Air Pollution and Pollutants YouTube Lecture Handouts (Environment and Ecology) Part 1

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Air Pollution, Pollutants and Control (Environment - Pollution)

LET՚s BEGIN! !

  • Pollution – Undesirable material in environment
  • Pollutant – Physical, chemical and biological substance released in atmosphere

Air Pollutants

Particulate Matter

  • Particles which are more than 10 in diameter settle down.
  • Particles less than 0.02 form persistent aerosols
  • Fly Ash - from coal burning – cause heavy metal pollution – used for brick and landfills
  • TEL – Tetraethyl Lead – anti-knocking in petrol to raise octane for smooth running of engines – lead is harmful to kidney and liver & interfere with RBC - create physiological, biochemical and developmental disorders in plants & reproductive failure in plants

Gaseous Pollutants

Illustration: Gaseous Pollutants

Indoor Air Pollution

  • VOCs – Paints, carpets, furniture
  • Hazardous gas – fumigant, disinfectants
  • Hospitals – occupational health hazards and spores
  • Slums – firewood and biomass with smoke

Prevention

  • Smokeless chullas
  • Biogas
  • CNG
  • Baval (Acacia nilotica) which are least smoky
  • Charcoal is cleaner fuel
  • Segregation of waste
  • Pretreatment at source
  • Sterilization of rooms

Prevention & Control

  • Clean fuel like LNG
  • Minimize hazardous waste
  • Increase height of chimneys
  • Close industries which pollute
  • Industries away from cities
  • Develop and maintain green belt
  • Emission standards for vehicles – Euro standards
  • Filters – Filters remove particulate matter from the gas stream. Baghouse filtration system is the most common one and is made of cotton or synthetic fibres (for low temperatures) or glass cloth fabrics (for higher temperature up to ) .
  • Electrostatic precipitators (ESP) - The emanating dust is charged with ions and the ionized particulate matter is collected on an oppositely charged surface. These are used in boilers, furnaces etc.
  • Inertial collectors – It works on the principle that inertia of SPM in a gas is higher than its solvent & this device collects heavier particles more efficiently. β€˜Cyclone’ is a common inertial collector used in gas cleaning plants.
  • Scrubbers – Scrubbers are wet collectors. They remove aerosols from a stream of gas either by collecting wet particles on a surface followed by their removal

✍ Manishika