london smog

7/27/2019 london smog

1/22

LONDON SMOG

CHERNOBYLDISASTER


2/22

INTRODUCTION

From Friday 5 December to Tuesday 9 December 1952, the smoke-ladenfog that shrouded the capital of England i.e. London which is known as

London smog or great smog or also famous as pea-souper.


3/22

What Is Smog ?

"Smog" is a term originally formed by the combination of the words"smoke" and "fog."

There are actually two kinds of smog: London smog (well know for its

fog) and L.A. smog (also know as photochemical smog).

Name: London smog( New York smog, gray smog)

Photochemical smog(L.A. smog, Denver smog, brown smog)

Weather: cool, damp sunnyContent: particulates, sulfur oxides NOx, ozone, hydrocarbons.Sources: coal, etc. gasoline, combustion.


4/22


5/22

Causes of London Smog

Early on 5 December, in the London area, the sky was clear, winds were lightand the air near the ground was moist. Accordingly, conditions were ideal for the

formation of radiation fog.

Because of the cold weather, households were burning morecoalthan usual to

keep warm. The smoke from approximately one million coal-fired stoves, in

addition to the emissions from local industry, was released into the atmosphere.

As night came, lightwinds, cool air, and highhumidityat ground-level wereideal conditions for the formation of thick, smoky fog, or smog. The smoke and

fumes from the heavy coalcombustionsettled close to the ground and due to a

temperature inversion, remained motionless and created dense smog.
http://www.eoearth.org/article/Coalhttp://www.eoearth.org/article/Atmospheric_compositionhttp://www.eoearth.org/article/Atmospheric_compositionhttp://www.eoearth.org/article/Windhttp://www.eoearth.org/article/Atmospheric_humidityhttp://www.eoearth.org/article/Combustionhttp://www.eoearth.org/article/Combustionhttp://www.eoearth.org/article/Combustionhttp://www.eoearth.org/article/Atmospheric_humidityhttp://www.eoearth.org/article/Windhttp://www.eoearth.org/article/Atmospheric_compositionhttp://www.eoearth.org/article/Coal


6/22

Temperature inversions are often reversed in the morning

whenradiationfrom the sun warms the ground below the mist. The suns

radiation was unable to break through the dense smog. This caused the staticlayer of cooler, polluted air to remain trapped in the loweratmosphere. The

fog lasted for 5 days, from December 5 through 10, until winds dispersed the

dense air mass and transported the pollution through the Thames Estuary

and into the North Sea.
http://www.eoearth.org/article/Solar_radiationhttp://www.eoearth.org/article/Solar_radiationhttp://www.eoearth.org/article/Atmosphere_layershttp://www.eoearth.org/article/Atmosphere_layershttp://www.eoearth.org/article/North_Sea,_Europehttp://www.eoearth.org/article/North_Sea,_Europehttp://www.eoearth.org/article/North_Sea,_Europehttp://www.eoearth.org/article/Atmosphere_layershttp://www.eoearth.org/article/Solar_radiation


7/22

Composition Of London Smog

On each day during the foggy period, the following pollutants were emitted:

1,000 tones of smoke particles .

2,000 tones of carbon dioxide .

140 tones of hydrochloric acid .

14 tones of fluorine compounds.

In addition, and perhaps most dangerously, 370 tones of sulphur dioxide were

converted into 800 tones of sulphuric acid


8/22

Effect Of London Smog

The fog finally cleared on December 10, but it had already taken a heavy toll.

About 12,000 people were known to have died as a result of the fog.

The thick smog caused all traffic to halt in London. This included automobiles,

railways, boats, and airplanes. Only the London Underground was in operation.

Ambulances were not able to attend emergencies.

Many people suffered from breathing problems.

Press reports claimed cattle at Smithfield had been asphyxiated by the smog.


9/22

Smog also posed a health risk due to the production of sulfuric acid whensulfur trioxide combined with the moisture droplets in the fog. This toxic mixture

impaired the functions of the lungs and heart.

The crime rate increased because perpetrators could escape without being

seen.

Schools were closed due to the risk of children not seeing their way on the

sidewalks. Outdoor activities, such as rugby matches, were cancelled. The dense

smog also made its way inside of buildings and settled in movie theaters, concert

houses and hospitals.

Most deaths were caused by the inhalation of acid aerosols, which inflamed

and irritated bronchial tubes.

The acid in the air caused a stinging sensation when inhaled so people who had

to go outside had to cover their noses and mouths with a cloth.
http://www.eoearth.org/article/Smog


10/22

The smog-related deaths were primarily attributed to :

pneumonia Bronchitis

Tuberculosis Heart failure

respiratory distress Cardiac distress

asphyxiation.

Non-fatal health effects from the smog included :

short-term chest pains Lung inflammation

diminished breathing ability Damaged respiratory cells

permanent lung damage

Increased incidence of asthma attacks.

