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1. DETR are proposing to review their air pollution information service to take account of the requirement to provide information on health effects to the public once levels of sulphur dioxide or nitrogen dioxide exceed a defined 'alert threshold' in the first EC Air Quality Daughter Directive (agreed June 1998). Other possible modifications to the information service would be considered at the same time. A paper (COMEAP/2000/16) was prepared seeking comments from COMEAP on two specific aspects - the air pollution concentrations relating to the subdivisions in a numerical index and the health advice to be linked to exceedances of EC alert thresholds. This paper was circulated to COMEAP for comments in writing. The conclusions were as set out below. These conclusions will feed into a DETR public consultation paper on a review of the air pollution information service to be sent out towards the end of this year. 2. COMEAP agreed to the general principle of using a numerical index at the October 1999 meeting. This would still be linked to the breakpoints previously agreed but would have arbitary subdivisions within the bands. An annex was attached to COMEAP/99/12 setting out these subdivisions. This allocated a numerical index of 1-3 to the low band, 4-5 to moderate, 6-7 to high and 8-10 to very high. Since pollutant levels almost never reach the very high band, the Secretariat subsequently proposed that a numerical index of 10 is allocated to the very high band and the remaining bands are each divided into 3. Details of the subdivisions are in the attached annex. COMEAP agreed to this proposal. 3. The first EC Air Quality Daughter Directive (agreed June 1998) contains a requirement to provide information on health effects to the public once levels of sulphur dioxide or nitrogen dioxide exceed a defined 'alert threshold'. The Committee was therefore asked to consider appropriate wording to describe the health effects. The wording needed to be short and simple in order to fit onto a CEEFAX/TELETEXT page. The agreed wording is given below. 4. The EC Alert Threshold for sulphur dioxide is 500 µg/m3 (187 ppb) as an hourly average measured over 3 consecutive hours. NETCEN* has undertaken an analysis of past UK data which suggested that 15 minute means of about 280 ppb or above are likely to occur in a situation where the Alert threshold is exceeded. This level is in the high band. The following wording is suggested to accompany the announcement of an exceedance of the EC Alert Threshold for sulphur dioxide: 'Tightness of the chest may occur in some asthmatics. Use of their 'reliever' inhaler may lessen this effect.' * NETCEN - AEA Technology National Environmental Technology Centre 5. The EC alert threshold for nitrogen dioxide is 400 µg/m3 (210ppb) as an hourly average over 3 consecutive hours. This is in the moderate band. The following wording is suggested when the alert threshold for nitrogen dioxide is exceeded: 'Lung irritability may be slightly increased in some people with lung disease. Use of a 'reliever' inhaler may lessen this effect. Exposure can be reduced by avoiding busy streets.' 6. Currently, there is an EC Information threshold at 90 ppb and an EC Alert threshold at 180 ppb. However, a new ozone directive is now under discussion and this contains a proposal to change the EC alert threshold for ozone from 180 ppb to 120 ppb. This is in the high band. The following wording is suggested presuming that the ozone alert threshold will be agreed at 120 ppb. 'Some people are more sensitive to ozone than others and may begin to notice an effect on their breathing. Exposure to ozone can be reduced by avoiding exercise outdoors in the afternoon. People with asthma are not necessarily more sensitive but, if affected, can use their 'reliever' inhaler.' (This wording will be reviewed if the alert threshold in the proposed ozone directive changes) 7. The description of the health effects has been based mainly on chamber study evidence. The information service as a whole is aimed at the general population including asthmatics. Epidemiological studies suggest effects at lower doses and it is thought that these effects occur in people who are more seriously ill. This is explained in the DETR leaflet 'Air Pollution - What it means for your health' and CEEFAX/TELETEXT refers people to this leaflet for further information. 8. EC alert thresholds have not been set for particles or carbon monoxide. August 2000 ANNEX: PROPOSED SUBDIVISIONS FOR NUMERICAL INDEX
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