Air Pollutants: Sources and Effects

Below is an overview of air pollutants based on our other article about pollutants.

Though effects of pollutants present in the air on humans are well known, they are less known in respect of other higher forms of animals. But we assumed that in some cases these effects may be similar between humans and other animals, and that is why we have provisionally put these two groups together.

Name
Form & Properties
Sources
Health & Other Effects
Other Notes
Sulfur Dioxide (SO2) Colorless gas with a sharp, suffocating odor Anthropogenic:

  • Power plants (main source – more than half of all emissions)
  • Production processes
  • Combustion for industry use
  • Fossil fuels – extraction & distribution
  • Petroleum refining
  • Road transport

Natural:

  • Marine phytoplankton
  • Decay processes in soil & vegetation
  • Volcanoes
 Human & Animal Health:

  • Irritates eyes, nose, throat
  • Damages lungs when inhaled

Environment: As part of acid rain:

  • Acidifies lakes and streams
  • Destroys plant and fish life in lakes and streams
  • May deplete mineral nutrients in the soil
  • May cause reduction of forest and agricultural yields
  • Corrodes metals
  • Damages surfaces of buildings
 Formed as a result of fossil fuel combustion

Nitrogen Oxides:

Nitric oxide (NO) and Nitrogen dioxide (NO2)

 NO is a colorless gas;

NO2 is a gas of reddish-brown color with a distinct sharp, biting odor

 Anthropogenic:

  • Road transport (main source – nearly half of all emissions)
  • Power plants
  • Production processes
  • Combustion for industry use
  • Fossil fuels – extraction & distribution
  • Petroleum refining

Natural:

  • NO is also emitted soils

For NO2:

Human & Animal Health:

  • Causes pulmonary edema (accumulation of excessive fluid in the lungs)

Environment:

As part of acid rain:

  • Acidifies lakes and streams
  • Destroys plant and fish life in lakes and streams
  • May deplete mineral nutrients in the soil
  • May cause reduction of forest and agricultural yields
  • Corrodes metals
  • Damages surfaces of buildings

Also:

  • Contributes to photochemical smog
 Formed as a result of fossil fuel combustion

Ammonia (NH3 and NH4)

 Colorless, pungent, hazardous caustic gas Agriculture is the biggest source of ammonia emissions, with the following breakdown:

  • Livestock (main source – more than half of all emissions)
  • Fertilizer application
  • Oceans
  • Vegetation
  • Biomass burning
 Human & Animal Health:

  • Lung damage and death

Carbon Monoxide (CO)

 Colorless, odorless, highly toxic gas Anthropogenic:

  • Road transport
  • Industry
 Human & Animal Health:

  • Intoxication of the central nervous system and heart
  • Severe effects on the baby of a pregnant woman
  • Headaches and dizziness
  • Problems with getting oxygen supplied to some body parts which may be life-threatening
 This air pollutant is formed as a result of incomplete fossil fuel combustion

Volatile Organic Compounds (VOCs)

 Organic compounds which easily evaporate. They include:

  • pure hydrocarbons
  • partially oxidized hydrocarbons
  • organic compounds containing chlorine, sulfur, or nitrogen
 Anthropogenic:

  • Solvent Use (paints, adhesives, aerosols, metal cleaning and printing)
  • Road transport
  • Production processes
  • Extraction and distribution of fossil fuels

Natural:

  • Forests (tropical forests produce about half of global natural non-methane VOC emissions)
 Human & Animal Health:

  • Cancer (specifically leukaemia)
  • “Sick building syndrome” indoors

Also as part of ozone:

  • Respiratory problems

Environment: As part of ozone:

  • Damage to crops and buildings
 These air pollutants take part in the formation of ozone and, therefore, photochemical smog

Ozone (O3)

 Colorless, poisonous gas with a sharp, cold, irritating odor; Ozone is not emitted directly into the atmosphere by sources.

It is a secondary pollutant, i.e. it is formed during the reaction between nitrogen dioxide and hydrocarbons (primary pollutants) in the presence of sunlight

 Human & Animal Health:

  • Irritation of the respiratory system causing coughing, throat irritation and an uncomfortable sensation in the chest
  • Susceptibility to respiratory infections
  • Compromised lung function harming the breathing process
  • Inflammation and damage to the lining of the lungs
  • Aggravation of asthma

Environment:

  • Reduction in agricultural yields
  • Interference with photosynthesis and suppression of growth of some plant species

Also:

  • Main component of photochemical smog
 Considered an air pollutant in the lower layer of the atmosphere (troposphere), but beneficial in blocking ultraviolet sun rays in the upper atmosphere

Persistent Organic Pollutants (POPs)

 Compounds which are resistant to degradation and persistent in the environment Anthropogenic:

  • Use of pesticides
  • Industrial processes
  • Production of goods such as solvents, polyvinyl chloride and medicines
 Human & Animal Health:

  • Death and illness including disruption of endocrine, reproductive and immune systems
  • Neurobehavioral disorders
  • Cancers
 Exposure to persistent organic pollutants takes place through diet (specifically, consumption of animal fats), environmental exposure or accidents

Airborne Particles

 Tiny fragments of solid or liquid nature suspended in the air Anthropogenic:

  • Road transport
  • Power generating plants
  • Production processes (such as dust blown away by winds from construction sites)

Natural:

  • Erosion of soil by wind which generates dust particles
  • Evaporation of droplets of sea water resulting in sea salt crystals being suspended in the air
  • Volcanoes
  • Forest fires
  • Living vegetation
 Human & Animal Health:

  • Asthma
  • Lung cancer
  • Cardiovascular problems
 Most dangerous particulates are the ones less than 10 µm (micrometres) in diameter as they can be easily inhaled and trapped in the system
Also Check Out →  Air Pollution Causes