'When the pollen count is high, the usual symptoms of hay fever, the watery itchy eyes, the runny nose, the cough. Jo has asthma and pollen can cause her serious health problems. I've come to Cyfarthfa Park in Merthyr Tydfil, where the flowers are blooming, to meet Jo Cole. I wanted to find out how other people like me cope with their allergies during hay fever season. 'We combine that with the weather forecast for a few days ahead and we have a look to see whether that trend is likely to continue.' 'Then we can say if it's on the rise or decreasing or plateauing. We have a look at the pollen trends of the data that has come into us. 'Pollen data is one element of the pollen forecast. 'High pollen count is over 50 and a very high pollen count is over 150.' Then we pop that piece of tape under the microscope on a slide and we count every two hours and from that we get the daily pollen count in cubic metres per air.

That clockwork turns the piece of tape around into the airstream and over a 24 hour period we can collect the pollen. 'Basically we have a pollen trap, that's 10m (32ft) above sea level on average, depending on the site, and inside that trap is a sticky surface, based on a clockwork mechanism. There are a number of these at sites across the UK, including one in Cardiff. It's measured by a device called a Seven Day Volumetric Pollen Sampler, on the roof of the University of Worcester. Dr Beverley Adams-Groom leads the team that works with the Met Office to provide the UK's pollen forecast.

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