AIR QUALITY INDEX (Syllabus: GS Paper 3 – Env & Eco)

Context: A research study conducted released recently in July last year, highlighted that the air quality throughout the entire Indo-Gangetic Plains was favorable on Diwali night. This improvement was attributed not to the city's cracker ban but rather to the prevailing winds that effectively dispersed pollutants across the northern region of India.

Key Points of Study

• The PGIMER study found that PM2.5 and sulphur dioxide (SO2) were the major pollutants generated by firecrackers. There was no effect on the ozone level, contrary to earlier assumptions. 
• The rate of growth of PM2.5 and SO2 due to crackers dropped dramatically by 42% and 67% on Diwali night in 2020 compared with 2017-19 in the entire Indo-Gangetic Plain due to the windy conditions.
• According to study: The good air of recent days is largely because there have been more rainy days. The number of days with better air quality is always in proportion to rainy and windy days. 
• This means that the weather condition is the single most important factor in the pollution level

Air Quality Index

• Air Quality Assessment: AQI is a tool for assessing the safety of the air you breathe.
• Monitoring and Reporting: Organizations responsible for AQI reporting measure the concentration of 6 diverse air pollutants - Particulate matter (PM2. 5 and PM10), Ozone (O3), Carbon Monoxide (CO), Nitrogen Dioxide (NO2), Sulphur Dioxide (SO2), Lead (Pb) and Ammonia (NH3)  at various monitoring stations.
• National Air Quality Index (NAQI): The widely employed NAQI, issued by the Central Pollution Control Board, provides a 24-hour average.
• Unit of Measurement: AQI is measured in micrograms per cubic meter (µg/m³).