Black Carbon (BC) is one of the most significant components of atmospheric particulate matter generated by combustion processes. In recent years, the scientific interest in this pollutant has grown significantly due to both its effects on public health and its contribution to climate change. International organizations such as the World Health Organization (WHO) and the European Environment Agency (EEA) recognize the increasing importance of monitoring the carbonaceous components of atmospheric particulate matter, particularly BC, to better understand the impacts of air pollution on health and the environment.<\/p>\n\n\n\n
From a regulatory perspective, Black Carbon has been included among the parameters subject to monitoring under Directive (EU) 2024\/2881<\/a> on ambient air quality. However, a harmonized measurement method at the European level is still being defined.<\/p>\n\n\n\n In this article, we explore the role of BC in air quality monitoring, examining its effects on human health and climate, the main methodologies used for its determination, and the technologies currently available for its monitoring. We also present the principal instruments employed in scientific and environmental applications, ranging from optical techniques to advanced systems for the characterization of carbonaceous aerosols, while providing an overview of future perspectives and ongoing standardization activities aimed at establishing shared criteria for Black Carbon measurement.<\/p>\n\n\n\n Black Carbon is produced primarily by the incomplete combustion of fossil fuels, biomass, and oils. It belongs to the category of carbonaceous aerosols, a complex family of particles that includes different forms of carbon present in the atmosphere, and is characterized by a strong ability to absorb light radiation across much of the visible and infrared spectrum.<\/p>\n\n\n\n In scientific literature, the term Black Carbon is commonly used to identify the carbonaceous fraction of particulate matter determined through optical techniques, that is, methods based on the measurement of light attenuation and\/or light absorption.<\/p>\n\n\n\n Interest in BC has grown significantly in recent years as evidence of its impact on human health has increased. Numerous epidemiological studies have highlighted a correlation between exposure to carbonaceous aerosols and an elevated risk of cardiovascular and respiratory diseases. Black Carbon particles are predominantly found within the fine particulate fraction and can penetrate deep into the respiratory system, reaching the pulmonary alveoli and, in some cases, entering the bloodstream.<\/p>\n\n\n\n In addition to its health impacts, BC plays an important role in the climate system. Owing to its optical properties and high capacity to absorb solar radiation, it is considered the primary anthropogenic light-absorbing component in the atmosphere. Consequently, it contributes to atmospheric warming and can influence various climatic processes at both local and global scales.<\/p>\n\n\n\n Today, Black Carbon is regarded not only as an indicator of air quality but also as a key parameter in climate change mitigation strategies.<\/p>\n\n\n\n Although European legislation still focuses primarily on monitoring PM10 and PM2.5 concentrations, interest is growing in the integration of additional indicators capable of improving the understanding of the effects of air quality on health and the environment.<\/p>\n\n\n\n The inclusion of Black Carbon in Directive EU 2024\/2881<\/a> represents an important step forward in the effort to improve the understanding and monitoring of atmospheric pollutants. However, for data collected across European countries to be reliably compared, harmonized and standardized measurement methodologies are required.<\/p>\n\n\n\n At present, no dedicated CEN standard exists for BC monitoring. The available measurement techniques encompass several instrumental approaches, each characterized by specific advantages, limitations, and measurement principles. The development of a European standard would improve data comparability among monitoring networks, support future environmental policies, and provide a more accurate assessment of the effects of BC on health and climate.<\/p>\n\n\n\n European standardization activities in the field of air quality are coordinated by CEN\/TC 264 “Air Quality”, the CEN Technical Committee responsible for developing and updating standards related to air quality monitoring.