Paragraph
England and Wales
The following data quality objectives, for allowed uncertainty of assessment methods, and of minimum time coverage and of data capture of measurement are provided to guide quality assurance programmes.
| Benzene | Carbon monoxide | |
|---|---|---|
| Fixed measurements | ||
| Uncertainty | 25% | 15% |
| Minimum data capture | 90% | 90% |
| Minimum time coverage | 35% urban background and traffic sites (distributed over the year to be representative of various conditions for climate and traffic) 90% industrial sites | |
| Indicative measurements | ||
| Uncertainty | 30% | 25% |
| Minimum data capture | 90% | 90% |
| Minimum time coverage | 14% (one day’s measurement a week at random, evenly distributed over the year, or 8 weeks evenly distributed over the year) | 14% (one measurement a week at random, evenly distributed over the year, or 8 weeks evenly distributed over the year) |
| Modelling | ||
| Uncertainty: | ||
| Eight-hour averages | 50% | |
| Annual averages | 50% | |
| Objective estimation | ||
| Uncertainty | 100% | 75% |