Particulate Matter

  • Particulate matter (PM particles as popularly known) are complex mixtures of organic and inorganic substances.
  • Particulate air pollution is a mixture of solid and liquid particles suspended in the air. These suspended particles vary in size, composition and origin.
  • These vary in size from few nanometers to tens of micrometer.
    1. PM10 : inhalable particles, with diameters that are generally 10 micrometers and smaller.
    2. PM2.5 : fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller.


Sources of Particulate Pollution

Industrial: brickworks, refineries, cement works, iron and steel making, quarrying, and fossil fuel power plants.

Natural Sources: bushfires, dust storms, pollens and sea spray.

Transport: direct emissions from the burning of fuels (especially diesel powered vehicles) or from wear of tyres or vehicle-generated air turbulence on roadways.

Consumer goods: for e.g. talc and other such products.

Health Effects

As the particle size decreases, magnitude of adverse health effects increases.

Exposure to such particles affect both lungs and heart. Numerous scientific studies have linked particle pollution exposure to a variety of problems, including:

    • premature death in people with heart or lung disease
    • nonfatal heart attacks
    • irregular heartbeat
    • aggravated asthma
    • decreased lung function
    • increased respiratory symptoms, such as irritation of the airways, coughing or difficulty in breathing.

Environmental Effects

These are quite harmful for environment as well.

    • Reduces visibility
    • Particulate matter (PM) can stain and damage stone and other materials, including culturally important objects such as statues and monuments.
    • Further causes harm to environment for e.g. acidification of lakes, affecting diversity of ecosystem, damaging crops and nutrient balance of soil etc.


A general trend has been observed that the Air quality index of Delhi is Moderate (101-200)  during  the months of January to September, and after that it drastically deteriorates to Very Poor (301-400) or Severe (401-500) and to even Hazardous (500+) levels in three months between October to December. During these months’ levels of PM 2.5 and PM 10 particulate matter go up to 999 micrograms per cubic meter, while the safe limits for those pollutants are 60 and 100 respectively. One of the major cause is meteorological conditions that trap the pollutants over the surface of Delhi.

Causes of low AQI in Delhi


Figure 1: Sources of PM 2.5 emission in Delhi

Other Important factors that release Particulate matter

    • Badarpur Power Plant
    • Bhalaswa landfill site
    • Stubble Burning
    • Heavy metal rich fire crackers

Necessary DO’s to reduce PM pollution

    • BS VI norms should be implemented strictly, promote policies like Odd-Even to reduce Vehicular pollution.
    • Alternative to stubble burnings like ‘Happy Seeders’ and other techniques should be made available to all the farmers and made cost effective.
    • CPCB and EPCA should make effective guidelines for government to tackle the problem of pollution.
    • Guidelines by Supreme court and government should be followed strictly.
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