Air Quality Monitoring in India

Air Quality Monitoring in India

• Air quality monitoring is the process of measuring various pollutants in the atmosphere to assess pollution levels, identify sources, and support policy, research, and climate change mitigation efforts.
• Delhi’s air quality recently dipped to ‘very poor’ with heavy haze, highlighting urban air pollution concerns.

National Air Quality Monitoring Programme (NAMP)

• Implemented by the Central Pollution Control Board (CPCB).
• Comprises 800+ monitoring stations in 344 cities/towns across 28 States and 6 Union Territories.
• Key pollutants monitored: SO₂, NO₂, PM10, PM2.5.
• Also includes meteorological parameters: wind speed, wind direction, temperature, and humidity.
• Objectives:
  • Determine air quality status and trends.
  • Assess compliance with national standards.
  • Identify non-attainment cities.

National Ambient Air Quality Standards (NAAQS)

• Set by CPCB in 2009 under the Air (Prevention & Control of Pollution) Act, 1981.
• Specifies permissible concentration limits for 12 pollutants:
  • SO₂, NO₂, PM10, PM2.5, O₃, Pb, CO, NH₃, Benzene, Benzopyrene, Arsenic (As), Nickel (Ni).
• Different standards for general areas and ecologically sensitive areas.
• Example:
  • PM2.5 Annual: 40 µg/m³ (both area types)
  • NO₂ Annual: 40 µg/m³ (general), 30 µg/m³ (sensitive)

Air Quality Index (AQI)

• Launched in 2014 by CPCB with the principle “One Number – One Color – One Description”.
• Makes air quality data accessible and understandable to the public.
• Based on 8 pollutants:
  • PM10, PM2.5, NO₂, SO₂, CO, O₃, NH₃, Pb
• AQI has 6 categories:
  • Good (0–50), Satisfactory (51–100), Moderate (101–200), Poor (201–300), Very Poor (301–400), Severe (401–500)

System of Air Quality and Weather Forecasting and Research (SAFAR)

• Developed by Indian Institute of Tropical Meteorology (IITM), Pune under the Ministry of Earth Sciences.
• Provides location-specific, real-time AQI and forecasts for major metropolitan cities.
• Measures:
  • PM2.5, PM10, O₃, CO, NOx, SO₂, along with benzene, toluene, xylene, and mercury.
• Enhances public awareness and helps in planning health advisories.

Continuous Ambient Air Quality Monitoring System (CAAQMS)

• Installed by the Indian Army at Eastern Command HQ, Fort William, Kolkata.
• Offers real-time ambient air quality monitoring using automated stations.

2021 WHO Air Quality Guidelines (AQGs)

• Updated from 2005 to reflect new scientific evidence on health impacts at lower pollution levels.
• Revised recommended limits:
  • PM2.5 Annual: from 10 µg/m³ (2005) to 5 µg/m³ (2021)
  • PM10 Annual: from 20 µg/m³ to 15 µg/m³
  • NO₂ Annual: from 40 µg/m³ to 10 µg/m³
  • SO₂ 24-hour: increased from 20 µg/m³ to 40 µg/m³
  • CO 24-hour mean: set at 4 mg/m³
  • Introduced new standard for O₃ peak season: 60 µg/m³

WHO Ambient Air Quality Database

• Global database initiated in 2011, compiled by WHO using ground measurements.
• Includes annual mean concentrations of NO₂, PM10, and PM2.5.
• 6th update released in 2023.
• 5th update (2022) was the first to include ground measurements of NO₂, labeled as a common urban pollutant and precursor to PM and ozone.