Tiny Sensor, Big Impact

TECH TALK /POCKET SENSOR FOR SO₂

In a significant breakthrough for environmental safety and public health, a team of scientists from the Centre for Nano and Soft Matter Sci­ences (CeNS), Bengaluru, has developed a pocket-sized sensor capable of detect­ing sulfur dioxide (SO₂)—a silent but dangerous air pollutant—at extremely low concentrations.

Sulfur dioxide, a toxic gas commonly released from vehicular emissions, in­dustrial processes, and power plants, is notorious for triggering respiratory problems such as asthma attacks, irrita­tion of the airways, and long-term lung damage. Due to its colourless nature and the delay between exposure and visible symptoms, SO₂ often escapes detection until it causes serious harm. Convention­al gas detection technologies are often bulky, costly, energy-intensive, or lack the sensitivity required for early-stage detection—posing a challenge for wide­spread monitoring.

A SMART SOLUTION FROM INDIAN SCIENTISTS

To address this issue, the CeNS team, under the guidance of Dr S Angappane, developed a novel, low-cost sensor using a clever combination of materials—nick­el oxide (NiO) and neodymium nickelate (NdNiO₃). The NiO component serves as the gas receptor, effectively attracting SO₂ molecules, while NdNiO3 acts as the signal transducer, converting the gas interaction into measurable data.

Thanks to this dual-material de­sign, the sensor is capable of detecting SO₂ concentrations as low as 320 parts per billion (ppb), a sensitivity level that outperforms many existing commercial sensors. This technological advance­ment marks a significant step toward real-time, ultra-sensitive air monitoring in both public and private settings.

FOR REAL-WORLD APPLICATION

To demonstrate the real-world potential of their innovation, the researchers cre­ated a portable prototype incorporating the sensor. Designed for ease of use, the device features a simple traffic-light-style alert system:

• Green indicates safe levels of SO₂
• Yellow signals a warning threshold
• Red warns of dangerous levels requir­ing immediate attention

This intuitive display enables even non-experts to interpret air quality sta­tus and respond accordingly. Its com­pact size, lightweight design, and low power requirements make it suitable for industrial zones, urban environments, indoor air quality monitoring, and even personal safety devices.

The sensor was designed by Vishnu G Nath, with key contributions from Dr Shalini Tomar, Nikhil N Rao, Dr Mu­hammed Safeer Naduvil Kovilakath, Dr Neena S John, Dr Satadeep Bhattacha­rjee, and Prof Seung-Cheol Lee. Their collaborative work has been published in the journal Small.

This sensor not only demonstrates the power of material science in address­ing environmental challenges but also sets a precedent for developing acces­sible, real-world tools for air pollution monitoring. As India and the world grapple with rising pollution levels, es­pecially in densely populated and indus­trialised regions, such cost-effective and user-friendly innovations could play a vital role in preventing health crises and improving air quality management. With this development, CeNS once again reinforces its position as a leading institute in the field of nano and soft mat­ter technologies, translating high-end research into meaningful solutions for the society at large.