Major national research into the effects of climate change on hay fever will begin January 1

Because of the warm autumn and December, the first flowers of the hazel trees and the first flowering alders are already beginning to bloom

Although it’s winter, the first allergens pollen are already there. With the warmth of autumn and December, the first hazel trees and early alder flowers are already beginning to bloom, and that fits in with the trend of bringing hay fever season in the Benelux forward. A large national study will begin Jan. 1 to bring the effects of climate change on allergies under control.

A recent analysis of 42 years of pollen counts by Elkerliek Hospital in Helmond and Leiden University Medical Center showed the early start of flowering seasons for trees, grasses and herbs. The driving force behind this is likely climate change. Since the grass and legume season ends later and later, the pollen season gradually increases. The amount of tree pollen increased as well as the peak concentration while the amount of weeds and mugwort decreased. The decrease in the amount of pollen from grasses and legumes is likely related to the increase in urbanization in the area around pollen sampling. This leaves less room for plants to grow. An article about this was recently published in Frontiers Scientific Journal of Allergy.

Hay fever at Christmas and New Year
The fact that the first hazel and alder trees have already begun to bloom again fits the trend. Early flowering occurs due to the high temperatures in the fall and the warm beginning of December. With an average temperature of 11.6 ° C, autumn 2021 has been ranked sixth in the list of temperate autumn seasons since 1901. In the coming weeks, people with pollen from hazel and alder should take hay fever complaints into account.

Changes in the start and duration of the pollen season and pollen counts have consequences for allergy sufferers. They may face more complaints and the period in which they expect complaints will change. Higher peak concentrations may also lead to more severe complaints. So good information for allergy sufferers when they can be experiencing symptoms is of great importance. A large national study will begin Jan. 1 to make the effects of climate change on sensitivity more manageable. The research is supported by the Research Funder ZonMw Climate and Health Program, based on Climate change and health knowledge agenda.

Pollen forecast, disease burden and tree guide
In the framework of the research we are developing spatial predictions for pollen. We also want to determine how exposure to different pollens determines disease burden and how climate-related factors such as heat and air pollution affect disease burden. We are also looking for the best way to provide this information to patients. We also prepare a guide describing allergies to pollen from different tree species. Tree owners, landscape architects, and gardeners can better take sensitivity into account when selecting new plantings.

This research involves collaborations between healthcare institutions (Leids University Medical Centre, Elkerliek Hospital, Service Pharmacy), universities (Wageningen University, University of Twente), government agencies (RIVM, GGD Rotterdam) and the business community (Terra Nostra).