The Expert Panel on Air Quality Standards (EPAQS), has drawn up the guidelines from several halogen gases and hydrogen halides, all of which can be potentially harmful to human health and the environment.

The corrosive gases covered by the new guidelines are bromine, chlorine, hydrogen bromide, hydrogen chloride, hydrogen fluoride and hydrogen iodide.

While the most common source of halides is the burning of fossil fuels, the halogens come from a variety of industrial processes such as aluminium smelting, firing ceramics and manufacturing certain plastics and electronic goods.

Even at relatively low levels the gases can cause acute irritation to those particularly susceptible.

The guidelines will be used mainly by pollution control authorities such as the Environment Agency and the Scottish Environmental Protection Agency which are responsible for regulating the release of these substances from major industrial processes.

In terms of their impact on national air quality, the effects of the gases covered in the EPAQS report is negligible and the report is not meant to provide guidelines for setting national standards.

But current levels of gases in areas near the industrial sources which emit them are sufficient to warrant attention and the new guidelines are intended to protect populations neighbouring the sites.

The guidelines will be used as part of the Integrated Pollution Prevention and Control regime which, when fully implemented, will monitor 4,000 of the most polluting industrial sites in England and Wales as well as many smaller factories.

EPAQS was established in 1991 to advise Defra ministers and their equivalents in the devolved assemblies of Scotland, Wales and Northern Ireland and is made up of experts from industry, medicine and academia.

By Sam Bond

Action inspires action. Stay ahead of the curve with sustainability and energy newsletters from edie