Upper assessment threshold,60% of 24-hour limit value (75 μg/m 3 ) not to be exceeded more than 3 times in any calendar year,60% of winter limit value (12 μg/m 3 ),
Lower assessment threshold,40% of 24-hour limit value (50 μg/m 3 ) not to be exceeded more than 3 times in any calendar year,40% of winter limit value (8 μg/m 3 ),

Upper assessment threshold,70% of limit value (140 μg/m 3 ) not to be exceeded more than 18 times in any calendar year,80% of limit value (32 μg/m 3 ),80% of limit value (24 μg/m 3 ),
Lower assessment threshold,50% of limit value (100 μg/m 3 ) not to be exceeded more than 18 times in any calendar year,65% of limit value (26 μg/m 3 ),65% of limit value (19.5 μg/m 3 ),

Upper assessment threshold,60% of limit value (30 μg/m 3 ) not to be exceeded more than 7 times in any calendar year,70% of limit value (14 μg/m 3 ),
Lower assessment threshold,40% of limit value (20 μg/m 3 ) not to be exceeded more than 7 times in any calendar year,50% of limit value (10 μg/m 3 ),

1 24-hour limit value for the protection of human health,24 hours,50mg/m 3 PM 10 not to be exceeded more than 7 times a calendar year,To be derived from data and to be equivalent to Stage 1 limit value.,1st January 2010,
2 Annual limit value for the protection of human health,Calendar year,20 mg/m 3 PM 10,50% on 1st January 2005 reducing every 12 months thereafter by equal annual percentages to reach 0% by 1st January 2010,1st January 2010,

Upper assessment threshold,70% of limit value (0.35 μg/m 3 ),
Lower assessment threshold,50% of limit value (0.25 μg/m 3 ),

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 NO 2 and particulate matter: to include at least one urban-background station and one traffic-orientated station,

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 km 2,1 station every 40 000 km 2,

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%,