Today could be the UK’s warmest day of the year so far as temperatures reach 22C but those heading outside are being warned of high pollution and dust from the Sahara.
Much of the country will enjoy summer-like conditions but the sunshine will be made hazy by clouds of pollutants sweeping in from Europe.
Dust churned up by a storm 2,000 miles away in the Sahara Desert will also add to the problem, with reddish particles clogging the air and possibly falling as “blood rain” on to houses and cars. Dan Williams, a forecaster at the Met Office, said counties immediately to the north of London were seeing the highest temperatures of 22C.
"Not everywhere is going to have its warmest day of the year, but there's plenty of sunshine around," he added.
"It's really where that sunshine stays the longest that we'll see the warmest temperatures.
"It's not record-breaking by any means, but it's pretty warm for this time of year - early April maximum average temperatures are around 11C to 12C, so to see 22C is well above average."
The Department for Environment, Food and Rural Affairs said that air pollution levels across the UK would range from moderate to very high today, spiking in eastern and south-eastern parts.
Highs of 21/22 °C tomorrow in the south and east, but feeling cooler over the weekend as a front moves across the UK pic.twitter.com/XbFuuGxej6— Met Office (@metoffice) April 9, 2015
“This is due to a combination of pollutants trapped near the ground, a light south-easterly flow bringing additional pollutants from the continent and, in addition, a small amount of Saharan dust in the air,” a spokesperson said.
In pictures: High air pollution levels across the UK
In pictures: High air pollution levels across the UK
Dust particles and pollution from cars hang over Birmingham as people suffering the effects of high levels of pollution
A view of Dover in Kent, covered in haze and smog
Dover Castle in Kent shrouded in haze and smog
The River Trent in Nottingham is surrounded by smog and haze as record levels of air pollution continue to plague the UK
A view of London skyline covered in smog.The environment department confirmed that the air pollution level could reach the top rung on its 10-point scale
A view through smog over the 02 Arena and the Canary Wharf financial district in London. The BBC weather centre predicts a potential 8 or 9 out of 10 level of air pollution likely to be found in East Anglia and the East Midlands
Dust from the Sahara combined with pollution from mainland Europe has contributed to one of the worst smogs of the year this week with record levels being recorded in parts of England
The skyscrapers of the Canary Wharf business district in London are shrouded in smog, as seen from a viewing gallery on the Orbit sculpture in the Queen Elizabeth Olympic Park during an tour of the park organized for the media
Air pollution hangs in the air lowering visibility towards central London and the City from east London
The 02 Arena through smog in London
The Shard and St Paul's Cathedral from Hampstead Heath in London
A general view of City Hall and the River Thames in London
The low air quality has sparked public health warnings for older people and anyone with respiratory conditions to avoid exercising outside.
Simon Birkett, from campaign group Clean Air in London, told the Evening Standard that marathon runners should “very seriously consider” not training in the conditions.
“This is not something to take lightly and dismiss,” he added.
Dr Sotiris Vardoulakis, head of the air pollution and climate change group at Public Health England, said that most people will not be affected but those with existing heart of lung conditions should be wary.
“On occasions where levels are high, adults and children with lung problems, and adults with heart problems, should reduce strenuous physical exertion, particularly outdoors, and particularly if they experience symptoms,” she added.
“Older people should also reduce physical exertion. Anyone experiencing discomfort such as sore eyes, cough or sore throat should consider reducing activity, particularly outdoors.”
Asthma sufferers are being urged to ensure they carry their reliever inhaler as it may be needed more.
The pollution will melt away as fresher, cleaner air from the Atlantic reaches the whole of the UK on Saturday, although levels could still reach “moderate” until falling to “low” by Tuesday.
The unseasonably warm temperatures will also plummet over the next few days as rain spreads across the country.
Charles Powell, a meteorologist with the Met Office, said: “On Friday we could see temperatures of up to 22C across parts of eastern England, particularly to the north of London and into Cambridgeshire.
"But by Saturday morning temperatures will be lower after a band of rain overnight.
"But it's not that it's going to be particularly cold, it's just returning to nearer normal after a week of temperatures being above average, so it will feel slightly colder."
Rain will be possible in many parts of the country overnight and temperatures of around 10C or 11C in the north and around 14C or 15C further south will feel chilly on Saturday.
Doctors have also cautioned hayfever sufferers of an early onslaught of pollen, which is ranging between moderate and low levels according to the Met Office.
Additional reporting by PAReuse content