prEN 18168

Ambient air - Biomonitoring with higher plants - Method of the standardised grass exposure

This document applies to the use of the grass Lolium multiflorum ssp. italicum designated hereafter as Italian ryegrass for the bioaccumulation of substances liable to cause atmospheric pollution. It is an active biomonitoring approach insofar as the plants used are first cultivated in set conditions before being exposed at the monitoring locations in the field. The plants then record any pollution events that occur while they are being exposed, allowing such events to be accurately dated.
The method described in this document can be applied for identification and localization of one or more single pollution sources and the tracking of their “plume” on a local or regional scale. It also offers a tool to monitor sites in the long term by the repeated application of a clearly defined procedure and to describe the local or regional air pollution situation.
The method applies to solid and gaseous substances deposited on plants, where they may accumulate on their surface or in their tissues. These substances include sulphur, chloride, fluoride and especially metals as well as low volatile organic and halo-organic compounds such as polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), polybrominated diphenyl ethers (PBDE), polychlorinated dibenzo dioxins (PCDD) and polychlorinated dibenzo furans (PCDF). It is as well possible to verify pesticides which are used in plant protection products. The range of potential substances may be expanded according to the task at hand and the capabilities of conducting trace analyses and assessment.
The method described in this document allows spatial and temporal comparisons and allows for screening, thus providing a first indication of risk. The results of grass culture studies can suggest risks to biota (e.g. via the food chain) which require further investigation.
The method described in this document does not replace physico-chemical methods of direct measurement or modelling of air pollutants and cannot be replaced by them for its part; it complements them by indicating biological effects.
Potential areas of deployment are:
-   Permit procedures related to air pollution legislation;
-   Preservation of evidence related to the code for protection from pollution;
-   Monitoring of emission sources and performance control;
-   Assessment of local-scale emission transport;
-   Evidence of causation, e.g. related to environmental liability;
-   Air quality maintenance plans/strategies;
-   Long-term monitoring of ecological effects of atmospheric depositions;
-   Detection and assessment of local, regional, and countrywide effects of atmospheric depositions;
-   Assessment of risks for humans and/or animals via the food chain.
This document is of interest to those involved in environmental monitoring.

Außenluft - Biomonitoring mit Höheren Pflanzen - Verfahren der standardisierten Graskultur

