A toxic cloud of dirty air is set to hit Yorkshire later this week.
Dirty air from the Continent will hit London on Thursday before spreading north on Friday, according to reports.
The Government has put out a warning for “moderate” air pollution sweeping into southern England tomorrow which is predicted to spread to some northern areas on Friday, with a risk of “high” air pollution in some parts.
Official health advice on days of moderate air pollution says that adults and children with lung problems, and adults with heart problems, who experience symptoms, should consider reducing strenuous physical activity.
Air purifier expert Graham Curtis of vacuum cleaner firm Vax said: “Dirty air from the continent is set to hit the UK on Thursday. This is a problem that’s not going to go away anytime soon. It’s the latest in an increasingly common series of health warnings related to poor air quality."
Susceptible people have been warned to stay indoors wherever possible and keep windows and doors closed.
"As air quality drops the impact on health will increase. Taking steps to reduce outdoor activity during high air pollution times is a positive step to help reduce the effects for you and your family," he added.