Why Air Quality Monitoring Matters

Air pollution is one of the most pressing environmental challenges facing Maharashtra's rapidly urbanising and industrialising landscape. The Maharashtra Pollution Control Board (MPCB) operates an extensive network of monitoring stations to track ambient air quality — the quality of the outdoor air we breathe — across the state's cities, industrial clusters, and sensitive zones.

Effective monitoring helps policymakers take corrective action, enables industries to assess their impact, and keeps the public informed about the air they breathe.

National Ambient Air Quality Standards (NAAQS)

India's National Ambient Air Quality Standards (NAAQS), notified by the Central Pollution Control Board (CPCB) under the Environment (Protection) Act, 1986, set the permissible concentration limits for key air pollutants. MPCB enforces these standards across Maharashtra.

Pollutant Averaging Period Standard (µg/m³)
Particulate Matter (PM10) 24-Hour 100
Particulate Matter (PM2.5) 24-Hour 60
Sulphur Dioxide (SO₂) 24-Hour 80
Nitrogen Dioxide (NO₂) 24-Hour 80
Carbon Monoxide (CO) 8-Hour 2,000
Ozone (O₃) 8-Hour 100

MPCB's Air Quality Monitoring Network

MPCB maintains a combination of Continuous Ambient Air Quality Monitoring Stations (CAAQMS) and manual monitoring stations across major cities and industrial areas. Key locations include Mumbai, Pune, Nagpur, Nashik, Aurangabad, and industrial zones such as Tarapur, Taloja, and Ambernath.

Continuous (Automatic) Monitoring Stations

CAAQMS use real-time sensor-based instruments to measure PM2.5, PM10, SO₂, NO₂, CO, and O₃ on a 24/7 basis. Data is transmitted automatically to a central server and is often made available publicly through dashboards.

Manual Monitoring Stations

These use standardised sampling and laboratory analysis methods. While less real-time, they are used to validate CAAQMS data and to monitor additional parameters such as heavy metals in particulate matter.

Key Pollutants Monitored and Their Sources

  • PM2.5 and PM10: Generated by vehicles, construction, industrial combustion, and road dust. PM2.5 is the more dangerous as it penetrates deep into the lungs.
  • SO₂: Primarily from thermal power plants, refineries, and industries burning sulphur-containing fuels.
  • NO₂: Emitted by vehicular exhaust and high-temperature combustion processes.
  • CO: Produced by incomplete combustion in vehicles and industries.
  • Ozone (O₃): A secondary pollutant formed by chemical reactions between NO₂ and hydrocarbons in sunlight.

The Air Quality Index (AQI)

MPCB and CPCB use the Air Quality Index (AQI) — a standardised scale from 0 to 500 — to communicate air quality conditions to the public in an easy-to-understand format.

  • 0–50: Good
  • 51–100: Satisfactory
  • 101–200: Moderate
  • 201–300: Poor
  • 301–400: Very Poor
  • 401–500: Severe

MPCB's Enforcement Role

When monitoring data reveals persistent exceedances of NAAQS, MPCB can issue notices to industries operating in the area, mandate stack emission testing, and direct units to upgrade their air pollution control systems. Industries are also required to conduct self-monitoring of stack emissions and submit reports to MPCB periodically.

How Industries Can Stay Compliant

  • Install and maintain approved air pollution control equipment (bag filters, scrubbers, ESPs)
  • Conduct regular stack emission monitoring through MPCB-approved laboratories
  • Submit emission data in annual environmental statements
  • Display stack emission data at the factory gate if required by consent conditions