Schools are keeping students indoors at recess and the elderly and officials are warning those with lung and heart conditions against strenuous outdoor activity. While this might sound like a normal day in smog-choked Beijing, the warnings are for Londoners. This week, dust blowing in from the Sahara has mixed with industrial pollution originating in Europe and the U.K.’s own traffic fumes to create a thick, yellow smog shrouding southern England.
The U.K. Department of the Environment, Food and Rural Affairs (DEFRA) measures outdoor air pollution on a one-to-ten scale. Parts of north-west Norfolk hit level ten on Tuesday and London came in at a nine Thursday morning.
DEFRA calculates air quality based on the concentrations of five pollutants — ozone, nitrogen dioxide, sulfur dioxide, PM2.5 and PM10
Last month, the E.U. announced it was taking legal action against the U.K. because air quality testing showed concentrations of nitrogen dioxide consistently exceeded safe limits.
The U.K. is in “good” company though — the E.U. is currently taking action against 17 out of 28 member states for air quality violations.
Last month, air pollution in Paris became so serious that half of all vehicles were blocked from entering the city in a desperate attempt to help clear the air.
For comparison, Paris saw air quality index readings as high as 185. London is flirting with 100, while Beijing somewhat routinely breaks 300 and has seen levels even exceed 600.
These numbers refer to concentrations of fine particulate matter known as PM2.5. Measured in micrograms per cubic meter, the World Health Organization (WHO) considers a reading of 25 or less ideal for human health. Above 300 is considered hazardous.
In 2012, air pollution caused 7 million premature deaths worldwide according to WHO.
That figure includes indoor air pollution for cooking stoves in developing countries as well as outdoor pollution from fires and industrial pollution. Outdoor air pollution was responsible for 3.7 million premature deaths in 2012.
About 80 percent of deaths related to outdoor pollution are linked to heart disease and strokes, while 14 percent are due to lung or respiratory diseases, and 6 percent to cancer.
Perhaps as many as 30,000 premature deaths in the U.K. are linked to poor air quality. The BBC has reported that there has been a 14 percent jump in emergency calls in London related to breathing problems. Historically, London is no stranger to smog. The “Great Smog” of 1952 in London, which lasted just 4 days, is believed to have caused 4,000 deaths.
Conditions in London are expected to get better on Friday as winds move the pollutants out to sea.