1. The data-quality objectives set out in the following table, for the required accuracy of assessment methods, of minimum time coverage and of data capture of measurement are laid down to guide quality assurance programmes—
| Sulphur dioxide, nitrogen dioxide and oxides of nitrogen | Lead, PM2.5 and PM10 | |
|---|---|---|
| Continuous measurement | ||
| Accuracy | 15% | 25% |
| Minimum data capture | 90% | 90% |
| Indicative measurement | ||
| Accuracy | 25% | 50% |
| Minimum data capture | 90% | 90% |
| Minimum time coverage | 14% (One measurement a week at random, evenly distributed over the year, or eight weeks evenly distributed over the year) | 14% (One measurement a week at random, evenly distributed over the year, or eight weeks evenly distributed over the year) |
| Modelling | ||
| Accuracy: | ||
| Hourly averages | 50%–60% | |
| Daily averages | 50% | |
| Annual averages | 30% | 50% |
| Objective estimation | ||
| Accuracy | 75% | 100% |