Australian_Science_Illustrated_Issue_52_2017

66 | SCIENCE ILLUSTRATED

CHEMISTRY POLLUTION

For people in London, “pea soup” smog has

been a part of life for centuries. So, it was no

surprise, when yellowish black smoke

shrouded the city for an entire week in

December 1952. The citizens did not realise

the gravity of the situation, until it became

difficult to obtain enough coffins and flowers.

The Fog

That (Almost)

Killed London

LONDON FOG

COULD SAVE

BEIJING

Recently, an team of

scientists discovered

why the London fog

of 1952 was so fatal.

Smog becomes

hazardous, when sul-

phur dioxide is

converted into

sulphate, which forms

part of tiny air

particles. In 1952,

the conversion was

boosted by NO 2 from

the burning of coal.

So, in the future, NO 2

threshold values could

prevent China’s fog

from becoming as

fatal as London's.

Smog in the Chinese city of Harbin forces

people to wear masks.

VCG/GETTY IMAGES

750

500

250

0

1,000

Days of December 1952

Casualties

4

Smoke and sulphur dioxide (mg/m^3 )

3

2

1

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SMOKE

SULPHUR DIOXIDE

CASUALTIES

FROM THE

SCIENTIFIC

ARCHIVES

PRESENT STATUS