§ 107. Mr. Michael J. MartinTo ask the Secretary of State for the Environment how many times carbon 649W monoxide levels in London's air have exceeded World Health Organisation deadlines in the last 12 months; and how many times nitrogen dioxide levels in London's air have exceeded the air quality standard contained in the European directive 85/201 over the last 12 months.
§ Mrs. Virginia BottomleyThe World Health Organisation has set guidelines for carbon monoxide concentrations using average periods of eight hours and one hour. These are targets for improved air quality and not limit values. In 1988 one exceedance of the eight hour guideline was measured at the Department of the Environment's monitoring station in central London. No exceedances of the one hour guideline were measured.
Provisional results from the United Kingdom nitrogen dioxide monitoring network indicate that the EC directive limit value, which is based on the 98th percentile of measurements throughout the year, was not exceeded in London in 1988.