How is Air Quality Measured?

Air Quality is measured using a metric called as Air Quality Index (AQI). AQI will display the changes in the air pollution in the atmosphere.  Clean air is extremely important to maintain good health and environment. Our atmosphere is predominantly made up of 2 important gases that is vital for life on earth, it is Oxygen and Nitrogen. AQI keeps a tab on 5 major air pollutants in the atmosphere namely,

  1. Airborne particles or aerosols.
  2. Sulfur Dioxide
  3. Carbon Monoxide
  4. Nitrogen Dioxide
  5. Ground level ozone

Aspirants would find this topic very helpful in the IAS Exam.

How is PM 2.5 Measured?

The most common measurement used to measure air quality is PM 2.5 and PM 10. It measures the particles in micrograms per cubic metre. PM 2.5 refers to the concentration of microscopic particles less than 2.5 microns in diameter and PM 10 refers to concentration of particles less than 10 microns in diameter. Across the globe all the countries use the same metrics for measuring he health of atmospheric air. India measures 2 additional pollutants namely lead and ammonia. AQI value less than 50 is considered safe.

What Instrument is used to Measure Air Quality?

Some of the instruments used are given below.

  1. PCE-RCM 05
  2. PCE-HFX 100
  3. PCE-RCM 8

How Does PM get into the air?

PM stands for Particulate Matter. It is term used to define mixture of solid particles and liquid droplets found in the  air. Some particles such as dust, smoke, soot is visible to the naked eye, but other particulate matter are too small that they are only visible in the electron microscope. Some of the sources of PM are construction sites, fire, fields, unpaved roads etc. Most of the particles are formed due to complex reactions of chemicals such as sulfur dioxide and nitrogen oxides. These are the pollutants emitted by automobiles, industries, power plants etc.


The above details would help candidates preparing for UPSC 2020.

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