<\/p>\n\n\n\n Within this framework, the revision of EN 16909:2017<\/a> is currently underway. The standard addresses the determination of Elemental Carbon (EC) and Organic Carbon (OC) content in PM2.5<\/a> atmospheric particulate matter. Its revision provides an opportunity to update existing procedures according to the latest scientific evidence and emerging needs in the monitoring of carbonaceous aerosols.<\/p>\n\n\n\n PM_TEN actively participates in this process through its experts, appointed by UNI – Ente Italiano di Normazione<\/a> (the Italian National Standardization Body) as Italian representatives within the working group.<\/p>\n\n\n\n During the Working Group meeting held on 1-2 October 2026, one of the topics discussed was the launch of activities aimed at establishing a new subgroup dedicated to the study of methodologies for Black Carbon determination. This initiative highlights the growing attention that the European technical and regulatory community is devoting to BC and may represent the first step toward the development of a future harmonized European reference method.<\/p>\n\n\n\n UNI is the national standardization body that represents Italy in major European and international standardization activities and contributes to the development of technical standards across numerous industrial, scientific, and environmental sectors.<\/p>\n\n\n\n PM_TEN’s participation in these activities allows the company to bring its expertise in atmospheric particulate monitoring, carbonaceous aerosol characterization, and the development of innovative Black Carbon measurement solutions to technical discussions. Direct collaboration with research institutes, environmental agencies, laboratories, and instrument manufacturers from across Europe provides an important opportunity to contribute to the evolution of future measurement methodologies and the standards that will guide BC monitoring in the years ahead.<\/p>\n\n\n\n The methodologies used for measuring carbonaceous aerosols can be broadly grouped into two categories: optical techniques and thermal-optical techniques.<\/p>\n\n\n\n Thermal-optical techniques are primarily used to determine the content of Elemental Carbon (EC) and Organic Carbon (OC)<\/a> in particulate samples collected on filters. These methods are currently among the main scientific references for characterizing the carbonaceous components of atmospheric particulate matter and are widely applied in chemical speciation studies and environmental monitoring activities.<\/p>\n\n\n\n Optical techniques, on the other hand, rely on the ability of Black Carbon to absorb light radiation. By measuring light absorption, it is possible to estimate the BC concentration present in the atmosphere. For this reason, the resulting parameter is more accurately defined as Equivalent Black Carbon (eBC), an indirect estimate of the mass concentration of light-absorbing particles derived from the optical properties of particulate matter.<\/p>\n\n\n\n Optical determination of Black Carbon generally involves two steps. First, the light absorption coefficient (babs<\/sub>) is measured on a filter sample. This parameter is then converted into eBC concentration through the application of a factor known as the Mass Absorption Cross-section (MAC), which represents the absorption efficiency of carbonaceous particles.<\/p>\n\n\n\n The correct selection of the MAC value is one of the most critical aspects in obtaining reliable estimates of Black Carbon concentrations.<\/p>\n\n\n\n Recent scientific evidence suggests that MAC cannot be considered a universal value. Instead, it depends on monitoring site characteristics, seasonal conditions, emission sources, and particle physical properties. Consequently, the use of locally derived MAC values, determined through simultaneous measurements of optical absorption and Elemental Carbon, is often recommended to reduce uncertainty in eBC estimates.<\/p>\n\n\n\n A variety of technologies are currently available for Black Carbon measurement, each designed to address specific monitoring and research requirements.<\/p>\n\n\n\n Among the most widely used instruments are aethalometers, which estimate BC concentrations by measuring light attenuation caused by particles deposited on a glass-fiber filter tape. Their capability to provide real-time data makes them extensively used in air quality monitoring networks. However, this technique may be affected by artifacts related to filter loading, particulate morphology, and multiple scattering effects.