Environment Pollution

first stage

Chemistry
Lec-9
4/10/2015

لمى النوري

Environment Pollution
Environment pollution:
May be defined as the contamination of air, water, food in such manner as to cause real or potential harm to human health or well-being or to damage the non-human nature.

Basically pollution can be classified to:

Air pollution
Water pollution
Noise pollution
Solid waste
Radio active waste
Air pollution
Comes from
increase the population in the world
increase the amount of power
power plant (factories)
automobiles (trucks, Buses, Personal car, aircraft)
The major source of air pollutant comes from the non stoichiometric combustion, dissociation of Nitrogen oxides and impurities in the fuel of air
The emission of concern are:
carbon monoxide CO
oxides of Nitrogen NO
hydro carbon HC
photo chemical smag
sulfur oxides SO
lead and phosphorous
solids particles


1- Carbon Monoxides CO:- is a product of in complete combustion of hydrocarbon fuel (CnHn). Most of CO comes from the exhaust of vehicles, CO is colorless, odorless.
O2 + HB HBO2 + CO HBCO
Stable
2- Hydro Carbon H-C
Comes from exhuse gases, and will be different for each gasoline
depend on the original fuel. HC emission act as irritants and odorant, all H-C except CH4 it may reach with atmosphere to form photochemical smog some of H-C when get into atmosphere act as carcinogenic
3-Oxides of Nitrogen (NO):-
Exhaust gases contion NO in most ofit's constituent and trace amount of NO2 and other nitrogen-oxygen combination NO2 is a very undesirable emission, especially released of NO react with atmosphere to form (ozone,O3)and is one of the major causes of photochemical smog, high temp produce (NO) which is then oxidized further to form NO2
N2 + O2 2NO
NO + H2 O NO2 + H2
4-Phatochemical smog
is one of the primary causes of photochemical reaction of automobile exhaust and atmosphere air in the presence of sunlight
NO2 + Energy of sunlight NO + O + Smog
O + O2 O3 (ozone)
Ground level ozone is harmful to lung and biological tissue, also it's harm tress and harm full to tress & other vegetable plant.
4-Phatochemical smog
of sunlight NO + O + Smog
O + O2 O3 (is one of the primary causes of photochemical reaction of automobile exhaust and atmosphere air in the presence of sunlight
NO2 + Energy ozone)
Ground level ozone is harmful to lung and biological tissue, also it's harm tress and harm full to tress & other vegetable plant.
5- Sulfur oxides
Many fuel used in engine contain sulfure in it's exhaust which contribute in acid rain formation, at high temp, sulfur combines with hydrogen to form H2S and with oxygen to form SO2
H2 + S H2S
O2 + S SO2
Then 2SO2 + O2 2SO3
SO3 combine with water vapour in the atmosphere to form sulfuric acid (H2SO4)and sulfurous acid (H2SO4) and sulfurous acid (H2SO3 ) which are ingredients in acid rain
SO3 + H2O H2SO4
SO2 + H2O H2SO3
6-Lead and phosphorans:
Lead was a major gasoline additive (tetraethyl lead) was effectively used to increase the gasoline, octane number which allowed higher compression ratio and more efficient engine. However the resulting lead engine exhaust was highly poisonous pollutant, small amount of phosphorous are emitted also, these comes from impurities in the air and small amount found in some fuel blends and lubrication oil.
7-Solid particles
Particulates) (
Small solid particles and liquid droplets collectively called
(Particulates) are present in air in great number, and at times
constitute a serious pollution problem, particulates are some
times classified as viable (capable of living), or non viable.
Some examples of viable particulates are bacteria, fungi, and spores. Non viable particulates, include such substances as organic compounds, metals, dust, and sea salt. Particulate air pollution warrant serious attention for several reasons:
Many particulates affect respiratory system, more effectively than air pollutant.
Particulates increase atmospheric turbidity and reduce visibility.
Particulates are formed within the atmosphere from some gaseous pollutant.
Some particulates behave as synergistic and enhance the toxic effects of other pollutants.
Health Effects
The respiratory system
The major target of air pollutants is the respiratory system. Air and entrained pollutants enter the body through the throat and nasal cavities and pass to the lungs through the trachea and bronchia.
Entrained pollutant particles can be prevented from entering the lung by the action of ting hairs called (cilia) that sweep mucus out through the throat and nose.
The bronchial cilia can be paralyzed by inhaled smoke enhancing the synergistic effect between smoking and air pollution.
In the lungs, the air movies through bronchial tubes to the alveoli, small air sacka in which oxygen from the lungs is transferred to the blood.
Effect of Carbon Monoxide
The effect of CO inhalation on human health is directly proportional to the quantity of CO bound to hemoglobin.
Oxygen is transported in the blood as oxyhemoglubin (HbO2 ), it is semi stable compound in which O2 is weakly bound to Fe+2 in hemoglobin in red blood cells. The O2 is removed for cell respiration and the regenerated hemoglobin is available for more oxygen transport.
CO reduces the oxygen-carring capacity of the blood by combining with hemoglobin and forming carboxyhemoglubin (HbCO
Hemoglobin that is tied up as (HbCO) can be regenerated and is not available for oxygen transport for the life of that particular red blood cell.
In this way (CO) effectively poisens the hemoglobin oxygen transport system. Hemoglobin has a greater affinity for (CO) than for molecular oxygen
Effect of Sulfer Oxide
The cilia that protect the respiratory system by sweeping out particles are effected by gaseous air contamination.
The predominant effect on the cilia of smokers is paralysis from the constituents of tobacco smoke. Sulfur dioxide also affect ciliar behaviour.
Thus SO2 affects the protection mechanism of the respiratory tract in addition to contracting the bronchia.
Effect of NO
NO2 is a pulmonary irritant. High concentration of NO2 can produce pulmonary edema; an abnormally high accumulation of fluid in the lung tissue
Effect of Ozone
Ozone and photo chemical oxidants are highly irritating, oxidizing gases, concentration of few parts million can produce pulmonary congestion, edema, and pulmonary heamorrage.
A one hour exposure of human subject to 25g/m3 can decrease effective lung volume and decrease maxium breathing capacity.
Symptoms of ozone and oxidixant exposure are a dry throat followed by headache, disorientation and altered breathing patterns
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Edited by Mohammed J ALRawi