count
- Watch for thunderstorm forecasts
- During a thunderstorm asthma outbreak stay inside with windows and doors closed
I asked Dr. Silver if there was anything he wished the public knew about thunderstorm asthma and his answer was: these events are difficult to forecast, but people need to be prepared all the same.
To misquote Benjamin Franklin:
A single raindrop of prevention is worth an entire cloud of cure.