
Jelle HofmanFlemish Institute for Technological Research | VITO · Sustainable Health
Jelle Hofman
PhD Bioscience Engineering
R&D Researcher @VITO
About
68
Publications
16,671
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Introduction
Working on innovative sensing technologies (IoT, sensors) and new methods for emerging pollutants (PFAS, UFPs, NH3). Data analysis (calibration, performance evaluation and spatiotemporal analysis) and methodological work (PFAS). Trying to bridge the gap between traditional (fixed-site) air quality monitoring and more fine-grained fixed & mobile monitoring applications for improved air quality exposure assessments.
Additional affiliations
February 2019 - July 2021
Position
- Researcher
Description
- Working on the potential of environmental sensors (air quality, microclimate) for Internet of Things (IoT) solutions in smart cities: - Sensor benchmarking & performance evaluation - Complementary sensor networks for environmental monitoring purposes - Indoor/outdoor ratio of PM and NO2 for smart building solutions - Indoor CO2 and comfort - AI/Machine Learning approaches for air quality interpolation in space and time
Education
September 2010 - September 2014
September 2008 - June 2010
September 2004 - June 2008
Publications
Publications (68)
Biomagnetic monitoring of atmospheric pollution is a growing application in the field of environmental magnetism. Particulate matter (PM) in atmospheric pollution contains readily-measurable concentrations of magnetic minerals. Biological surfaces, exposed to atmospheric pollution, accumulate magnetic particles over time, providing a record of loca...
Urban environments typically exhibit large atmospheric pollution variation, in both space and time. In contrast to traditional monitoring networks suffering from a limited spatial coverage, mobile platforms enable personalized high-resolution monitoring, providing valuable insights into personal atmospheric pollution exposure, and the identificatio...
Air quality improved significantly over the past decades. Nevertheless, air pollution continuous to have significant health impacts worldwide. To better assess people's exposure to air pollution, there is a need for higher, more personalized monitoring granularity. IoT sensor technologies can meet these requirements and pave the way towards more fi...
(1) Background: This work evaluated the usability of commercial “low-cost” air quality sensor systems to substantiate evidence-based policy making. (2) Methods: Two commercially available sensor systems (Airly, Kunak) were benchmarked at a regulatory air quality monitoring station (AQMS) and subsequently deployed in Kampenhout and Sint-Niklaas (Bel...
This study aimed to examine the validity of a mobile air quality sensor fleet in improving pollution exposure assessments in urban areas. The scope of this study involved experimental setup (sensor validation and calibration), evaluation of spatiotemporal data coverage, and analysis of the representativity of the collected mobile data. The results...
This study presents a fit-for-purpose lab and field evaluation of commercially available portable sensor systems for PM, NO2, and/or BC. The main aim of the study is to identify portable sensor systems that are capable of reliably quantifying dynamic exposure gradients in urban environments. After an initial literature and market study resulting in...
Mobile monitoring is used as an additional tool to collect air quality data at a high spatial resolution and to complement data from fixed air quality stations. Citizens are interested in contributing to air quality monitoring, and while the availability of low-cost air quality sensors can create opportunities to measure the air quality at a high s...
This study presents a fit-for-purpose evaluation of commercially available portable sensor systems, measuring PM, NO2 and/or BC, through extensive lab- and field benchmarking. The main aim of the study is to identify sensor systems that can be used for mobile monitoring by citizens to assess dynamic exposure in ambient air. After an initial literat...
Traditional fixed air quality monitoring networks fulfill requirements as set in the European Air Quality Directive (2008/50/EC) and provide valuable information on ambient concentrations and
temporal trends of air quality at the international, national, regional and urban level. Some shortlived pollutants or constituents, like ultrafine particle (...
Setting the scene: where do we stand in terms of technological developments on micro-sensors. Are sensors “fit-for-purpose” for stationary or mobile applications in cities?
Studying the air quality and exposure of the inhabitants of urban agglomerations to pollution is the basis for the creation and development of more sustainable cities. Although research on black carbon (BC) has not yet reached the official acceptable levels and guidelines, the World Health Organization clearly indicates the need to measure and cont...
Air pollution is currently regarded as top environmental threat for our health and top priority at the EU policy agenda (Zero Pollution EU Green Deal (1)). Moreover, more stringent EU regulations and newly emerging limit values can be expected following the WHO Guideline values. To face these challenges, cities will need to be prepared to provide t...
Humans are generally exposed to per- and polyfluoroalkyl substances (PFAS) through their diet. Whilst plenty of data are available on commercial food products, little information exists on the contribution of self-cultivated food, such as home-produced eggs (HPE), to the dietary PFAS intake in humans. The prevalence of 17 legacy and emerging PFAS i...
Urban air quality mapping has been widely applied in urban planning, air pollution control and personal air pollution exposure assessment. Urban air quality maps are traditionally derived using measurements from fixed monitoring stations. Due to high cost, these stations are generally sparsely deployed in a few representative locations, leading to...
