Schools in areas affected by severe air pollution have been stopping children from playing outside to protect their health.
Their actions came following advice from a government adviser who said temporarily banning kids from the playground was sensible to avoid children having asthma attacks and potentially lifelong lung damage.
Prof Frank Kelly said children should be stopped from using the playground during school hours to reduce their exposure to the smog, which, combined with dust from the Sahara, is affecting south-east England and is expected to spread to the Midlands and East Anglia.
Dr Kelly is the chair of the Department of Health's Committee on the Medical Effects of Air Pollution and a member of the Department for Environment, Food and Rural Affairs' Air Quality Expert Group.
Dr Kelly said: "As a general response this is a good approach as children tend to run around outside and therefore breathe deeper. Thus on days like this they will be inspiring a lot more pollution if outdoors than when they are breathing normally (hopefully) inside."
The policy should apply to morning and afternoon breaks, as well as lunchtime, Dr Kelly said. "Advice would be the same for breaktimes if pollution levels were increased at the school location."
He warned that pupils with asthma may need to use their inhalers, while those with other breathing conditions could suffer serious harm if exposed to the high level of pollution being seen in London.
He said: "Besides those children whose asthma may be exacerbated by pollution and who would then need to increase their medication, the main issue is related to pollution exposure on a chronic basis as current evidence indicates that lung growth is restricted. If there is no subsequent catch-up lung growth then this respiratory deficit is carried forward through life."
Bowes and Chesterfield primary schools in Enfield, north London, kept children inside on Wednesday.
Tom Sheldon, chair of governors at both schools."When schools are faced with conditions like these we have to decide what is best for children. In the absence of any formal advice from government we decided to keep children inside today as a precaution.
"But we can't do this forever, and in London we face the much wider problem of poor air quality every day. The Saharan dust will pass, but London will continue to fail its citizens on air quality. Children's developing lungs are at particular risk, both long- and short-term."
However, other schools – such as the primary my own sons attend – thought the move was over-nannying and even went ahead with a whole-school Fun Run yesterday – with zero ill effects on the kids, who all had a fantastic time being outside on a stuffy day!
What do you think? Should we keep our children locked up inside during the conditions we've experienced these past couple of days?