THE quality of the air in one of the busiest streets of a North Yorkshire town is being put under the spotlight for the next six months.

Residents and visitors to Castlegate, Malton, may have noticed that an air quality monitoring station has been installed on behalf of Ryedale District Council.

The move follows indications that the council may not achieve the nationally required level of nitrogen dioxide in the air at roadside areas before the deadline of December 31, 2005.

The danger is that over-exposure to the gas could result in breathing problems.

"In town centres and urban areas, most nitrogen dioxide pollution arises from motor vehicle exhaust emissions," said Paul Hunt, the council's environmental protection officer.

"Exposure to excessive levels may cause respiratory problems. Road vehicles are also a significant emission source for fine particulate matter and the station has additionally been equipped to monitor levels of this pollutant, which may also cause respiratory ailments."

The monitor will remain in place until spring next year, providing accurate data on pollutant levels.

If levels are too high, the council will have to designate the site as an Air Quality Management Area and produce an action plan for improvements in air quality.