Interestingly, sensitisation to grass pollen
and the development of hayfever and/or seasonal conjunctivitis are more common in urban than rural environments.
Each day's grass pollen
counts were obtained from the Children's Hospital of Pittsburgh's pollen count station as often as possible (the station was closed on weekends and holidays).
"They receive a one millilitre solution of grass pollen
. Patients can be refereed to our clinic through their GP."
In the long run, our vision is to be able to provide specific pollen forecasts for grass and unravel which species of grass pollen
are most likely causing allergic responses.
A joint research programme has identified 150 grass pollens
that cause most allergies.
The main triggers of hayfever are tree pollen, grass pollen
, weed pollen and fungal spores, with grass pollen
being the most common; it affects up to 90% of those who are unlucky enough to experience hay fever.
Approximately 30% of the population in Europe and 25% of the population of the United States are allergic to grass pollen
This time of year sees the highest levels of grass pollen
, in particular, the form which affects most hay fever sufferers.
According to the NHS, about nine out of 10 people with hay fever are allergic to Timothy and Rye grass pollen
. It's possible to be allergic to more than one variety.
"There is a very high risk of grass pollen
on warm, dry days," a spokesman for the Met Office said, "And weed pollen will also be airborne."
If your symptoms appear between late May and early August, when grass pollen
counts are high (the cause of 95 per cent of hayfever sufferings), you're more than likely not being affected by a cold but hayfever instead.