Thursday, September 12, 2013

Pollutants

There are two classification of pollutants in our atmosphere; PRIMARY and SECONDARY POLLUTANTS.

Primary Pollutants
Combustion of Solid Waste

Primary pollutants are those pollutants that are emitted from pollution sources directly into the atmosphere. They usually retain their chemical characteristics and therefore, they have direct effects on the atmosphere. A good example of a primary pollutant is ash, which is formed during combustion of solid wastes and carbon monoxide which is emitted from a motor vehicle exhaust.
    
Carbon Monoxide Emitted by Cars
List of Primary Pollutants
  • Carbon monoxide (CO)
Created by incomplete combustion (especially bad with older cars
Generates headaches, drowsiness, fatigue, can result in death
Odorless, colorless, poisonous gas 
  • Oxides of nitrogen (NOx, NO) 
Emitted directly by autos, industry
NO - nitric oxide
  • Sulfur oxides (SOx) 
Responsible for acid rain problemProduced largely through coal burning
  • Volatile organic compounds (VOCs)
Highly reactive organic compounds
Release through incomplete combustion and industrial sources
 
  • Particulate matter (dust, ash, salt particles)
Bad for your lungs

Secondary Pollutants
 
Acid Rain Formation
On the other hand, secondary pollutant is not directly emitted as such, but forms when other pollutants (primary pollutants) react in the atmosphere.
Examples of a secondary pollutant include ozone, which is formed when hydrocarbons (HC) and nitrogen oxides (NOx) combine in the presence of sunlight; NO2, which is formed as NO combines with oxygen in the air; and acid rain, which is formed when sulfur dioxide or nitrogen oxides react with water.

List of Secondary Pollutants
  • Sulfuric acid (H2SO4)
    Ozone Formation
Can cause respiratory problems

  • Nitrogen dioxide (NO2)
Gives air a brownish coloration

  • Ozone (O3)
Colorless gas
Has a sweet smell
Is an oxidizing agent - lung tissue to rubber products
Irritates the eyes




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