Greenhouse gas

Sulphuryl fluoride gas used for fumigation has the potential to contribute significantly to future greenhouse warming, according to US researchers.

Scientists at MIT, the Scripps Institution of Oceanography in San Diego and other institutions are reporting the results of their study of the gas this month in the Journal of Geophysical Research.

Sulphuryl fluoride was introduced as a replacement for methyl bromide, a widely used fumigant that is being phased out under the Montreal Protocol because of its ozone-destroying chemistry. Methyl bromide has been used for insect control in grain-storage facilities, and in intensive agriculture in arid lands where drip irrigation is combined with covering of the land with plastic sheets to control evaporation.

'Such fumigants are very important for controlling pests in the agricultural and building sectors,' said Ron Prinn, director of MIT's Center for Global Change Science. 'But with methyl bromide being phased out, industry had to find alternatives, so sulphuryl fluoride has evolved to fill the role,' he added.