Reviewing twenty years of pollen data at The Ipswich Hospital pollen monitoring site and comparison with central UK regions

Background Grass pollen levels were monitored at The Ipswich Hospital Site, in the East of England for twenty years and tree pollen for fourteen years. This data has contributed to the UK national pollen databank and pollen forecasts over that time. The pollen data throughout this period has been collected by a Specialist Allergy Nurse who provides allergy skin prick testing for an Ear Nose and Throat Department at Ipswich Hospital. Understanding and knowing the exact pollen levels in the eastern region throughout the seasons has supported correct clinical diagnosis and optimal delivery of treatments for hayfever sufferers. In 2025 pollen monitoring ended at the Ipswich site. This review assesses Ipswich grass and birch tree pollen data, comparing trends within central UK pollen monitoring regions1. The start and end of the Ipswich pollen seasons were established using the 2.5% method, reflecting similar research. Case presentation Recent research1 has calculated that changes are occurring in the pollen seasons for central UK. This is due to climate change, with trends to more severe birch pollen seasons (Fig. 1) and earlier occurrence of the first high count day for grass pollen in central England. Ipswich data for grass pollen did not show consistent changes in the onset of first high count day, duration (Fig. 2) or severity as indicated for central UK. Not using the 2.5% method in earlier observations of Ipswich grass pollen data had caused the appearance of a longer season. The low level of grains noted early in the season before the first high day were not significant enough and therefore does not indicate the season for grass dispersal as lengthening. Further years of grass pollen dispersal data would be needed to see if these low levels increase to become significant showing a positive trend. The birch pollen trends in Ipswich however are showing similar changes to that of central UK, which are affected by changing temperatures2 (Fig.1 & Fig.4). Ipswich pollen will similarly be associated with weather variation in East Anglia, particularly the changes in pre-season temperature influencing pollen production and warmer, drier weather experienced during pollen release. Discussion The value of this data is knowledge and awareness of pollen air pollution supporting accurate diagnosis for allergic rhinitis and also for those people who have asthma. The question maybe ‘are the public becoming more sensitive and reactive to the lower levels of pollen?’ The pollen itself may become more allergenic, due to the climatic change stressing the plants as they experience more frequent extreme weather conditions and more CO2 in the atmosphere3. This review does not answer those questions. Ipswich birch pollen seasons vary in a similar way to central UK regions but grass pollen seasons show less similarity to the changes noted in central UK regions1. From a human perspective, timing of symptom onset for individuals is vital for effective treatment and may be triggered at different times in different parts of the UK. Advice on when to start treating pollen allergy in Ipswich has not changed over the twenty years. The treatment start dates for tree pollen remain March and for grass pollen remains May.