Air Pollution: Urgent of Cause of Concern

Imhealthist | Sunday 15th of November 2015 10:16:03 AM

Introduction of any form of gaseous substances, dust, fumes and other particles in the atmosphere that leads to contamination and which can be a health hazard is air pollution. As per the statistical data of WHO, 1 out of 8 deaths occur due to air pollution. Air pollution can be broadly classified as indoor or household pollution and outdoor or ambience pollution.

Indoor Air Pollution:

As the name suggests, it happens when chemicals which are present in the air, degrade the quality of air indoors. Indoor air pollution is ten times more harmful than outdoor air pollution and hence causes more death. This is because, the pollutants remain suspended in a closed environment and does not easily get diluted by spreading. Indoor air pollution is mainly caused by

  • Burning of solid fuels like coal, wood and cow dung.
  • Dust mites, molds  and pollens
  • Smoking and usage of pesticides
  • Heating appliances and also from building materials 

According to WHO data, more than 4 million people prematurely die from illness because of cooking with solid fuels. The data further says that over 50% of deaths which happens prematurely among children under 5 are due to indoor air pollution.

Outdoor Air Pollution:

            Outdoor air pollution occurs when any toxic substances, chemical or biological, contaminates the ambient outdoor air. A common example of outdoor air pollution is smog which is nothing but a combination of smoke and fog.

Outdoor Air Pollution Is Mainly Caused By:

  • Emission of smoke from vehicles
  • Smoke from industries
  • Toxic fumes from solvents
  • Forest fires
  • Burning of fossil fuels
  • Volcanic eruptions
  • Decaying of plants and animals
  • Chemical used in farming such as fertilizers, pesticides etc.

WHO says 3.7 million deaths occurs due to outdoor air pollution globally. 88% of these deaths occur in low and middle income countries which contributes 82% of world population.


Pollutants are the agent which causes pollution and can be either or combination of gaseous pollutants, odor and Suspended Particulate Matters (SPM). Pollutants are generally categorized into primary pollutants and secondary pollutants. While the former is emitted directly into atmosphere and the latter is the resultant product when primary pollutants reacts with environment.

Examples of Primary Pollutants and Their Sources Are:

  • Carbon Monoxide (CO) : volcanic activity; Combustion of coal, oil and gas
  • Oxides of Nitrogen (NOx): Fuel combustion and wood burning; Industrial boilers; Agriculture soil because of fertilizers and also from livestock manure                                                                                                         
  • Oxides of Sulphur (SOx): Thermal Power Plants.
  • Toxic metals like lead, mercury , arsenic
  • Volatile organic compounds((VOC):  Methane, Propane
  • SPM : Ash, dust, pollen, cigarette smoke 

Secondary Pollutants:

When primary pollutants react with other elements in atmosphere and causes a chemical reaction then it is secondary pollutant.

Sulphuric acid H2SO4

Ozone which is at ground level is formed from the reaction of nitrogen oxides and VOCs                                    

Health Hazards:

Air pollution poses severe health risks in the lives of human being. Some of them are Asthma, nausea, headache. Bronchitis, throat irritation and cough, skin and eye rashes and it is also a source for major illness like cancer, birth defects, Miscarriages , damage in nervous system, cardiovascular disease, stroke.

Environmental Threats:

Toxic chemicals and gases causes acid rain which damages natural resources. Over use of fertilizers causes deposition of nitrogen. Crop production may be reduced and also it is a serious threat to animals too.