Engineers develop new method to check air pollution

PUBLISHED : Wednesday, 07 September, 2011, 12:00am
UPDATED : Wednesday, 07 September, 2011, 12:00am


Chinese University engineers have developed technology previously used by the US military to detect explosives to check for toxic air pollutants.

Professor Douglas Yung Pun-to, of the department of electronic engineering, and his team are using sensor chips as small as a fingernail to capture different types of toxic air pollutants, such as car exhaust fumes and cigarette smoke.

These chips can be used for roadside monitoring of air pollution, and provide real-time measurements.

It is a leap forward from the traditional technology for roadside monitoring that requires extracting samples of air and analysis in laboratories. The old process is not only expensive, but time-consuming.

The original purpose of the hyper-sensitive sensors was to detect explosives by looking for the volatile molecules that were emitted. Yung's team is the first in the world to build on this technology to assess air pollution.

'We hope this will help move us towards seeing bluer skies in Hong Kong, and will provide the public with more information on their health,' Yung said.

His research is significant in improving air quality and identifying health hazards after the International Agency for Research on Cancer declared 16 types of pollutants to be cancer-inducing.

The project received funding of HK$1 million from the government's Innovation and Technology Commission.

The chips have eight keyhole-like sensors - called cantilevers - that match with the various types of pollutants like a key, thereby showing what chemical compounds are in the air.

The price for creating the sensors is still uncertain as the project is still in its early stages. 'It will certainly be much cheaper than the traditional detectors of air pollution as the plastic cantilevers are simple to make and can easily be mass-produced.'

There are two ways of telling how many toxins are in the air. One is when a light beam is shone on the cantilever, and when the pollutants are attached, the thin and sensitive cantilever bends and will deflect the light beam to an angle to show their weight. The other is by observing the vibrating frequency of the cantilevers. The more pollutants there are, the wider the frequency.

Yung's team has also developed a hand-held portable device for users to breathe into to identify markers for illnesses. For example, if exhaled nitric oxide is detected, this indicates respiratory inflammation.