Millions to die from choking smog, warn scientists

Smog is caused by stagnation in the air mass. Picture: AFP

Scientists predict that more than half of the planet’s population could be hit by a rise in the frequency and duration of polluted “dead” air.

Studies by US researchers suggest 55 per cent of people will be affected by atmospheric stagnation events, which are predicted to increase by up to 40 days a year in certain parts of the world.

Stagnation occurs when an air mass hangs over an area for an extended period, posing a serious pollution threat and leading to soaring rates of heart and lung disease.

Poor air quality is the cause of an estimated seven million premature deaths around the world each year, according to the World Health Organisation.

Lead researcher Dr Daniel Horton, from the school of earth sciences at California’s Stanford University, wrote in the journal Nature Climate Change: “The potential public health impact increases as the duration of stagnation events lengthens,” said

“Multi-day stagnation episodes can lead to prolonged hazardous air exposure associated with extreme air pollution, severe outbreaks of acute cardiovascular and respiratory illness, and increased incidence of mortality.”

The prediction was based on a collection of climate models and assumed carbon emissions to remain high.

India, Mexico and the western US were said to be most at risk from health impacts due to smogs affecting areas of high population.

Los Angeles, on the US west coast, is already famous for its choking smogs.

The prediction is based on studies using climate models and assumes emissions of greenhouse gases will remain high.

“Considering the strong links between air stagnation, air quality and public health impacts, our results suggest that continued increases in greenhouse gas concentrations are likely to alter the atmosphere in ways that impact efforts to protect public health,” Dr Horton said.

A recent report by Public Health England blamed the effects of airborne pollution for nearly 300,000 annual deaths across the UK, with 40 people dying each week in Scotland alone.

Warmer temperatures are forecast to increase the incidence of smogs, brought about by changes in air circulation and the water cycle.

Dr Sean Semple, an air pollution expert at Aberdeen University, said: “If climate change causes an increase in the frequency and length of smog or pollution events then it is likely the health burden from poor air quality will increase.

“Scotland has generally very good outdoor air quality that has improved substantially over the past 50 years, although specific urban areas can suffer.”