Health experts have warned that thunderstorms, air pollution and high levels of pollen could create a “triple threat” for asthma sufferers on Thursday.
Charity Asthma + Lung UK said those with the condition could be at higher risk of hospitalisation due to thundery showers in the capital.
More than five million people in the UK suffer from asthma and changes in weather and pollen can act as triggers.
Data published by the UK Health Security Agency has shown that thunderstorms coincide with an unseasonal spike in asthma hospitalisations.
Emma Rubach, Head of Health Advice at Asthma + Lung UK, said: “People with asthma who have hay fever can experience much more severe symptoms during thunderstorms.
“This is because thunder breaks pollen into smaller particles, which can then be inhaled deep into the lungs, causing wheezing, coughing, a tight chest and shortness of breath.
“If there is also higher pollution in the atmosphere – which tends to be the case when the weather is warm – this is an added threat.”
She advised anyone suffering from the condition to take their preventer inhaler and ensure they are taking antihistamines and steroid nasal spray if needed.
“We’d also advise staying indoors during thunderstorms if possible, and on hot, stormy days keeping inhaler medications in cool, dry areas at home and in a dry cool bag when outdoors as they may not work as well when exposed to hot temperatures or damp environments,” she added.
The warning comes as large swathes of the UK are braced for torrential rain and thunderstorms, with flooding and travel disruption expected.
London will see light rain showers and a gentle breeze today, before thundery showers begin on Thursday afternoon, according to BBC Weather.
The Met Office said that high pressure from the western coast of England will help “slowly kill” off the rain in time for the weekend.
Met Office forecaster Dan Stroud said: “It’ll become generally dry with sunny spells during the course of the weekend, temperatures generally slightly above average, so the sunshine is going to feel quite pleasant.”
