Air Poluution

Topics: Air pollution, Ozone, Smog Pages: 6 (973 words) Published: May 2, 2013

“Environment and Health” B. Tech. III, 6th Semester

Bhaven N. Tandel Assistant Professor, Department of Civil Engineering, SV National Institute of Technology, Surat. (+91) 98255 53175


Importance of Air pollution
   

Air pollution is a major threat of the 21st century. Air pollution is woven throughout the fabric of modern life. Man has polluted air so much that clean air has become more than a luxury for him today. Every man must fight against air pollution on a war front, instead of wringing his hands in despair or joining the carping crowds demanding a halt to our technological advances.

Sources of air pollution

Mobile sources:
Motor vehicles, rail, shipping, aviation

Industry sources:
Power stations, petroleum refining, chemical manufacturing

Area based sources (point sources):
Service stations, combustion sources, lawn mowing

Classification of air pollutants:

Primary and secondary pollutants:

Primary pollutants are those which are emitted directly from identifiable sources. e.g. Particulates, SO2, NOx, CO Secondary pollutants are those which are formed in the air due to interaction of primary pollutants among themselves or by reaction with normal atmospheric constituents like sunlight, water vapour etc.

Why is Air Pollution an issue???

    

Involuntary exposure Affects large numbers of people No threshold effect The health costs are enormous Affects the health of flora and fauna Other health effects of air pollution: road trauma , physical activity 

 The particulates consist of fine solids or liquid droplets

suspended in air. These different types have definitive meanings, as follows: † † † †



† †

Grit – solid particles suspended in air with a diameter over 500 µm; Dust – solid particles suspended in air with a diameter between 0.25 and 500µm; Smoke – gas borne solids with particles usually less than 2µm in diameter. Fumes – suspended solids in air less than 1µm in diameter, normally released from chemical or metallurgical processes; Mist – liquid droplets suspended in air with a diameter of less than 2 µm; Aerosol – solid or liquid particles in suspension in air or some other gas, with a diameter of less than 1 µm.


Effects – environmental (i) Smoke and fumes can increase the atmospheric turbidity and reduce the amount of solar radiation reaching the ground. (ii) Mist, smoke and fog affects the erosion and corrosion of buildings, materials and metals, and also the plant life. (i) Reduced visibility (ii) Brown haze

Effects – human health (i) Inhalation causes irritation of lungs and over a period of time can cause fibrosis of the lung lining. (i) Increased rates of respiratory illnesses and symptoms. (ii) Decreased lung function. (iii) Excess mortality from heart and lung disease. (iv) Exaggeration of symptoms in asthma patients. (v) Causes well known occupational diseases such as pneumoconiosis (dust disease), silicosis (stone dust disease) and asbestosis.

 Exposure

to oxidants causes severe chest pain, headache, damage to red blood cells, loss of coordination and difficulty in articulation.  Oxidants means the following: † • •

† † †

Ozone Concentrations of ozone exceeding 200 µg/m3 will cause eye irritation. When the level of ozone in the ambient air is more than 0.7 ppm over a period of 20 to 90 minutes, coughing, chocking and severe fatigue will result. Nascent oxygen ‘O’ Peroxy Acetyl Nitrate (PAN) Peroxy Propynol Nitrate (PPN) Peroxy Butyl Nitrate (PBN) Hydrogen Peroxide (H2O2) Nitrogen Dioxide (NO2)

Environmental & human health effects of major air pollutants Pollutant

Effects – environmental

Effects – human health
(i) Irritation of eyes, throats and lungs, and retarded mental capacity. (ii) Decreased lung function and...
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