Why pollen levels may not predict hay fever symptoms
07 Oct 2026
Researchers from the University of Queensland reviewed nearly 115,000 symptom reports recorded by around 25,000 users of the Melbourne Pollen app between 2017 and 2023.
The study found that a person's response could not always be predicted by the reported grass pollen level. Some users experienced hay fever symptoms on days when grass pollen was considered low.
Researchers also looked at other conditions in the environment. Air pollution from fine particles and pollen from other plants were among the factors associated with reported symptoms.
The findings suggest that pollen exposure alone does not explain why some people experience stronger symptoms than others.
This is particularly relevant for people with asthma and those who have previously experienced more severe hay fever symptoms.
Dr Nick Cooling, Chair of RACGP Specific Interests Allergy, said GPs should consider each patient's medical history when discussing their risk. He also identified people with allergic conjunctivitis and those who have previously required significant medication as groups who may need a more individual approach.
Hay fever is now reported in almost one in four Australians. The proportion of Australians affected rose from 19% in 2017–18 to 24% in 2022.
The study also had some limitations. Older people were less likely to be represented among the app users. Those aged 31–50 accounted for 47% of users, although this age group makes up about 29% of the Greater Melbourne population. People aged 61 and over accounted for 8% of users, compared with 19% of the Greater Melbourne population.
The Melbourne Pollen app has since become part of AirRater, a national app that provides information about pollen and air quality.
Dr Cooling said these types of apps can give patients and GPs a useful way to track symptoms alongside environmental conditions. This can help people recognise how they personally respond to changes in pollen and air quality.
The researchers believe the results could contribute to more personalised pollen forecasting, giving people information that may better reflect their individual risk.
Why pollen levels may not predict hay fever symptoms
Source: University of Queensland research published in GeoHealth