Dieses Dokument gilt für die Verwendung des Grases Lolium multiflorum ssp. italicum – nachfolgend als Italienisches Raygras bezeichnet – für die Bioakkumulation von Substanzen, die Luftverunreinigungen verursachen. Es handelt sich insofern um ein aktives Biomonitoringverfahren, da die verwendeten Pflanzen vor der Exposition an den Monitoringmesspunkten im Freiland zunächst unter vorgegebenen Bedingungen kultiviert werden. Die Pflanzen erfassen dann jegliche Verschmutzungsereignisse, die während ihrer Exposition auftreten, so dass solche Vorfälle genau datiert werden können.
Das in diesem Dokument beschriebene Verfahren kann für die Ermittlung und Lokalisierung von einer oder mehreren Quellen von Schadstoffen sowie für die Nachverfolgung ihrer Schadstofffahne auf lokaler oder regionaler Ebene verwendet werden. Es ist zudem ein Instrument zur langfristigen Überwachung von Standorten durch wiederholte Anwendung eines klar definierten Verfahrens sowie zur Beschreibung der lokalen oder regionalen Luftverschmutzungslage.
Das Verfahren ist für feste und gasförmige Substanzen anwendbar, die sich auf der Oberfläche von Pflanzen oder in deren Gewebestrukturen ablagern. Zu diesen Substanzen zählen Schwefel, Chlorid, Fluorid und insbesondere Metalle sowie langlebige organische und halogenierte organische Verbindungen wie polyzyklische aromatische Kohlenwasserstoffe (PAH), polychlorierte Biphenyle (PCB), polybromierte Diphenylether (PBDE), polychlorierte Dibenzodioxine (PCDD) und polychlorierte Dibenzofurane (PCDF). Auch in Pflanzenschutzprodukten verwendete Pestizide können damit nachgewiesen werden. Das Spektrum an potenziell nachweisbaren Substanzen kann je nach anstehender Aufgabe und den Fähigkeiten zur Durchführung von Spurenanalysen und Beurteilungen ausgeweitet werden.
Das in diesem Dokument beschriebene Verfahren ermöglicht räumliche und zeitliche Vergleiche sowie Screening zur Erkennung erster Anzeichen eines Risikos. Die Ergebnisse der Untersuchungen an Graskulturen können auf Risiken für Biota hinweisen (z. B. über die Nahrungskette), die eine weitere Untersuchung erfordern.
Das in diesem Dokument beschriebene Verfahren ersetzt physikalisch-chemische Verfahren zur direkten Messung oder die Modellierung von Luftschadstoffen nicht und kann im Gegenzug nicht durch sie ersetzt werden; es stellt vielmehr eine Ergänzung dieser Verfahren dar, indem es die biologischen Auswirkungen anzeigt.
Potenzielle Einsatzgebiete sind:
-   Genehmigungsverfahren mit Bezug zur Gesetzgebung zu Luftverschmutzung;
-   Beweissicherungsverfahren im Immissionsschutz;
-   Überwachung von Emissionsquellen und Erfolgskontrolle;
-   Beurteilung des Transports von Emissionen auf lokaler Ebene;
-   Ursachenklärung, z. B. im Zusammenhang mit Umwelthaftungsregelungen;
-   Luftreinhaltepläne/-strategien;
-   Dauerbeobachtung der Umweltauswirkungen von atmosphärischer Immission;
-   Erkennung und Beurteilung der lokalen, regionalen und landesweiten Auswirkungen von atmosphärischer Immission;
-   Beurteilung der Risiken für Menschen und/oder Tiere über die Nahrungskette.
Dieses Dokument richtet sich an Akteurinnen und Akteure im Umweltmonitoring.

Air ambiant - Biosurveillance à l’aide de plantes supérieures - Méthode de l’exposition normalisée de ray-grass

Le présent document s’applique à l’utilisation de la variété de graminées Lolium multiflorum ssp. italicum, dénommée ci-après ray-grass italien, en vue de l’étude de la bioaccumulation de substances caractérisant une pollution atmosphérique. Il s’agit d’une approche de biosurveillance active dans le sens où les organismes végétaux employés sont au préalable cultivés dans des conditions définies avant d’être exposés sur les sites de surveillance sur le terrain. Les plantes témoignent alors des évènements de pollution qui ont pu avoir lieu durant leur phase d’exposition, ce qui permet de dater avec précision ces événements.
La méthode décrite dans le présent document peut être appliquée pour l’identification et la localisation d’une ou plusieurs de sources ponctuelles de pollution et le suivi de leur « panache » à l’échelle locale ou régionale. Elle offre également un moyen de surveiller des sites sur le long terme par la répétition d’une procédure clairement définie et de décrire la situation locale ou régionale en matière de pollution atmosphérique.
La méthode s’applique aux substances gazeuses et solides qui se sont déposées sur les plantes, lesquelles peuvent accumuler les substances à leur surface ou dans leurs tissus. Ces substances incluent le soufre, les chlorures, les fluorures et en particulier les métaux, ainsi que les composés organiques et organohalogénés peu volatils tels que les hydrocarbures aromatiques polycycliques (HAP), les polychlorobinphényles (PCB), les polybromodiphényléthers (PBDE), les polychlorodibenzo-dioxines (PCDD) et les polychlorodibenzofuranes (PCDF). Il est également possible de contrôler la présence des pesticides utilisés dans les produits phytosanitaires. La gamme de substances potentielles peut être élargie en fonction de la tâche à accomplir et de la capacité à mener des analyses et une évaluation des substances à l’état de traces.
La méthode décrite dans le présent document permet d’effectuer des comparaisons spatiales et temporelles et permet une recherche à large spectre des polluants, fournissant ainsi une première indication d’un risque. Les résultats des études de plants de ray-grass peuvent indiquer des risques pour le biote (par exemple, via la chaîne alimentaire) qui exigent de mener des études complémentaires.
La méthode décrite dans le présent document ne remplace pas les méthodes physico-chimiques de mesurage direct, ni la modélisation des polluants atmosphériques et ne peut pas non plus être remplacée par celles-ci ; elle les complète en indiquant des effets biologiques.
Les domaines potentiels de déploiement sont :
-   les processus d’autorisation en lien avec la réglementation en matière de pollution atmosphérique ;
-   la préservation de preuves en lien avec le code de protection contre la pollution ;
-   la surveillance des sources d’émission et le contrôle des performances ;
-   l’évaluation du transport d’émissions polluantes à l’échelle locale ;
-   les preuves de causalité, par exemple en lien avec la responsabilité environnementale ;
-   les plans/stratégies de préservation de la qualité de l’air ;
-   la surveillance sur le long terme des effets écologiques des dépôts atmosphériques ;
-   la détection et l’évaluation des effets des dépôts atmosphériques à l’échelle locale, régionale et nationale ;
-   l’évaluation des risques pour les êtres humains et/ou les animaux via la chaîne alimentaire.
Le présent document est destiné à tous les acteurs impliqués dans la surveillance environnementale.

