Pollen Counting

Did you know that The David Hide Asthma and Allergy Research Centre provide pollen counts for the South of England? Pollen samples are collected daily at St Mary’s Hospital and counted here within the Allergy Research Centre. Counts start in March and continue until September each year. The data is sent to The Met Office to be used for forecasting in future years.

The pollen counting season is split roughly into 3. Early season is March to mid May, this is the tree season where we look for Hazel, Alder, Willow, Birch, Ash, Elm, Oak and Plane. Mid season is May to August where we look for Grass and Nettle. Late season is July to September when we look for weed pollens; Mugwort and Ragweed.

We are coming to the end of the mid-season now, Grass pollen is starting to decline but nettle should remain relatively high for a few weeks yet, it is not uncommon for Nettle to have a second peak later in the year. We are also starting to see the weed pollens from the late-season appearing in small numbers.

How is the pollen count performed?

The highest counts recorded so far this year are:

Hazel 13
Ash 21
Alder 51
Willow 11
Oak 311
Birch 284
Grass 423
Nettle 202
Pollen trap