Deze literatuurstudie geeft een overzicht van de nomenclatuur, eigenschappen en het algemeen voorkomen van PFAS (HOOFDSTUK 1), gekende bronnen en gemeten concentratieniveaus van PFAS in onze omgeving (HOOFDSTUK 2), beschikbare meetmethoden voor het bepalen van PFAS in de omgevingslucht (HOOFDSTUK 3) en de huidige kennis met betrekking tot thermisch...
Recent advances in sensor and IoT technologies allow for denser and mobile air quality measurements. These measurements are still spatiotemporally sparse at city-level, but can be interpolated using data-driven techniques. This work presents validation results of two machine-learning models to infer air quality sensor data in both space and time. T...
Graph neural networks (GNNs) have proven their ability in modelling graph-structured data in diverse domains, including natural language processing and computer vision. However, like other deep learning models, the lack of explainability is becoming a major drawback for GNNs, especially in health-related applications such as air pollution estimatio...
This blueprint was developed together with municipalities and the Flanders Environment Agency (VMM), based on insights from the project "Municipal sensor network for air quality measurements", a cooperation of municipalities Kampenhout, Sint-Niklaas, Schoten, Dilbeek and Oudenaarde, funded through the CoT call (2018) of the Flemish Agency for Innov...
One of the most widely available technologies to clean the air in homes of particulate matter of less than 2.5 µm in diameter (PM2.5), known to have negative health impacts, are portable home air purifiers (HAPs). This paper presents research which (1) explored the effectiveness of HAPs in real-world conditions in 57 homes in three European cities;...
Air pollution is difficult to detect with human senses. It is to a large extent out of sight and out of sense, while causing a burden on our economy, our health and our environment. A relevant illustration of this is the exposure to air pollution during commutes. The air pollution commuters are exposed to remains to a considerable extent a hidden g...
Air Pollution is difficult to detect with human senses. It is to a large extent, out of sight and out of sense, while causing a burden on our economy, our health and our environment. A relevant illustration of this is exposure to air pollution during commutes. The air pollution commuters are exposed to remains to a considerable extent an hidden geo...
PFAS kunnen in het milieu terechtkomen via de productie of afvalstromen en kunnen zeer persistent zijn in het milieu en in het menselijk lichaam. PFAS kunnen voorkomen in de verschillende afvalstromen, wat problemen kan opleveren voor de uiteindelijke verwijdering. PFAS-verbindingen zijn moeilijk af te breken door de elektronegativiteit van fluor e...
Particulate matter (PM) deposition on urban green enables the collection of particulate pollution from a diversity of contexts, and insight into the physico-chemical profiles of PM is key for identifying main polluting sources. This study reports on the morphological and elemental characterization of PM2–10 deposited on ivy leaves from five differe...
Air quality monitoring in heterogeneous cities is challenging as a high resolution in both space and time is required to accurately assess population exposure. As regulatory monitoring networks are sparse due to high investment and maintenance costs, recent advances in sensor and IoT technologies have resulted in innovative sensing approaches like...
In recent years, low-cost air quality sensor technologies disrupted the field of environmental sensing, resulting in a wide range of applications in research-, policy-, commercial-and citizen science-oriented initiatives. Sensors provide promising low-threshold tools for air quality monitoring, tackling some of the major current limitations of regu...
Air quality monitoring in heterogeneous cities is challenging as a high resolution in both space and time is required to accurately assess population exposure. As regulatory monitoring networks are sparse due to high investment and maintenance costs, recent advances in sensor and IoT technologies have resulted in innovative sensing approaches like...
One of the main challenges of today's policy makers is to conduct evidence based decision making in order to proof the public that local environmental interventions are effective and efficient. Providing environmental information at a representative spatial and temporal granularity is challenging but indispensable to engage the general public in ad...
Monitoring air quality in cities is challenging as a high resolution in both space and time is required to accurately assess population exposure. This paper presents an innovative IoT approach for highly granular air quality mapping in cities relying on (1) a combination of cloud-calibrated fixed and mobile air quality sensors and (2) machine learn...
In confined spaces, such as vehicle cabins, air quality can easily improve or deteriorate as it can be considered as a semi-controlled environment. By controlling the indoor-outdoor exchange rate using the vehicle's ventilation system or by opening or closing of windows, car drivers have the ability to control their exposure to both indoor and outd...
Particulate black carbon has a range of negative impacts on health, the environment and climate, however despite this there are relatively few long-term studies on its ambient distribution as a tropospheric air pollutant. In order to address this lack of data, to help to provide greater insight into the spatio-temporal distribution of particulate b...
Air pollution is becoming an important environmental issue and attracting increasing public attention. In urban environments, air pollution changes very dynamically both with time and space and is affected by a large variety of factors such as road type, urban architecture, land use and variety of emission sources. In order to better understand the...
