People living in urban areas have worse hay fever symptoms than those living in rural areas of the country, according to the first study of its kind.
Researchers at the University of Manchester, UK, compared pollution levels with the severity and duration of real-time symptoms, studying 36,145 symptom reports submitted between 2016 and 2020 by more than 700 Britons using Britain Breathing, a citizen science application.
The findings, published in *Scientific Reports*, show the severity of three symptoms – runny nose, sore eyes and wheezy breathing – reported in the app were about twice as severe in urban areas than in rural ones across all years.
Combining pollution measurements and pollen and meteorological data taken from the UK Met Office with the real-time, geo-positioned reports, they found urban areas record significantly higher symptom severity and longer symptom duration for all years except 2017. Rural areas did not record significantly higher symptom severity in any year.
Symptom severity was also significantly correlated with ozone levels. Ozone has previously been linked to respiratory problems.
Study author Professor Sheena Cruickshank, an immunologist, said: “The worldwide prevalence of allergic respiratory disease has risen considerably in recent years.
“However hay fever affects people differently and can change over a lifetime and data is lacking on how environmental factors may influence this.
“This study provides evidence that urban surroundings may exacerbate hay fever and asthma symptoms.
“It also provides a broader picture of chronic health issues experienced by hay fever and asthma sufferers, as opposed to only observing those with more acute and/or problematic reactions.
“These differences in allergy symptoms may be due to variation in the levels of pollutants, pollen counts and seasonality across land-use types.”
The researchers say 2017 was an exception and this could be because the number of days with moderate or higher O3 levels dropped slightly that year before rising sharply and staying relatively high in subsequent years.
It was also warmer and wetter than the other years, which may have had an effect, either on pollen counts, pollution or participants’ biological reactions, they add.
Gledson A, Lowe D, Reani M et al. A comparison of experience sampled hay fever symptom severity across rural and urban areas of the UK. *Scientific Reports* 22 February 2023
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