According to the World Health Organisation (WHO), nitrogen dioxide (NO2) contributes to more than seven million deaths worldwide each year, researchers said.

The gas increases the risk of respiratory disorders in children and can severely affect the elderly in particular, they said.

The negative impact of nitrogen dioxide could be prevented by access to personalised, highly selective, sensitive and reliable monitoring systems that could detect harmful levels of the gas early, project leader Professor Kourosh Kalantar-zadeh, from RMIT's Centre for Advanced Electronics and Sensors (CADES), said.

The main contributors of nitrogen dioxide are the burning of fossil fuels, particularly in coal-fired power stations and diesel engines, which can impact the health of people in urban areas.

"The method we have developed is not only more cost-effective, it also works better than the sensors currently used to detect this dangerous gas," said Kalantar-zadeh.

Kalantar-zadeh developed the new method for sensing nitrogen dioxide together with fellow RMIT researchers and colleagues from the Chinese Academy of Sciences.

The sensors, which operate by physically absorbing nitrogen dioxide gas molecules onto flakes of tin disulphide, not only increase the level of sensitivity to accepted EPA standards but outperform any other nitrogen dioxide sensing solutions on the market.

Tin disulphide is a yellowish-brown pigment generally used in varnish for gilding. To create sensors, researchers transformed this material into flakes just a few atoms thick.

The large surface area of these flakes has a high affinity to nitrogen dioxide molecules that allows it's highly selective absorption.