Blue Skies – The Fascinating History of London Air Pollution

A London policeman wearing a mask for protection against the thick fog which hit most of the country and turned to smog in the city. (Photo by Keystone/Getty Images)

Like most cities, London has had its share of air quality problems over the centuries.  Most people would think that air pollution in this part of the UK would be only a couple hundred years old, but London’s history with keeping the air clean goes back much further than that.  Arguably the first-ever clean air legislation was the direct result of King Edward I banned the burning of sea-coal due to the amounts of smoke it created.  The burning of coal dated back even further than this to the Romans, but Edward’s proclamation shows how prevalent it had become even by the 14^th Century.  While Edward banned the burning of coal on penalty of death, virtually no one stopped burning it for warmth or fuel, and the proclamation was very seldomly if ever, enforced.

And while coal continued to be used mostly in the home, by the 18^th Century, it began to see use for industrial purposes as well.  With the industrial revolution came now factories and later power plants that burned coal almost around the clock.  By the mid-19^th Century, the United Kingdom’s industry had made it one of the leading powers in the world and London swelled in populations size from 1 to 2 million by 1850 and 6.5 million by 1900.  With these increases also came an increase in air pollution from London’s factories, power plants, and people burning coal.  This concern for the increase in air pollution was reflected in the Public Health Act for London 1891 that limited how much smoke a business could produce.  This and the ever-increasing use of gas for heat, light, and power helped curb emissions somewhat, but air quality continued to worsen over time.

It was also during the 19^th Century that London first dealt with a new environmental threat—smog.  Smog is the mixing of smoke and fog, the latter of which was as prevalent in London as the coal smoke.  By 1885, London recorded some 80 fog days per year and even 180 in some parts of the city.  Fog and smog often stopped most activity when it became too dense, though it proved a fertile ground for crimes as it allowed criminals to virtually disappear.  In the 1850s, London also had to contend with foul odors that sprung from a heavily polluted Thames.  The Thames had essentially become a great sewer basin for the city until Joseph Bazelgette’s proposal for a public sewer system took root and help purge at least one air quality problem from the city.

And even as public parks began to give the city a breath of fresh air thanks to the deliberate construction of green spaces that helped filter the toxicity, the problem of air pollution continued practically unabated.  By the 20^th Century, smog was a recurring problem in London, sometimes jokingly referred to as a “pea-souper” for its thickness.  It all came to a head in December 1952, when a smog descended upon the city that lasted for five days.  Visibility was reduced to such a level that 200,000 people were injured and the air got so bad for breathing that 12,000 people died.  The result was the Clean Air Act of 1956 that introduced “smoke control areas” and mandated the burning of cleaner fuel sources.

In the latter half of the 20^th Century, new energy technologies from relying on gas and clean coal to green technology such as wind, solar, and hydrogen fuel cells have helped ease the burden.  However, in the place of factories and power plants belching smoke into the air, fumes from the cars and busses of the city have taken their place.  Greater London has since made efforts to reduce the amount of this pollution within the city by encouraging more charging stations for electric and hybrid vehicles and through the congestion charge, which adds a fee for entering certain parts of the city.  While the charge was instituted primarily to reduce traffic, it naturally has had the effect of boosting air quality, and studies have noted that air pollution has dropped by 1/3 inside the Ultra-Low Emission Zone since it was instituted in 2019 as part of the congestion charge.  Certainly, in an age when climate change is on the minds of many in government and environmentalism, the city will undoubtedly take continued steps to improve the air quality for its citizens.