Internet of Things (IoT) technologies incorporate a large number of different sensing devices and communication technologies to collect a large amount of data for various applications. Smart cities employ IoT infrastructures to build services useful for the administration of the city and the citizens. In this paper, we present an IoT pipeline for a...
One of the main challenges of today's policy makers is to conduct informed decision making in order to proof the public that local environmental interventions are effective and efficient. Providing this information in a relevant spatial and temporal resolution for the local policy makers is challenging but indispensable to engage the general public...
Atmospheric dust deposition on plants enables the collection of site-specific particulate matter (PM). Knowing the morphology and composition of PM aids in disclosing their emitting sources as well as the associated human health risk. Therefore, this study aimed for a leaf-level holistic analysis of dust accumulation on plant leaves. Plant species...
As real-life experimental data on natural ventilation of atmospheric pollution levels in urban street canyons is still scarce and has proven to be complex, this study, experimentally evaluated the impact of an urban street canyon opening on local atmospheric pollution levels, during a 2-week field campaign in a typical urban street canyon in Antwer...
Bacterial endotoxins are a component of particulate matter (PM) with anticipated health implications, yet we know little about how host reception of endotoxin through toll-like receptor 4 (TLR4) is affected
by its association with other PM components. Subsequently, we investigated the relationship between endotoxin concentration (recombinant Factor...
Environmental magnetism, and the magnetic leaf signal in particular, is amply investigated and applied as proxy for atmospheric particulate matter pollution. In this study, we investigated the magnetic signal of annual segments of tree branches, and the composition of particles deposited hereon. Branches are, contrary to leaves, available during le...
SI1: Theoretical background on different magnetic minerals, their responses to an induced magnetic field, magnetic units, domain states and grain sizes.
SI2: Inventory table of reported magnetic studies on pumped-air filters and biological sensors.
Video on my PhD research on biomagnetic monitoring of tree leaves in urban environments, in the context of the EOS pipet 2014 award
Atmospheric particulate pollution is a significant problem across the EU and there is concern that there may be an increasing contribution from biomass burning, driven by rising fuel prices and an increased interest in the use of renewable energy sources. This study was carried out to assess current levels of biomass burning and their contribution...
This report describes 2-year long measurements of ultrafine particles (UFP) and black carbon (BC) at
four monitoring stations and a mobile trailer in the North-West European region. The study was carried
out as part of the Joint Air Quality Initiative (Joaquin project, Work Package 1 Action 1 and 3).
Current European air quality legislation is centred on monitoring, limiting and reducing mass concentrations of airborne particles. However, recent toxicological and epidemiological research argues that new particle metrics may constitute better links to health endpoints than mass concentration. For instance, the potential of inhaled ultrafine part...
Work package 1 of Joaquin aimed at a better understanding of UFP’s in urban environments by evaluating the temporal variation of UFP number concentration and size distribution in four NW- European cities (Amsterdam, Antwerp, Leicester and London). Apart from the temporal variation, relations of UFP with more commonly monitored pollutants such as ni...
Although the total particle mass of PM10 and PM2.5 is currently measured to assess air quality, the number and composition of particulates are believed to be the key determinants in causing illness. This is information that does not generally exist outside the research arena and its acquisition is imperative for us to better understand the air poll...
Presentation on the UFP results from the Joint Air Quality Innitiative (Joaquin) monitoring campaigns in Amsterdam, Antwerp, Leicester and London.
Increasing the spatial resolution of air quality assessments in urban environments is designated as a priority area within current research. Biomagnetic monitoring and air quality modelling are both methodologies able to provide information about the spatial variation of particulate pollutant levels within urban environments. This study evaluates b...
Objective:
Determination of weight, size fraction and magnetism of leaf deposited particles in an urban street canyon.
Conclusions:
• Urban Plane trees have a considerable filtration capacity, especially for the fine (PM 3) fraction.
• While the leaf deposited particulate weight (and thus also the SIRM) is dominated mostly by the largest size fra...
Objective
Is biomagnetic tree leaf monitoring a good proxy to evaluate the spatial distribution of particulate matter in an urban street canyon?
Conclusion
o First study to present biomagnetic monitoring results at such a small spatial scale
o Leaf biomagnetic monitoring is a useful tool to evaluate spatial PM distribution, even within a single...
To circumvent difficulties associated with monitoring adult predatory birds, we investigated the feasibility of different non-destructive strategies for nestling white-tailed eagles (Haliaeetus albicilla). We were able to quantify polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorinated pesticides (OCPs) in bod...
Questions
Question (1)
Based on a short review, I found SEM-EDX (particle-based) and ED-XRF, ICP-MS, ICP-OES, ICP-AES, AAS,... (bulk). What method should be preferred and why? Filter material consists of teflon-coated borosilicate filters and Nuclepore track-etched polycarbonate membranes (Whatman).
I'm interested in the following elements: Cu, Cr, V, Mn, Fe, Ni, Zn, Pb, Ca, Na, Mg, Al, As