IIS VIOLA MARCHESINI CLIL MODULE “AIR POLLUTION” A.S. 2015/2016 classi 5° chimica
READING N°1
Introduction/Motivation
There has always been air pollution. Whenever anything is burned or combusted, air pollution is created. Therefore, when cave men had fires in caves without chimneys (for ventilation), significant pollution was created. Air pollution first became a problem during the industrial revolution when the use of coal increased.
Initially, it seemed adequate for industries to protect humans from harmful smoke emissions by building smoke stacks that delivered the smoke high into the air, away from the people. This thinking was logical at the time: if harmful smoke was emitted high in the atmosphere, then natural weather patterns — such as changing wind and rain storms — would disperse the pollutants throughout the atmosphere. Unfortunately, humans started to produce more pollution than natural weather patterns could disperse.
Air pollution began to attract people's attention in the 1950s when several pollution incidences lead to illness and even death of local residents.
The worst incident occurred in London, England, in 1952 during a four-day period in which the air sat stagnant over the city because there were no changes in the weather and little wind. The stagnant air, combined with the large amount of pollution emitted in an industrial city, proved to be devastating. A thick blanket of black smog (a combination of smoke and fog) covered the city, making it difficult to see. Breathing in this harmful smoke is thought to have killed 4,000 residents and caused illness for many others.
As a result of the deaths in London, legislation controlling air pollution was passed.
Do you think air pollution affects you right now? Do you live in a big city? Is there a lot of industry around? Is there pollution in this classroom?
Yes, there are many things floating in the air called particulate matter. Mostly they are not very harmful, but if a person inhales a lot of particulate matter over lengthy periods of time, it can have adverse health effects.
Particulate matter is made up of lots of little things: from dirt and ash mentioned above to heavy metals like lead and arsenic. The most concerning of the particulate matter is the very small pieces (less then 2.5 microns — one micron is a millionth of a meter). Because of their microscopic size, our bodies have trouble filtering out these very small pieces of particulate matter, and they can collect in our lungs and then cause many different respiratory diseases, like asthma.
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