US chemists have come up with a way of detecting the amounts of toxic and volatile chemicals given off from industrial chimneys.

Environmental pollution and global warming are topics rarely out of the headlines these days, but what if we were able to accurately monitor the chemical pollutants released at their source? Yusuf Sulub and Gary Small at the University of Iowa think they have an answer.

Small passively measured the infrared (IR) radiation absorption of plumes of chemical vapour and used the data to work out the amounts of a particular compound it contained.

By using polyvinyl chloride as a reference background surface, Small remotely measured the slight changes that occur in its IR spectrum when a plume of ethanol vapour is passed between it and his detector. He then used these changes to calculate the amount of ethanol it contained at any given time.

'Ethanol is used here as [it is] representative of a variety of industrially relevant volatile organic compounds that could be monitored [in this way],' he said.

Wytze van der Veer, director of the laser spectroscopy facility at the University of California, US, pointed out that Small's measurements were successfully made using only a basic IR spectrometer, 'promising a powerful, versatile and affordable remote monitoring technique for smoke stacks'.

David Parker