ANNEX IV

Ambient air quality shall be assessed in all zones as follows: Ambient air quality shall be assessed at all locations except those listed in point 2. Points B and C shall apply to the location of sampling points. The principles established by Points B and C shall also apply in so far as they are relevant in identifying the specific locations in which concentrations of the relevant pollutants are established where ambient air quality is assessed through indicative measurements or modelling applications. Compliance with the limit values and target values directed at the protection of human health shall not be assessed at the following locations: any locations situated within areas where members of the public do not have access and there is no fixed habitation; in accordance with Article 4, point (1), on factory premises or at industrial sites to which all relevant provisions concerning health and safety at work apply; on the carriageway of roads; and on the central reservations of roads except where there is normally pedestrian or cycling access to the central reservation. The siting of sampling points shall take into account national gridded data of emissions reported pursuant to Directive (EU) 2016/2284, emission data reported under the European Pollutant Release and Transfer Register and, where available, local emission inventories. Sampling points directed at the protection of human health shall be sited in such a way as to provide reliable data on all of the following: concentration levels at air pollution hotspots within the zones; concentration levels in other areas within the zones which are representative of the exposure of the general population, both in urban background locations and rural background locations; for arsenic, cadmium, lead, mercury, nickel and polycyclic aromatic hydrocarbons, the deposition rates representing the indirect exposure of the population through the food chain; sampling points shall in general be sited in such a way as to avoid measuring micro-environments in the immediate vicinity of the sampling point, which means that a sampling point shall, where feasible, be sited in such a way that the air sampled is representative of air quality for a street segment no less than 100 m in length at locations measuring the contribution of road traffic, at least 25 m × 25 m at locations measuring the contribution from domestic heating, and at least 250 m × 250 m at locations measuring the contribution from industrial sites or other sources such as ports or airports; where the objective is to assess air quality at air pollution hotspots, sampling points shall be installed in the areas within zones with the highest concentrations to which the population is likely to be directly or indirectly exposed for a period which is significant in relation to the averaging period of the limit values or target values; such sampling points shall be located, where relevant and to the extent possible, in areas where sensitive population and vulnerable groups are likely to be directly or indirectly exposed for a period which is significant in relation to the averaging period of the limit values or target values, including but not limited to residential areas, schools, hospitals, assisted living facilities, or office areas; sampling points in urban background locations shall be located so that their pollution level is influenced by the integrated contribution from all relevant sources; the pollution level shall not be dominated by a single source unless such a situation is typical for a larger urban area; those sampling points shall, as a general rule, be representative for several square kilometres; sampling points in rural background locations shall be located so that their pollution level is influenced by the integrated contribution from relevant sources but not by urban areas, major roads or industrial sites in their vicinity, i.e. closer than 5 km; where the objective is to assess the contribution of road traffic, sampling points shall be located in such a way as to provide data on the streets where the highest concentrations occur, taking into consideration traffic volume (representing the largest traffic density in the zone), local dispersion conditions and spatial land use (for example, in street canyons); where the objective is to assess the contribution of domestic heating, sampling points shall be installed downwind of the main sources within the relevant predominant wind direction of those sources; where the objective is to assess the contributions of industrial sources, ports or airports, at least one sampling point shall be installed downwind of the main source within the relevant predominant wind direction in the nearest residential area; where the background concentration is not known, an additional sampling point shall be situated upwind of the main source, relative to the relevant predominant wind direction; the sampling points may be sited such that the application of BAT can be monitored; sampling points shall, where possible, also be representative of similar locations not in the immediate vicinity of the sampling points; in the zones where the level of air pollutants is above the assessment threshold, the area which each sampling point is representative of shall be clearly defined; the whole zone shall, where possible, be covered by the different areas of representativeness defined for those sampling points; concentrations in areas in a zone that are not covered by that zone’s sampling points shall be assessed with appropriate methods; account shall be taken of the need to locate sampling points on islands where that is necessary for the protection of human health; sampling points measuring arsenic, cadmium, lead, mercury, nickel and polycyclic aromatic hydrocarbons shall, where possible, be co-located with sampling points for PM10. Sampling points targeted at the protection of vegetation and natural ecosystems shall be sited more than 20 km away from urban areas or more than 5 km away from other built-up areas, industrial sites or motorways or major roads with traffic counts of more than 50 000 vehicles per day, which means that a sampling point shall be sited in such a way that the air sampled is representative of air quality in a surrounding area of at least 1 000 km2. 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 or of the opportunities to protect particularly vulnerable areas. Account shall be taken of the need to assess air quality on islands. The following apply to fixed and indicative measurements: Type of sampling point | Objectives of measurement | Representativeness (1) | Macro-scale siting criteria Urban background locations for ozone assessments | Protection of human health: to assess the exposure of the urban population to ozone, i.e. where population density and ozone concentration are relatively high and representative of the exposure of the general population. | 1 to 10 km2 | Away from the influence of local emissions such as traffic, petrol stations, etc.; vented locations where well mixed levels can be measured; where relevant and to the extent possible, locations frequented by sensitive population and vulnerable groups, such as schools, playgrounds, hospitals and homes for elderly; locations such as residential and commercial areas of cities, parks (away from trees), wide streets or squares with very little or no traffic, open areas characteristic of educational, sports or recreation facilities. Suburban locations for ozone assessments | Protection of human health and vegetation: to assess the exposure of the population and vegetation located in the outskirts of the urban area, with the highest ozone levels to which the population and vegetation are likely to be directly or indirectly exposed. | 10 to 100 km2 | At a certain distance from the area of maximum emissions, downwind following the main wind direction/directions during conditions favourable to ozone