The combination of the springtime pollen explosion and an ongoing risk of bushfire smoke has prompted NSW Health to issue a warning for people with asthma.
The health agency said October to December was the highest risk period for thunderstorm asthma events, which can cause very severe asthma attacks that develop quickly.
While not common, thunderstorm asthma can occur when high pollen counts, thunderstorms and strong winds occur together.
They can affect many people including those with pollen allergies and people with current or previously diagnosed asthma, NSW Health said.
The Illawarra has a higher percentage of people with asthma than across NSW, with data on chronic diseases from the last Census showing 8.7 per cent of people in the region have the condition.
This was compared to 7.8 per cent in NSW.
The 2530 Dapto postcode has the highest percentage of people with asthma, at 10.1 per cent, followed by Albion Park, Berkeley, Windang and Woonona.
The 2515 suburb of Thirroul had the lowest rate of asthma, with 7.2 per cent of people there reporting the condition in the Census.
Wollongong, Fairy Meadow and Figtree also had less than 8 per cent of residents with asthma.
Respiratory Physician and Head of Respiratory Medicine at Concord Hospital Professor Matthew Peters said now was the time for people to update their Asthma Action Plans.
"Anyone with diagnosed asthma should have access to their asthma medication at all times during this high-risk period, avoid exposure to triggers where possible and proactively manage their asthma by regularly taking their inhaler treatments and monitoring symptoms," he said.
"Even if you don't have asthma, pollen is at its highest throughout spring and may spark problems in people with allergies like hay fever and sinus problems."
Thunderstorm asthma events have occurred most commonly in the Riverina and other regional and rural areas but can occur anywhere when the conditions combine.
To prepare, people should know how to manage their symptoms during a flare up due to bushfire smoke or pollen and should be aware of warning signs like wheezing, breathlessness, feeling tight in the chest or a persistent cough.
For children with asthma, parents should provide updated asthma action plans to their preschool, childcare centre or school and check that asthma reliever medication and spacer is up-to-date and stored in an easy to access spot.
During times of high pollen, bushfire smoke or thunderstorms people with these conditions should remain inside and keep windows and doors closed.
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