The Air Quality Limit Values (Scotland) Regulations 2003

1.1  The following data-quality objectives 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 nitrogenParticulate matter and lead
Continuous measurement
Accuracy15%25%
Minimum data capture90%90%
Indicative measurement
Accuracy25%50%
Minimum data capture90%90%
Minimum time coverage14% (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 averages50%–60%
Daily averages50%
Annual averages30%50%
Objective estimation
Accuracy:75%100%