The study, by King’s College London and Imperial College London, looked at grass pollen, or Phl p 5, which is the most common hay fever trigger.
Some 93 patients with the complaint, said to be incurable, filled in diary cards. Experts took air samples at the location for the same period.
Dr Elaine Fuertes, of ICL, said Phl p 5 levels were “more consistently associated with allergic respiratory symptoms than grass pollen counts”.