It is also thought that the smog could have increased the populations risk of

cancer.
http://www.eoearth.org/article/Smoghttp://www.eoearth.org/article/Smog


11/22

Response Of 1952 London Smog

Four years later, the 1956 Clean Air Act was passed. The prime initiative was the introduction

of smokeless zones, which banned the burning of fuel.

The Act provided grants to homeowners in order to encourage them to switch from coal to

other less-polluting heating methods such as electric fireplaces or central heating

A cleaner coal was also introduced which reduced the emission of sulphur dioxide.


12/22

The April 1986 disaster at the Chernobyl nuclear power plant inUkrainewas

the product of a flawed Soviet reactor design coupled with serious mistakesmade by the plant operators. It was a direct consequence of Cold War isolation

and the resulting lack of any safety culture.
http://www.world-nuclear.org/info/inf46.htmlhttp://www.world-nuclear.org/info/inf46.htmlhttp://www.world-nuclear.org/info/inf46.html


13/22

Structure Of Chernobyl Nuclear Power Plant

The Chernobyl Power Complex, lying about 130 km north of Kiev, Ukraine,

and about 20 km south of the border with Belarus, consisted of four nuclear

reactors of the RBMK-1000 design.

Units 1 and 2 being constructed between 1970 and 1977, while units 3 and

4 of the same design were completed in 1983. Two more RBMK reactors wereunder construction at the site at the time of the accident.
http://world-nuclear.org/NuclearDatabase/rdresults.aspx?id=27569&ExampleId=130http://world-nuclear.org/NuclearDatabase/rdresults.aspx?id=27569&ExampleId=130


14/22

Within a 30 km radius of the power plant, the total population was between

115,000 and 135,000.


15/22

The RBMK-1000 is a Soviet-designed and built graphite moderated pressure

tube type reactor, using slightly enriched (2% U-235) uranium dioxide fuel.

One of the most important characteristics of the RBMK reactor is that it can

possess a 'positive void coefficient', where an increase in steam bubbles ('voids') is

accompanied by an increase in core reactivity.

However, at the time of the accident at Chernobyl 4, the reactor's fuel burn-up,

control rod configuration and power level led to a positive void coefficient largeenough to overwhelm all other influences on the power coefficient.


16/22


17/22

Two explosions were reported, the first being the initial steam explosion,

followed two or three seconds later by a second explosion, possibly from the build-

up of hydrogen due to zirconium-steam reactions.

Fuel, moderator, and structural materials were ejected, starting a number offires, and the destroyed core was exposed to the atmosphere..One worker, whose body was never recovered, was killed in the explosions,

and a second worker died in hospital a few hours later as a result of injuries

received in the explosions


18/22

Impacts Of Chernobyl Disaster

The accident destroyed the Chernobyl 4 reactor, killing 30 operators and firemen withinthree months and several further deaths later.

The accident caused the largest uncontrolled radioactive release into the environment ever

recorded for any civilian operation, and large quantities of radioactive substances were released

into the air for about 10 days. This caused serious social and economic disruption for large

populations in Belarus, Russia and Ukraine.

Two radionuclide, the short-lived iodine-131 and the long-lived caesium-137, were particularly

significant for the radiation dose they delivered to members of the public.

It is estimated that all of the xenon gas, about half of the iodine and caesium, and at least

5% of the remaining radioactive material in the Chernobyl 4 reactor core (which had 192 tonnesof fuel) was released in the accident.

Acute radiation syndrome (ARS) was originally diagnosed in 237 people on-site and

involved with the clean-up and it was later confirmed in 134 cases.
http://world-nuclear.org/NuclearDatabase/rdresults.aspx?id=27569&ExampleId=130http://world-nuclear.org/NuclearDatabase/rdresults.aspx?id=27569&ExampleId=130


19/22

By 2000, about 4000 cases of thyroid cancer had been diagnosed in exposed

children.

United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) saysthat "the great majority of the population is not likely to experience serious health

consequences as a result of radiation from the Chernobyl accident.


20/22

Progressive Closure Of Chernobyl Plant

In the early 1990s, some US$400 million was spent on improvements to the remaining

reactors at Chernobyl, considerably enhancing their safety. Energy shortages necessitated thecontinued operation of one of them (unit 3) until December 2000.

Unit 2 was shut down after a turbine hall fire in 1991, and unit 1 at the end of 1997.

Chernobyl Today

Chernobyl unit 4 is now enclosed in a large concrete shelter which was erected quickly (by

October 1986) to allow continuing operation of the other reactors at the plant. However, the

structure is neither strong nor durable.

Some major work on the shelter was carried out in 1998 and 1999. Some 200 tonnes of

highly radioactive material remains deep within it


21/22

ANew Safe Confinement structure is due to be completed in 2016, being built adjacent andthen moved into place on rails. It is to be a 20,000 tonne arch 108 metres high, 150 metres long

and spanning 257 metres, to cover both unit 4 and the hastily-built 1986 structure.


22/22

london smog

Documents