The highest pollen levels are set to appear across England and Wales.
The rest of the UK is expected to see medium levels of pollen.
How to lower risk of life-threatening attacks
Dr Whittamore said: “These attacks can leave people fighting for breath, which can be terrifying, but there are things they can do to look after themselves.
“Using your preventer inhalers as prescribed is important as the medicine reduces sensitivity and swelling in the airways, helping to prevent symptoms such as wheezing and coughing before they even start.