In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index? 1. Carbon dioxide 2. Carbon monoxide 3. Nitrogen dioxide 4. Sulfur dioxide 5. Methane Select the correct answer using the code given below.
Contents7
- A1, 2 and 3 only
- B2, 3 and 4 only
- C1, 4 and 5 only
- D1, 2, 3, 4 and 5
Show answer
Answer: (B) 2, 3 and 4 only
Answer: (b) 2, 3 and 4 only
India's National Air Quality Index (AQI) considers 8 pollutants:
- PM10
- PM2.5
- NO2
- SO2
- CO
- O3
- NH3
- Pb (Lead)
Now checking the question's options:
- Carbon dioxide (CO2) - NOT included (CO2 is a greenhouse gas, not tracked in AQI)
- Carbon monoxide (CO) - INCLUDED
- Nitrogen dioxide (NO2) - INCLUDED
- Sulphur dioxide (SO2) - INCLUDED
- Methane (CH4) - NOT included (methane is a greenhouse gas, not in AQI)
Common confusion: Students mix up greenhouse gases (CO2, methane) with air quality pollutants (CO, NO2, SO2). AQI measures pollutants that directly harm health when breathed in. CO2 and methane affect climate but are not directly toxic at normal levels.
Memory trick: AQI's 8 pollutants = PM10, PM2.5, NO2, SO2, CO, O3, NH3, Pb.
India's Air Quality Index measures 8 pollutants that directly harm human health when breathed in: PM10, PM2.5, NO2, SO2, CO, O3, NH3, and Lead.
The main trap is confusing greenhouse gases (CO2, methane) with air quality pollutants - CO2 and methane affect climate but are not directly toxic at normal atmospheric levels.
Air Quality Index (AQI)
Environment Air Quality Index
Air Quality Index (AQI): Parameters & UPSC Traps
India's AQI measures 8 pollutants: PM10, PM2.5, NO₂, SO₂, CO, O₃, NH₃, Pb
AQI scale: 0-50 Good, 51-100 Satisfactory, 101-200 Moderate, 201-300 Poor, 301-400 Very Poor, 401-500 Severe
Launched by Ministry of Environment in 2014
Real-time monitoring through CPCB and State Pollution Control Boards
India's National Air Quality Index measures air pollution to inform public health decisions. It tracks pollutants that directly harm human health when inhaled, not greenhouse gases that affect climate.
AQI Parameters
Pollutant | Full Name | Source | Health Impact |
|---|---|---|---|
PM10 | Particulate Matter (10 μm) | Dust, construction, vehicles | Respiratory problems |
PM2.5 | Fine Particles (2.5 μm) | Combustion, industrial | Deep lung penetration |
NO₂ | Nitrogen Dioxide | Vehicle emissions, power plants | Lung inflammation |
SO₂ | Sulphur Dioxide | Coal burning, industries | Respiratory irritation |
CO | Carbon Monoxide | Incomplete combustion | Reduces oxygen in blood |
O₃ | Ground-level Ozone | Photochemical reactions | Lung damage |
NH₃ | Ammonia | Agriculture, waste | Eye and throat irritation |
Pb | Lead | Industries, old paints | Nervous system damage |
This question tests CO, NO₂, SO₂ from the AQI list. The trap lies in including CO₂ and methane - these are greenhouse gases for climate change, not air quality pollutants for immediate health.
CO₂ vs CO: Carbon dioxide is greenhouse gas (climate), carbon monoxide is toxic pollutant (AQI)
Methane is greenhouse gas - not tracked in AQI despite being air pollutant
AQI measures health impact, not climate impact - don't mix the two
Ground-level ozone (bad) vs stratospheric ozone (good) - only ground-level in AQI
Greenhouse Gases vs Air Pollutants
Environment Carbon dioxide Carbon monoxide Methane
Greenhouse Gases vs Air Pollutants: Key Distinctions
Greenhouse gases: CO₂, CH₄, N₂O, CFCs - cause climate change
Air pollutants: PM, NO₂, SO₂, CO - cause immediate health problems
CO₂ safe to breathe at normal levels but traps heat
CO toxic to breathe but doesn't cause global warming
UPSC frequently tests the distinction between gases that harm climate versus gases that harm health. The same chemical can sometimes do both, but monitoring systems track them differently.
Gas Classification
Gas | Type | Health Effect | Climate Effect | Monitored By |
|---|---|---|---|---|
CO₂ | Greenhouse Gas | Safe at normal levels | Major global warming | Climate monitoring |
CH₄ | Greenhouse Gas | Safe at normal levels | 28x stronger than CO₂ | Climate monitoring |
CO | Air Pollutant | Toxic, reduces oxygen | Minimal climate impact | AQI monitoring |
NO₂ | Both | Lung inflammation | Minor greenhouse effect | AQI monitoring |
SO₂ | Air Pollutant | Respiratory problems | Cooling effect (aerosols) | AQI monitoring |
O₃ | Both | Lung damage (ground) | Greenhouse gas (upper) | AQI + Climate monitoring |
CO₂ is most important greenhouse gas but NOT in AQI - safe to breathe normally
Methane 28x more potent than CO₂ for warming but not health pollutant
Ozone good in stratosphere (UV protection) but bad at ground level (health)
Some gases like NO₂ affect both health and climate - context determines monitoring
Air Pollution Monitoring in India
Environment
Air Pollution Monitoring Framework in India
CPCB (Central Pollution Control Board) coordinates national air quality monitoring
NAMP (National Air Monitoring Programme) covers 280+ cities
Real-time data through CAAQMS (Continuous Ambient Air Quality Monitoring Stations)
State Pollution Control Boards implement at state level
Monitoring Structure
# Air Quality Monitoring
## Central Level
- CPCB
- Ministry of Environment
- NAMP coordination
- Standards setting
## State Level
- State PCBs
- Regional monitoring
- Local implementation
- Data collection
## Technology
- CAAQMS stations
- Manual monitoring
- Satellite data
- Mobile monitoring
## Public Interface
- AQI mobile app
- Daily bulletins
- Health advisories
- Emergency alertsIndia's air quality monitoring evolved from basic manual sampling to real-time digital networks. CAAQMS stations provide hourly data, while traditional methods still supplement in smaller cities.
Recent Developments
National Clean Air Programme (NCAP) targets 20-30% pollution reduction by 2024
Graded Response Action Plan triggers emergency measures in NCR during severe pollution
BS-VI emission norms implemented nationwide from April 2020
Integration with SAFAR (System of Air Quality and Weather Forecasting) for predictions