People with heart and lung disease have been urged to avoid strenuous physical activity.
The government has warned people in parts of England to be braced for “very high” levels of air pollution today.
The pollution is a mixture of local and European emissions and dust from the Sahara Desert.
The Department for Environment, Food and Rural Affairs (Defra) has warned the high pollution levels recorded in the Midlands and eastern England yesterday are expected to spread across the south of the country and East Anglia.
Defra uses a 10-point scale to measure air quality, with 1 to 3 seen as low risk of pollution and 10 being very high.
Suzanne Plunkett / Reuters
On Tuesday, north-west Norfolk saw pollution levels hit 10 on the scale and some parts of southern England and Wales could reach 9 later today.
A Defra spokesperson is quoted as saying: “The high level of air pollution this week is due to a combination of local emissions, light winds, pollution from the continent and dust blown over from the Sahara.
“We want to keep improving air quality and have introduced a new five-day forecast service in addition to investing heavily in local and transport initiatives to tackle this issue head-on.”
Suzanne Plunkett / Reuters
Earlier this week motorists in parts of the country discovered their cars covered in a thin coating of red dust.
The Met Office has blamed the phenomenon on sand and dust being blown in by strong winds from the Sahara.
A statement declared: "A large amount of sand and dust was swept up by storm winds in the desert, around 2,000 miles away in north-west Africa.
"The airborne particles were blown north to the UK, where they combined with our warm air and were deposited during showers."
