In a report from the Health Protection Agency, aerobiologist and microbial science expert Roy Kennedy said that warming temperatures could cause pollen grains to burst more often, making the allergens they contain more pervasive in the environment.
He also said that the main pollen sources, grasses and birch trees, are increasing as the climate warms.
“Hay fever and asthma significantly reduce quality of life and have a significant economic impact on society,” the report cautioned.
On average, about one in five people currently suffers from hay fever, which can trigger potentially life-threatening asthma.
The agency said that global warming is likely to make the allergy seasons last about six weeks longer in the decades to come.