formation; where population, sensitive crops or natural ecosystems located in the outer fringe of an urban area are exposed to high ozone levels; where appropriate, some suburban sampling points also upwind of the area of maximum emissions, in order to determine the regional background levels of ozone. Rural locations for ozone assessments | Protection of human health and vegetation: to assess the exposure of population, crops and natural ecosystems to sub-regional scale ozone concentrations. | Sub-regional levels (100 to 1 000 km2) | Sampling points may be located in small settlements or areas with natural ecosystems, forests or crops; representative for ozone away from the influence of immediate local emissions such as industrial sites and roads; at open area sites. Rural background locations for ozone assessments | Protection of human health and vegetation: to assess the exposure of crops and natural ecosystems to regional-scale ozone concentrations as well as exposure of the population. | Regional/national/continental levels (1 000 to 10 000 km2) | Sampling points located in areas with lower population density, e.g. with natural ecosystems, forests, at a distance of at least 20 km from urban and industrial areas and away from local emissions; avoid locations which are subject to locally enhanced formation of ground-near inversion conditions; coastal sites with pronounced diurnal wind cycles of local character are not recommended. The locations of sampling points for rural locations and rural background locations for ozone assessment shall, where appropriate, be coordinated with the monitoring requirements of Commission Regulation (EC) No 1737/2006 (2). When determining the spatial representativeness area, the following characteristics shall be considered: the geographical area may include non-contiguous domains but shall be limited in its extension by the borders of the zone under consideration; if assessed via modelling applications, a fit-for-purpose modelling system shall be used and modelled concentrations shall be used at location of the sampling point to prevent systematic model-measurement biases from distorting the assessment; other metrics than absolute concentrations may be considered, e.g. percentiles; the tolerance levels and possible cut-offs for the different pollutants may vary depending on the characteristics of the sampling point; the annual average of the observed pollutant concentration shall be used as the air quality metric for a specific year. Insofar as it is practicable, the following shall apply: the flow around the sampling point inlet shall be unrestricted (in general free in an arc of at least 270o, or, for sampling points at the building line, of at least 180o) without any obstructions affecting the airflow in the vicinity of the inlet (at least 1,5 m away from buildings, balconies, trees and other obstacles, and at least 0,5 m from the nearest building in the case of sampling points representing air quality at the building line); in general, the sampling point inlet shall be between 0,5 m (the breathing zone) and 4 m above the ground; higher siting may also be appropriate if the sampling point is located in a background location; the decision to apply such higher siting shall be fully documented; the inlet probe shall not be positioned in the immediate vicinity of sources in order to avoid the direct intake of emissions unmixed with ambient air to which members of the public are unlikely to be exposed; the sampler’s exhaust outlet shall be positioned so that recirculation of exhaust air to the sampler inlet is avoided; for all pollutants, sampling probes focused on measuring contributions from road traffic shall be at least 25 m from the edge of major junctions and no more than 10 m from the kerbside; for the purposes of this point, a ‘kerbside’ means the line that separates motorised traffic from other areas; a ‘major junction’ means a junction which interrupts the traffic flow and causes different emissions (stop&go) from the rest of the road; for the deposition measurements in background locations, the guidelines and criteria of EMEP shall apply; for ozone measurement, Member States shall ensure that the sampling point is positioned well away from sources such as furnaces and incineration flues, and more than 10 m from the nearest road, with distance increasing as a function of traffic intensity; the following factors may also be taken into account: interfering sources; security; access; availability of electrical power and telephone communications; visibility of the site in relation to its surroundings; safety of the public and operators; the desirability of co-locating sampling points for different pollutants; planning requirements. | 1. | The competent authorities responsible for air quality assessment shall for all zones fully document the site-selection procedures and record information to support the network design and choice of location for all monitoring sites. The design of the monitoring network shall be supported at least by either modelling applications or indicative measurements. | 2. | The documentation shall include the location of the sampling points through spatial coordinates, detailed maps and compass point photographs of the area surrounding monitoring sites, and shall include information on the spatial representativeness of all sampling points. | 3. | The documentation shall include evidence as regards reasons for the network design and demonstrating compliance with Points B and C, in particular: (a) justification for the selection of locations representative of the highest levels of pollution in the zone or agglomeration for each pollutant; (b) reasons for selection of locations representative of the general exposure of population; and (c) any deviation from the micro-scale siting criteria, their underlying reasons and the likely impact on measured levels. | 4. | Where indicative measurements, modelling applications or objective estimation, or a combination thereof are used within a zone, the documentation shall include details of those methods and information on how the conditions set out in Article 9(3) are met. | 5. | Where indicative measurements, modelling applications or objective estimation are used, competent authorities shall use gridded data reported pursuant to Directive (EU) 2016/2284, emission information reported under Directive 2010/75/EU and, where available, local emission inventories. | 6. | For ozone measurements, Member States shall apply proper screening and interpretation of the monitoring data in the context of the meteorological and photochemical processes affecting the ozone concentrations measured at the respective sites. | 7. | Where applicable, the list of ozone precursors substances, the objective sought for measuring them and the methods used to sample and measure them shall be part of the documentation. | 8. | Where applicable, information of the measurement methods used for the measurement of the chemical composition of PM2,5 shall also be part of the documentation. | 9. | At least every 5 years the selection criteria, network design and monitoring site locations, defined by the competent authorities in view of the requirements of this Annex, shall be reviewed to ensure they remain valid and optimal overtime. The review shall be supported at least by either modelling applications or indicative measurements. Where such a review finds that the network design and monitoring site locations are no longer valid, the competent authority shall update them as soon as possible. | 10. | The documentation shall be updated following every review and other relevant changes to the monitoring network, and shall be made public through appropriate communication channels.

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Source: EUR-Lex (Cellar) · retrieved 2026-10-16 · Text as adopted (Official Journal); later amendments are not incorporated in this text.