Regulation 9(4), (6), (7), (9), (11)
1.1
| Population of zone (thousands) | If concentrations exceed the upper assessment threshold | If maximum concentrations are between the upper and lower assessment thresholds | For SO2 and NO2 in agglomerations where maximum concentrations are below the lower assessment thresholds |
|---|---|---|---|
| 0 –250 | 1 | 1 | not applicable |
| 250 –499 | 2 | 1 | 1 |
| 500 –749 | 2 | 1 | 1 |
| 750 –999 | 3 | 1 | 1 |
| 1,000 –1,499 | 4 | 2 | 1 |
| 1,500 –1,999 | 5 | 2 | 1 |
| 2,000 –2,749 | 6 | 3 | 2 |
| 2,750 –3,749 | 7 | 3 | 2 |
| 3,750 –4,749 | 8 | 4 | 2 |
| 4,750 –5,999 | 9 | 4 | 2 |
| >6,000 | 10 | 5 | 3 |
| For NO2 and particulate matter: to include at least one urban-background station and one traffic-orientated station – this requirement shall also apply to benzene and carbon MONOXIDE provided that it does not increase the number of sampling points. |
1.2 For the assessment of pollution in the vicinity of point sources, the number of sampling points for fixed measurement should be calculated taking into account emission densities, the likely distribution patterns of ambient-air pollution and the potential exposure of the population.
| If maximum concentrations exceed the upper assessment threshold | If maximum concentrations are between the upper and lower assessment thresholds |
|---|---|
| In island zones the number of sampling points for fixed measurement should be calculated taking into account the likely distribution patterns of ambient-air pollution and the potential exposure of ecosystems or vegetation. | |
| 1 station every 20,000 km2 | 1 station every 40,000 km2 |
| Population (× 1,000) | Agglomerations (urban and suburban) (a) | Other zones (suburban and rural (b) | Rural background |
|---|---|---|---|
(a) At least 1 station in suburban areas, where the highest exposure of the population is likely to occur. In agglomerations at least 50% of the stations should be located in suburban areas. | |||
(b) One station per 25,000 km2 for complex terrain is recommended. | |||
| 0–250 | 1 | 1 station/50,000 km2 as an average density over all zones | |
| 251–500 | 1 | 2 | “ |
| 501–1,000 | 2 | 2 | “ |
| 1,001–1,500 | 3 | 3 | “ |
| 1,501–2,000 | 3 | 4 | “ |
| 2,001–2,750 | 4 | 5 | “ |
| 2,751–3,750 | 5 | 6 | “ |
| > 3,750 | 1 additional station per 2 million inhabitants | 1 additional station per 2 million inhabitants | |
4.1 The number of sampling points for ozone must, in combination with other means of supplementary assessment such as air quality modelling and co-located nitrogen dioxide measurements, be sufficient to examine the trend of ozone pollution and check compliance with the long-term objectives. The number of stations located in agglomerations and other zones may be reduced to one-third of the number specified in Part III. Where information from fixed measurement stations is the sole source of information, at least one monitoring station should be kept. If, in zones where there is supplementary assessment, the result of this is that a zone has no remaining station, co-ordination with the number of stations in neighbouring zones must ensure adequate assessment of ozone concentrations against long-term objectives. The number of rural background stations should be 1 per 100,000 km2.