<\/p>\n\n\n\n Another widely adopted technology is the MAAP (Multi-Angle Absorption Photometer), which combines transmission and scattering measurements to provide a more accurate estimate of aerosol optical absorption. Although production of the MAAP has been discontinued in recent years, it remains one of the most authoritative reference instruments for aerosol absorption measurements due to its low uncertainty and its approach of simultaneously accounting for transmitted and scattered light.<\/p>\n\n\n\n Scientific research also employs more advanced instruments such as photoacoustic systems, which measure the energy absorbed by particles as an acoustic signal, and laser-induced incandescence instruments, which characterize absorbing carbon at the level of individual BC particles.<\/p>\n\n\n\n For advanced characterization of carbonaceous aerosols, multi-spectral analyzers such as the MWAA (Multi-Wavelength Absorption Analyzer) are also used. These instruments enable the study of particulate optical properties on collected filters and support source apportionment investigations.<\/p>\n\n\n\n Alongside ground-based measurements, satellite-based approaches using Aerosol Optical Depth (AOD) observations allow the assessment of aerosol distribution and evolution at regional and global scales.<\/p>\n\n\n\n Comparison of the main techniques and instruments for measuring Black Carbon:<\/p>\n\n\n\n The available technologies address complementary monitoring needs. Continuous monitoring instruments allow the temporal evolution of Black Carbon concentrations to be tracked, while laboratory techniques provide deeper insight into the chemical and optical characteristics of collected particulate matter.<\/p>\n\n\n\n As part of its monitoring and research activities, PM_TEN uses the MWAA<\/a> (Multi-Wavelength Absorption Analyzer) for post-sampling filter analysis. This technology enables the determination of aerosol absorption properties at multiple wavelengths and supports source apportionment studies, helping to identify emission sources more effectively.<\/p>\n\n\n\nThe Importance of Monitoring<\/mark> Black Carbon<\/h2>\n\n\n\n
The Effects of Black Carbon on Health and Climate<\/h3>\n\n\n\n
Towards a European Standard<\/mark> for Black Carbon: The Work of CEN<\/h2>\n\n\n\n
CEN\/TC 264 and the New Black Carbon Subgroup<\/h3>\n\n\n\n
PM_TEN’s Participation as UNI’s Italian Delegate<\/h3>\n\n\n\n
Techniques<\/mark> and Methods<\/mark> for Monitoring Black Carbon<\/h2>\n\n\n\n
Main Methodologies<\/h3>\n\n\n\n
Optical Techniques and Equivalent Black Carbon (eBC)<\/h4>\n\n\n\n
The Role of MAC in Black Carbon Estimation<\/h4>\n\n\n\n
Main Instrumentation<\/h3>\n\n\n\n
Instruments for Continuous Monitoring: Aethalometers and MAAP<\/h4>\n\n\n\n
Instruments for Research and Advanced Characterization<\/h4>\n\n\n\n
Technique \/ instrument<\/strong><\/th> Measurement principle<\/strong><\/th> Quantity<\/strong><\/th> Real time<\/strong><\/strong><\/th> Typical context of use<\/strong><\/th><\/tr><\/thead> Thermo-optical (OC\/EC analyzer)<\/td> Thermal analysis of the sample on a filter, with optical correction for charring<\/td> EC, OC<\/td> No, laboratory<\/td> Reference for characterization (UNI EN 16909) and for estimating the local MAC<\/td><\/tr> Aethalometer<\/td> Attenuation of light through a filter tape, at multiple wavelengths<\/td> eBC<\/td> Yes<\/td> Air quality monitoring networks, supersites<\/td><\/tr> MAAP<\/td> Light transmission and scattering at multiple angles on a filter<\/td> eBC<\/td> Yes<\/td> Reference and background stations (production discontinued)<\/td><\/tr> Photoacoustic<\/td> Energy absorbed by suspended particles, converted into an acoustic signal<\/td> Absorption, eBC<\/td> Yes<\/td> Scientific research<\/td><\/tr> Laser-induced incandescence<\/td> Incandescence of individual particles heated by a laser<\/td> rBC<\/td> Yes<\/td> Research, characterization of individual particles<\/td><\/tr> MWAA<\/td> Absorption at multiple wavelengths on an already-sampled filter<\/td> eBC, spectral absorption, source contributions<\/td> No, post-sampling<\/td> Source apportionment studies<\/td><\/tr> GIANO BC1<\/td> Regulatory sampling of PM10 or PM2.5 and optical measurement of BC on the same filter<\/td> PM, eBC<\/td> Near real time<\/td> Environmental monitoring with subsequent analyses on the sample<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n Focus on Instrumentation<\/mark><\/h2>\n\n\n\n