PEOPLE in Gwent and other parts of Wales have been warned of high levels of pollution tomorrow caused by dust blown up from the Sahara desert and prevailing winds.
People suffering the effects of high levels of pollution - including sore eyes, coughs and sore throats - should cut down the amount of activity they take outside, experts have warned.
The elevated pollution levels have been caused by a combination of light south-easterly winds, the continental air flow and dust which has blown up from the Sahara desert.
Asthmatics might need to use their blue reliever inhalers more often as they could be prone to attacks today and over the next few days. Other people with lung and heart problems, and those who are older, should also avoid strenuous exercise or activity.
Tomorrow, high levels of pollution are forecast for eastern parts and the north coast of Wales. Other areas affected are East Anglia, the Midlands, Lincolnshire and the Wirral. High levels will move north over much of coastal north-west England, to south-west Scotland and the north-east of Northern Ireland.
Today, advice has come from Public Health England (PHE), Asthma UK and the Department for Environment, Food and Rural Affairs (Defra), comes after a warning that people in parts of England should be braced for the highest level of air pollution recorded by Defra.
This morning's forecast says large parts of southern England have "high" levels of pollution, with some parts "very high".
Defra ranks air pollution from one to 10, with one being the lowest and 10 the highest.
Across most of England, moderate to high air pollution levels are forecast, with level 10 expected in parts of East Anglia and the East Midlands.
"This is due to light easterly winds continuing to bring in pollutants and allowing local pollutants to remain close to source," the forecast from Defra said. "There may also be some component due to Saharan dust."
Sotiris Vardoulakis, head of air pollution at PHE's centre for radiation, chemical and environmental hazards, said: "Whilst most people will not be affected by short-term peaks in air pollution, some individuals, particularly vulnerable groups such as those with existing heart or lung conditions, may experience increased symptoms.
"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.
"People with asthma may find they need to use their reliever inhaler more often. Older people should also reduce physical exertion.
"Anyone experiencing discomfort such as sore eyes, cough or sore throat should consider reducing activity, particularly outdoors."
Kay Boycott, chief executive of Asthma UK, said: "The two-thirds of people with asthma who find that air pollution makes their asthma worse will be at an increased risk of an attack following the alarming Defra warning of high pollution levels around the country.
"Asthma UK warns the 3.6 million people at increased risk to be sure they always have a working blue reliever inhaler on them and take their preventer inhalers as prescribed."
Frank Kelly, professor of environmental health at King's College London, said: "Whether home-produced or arriving from the continent, the tiny particles we take into our bodies with each breath cause immediate problems for some individuals such as those with asthma and contribute to longer term problems for most of us in the form of heart disease and stroke.
"For those who are sensitive to air pollution, it's important they are provided with accurate forecasts of when air quality will deteriorate so they can plan their activities to reduce exposure, perhaps by taking different routes to work or school or avoiding strenuous exercise on those days.
"Even those who do not feel any particular sensitivity to air pollution can benefit from such avoidance techniques but they will have to wait several decades to see the benefit."
Paul Cosford, director of health protection at PHE, told BBC Radio 4's Today programme: "Clearly this is a serious issue but it's important that we don't get it out of proportion.
"It's a small number of days of very high air pollution levels. The pollution will go down towards the end of the week.
"For the vast majority of people, they will suffer no harm as a result. We may notice sore eyes, coughs, sore throats and perhaps a little bit of a wheeze if we are taking physical activity outdoors.
"If that occurs, it is sensible just to reduce during these high pollution episodes the amount of physical activity.
"The most important advice is for those people who are vulnerable - people who have lung disease or heart disease and particularly asthma. That's where the advice - if you are in a very high-polluted area, to reduce the amount of strenuous physical activity that you are taking outdoors - is sensible just for these few days."
Pollution forecast for tomorrow:
Let us know if you are affected by the smog tomorrow