CeNS Scientists Develop Low-Cost Sensor to Detect Toxic Sulfur Dioxide Gas

Sulfur dioxide is a toxic air pollutant released predominantly from vehicle exhaust, industrial emissions, and burning fossil fuels.

In a major advance for public health and environmental safety, researchers at the Centre for Nano and Soft Matter Sciences (CeNS), Bengaluru, have developed a cost-effective and highly sensitive sensor capable of detecting sulfur dioxide (SO₂) at trace levels. The compact device, designed with everyday usability in mind, marks a significant step forward in real-time air quality monitoring—particularly in urban and industrial environments.

Sulfur dioxide is a toxic air pollutant released predominantly from vehicle exhaust, industrial emissions, and burning fossil fuels. Even at low concentrations, it poses severe risks, including respiratory irritation, asthma attacks, cardiovascular issues, and long-term pulmonary damage. Until now, detecting SO₂ in the air at such low levels required expensive, bulky, or inefficient equipment.

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Innovation in Material Science: NiO + NdNiO₃ = Detection Breakthrough

Led by Dr. S. Angappane, the CeNS team engineered the new sensor using a unique combination of two metal oxides:

• Nickel Oxide (NiO): Serves as the receptor, interacting directly with SO₂ molecules.

• Neodymium Nickelate (NdNiO₃): Acts as the transducer, converting gas interaction into a measurable electrical signal.

This clever combination leverages the chemical sensitivity of NiO and the high signal transmission efficiency of NdNiO₃, resulting in detection capabilities as low as 320 parts per billion (ppb). This surpasses the sensitivity of many commercial SO₂ sensors, making it suitable for environments where early detection can make a life-saving difference.

The materials were synthesized using a simple, scalable fabrication method, ensuring that the technology remains affordable and accessible for large-scale deployment.

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Real-Time Monitoring with User-Friendly Alerts

To showcase the practical potential of the sensor, the research team developed a portable prototype that delivers real-time SO₂ monitoring. This device includes a threshold-triggered visual alert system, which simplifies the complex data into easily interpretable visual cues:

• Green: Safe air quality

• Yellow: Warning—SO₂ levels rising

• Red: Danger—immediate action required

This feature makes the sensor usable by non-specialists, such as factory workers, city administrators, or household users. The compact, lightweight design enhances portability, enabling placement in industrial zones, public buildings, transportation hubs, or indoor spaces.

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Applications Across Sectors

The SO₂ sensor offers a broad range of applications:

• Industrial Facilities: Detect gas leaks and emissions in real time.

• Urban Monitoring: Integrate into smart city infrastructure to track pollution levels.

• Occupational Safety: Protect workers in factories, chemical plants, and power stations.

• Home & Indoor Use: Ensure clean air in enclosed or poorly ventilated areas.

With its low energy consumption, high reliability, and user-friendly interface, the sensor stands out as a versatile, accessible, and scalable solution for environmental safety.

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Team and Publication

This promising innovation was spearheaded by Mr. Vishnu G Nath, with significant contributions from:

• Dr. Shalini Tomar

• Mr. Nikhil N. Rao

• Dr. Muhammed Safeer Naduvil Kovilakath

• Dr. Neena S. John

• Dr. Satadeep Bhattacharjee

• Prof. Seung-Cheol Lee

The study has been published in the prestigious journal Small, further highlighting the global significance of this work.

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A Step Toward Healthier Cities

The development of this sensor underlines the transformational role of material science in addressing pressing societal challenges. As countries grapple with air pollution and its dire health consequences, low-cost, real-time monitoring solutions like this can empower citizens, administrators, and policymakers alike.

By democratizing access to environmental data, this sensor embodies the vision of technology for public good, aligning with broader initiatives such as clean air missions, sustainable urban development, and citizen-centric health innovation.

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