Air Quality Index [AQI]

Air Quality Index [AQI]

What is the Air Quality Index (AQI)?

  • AQI is a number used to communicate to the public how polluted the air currently is or how polluted it is forecasted to become.
  • As AQI increases, an increasingly large percentage of the population is likely to experience increasingly adverse health effects.
  • Different countries have their own air quality indexes, corresponding to different national air quality standards.
  • The AQI is most commonly used to describe ground-level ozone levels. 
  • However, the AQI can be used to represent five pollutants that pose a threat to human health. 

These pollutants are:

  1. Ground-level Ozone or O3
  2. Particulate Matter (soot and dust) or PM
  3. Carbon Monoxide or CO
  4. Sulphur Dioxide or SO2 and
  5. Nitrogen Dioxide or NO2

How it is calculated?

  • The pollutants in the affected air are given a weight based on a formula. It has been developed by the CPCB in consultation with IIT-Kanpur.
  • That weight depends on the kind of impact it has on human health, each of the pollutants is given a weight.
  • The worst of these weights is given as a composite air quality.
  • So instead of giving six different numbers, six different colors, it throws up one single color, one single number.
  • The index will throw up one number which will be given to the public.
  • People will know the health of their air quality based on this number and one associated color code

What are NAAQ standards?

  • The mandate provided to the Central Pollution Control Board (CPCB) under the Air (Prevention and Control of Pollution) Act empowers it to set standards for the quality of air.
  • Hence the current National Ambient Air Quality Standards were notified in November 2009 by the CPCB.
  • Prior to this, India had set Air Quality standards in 1994, and this was later revised in 1998.
  • The 2009 standards further lowered the maximum permissible limits for pollutants and made the standards uniform across the nation.
  • Earlier, less stringent standards were prescribed for industrial zones as compared to residential areas.

What are the Initiatives Taken for Controlling Air Pollution?

  • System of Air Quality and Weather Forecasting and Research (SAFAR) Portal.
  • Air Quality Index: AQI has been developed for eight pollutants viz. PM2.5, PM10, Ammonia, Lead, nitrogen oxides, sulphur dioxide, ozone, and carbon monoxide.
  • Graded Response Action Plan (for Delhi).
  • For Reducing Vehicular Pollution:
    • BS-VI Vehicles,
    • Push for Electric Vehicles (EVs),
    • Odd-Even Policy as an emergency measure (for Delhi).
  • New Commission for Air Quality Management
  • Subsidy to farmers for buying Turbo Happy Seeder (THS) Machine for reducing stubble burning.
  • National Air Quality Monitoring Programme (NAMP): Under NAMP, four air pollutants viz. SO2, NO2, PM10, and PM2.5 have been identified for regular monitoring at all locations.

Related Links:

National Clean Air ProgrammeNamami Gange Project
National Tiger Conservation AuthorityWater Act 1974