A new method to identify unhealthy levels of nitrogen dioxide could let those at risk take control of their health with cheap, personalised sensors, according to new research by Australian and Chinese scientists.
Nitrogen dioxide contributes to the dangerous smog that lurks over many of the world’s cities, causing serious respiratory problems, among other health issues.
Australian scientist Kourosh Kalantar-zadeh, a professor at RMIT’s Centre for Advanced Electronics and Sensors, told Mashable Australia he helped discover a new use for the material tin disulphide, which could be used as a sensor to read the level of nitrogen dioxide in the air.
Kalantar-zadeh had a personal interest in finding a way to detect the gas after his pregnant wife was diagnosed with preeclampsia, a dangerous condition for mother and child associated with high blood pressure. Kalantar-zadeh realised nitrogen dioxide is considered by some scientists to be a risk factor in developing the illness.
Around 80% of the nitrogen dioxide in our cities comes from vehicle exhaust,according to Australia’s Department of Environment, as well as other instances where fossil fuels are burnt, such from coal-fired power stations and petrol refineries.
Pollution has been at unsafe levels across southeast Asia in recent weeks, as large scale agricultural fires continue to burn in Indonesia. At least 10 people have died from haze-associated ailments, and many more have been left ill with respiratory issues.
“In some suburbs of Melbourne, the measure of nitrogen dioxide is very high,” Kalantar-zadeh told Mashable Australia. The West Gate Freeway, which his wife drove on often, is regularly blocked up with hour-long traffic jams and is used by many diesel-fuelled trucks, he explained, meaning she was regularly exposed to the potentially-deadly gas.
Unhappy with the sensors available on the market, he began looking at different materials that could detect nitrogen dioxide, but came up short until his colleague from the Chinese Academy of Sciences brought tin disulphide to his attention.
“This was a magic material,” he said about the pigment, which is generally used in varnishes. “The surface of this material has a nice energy that attracts nitrogen dioxide gas molecules selectively onto the surface.”
To his knowledge, no one has used tin disulphide for this purpose before — and he hopes that one day we will see it built into our personal smartphones as a sensor, allowing people to monitor the gas in the air around them.
The sensor, which consists of tin disulphide a few atoms thick, works by absorbing nitrogen dioxide gas molecules, which can then be measured.
Importantly for the working of the sensor, no other gas can be attracted to the surface of the material. This makes it much better than any other available nitrogen dioxide sensors that have difficulty distinguishing different gases, Kalantar-zadeh claimed.
Most importantly the material is cheap. “The process of making this sensor is very low cost,” Kalantar-zadeh said. “It costs less than one A$1 to make.”
He believes it could act as a personal alert system when nitrogen dioxide levels are too high, and could also be useful as a monitor at home or in a car.
“At the moment, you must have a smoke detector everywhere,” he said. “There’s no regulation that requires people to have a nitrogen dioxide sensor … For areas near heavy traffic, and emissions coming from trucks with diesel engines, it should be required.”
Kalantar-zadeh said the team have made their research public in the hope others will take tin disulphide sensors into production. The team’s work was published Tuesday in the science journal, ACS Nano.
“This is why we put it in the public domain, to make sure people benefit right now, today,” he said. “Anyone can go ahead and start making it.”