An atomically thin graphene-based air pollution sensor has been created by a team of scientists from the University of Southampton and Japan Advanced Institute of Science and Technology (JAIST). This sensor detects individual CO2 molecules and volatile organic compound (VOC) gas molecules at very low power consumption.

“In contrast to the commercially available environmental monitoring tools, this extreme sensing technology enables us to realise significant miniaturisation, resulting in weight and cost reduction in addition to the remarkable improvement in the detection limit from the ppm levels to the ppb levels,” says lead researcher Hiroshi Mizuta.

The study, published on April 15 in the journal Science Advances, explains that these gas molecules have low concentrations of ppb (parts per billion) levels and can be found in building and interior materials, household goods and furniture, causing conditions including car sickness, sick school syndromes and sick building syndrome (SBS). However, current environmental sensor technologies are unable to detect these since these tools can only sense concentrations of parts per million (ppm).


A diagram of a graphene single molecular sensor (left) and the observed signal showing successful detection of single CO2 molecule adsorption / desorption events. Credit: University of Southampton

The air pollution sensor is able to detect the harmful gases through the electric field across the structure. The electrical resistance determines the adsorption and desorption of CO2 molecules, the process where a substance is released from or through a surface.

During its testing, the researcher found that the sensor was able to detect a small volume of CO2 gas, which has the concentration of about 30 ppb. It only took a few minutes to detect the gas. Unlike current technology, the new sensor only consumes very low energy. It turns out that it only uses below three bolts, enabling the sensor’s battery to last a long lifetime.

The researchers say that more studies are still needed. Presently, the research team is planning to create more environmental sensor systems that can detect individual molecules without consuming too much energy.