Nitrogen oxides (NOx) emissions are now a major environmental and safety issue in India, particularly from diesel generator (DG) sets used in commercial buildings, industries, hospitals, and infrastructure projects. Due to increased NOx emissions, the Central Pollution Control Board (CPCB) has enforced stricter emission standards, and DG set owners must be aware of their NOx emissions and develop compliant NOx management solutions. This guide provides information on NOx, including its hazards, CPCB norms, DG set pollution challenges, and how modern NOx control equipment, such as RECD, helps achieve compliance.

1. What is NOx?

The scientific term NOx refers to nitrogen oxides, which include Nitric Oxide (NO) and Nitrogen Dioxide (NO2). These gases form when oxygen and nitrogen in the atmosphere react at high temperatures during combustion.

In simple terms, NOx is a harmful gas produced by the combustion of diesel fuel within engines, particularly in DG sets. Because diesel generators operate at extremely high pressures and temperatures, they are among the primary sources of NOx emissions in industrial and urban areas.

2. Why is NOx Dangerous?

NOx emissions pose a serious risk to both human health and the environment.

Health Hazards:

  • Can cause respiratory issues such as asthma and asthmatic bronchitis
  • Decreases the amount of oxygen absorbed
  • Increases the risk of developing lung and heart diseases
  • Particularly dangerous for older people and children

Environmental Impact:

  • Contributes to the formation of smog and poor air quality
  • Produces acid rain that damages soil, water bodies, and vegetation
  • Plays a significant role in the formation of ground-level ozone
  • Accelerates damage to the ecosystem and climate

Due to these risks, NOx emissions are now highly regulated across India.

3. CPCB Norms Explained

The Central Pollution Control Board (CPCB) has introduced strict emission standards for diesel engines, in accordance with CPCB-II and CPCB-IV+.

Key CPCB Requirements:

  • Strict limits for NOx, CO, PM, and HC
  • Compliance is mandatory for new DG sets
  • Existing DG sets must be retrofitted with emission control devices
  • Regular emissions testing and certification are required

For DG sets exceeding specific capacities, NOx conformity is mandatory. Non-compliance can result in:

  • Severe penalties
  • Shutdown notices for DG sets
  • Legal action by pollution control authorities

4. DG Set Pollution Problem in India

India relies heavily on diesel generators due to:

  • Power outages
  • Remote infrastructure projects
  • Need for industrial backup power

However, DG sets are stationary sources of pollution often found in densely populated areas. The main pollution issues are:

  • Extremely high NOx levels for every hour of operation
  • Continuous use during peak demand
  • Older DG sets without emissions controls
  • Limited space for large after-treatment systems

As a result, DG sets significantly contribute to urban air pollution, making NOx control essential.

5. RECD Explained (Retrofit Emission Control Device)

The RECD (Retrofit Emission Control Device) is an advanced pollution control system that can be fitted to existing diesel generators to reduce harmful emissions without altering the engine.

Key Benefits of RECD:

  1. Effectively reduces NOx emissions
  2. Retrofit solution for both old and new DG sets
  3. No engine modification required
  4. CPCB-approved technology
  5. Suitable for space-constrained installations

RECD are essential for DG set owners who want to ensure compliance without replacing their existing equipment.

6. How NOx Control Devices Work

NOx control devices clean exhaust gases before they are released into the atmosphere.

Working Principle:

  1. Exhaust gases exit the DG engine
  2. Gases pass through the NOx control system
  3. Catalytic or chemical reactions convert NOx into harmless nitrogen and water vapor
  4. Clean exhaust is released into the air

Depending on the technology used, NOx control devices may feature:

  1. Catalytic reactions
  2. Temperature optimization
  3. Advanced exhaust treatment mechanisms

Modern RECD-based NOx monitoring devices are designed to ensure high efficiency, low backpressure, and stable DG performance.

7. Why Our NOx Control Solution Is CPCB Compliant

Our NOx control system is specifically designed to comply with Indian CPCB standards for DG sets.

Compliance Advantages:

  • Validated and tested to meet CPCB emission limits
  • Designed to fulfill CPCB-IV+ requirements
  • Does not affect DG performance
  • Ideal for commercial, industrial, and infrastructure DG sets
  • Documentation and emission testing support provided

By installing a CPCB-compliant NOx control RECD, DG set owners can:

  • avoid penalties and shutdowns.
  • Improve environmental responsibility
  • Expand DG set usability
  • Ensure compliance with long-term regulatory requirements

Conclusion

NOx emissions are a significant environmental problem, and DG sets are among the largest contributors in India. With the CPCB setting strict emission norms, an effective NOx control system for DG sets is essential. RECD-based NOx controls provide an efficient, reliable, and cost-effective solution to reduce emissions without replacing existing generators. Investing in a CPCB-approved NOx control device ensures legal compliance and supports cleaner air and a healthier future.