What are the SO2 and NOx Standards for Foundry Industry (Furnaces Based on Fuel)?
Foundry construction and metal casting play an important role but are also a major source of air productions. Combustion processes in Foundry furnaces release large amounts of SO2 and NOx.
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With the rapid growth of industrial activities in urban and peri-urban areas, air pollution has become a foremost public health concern. Major pollutants such as sulfur dioxide (SO2) and nitrogen oxides (NOx) are particularly harmful, contributing to respiratory diseases, acid rain, and environmental degradation. The Central Pollution Control Board (CPCB) and respective State Pollution Control Boards (SPCBs) have strengthened monitoring and enforcement in response to deteriorating air quality trends, especially in areas with compact industrial clusters.
Recent air quality data indicates a steady increase in NO2 levels and particulate matter (PM) levels in many Indian cities. Considering the direct health impact and urgency of the matter, the Ministry of Environment, Forest and Climate Change (MoEFCC) has amended the Environment Protection Rules, 1986. Strict emissions standards are imposed on several industrial sectors, including the foundry industry, which functions energy-intensive furnaces fuelled by coal, oil, natural gas or other combustible materials.
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Understanding the Role of Foundry Industry in Air Pollution
Foundry construction and metal casting play an important role but are also a major source of air productions. Combustion processes in Foundry furnaces release large amounts of SO2 and NOx, especially when fossil fuels such as coke, coal or oil are used. These gases not only affect the ambient air quality but also create secondary pollutants like ozone and sulphate, which further worsen the environmental problems.
To curb these emissions, CPCB along with SPCB have laid down industry specific emission standards. Foundries, as an industrial sector, fall under the realm of newly enforced emission limits as part of a national effort to mitigate pollution and ensure more clean air for their surrounding communities.
SO2 and NOx Emission Standards for Foundry Industries
As per the Environment (Protection) Amendment Rules, 2018, particular emission limits have been imposed on the foundry industry (fuel based furnaces). These standards are structured to control emissions at the source and are legally enforceable under the Environment Protection Act, 1986.
Foundry Industry and Its Environmental Impact
Foundries are an important part of India's manufacturing sector, involved in casting of metal parts and components in the automotive, machinery and infrastructure industries. These units typically function fuel-fired furnaces using coal, coke, oil or natural gas, which emit a significant amount of gaseous pollutants. Both gases pose severe health risks, causing respiratory disorders and contributing to acid rain, smog formation and ground level ozone depletion and other environmental issues.
Combustion processes in foundry furnaces are known for creating:
- Sulphur Dioxide (SO2): A by-product of burning sulfur-containing fuels like coal and furnace oil.
- Nitrogen Oxides (NOx): Formed due to high-temperature combustion of fuels in the presence of atmospheric nitrogen.
Importance of SO2 and NOx Compliance in Foundries
The implementation of emission standards by CPCB and SPCB regulatory authorities is a proactive step towards improving the Air Quality Index (AQI) in industrial areas. For foundries compliance with these emissions standards has many long-term environmental and operational benefits:
- Improved Environmental Footprint: Reduction in toxic gaseous emissions confirms reduced environmental degradation, decreased acid rain formation and ensures better protection of local air and water ecosystems.
- Healthier Communities: Lower pollutant exposure reduces respiratory illnesses and increases public health outcomes, especially in close-knit residential areas and among elderly and vulnerable populations.
- Enhanced Industry Credibility: Compliance enhances the foundry sector's environmental responsibility profile and fortifies its position among customers, regulators and an environmentally conscious global supply chain.
- Technological Upgrades: Encouraging the adoption of low emission technologies such as advanced burners, desulfurization units and cleaner fuels like natural gas, which increase energy efficiency and reduce maintenance costs.
Also Read: What are the Standards for Emission or Discharge of Environmental Pollutants for Hot Mix Plants?
Related Emission Norms for Other Industries
To provide context, the following are some of the other industry-specific SO₂ and NOx standards notified in the same amendment:
| SI. No. | Type of Industrial Sector | Standards | |
| SO2 (mg/Nm3) | NOx (mg/Nm3) | ||
| 107 | Ceramic | 400 | 600 |
| 108 | Foundry Industries (Furnaces based on Fuel) | 300 | 400 |
| 109 | Glass | 500 for natural gas firing 1500 for other fuels | 1000 |
| 110 | Lime Kiln | 400 | 500 |
| 111 | Reheating furnace | 300 | 1000 |
Notes:
- It is required to meet stack height criteria publication vide notification number G.S.R 475 (E), dated the 5th May, 1992 published in Gazette No. 202 dated 5th May 1992.
- It is required to meet stack height criteria publication vide notification number G.S.R. 742 (E), dated the 30th August,1990 published in Gazette No. 365 dated 30th August, 1990.
- It is required to meet stack height criteria publication vide notification number G.S.R 93 (E), dated 21st February, 1991 published in the Gazette No. 79 dated the 27th February, 1991.
- The lime kiln shall ensure that the minimum stack height is in accordance with Environment Protection Act, 1986 as amended from time to time and relevant direction of SPCBs / PCCs shall to adhere to. It shall be the concerned SPCB / PCC to increase the stake height, if required based on the scientific studies, keeping in view the habitations around such lime kilns.
- It is required to meet stack height criteria publication as prescribed by SPCBs/PCCs.
Stack Height Criteria for Foundry Units
In addition to fulfilling concentration based emissions limits, fuel based foundry furnaces need to adhere with stack height regulations. Proper stack height density is essential for effective dispersion of pollutants and to reduce exposure to ground- level pollution in surrounding residential or sensitive areas.
Monitoring and Legal Compliance
To ensure compliance with the prescribed SO2 and NOx emission standards, constant and periodic monitoring by CPCB and SPCB is compulsory. Foundries are required to install emission monitoring systems and keep records of stack emissions, which need to be submitted regularly to the relevant regulatory authorities. Non-compliance may result in legal action under the Environment (Protection) Act, 1986, which may include fine, suspension of operations or disconnection of utility. It is crucial for foundry operators to maintain updated surveys, environmental audit reports as per the latest regulatory guidelines and make sure that the pollution control equipment is functional and standardized. Legal compliance not only avoids penalties but also strengthens long-term operational legitimacy and public confidence.
Conclusion
The implementation of SO2 and NOx emission standards for fuel-based foundry furnaces under the Environment (Protection) Amendment Rules, 2018 is a significant step towards improving India's environmental and public health scenario. Through active enforcement of CPCB and SPCB, the foundry area is expected to function within clean, safe and sustainable environmental parameters.
These efforts represent India's strong regulatory push towards industrial compliance and determine a clear alignment with the country's broader air quality management objectives and climate commitments.
About the Author
Parul Bohral
Legal Content WriterParul Bohral, a BALLB graduate and experienced legal researcher and content writer with expertise in various legal areas, including corporate law and intellectual property. I have gained valuable experience in esteemed legal environments, where I have strengthened my research skills, allowing me to approach legal writing with precision and depth.
As a legal content writer, I am committed to delivering work that not only informs but also engages readers. By staying informed about the latest trends in content marketing and regulatory developments, I ensure that my writing remains sophisticated and meets industry standards. My dedication to thorough research enables me to craft content that is both insightful and impactful.
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