someone's concern :
As pollen is carried by the wind, the count can depend heavily on the wind direction.
The pollen count in the Midlands has very little dependency on the direction the winds are coming from. Being in the centre of England, winds from all directions bring pollen and the counts are often the highest in the UK. One June the count in Derby was 1024. To gauge how high this is, 150 is considered very high.
SOURCE:www.bbc.co.uk