An expert has sent a major warning to Britons planning to hang their clothes outside during the upcoming heatwave.
Speaking to the Mirror, MattressOnline specialists warned that while it may be tempting to dry your clothes outdoors during the sweltering sunshine, it could have an adverse affect on hay fever sufferers.
Britain is in for a treat as today marks the country's third heatwave within weeks - which could last for up to six days as temperatures soar to 33C.
It also marks a time when grass pollen is at its peak, with an expert warning hay fever sufferers to refrain from hanging clothes outdoors as they become a magnet for pollen and dust.
The expert told the publication: 'Don't dry clothes on an outside washing line. Some of your washing habits might need changing when dealing with hay fever symptoms.
'For example, avoid drying your clothes and bedsheets outside in the fresh air after doing your laundry, where pollen and dust can collect. Instead, dry them in a tumble dryer or hang them up inside.'
The Met Office said the incoming hot weather will be more widespread and longer lasting than the previous two heatwaves this summer in mid-June and early July.
According to the national weather advisory service, pollen levels will range from 'high' to 'very high' across the south of England and Wales from today.
By the end of the week, areas with recorded 'low' pollen counts like Strathclyde and Orkney & Shetland will progress to having higher pollen counts.
With pollen levels set to skyrocket over the next few days, home cleaning expert and founder of Daily Poppins, Nigel Bearman has also advised against drying your particulars outside.
Calling the practice a 'recipe for itchy eyes and a stuffy nose', he explained the science behind the warning.
'The wet laundry acts like a sponge, soaking up all the pollen. It settles into the fibres and clings on as the fabric dries, meaning it'll end up in your bed, wardrobe and on your skin' he told the MailOnline.
'It's no wonder so many people have allergy flare-ups even in their own homes'.
Most hay fever sufferers know to stock up on antihistamines and to stay inside during these conditions.
However, you might not be aware that it's also best to keep your clothes indoors during these so-called 'pollen bombs'.
Mr Bearman explained that laundry fibres - especially cotton, linen and towels - trap pollen easily.
And even when you take your washing inside, the pollen can linger for hours - aggravating symptoms like itchy eyes, blocked nose and sneezing.
'On high pollen days, I always recommend drying your clothes indoors, ideally near a window or with decent airflow,' he advised.
'If you're short on space, use a collapsible drying rack in a well-ventilated room.'
The Met Office has predicted the incoming hot weather will be more widespread and longer lasting than the previous two heatwaves this summer in mid-June and early July.
Today will be the last day of fresher weather with lows of only 2C (36F) in Scotland overnight and the mercury reaching 25C (77F) this afternoon in South East England.
Tomorrow, the heatwave under the Met Office's criteria will officially begin with highs of 28C (82F) expected in parts of central and eastern England and eastern Wales.
According to the Met Office, pollen levels will range from 'high' to 'very high' across the south of England and Wales from today.
Temperatures will build towards the end of this week with 30C (86F) by Thursday and 33C (91F) on Friday - with 30C also expected on Saturday, Sunday and Monday.
An official heatwave is recorded when areas reach a certain temperature for three consecutive days, with thresholds varying from 25C to 28C in different areas.
Meanwhile forecasters warned of a possible tropical night over the coming week which happens when temperatures stay above 20C (68F) through the night.
Met Office deputy chief meteorologist Dan Holley said: 'High pressure from the Atlantic will gradually exert its influence over the UK this week.
'We'll see temperatures build day-on-day, with the potential for hot conditions to become quite widespread by the end of the week and into the weekend.
'On Wednesday, temperatures could reach up to 28C in parts of England, climbing to 30C on Thursday and 32C by Friday. By this stage, heatwave criteria are likely to be met in parts of England and Wales, and in parts of Scotland over the weekend.'
Mr Holley said high temperatures would likely persist into the weekend, especially away from coasts with onshore winds - reaching the low 30Cs in parts of England and Wales, accompanied by 'rising humidity and warmer nights'.
He continued: 'This heatwave is likely to last longer than previous ones so far this summer, and affect a wider area, with the focus for some of the highest temperatures displaced across more central and western areas at times'.
Mr Holley said pollen and UV levels will also be 'very high' in some areas.
Forecasters believe there are signs that less hot, or fresher conditions may arrive from the west into the start of next week, but there is uncertainty over how quickly this will transfer eastwards.
The Met Office said it was possible that 'hot conditions may persist for a while longer, especially towards the South and East'.
But the UK is expected to avoid the stifling weather of the low 40Cs seen in the Mediterranean over the past few weeks.
Why DO some people suddenly develop hay fever out of the blue?
For most hay fever sufferers, symptoms begin in childhood and persist for the rest of their lives.
But some people appear to develop the condition suddenly and without any obvious reason, even well into their adult life.
No-one knows exactly why hay fever can appear out of the blue but there are a number of theories.
One is that they experienced very mild symptoms as a child that they did not notice.
Another is the 'hygiene hypothesis', that our bodies are weaker as we age because we aren't exposed to as many infections as children.
Research has indicated that youngsters who grow up on farms with regular contact with animals are less likely to develop allergies later in life.
Another possibility is that sudden hay fever happens when the body is exposed to new surroundings - like moving from the city to the countryside, where there is usually more pollen.
But the same might also be true in people moving from rural to urban areas, with some evidence that pollution can exacerbate hay fever.
A weakening of the immune system could also be a trigger.
A bad infection, illness or traumatic emotional event may leave the body vulnerable to normally harmless allergens.
Between 15 and 20 per cent of people in the UK are thought to be affected, with the numbers being even higher among teenagers and symptoms typically peaking in people's 20s.