Zunanji zrak - Biomonitoring z višjimi rastlinami - Metoda standardizirane izpostavljenosti trave

General Information

• Status: Not Published
• Publication Date: 09-Aug-2026
• ICS: 13.040.20 - Ambient atmospheres
• Technical Committee: CEN/TC 264 - Air quality
• Drafting Committee: CEN/TC 264/WG 30 - Biomonitoring methods with flowering plants
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 20-Mar-2025
• Due Date: 24-Mar-2025
• Completion Date: 20-Mar-2025
• Ref Project: oSIST prEN 18168:2025 - Ambient air - Biomonitoring with higher plants - Method of the standardised grass exposure

Standards Content (Sample)

SLOVENSKI STANDARD
01-april-2025
Zunanji zrak - Biomonitoring z višjimi rastlinami - Metoda standardizirane
izpostavljenosti trave
Ambient air - Biomonitoring with higher plants - Method of the standardised grass
exposure
Außenluft - Biomonitoring mit Höheren Pflanzen - Verfahren der standardisierten
Graskultur
Air ambiant - Biosurveillance végétale - Méthode de la culture standardisée de ray-grass
Ta slovenski standard je istoveten z: prEN 18168
ICS:
13.040.20 Kakovost okoljskega zraka Ambient atmospheres
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2025
ICS 13.040.20
English Version
Ambient air - Biomonitoring with higher plants - Method
of the standardised grass exposure
Air ambiant - Biosurveillance végétale - Méthode de la Außenluft - Biomonitoring mit Höheren Pflanzen -
culture standardisée de ray-grass Verfahren der standardisierten Graskultur
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 264.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 18168:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Principle of the method . 9
5 Test methods . 10
5.1 Material . 10
5.1.1 Grass species and cultivar . 10
5.1.2 Substrate . 10
5.1.3 Fertiliser solution . 11
5.1.4 Water . 11
5.1.5 Exposure device. 11
5.2 Cultivation . 12
5.3 Exposure . 14
5.4 Exposure location . 14
5.5 Exposure duration . 15
6 Sampling and handling of samples . 15
6.1 General. 15
6.2 Sampling . 15
6.3 Transport . 16
6.4 Preparation of the samples . 16
6.5 Storage . 16
7 Documentation . 16
8 Data handling and data reporting . 17
8.1 Performance characteristics. 17
8.2 Study design and data handling/reporting in dependence on the required explanatory
power of the study . 17
9 Quality control and quality assurance . 17
9.1 Control of the plant material . 17
9.2 Requirements for the exposure locations . 17
9.3 Requirements for the sample quantity . 17
9.4 Analytical requirements. 17
10 Presentation of measured data . 18
11 Assessment . 18
11.1 General. 18
11.2 Reference values for comparison . 18
11.3 Threshold values . 18
Annex A (informative) Recommended upper limits for element concentrations in substrate . 20
Annex B (informative) Examples of exposure devices . 22
Annex C (informative) Plates: cultivation and sampling . 26
Annex D (informative) Sample preparation (before analysis) . 27
Annex E (informative) Examples of protocols for documentation . 28
Annex F (informative) Study design, data analysis and interpretation . 30
Annex G (informative) Reference data . 35
Bibliography . 40

