Air Quality Index

What is air quality index?

The Air Quality Index is acquired by measuring emissions of eight major pollutants present in the air: Particulate matter (PM2.5 and PM10), Ozone (O3), Carbon Monoxide (CO), Nitrogen Dioxide (NO2), Sulphur Dioxide (SO2), Lead (Pb) and Ammonia (NH3) emissions. Readings are noted every hour. Each country has their air quality indexes based on its air quality standards.

Air Quality Index India

The government agencies are responsible for communicating to the public about the health hazards and how to keep a check on them. Under the Swachh Bharat Abhiyan, the National Air Quality Index was launched in September 2014 in New Delhi to measure India’s air quality index.

The Central Pollution Control Board (CPCB) has formed an expert group of medical professionals, air quality experts, academia, advocacy groups, and SPCBs. Also, a technical study was awarded to IIT Kanpur. In 2014, the IIT Kanpur and the expert group recommended an AQI scheme for India.

Six cities of India- New Delhi, Kolkata, Mumbai, Pune, and Ahmedabad have a continuous monitoring system that records data in real-time.

Instrument to Measure Air Quality

Few instruments that are used for measuring air quality are:

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

Calculation of AQI

The computation of the AQI is based on the average air pollutant concentration over a specified period, which is obtained from an air monitor or model.

The AQI increases because of an increase in the emission of air pollutants; for example, during heavy traffic or forest fire, a high value of AQI is observed. In addition, due to anticyclone or temperature inversion, Stagnant air leads to high concentrations of pollutants in the air. This results in chemical reactions between air pollutants and hazy conditions, thus increasing the AQI.

Particulate Matter or PM: A substantial pollutant

PM 2.5 and PM 10 is the most common method of measuring air quality. It measures the particles in micrograms per cubic metre. As a UPSC 2023 aspirant, you must know about Particulate Matter or PM. It is a mixture of solid particles and liquid droplets present in the air. While some particles such as dust, smoke and soot are visible through naked eyes, numerous others are visible only through an electron microscope. Pollutants emitted by power plants, industries, automobiles, etc., form complex chemical reactions in the air, thus producing particulate matter.

Categories of Air Quality Index

The National Air Quality Index has set up six AQI categories: Good, Satisfactory, Moderately polluted, Poor, Very Poor, and Severe. Each category specifies health impacts associated with it as mentioned below given table:

Under the current affairs quiz, you will come across questions related to the air quality index of India and measures taken to manage the value to a safer level or how to protect our health from the adverse effects of air pollution.

Graded Response Action Plan (GRAP)is a set of emergency anti-air pollution measures that kick in when air quality deteriorates to certain threshold in the Delhi-NCR region which was notified in 2017.

Graded Response Action Plan (GRAP)

With the National Capital Region’s (NCR) Air Quality Index (AQI) deteriorating to the ‘severe’ category, the Commission for Air Quality Management invoked measures under Stage 4 of the Graded Response Action Plan (GRAP) with immediate effect.

Commission for Air Quality Management (CAQM) is a statutory body responsible for formulating strategies to combat pollution in the region.

• GRAP is a set of emergency measures to be taken to reduce air pollution.
• Formation - The Supreme Court mandated Environment Pollution (Prevention and Control) Authority (EPCA) formulated and notified the plan in 2017 after SC approval in 2016.
• Activation of GRAP – GRAP does not include yearlong measures and only incremental actions which gets activated on the basis of values of AQI.

• Imposition of measures – Before imposing measures, EPCA holds a meeting with representatives from all NCR states.

The BS-VI fuel was estimated to bring around an 80% reduction of sulphur, from 50 parts per million to 10 ppm.

• Coordination - GRAP creates a step-by-step plan for the entire Delhi-NCR region and getting on board 13 different agencies of NCR regions (Delhi, Uttar Pradesh, Haryana and Rajasthan).

3 major policy decisions of EPCA and GRAP are the closure of the thermal power plant at Badarpur, bringing BS-VI fuel to Delhi before the deadline set initially, and the ban on Pet coke as a fuel in Delhi NCR.