Sampling points targeted at the protection of vegetation and natural ecosystems shall be sited more than 20 km away from agglomerations or more than 5 km away from other built-up areas, industrial installations or motorways or major roads with traffic counts of more than 50 000 vehicles per day, which means that a sampling point must be sited in such a way that the air sampled is representative of air quality in a surrounding area of at least 1 000 km. A Member State may provide for a sampling point to be sited at a lesser distance or to be representative of air quality in a less extended area, taking account of geographical conditions o ...[+++]r of the opportunities to protect particularly vulnerable areas.

the number of sampling points in each zone or agglomeration amounts to at least one sampling point per two million inhabitants or one sampling point per 50 000 km, whichever produces the greater number of sampling points, but must not be less than one sampling point in each zone or agglomeration.

EUROPA - EU law and publications - EUR-Lex - EUR-Lex - 32008L0050 - EN - Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008 on ambient air quality and cleaner air for Europe - DIRECTIVE 2008/50/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL // DATA QUALITY OBJECTIVES // Determination of requirements for assessment of concentrations of sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter (PM - and PM - ), lead, benzene and carbon monoxide in ambient air within a zone or agglomeration // Assessment of ambient air quality and location of sampling points for the measurement of sulphur ...[+++]dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter (PM // MEASUREMENTS AT RURAL BACKGROUND LOCATIONS IRRESPECTIVE OF CONCENTRATION // Criteria for determining minimum numbers of sampling points for fixed measurement of concentrations of sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter (PM - , PM // Reference methods for assessment of concentrations of sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter (PM - ), lead, benzene, carbon monoxide, and ozone // OZONE TARGET VALUES AND LONG-TERM OBJECTIVES // Criteria for classifying and locating sampling points for assessments of ozone concentrations // Criteria for determining the minimum number of sampling points for fixed measurement of concentrations of ozone // MEASUREMENTS OF OZONE PRECURSOR SUBSTANCES // LIMIT VALUES FOR THE PROTECTION OF HUMAN HEALTH // INFORMATION AND ALERT THRESHOLDS // CRITICAL LEVELS FOR THE PROTECTION OF VEGETATION // NATIONAL EXPOSURE REDUCTION TARGET, TARGET VALUE AND LIMIT VALUE FOR PM // Information to be included in the local, regional or national air quality plans for improvement in ambient air quality // PUBLIC INFORMATION // CORRELATION TABLE

The gas velocity at the sampling zone must be higher than 10 m/s except at idle mode.

Torque shall be reduced from 100 percent torque while maintaining the rated speed condition as necessary so as not to exceed the 191 C maximum sample zone temperature specifications.

The flow capacity of the PDP or CFV or SSV must be sufficient to maintain the diluted exhaust stream in the DT at a temperature of less than or equal to 464 K (191°C) at the sampling zone.