European foreword
This document (prEN 18168:2025) has been prepared by Technical Committee CEN/TC 264 “Air
Quality”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
Introduction
The impact of air pollution is of growing importance worldwide. Local and regional assessment is
necessary as a first step to collect fundamental information, which can be used to avoid, prevent, and
minimize harmful effects on human health and the environment as a whole. Biomonitoring can serve as
a tool for such a purpose. As the effects on indicator organisms are a time-integrated result of complex
influences combining both air quality and local climatic conditions, this holistic biological approach is
considered particularly close to human and environmental health end points and thus is relevant to air
quality management.
It is important to emphasize that biomonitoring data are completely different from those obtained
through physico-chemical measurements (ambient concentrations and deposition) and computer
modelling (emissions data). Biomonitoring provides evidence of the effects that airborne pollutants have
on organisms. As such it reveals biologically relevant, field-based, time- and space-integrated indications
of environmental health as a whole. Legislation states that there should be no harmful environmental
effects from air pollution. Only by investigating the effects at the biological level can this requirement be
met. The application of biomonitoring in air quality and environmental management requires rigorous
standards and a recognized regime so that it can be evaluated in the same way as physico-chemical
measurements and modelling in pollution management.
Biomonitoring is the traditional way through which environmental changes have been detected
historically. Various standard works on biomonitoring provide an overview of the state of the science at
the time, e.g. [1; 2; 3]. The first investigations of passive biomonitoring are documented in the middle of
the 19th century: By monitoring the development of epiphytic lichens it was discovered that the lichens
were damaged during the polluted period in winter and recovered and showed strong growth in summer
[4]. These observations identified lichens as important bioindicators. Later investigations also dealt with
bioaccumulators. An active biomonitoring procedure with bush beans was first initiated in 1899 [5].
Biomonitoring and EU-legislation
Biomonitoring methods in terrestrial environments respond to a variety of requirements and objectives
of EU environmental policy primarily in the fields of air quality (Directive 2008/50/EC on ambient air,
[6]), integrated pollution prevention and control (IPPC; Directive 2010/75/EU, [7]) and conservation
(92/43/EEC on the Conservation of Natural Habitats and of Wild Fauna and Flora, [8]). The topics food
chain [9] and animal feed [10; 11; 12] are alluded to as well.
For air quality in Europe, the legislator requires adequate monitoring of air quality, including pollution
deposition as well as avoidance, prevention, or reduction of harmful effects. Biomonitoring methods
appertain to the scope of short-term and long-term air quality assessment.
Directive 2004/107/EC of 15 December 2004 relating to arsenic, cadmium, mercury, nickel, and
polycyclic aromatic hydrocarbons in ambient air [13] states that “the use of bio indicators may be
considered where regional patterns of the impact on ecosystems are to be assessed”.
Concerning IPPC from industrial installations, the permit procedure includes two particular
environmental conditions for setting adequate emission limit values. The asserted concepts of “effects”
and “sensitivity of the local environment” open a broad field for biomonitoring methods, in relation to
the general impact on air quality and the deposition of operational-specific pollutants. The basic
properties of biomonitoring methods can be used advantageously for various applications such as
reference inventories prior to the start of a new installation, the mapping of the potential pollution
reception areas and (long-term) monitoring of the impact caused by industrial activity. The
environmental inspection of installations demands the examination of the full
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