Standards Development

Scope

This document provides the scope and basic principles for a standardized method for the quantitative analysis and characterization of microplastics (MPs) in air. It establishes a consistent procedural framework covering the entire analytical process, from sampling to pretreatment, analysis, quantification, and characterization of airborne MPs.

This document addresses the collection of air samples using low- or high-volume samplers, recovery and pretreatment of samples using metal filters, and the determination of the number, size, shape, and polymer type of MPs by means of vibrational spectroscopic techniques (e.g., -FTIR or -Raman) coupled with an image processing system equipped with a microscope. The standardized approach aims to improve the reliability, reproducibility, and comparability of measurement results obtained by different laboratories and studies.

This document applies to the analysis of ambient air, recognizing that MPs can be present as a result of atmospheric transport, deposition, and resuspension and may coexist with particulate matters. It supports the generation of harmonized data for environmental monitoring of airborne MPs and the assessment of their potential impacts on human health and the environment.

This document is applicable to:

a) research institutes, testing and inspection laboratories, and academic bodies conducting quantitative and qualitative analyses of MPs in air;

b) governmental and public authorities involved in air quality management, environmental monitoring, and risk assessment related to airborne MPs;

c) industries and service providers engaged in the development of analytical instruments or managemental technologies for MPs in air.

Purpose

The purpose of this document is to establish a standardized and harmonized spectroscopic method for the quantitative determination and characterization of microplastics (MPs) in air. The document aims to provide a technically sound and internationally agreeable procedure that enables the generation of reliable, reproducible, and comparable data on airborne MPs.

MPs have been identified in all environmental compartments, including air, water, and soils. Especially, airborne MPs can be transported over long distances through atmospheric processes such as dispersion, deposition, and resuspension. Inhalation of airborne MPs has raised growing concern due to their potential impacts on human health. Despite increasing scientific attention and a rapidly growing body of research, there is currently no International Standard that specifies the method for accurately analysing MPs in air.

Existing ISO standards and draft standards address the analysis of MPs in water, textiles, and composts (see Table 1). However, these documents do not cover airborne MPs, which require different sampling strategies, pretreatment procedures, and analytical considerations. As a result, current studies on airborne MPs apply a wide variety of analytical approaches, leading to significant variability in reported results and limiting the comparability and usability of the data.

This document responds to this gap by proposing a standardized method for quantifying airborne MPs, which covers air sampling, sample pretreatment, and analysis using vibrational spectroscopic techniques coupled with image processing systems. By harmonizing analytical practices, the document will facilitate comparison of data between laboratories and investigators, support long-term environmental monitoring, and provide a reliable scientific basis for exposure assessment, risk evaluation, and policy development related to airborne MPs.

The development of this document is expected to support the work of regulatory authorities, research organizations, and industry by enabling consistent data generation and interpretation. It will also contribute to raising public confidence by addressing societal concerns regarding the presence of plastic particles in the air and their potential effects on human health and the environment.

Table 1— Relevant international standards in this field

Number Name Scope

ISO/DIS 5667-27 Water quality — Sampling - Part 27: Guidance on sampling for microplastics in water It specifies the methodology for the sampling of suspended microplastic particles in water for their subsequent characterisation which may include particle count, sizing, polymer identification and other physical or chemical analyses.

ISO/AWI 24899 A method for the extraction of biodegradable and non-biodegradable microplastics from compost It specifies a laboratory method for the extraction of non-biodegradable and biodegradable plastic particles including microplastics from compost matrices from industrial or home composting origin

ISO/DIS 16094 Water quality — Analysis of microplastic in water It specifies a method for the qualitative and quantitative analysis of microparticles of plastic or elastomeric materials in water using a microscopy technique coupled with vibrational spectroscopy

ISO/TR 21960:2020 Plastics — Environmental aspects — State of knowledge and methodologies It gives recommendations for three steps necessary for the standardization of methods towards harmonized procedures for sampling, sample preparation and analysis.

ISO 24187:2023 Principles for the analysis of microplastics present in the environment It specifies the principles to be followed in the analysis of microplastics in various environmental matrices

ISO 4484-2:2023 Textiles and textile products — Microplastics from textile sources - Part 2: Qualitative and quantitative analysis of microplastics It establishes a qualitative-quantitative analytical evaluation (i. e. determination) of microplastics.