Comparing the BAMA indoor air and ConsExpo inhalation models

Voor chemische stoffen die onder REACh gereguleerd worden en die bedoeld zijn om in consumentenproducten gebruikt te worden, vereist REACh een z.g. 'Chemical Safety Assessment (CSA)'. In een dergelijke CSA moet gedemonstreerd worden dat het gebruik van de stof in een consumentenproduct veilig is. Bij gebrek aan blootstellingsgegevens kan bij het maken van een CSA gebruik gemaakt worden van blootstellingmodellering. Er bestaan verschillende modellen voor de schatting van de blootstelling van consumenten aan chemische stoffen. Voor stoffen uit consumentenproducten in spuitbussen m.n. zijn er twee modellen die waarschijnlijk veelvudig gebruikt zullen worden bij de ontwikkeling van CSAs. Dit zijn het 'Indoor Air' model van de 'British Aerosol Manufacturers Association (BAMA)' en het spuitbus model uit het ConsExpo programma dat is ontwikkeld door het RIVM. Voor een beoordeling van de kwaliteit van een CSA, zoals die door de industrie worden gemaakt, is het belangrijk goed inzicht te krijgen in de verschillen en overeenkomsten tussen verschillende methodes en modellen die in de praktijk gebruikt kunnen worden. In dit rapport worden de BAMA en het ConsExpo programma met elkaar vergeleken, In het rapport worden de aannames en modelstructuur van beide modellen beschreven. De verschillen tussen beide modellen worden aan de hand van simulaties geïllustreerd. Het BAMA model is op meer versimpelende aannames gebaseerd dan het ConsExpo spuitmodel. Deze vereenvoudigingen zijn met name van belang als het model gebruikt wordt voor het schatten van de blootstelling aan niet-vluchtige stoffen in spuitbussen die vrijkomen als aerosoldeeltjes. Voor dit type stoffen geeft het BAMA model hogere schattingen dan het ConsExpo spuitmodel. Het is de verwachting dat de BAMA schattingen in de meeste van deze gevallen onrealistisch hoog zijn. Het model is slechts geschikt voor een ruwe schatting van de mogelijke blootstelling aan deze stoffen. Een andere beperking van het BAMA model is de aanname dat het gespoten materiaal onmiddellijk vrijkomt. Deze aanname beperkt de toepasbaarheid van het BAMA model bij het schatten van kortdurige (acute) blootstellingen. Het is aan te nemen dat het BAMA model alleen geschikt is voor het schatten van langer durende blootstellingen.For chemical substances regulated under REACh, that are intended to be used in consumer products, REACh regulation requires that safe use of chemicals in these products is demonstrated. Such Chemical Safety Assessments (CSAs) require an evaluation of the consumer exposure to the chemical substances in the product. Due of the lack of data on exposure, this evaluation is often done by modelling. Various tools to estimate human exposure from consumer products exist. Specifically, for substances contained in consumer spray products, two modelling tools are expected to be frequently used in the development of Chemical Safety Reports: the BAMA Indoor Air model and ConsExpo. The first tool is developed by the British Aerosol Manufacturers Association (BAMA), ConsExpo is developed at RIVM. For the evaluation of Chemical Safety Reports provided by industry, insight in the differences and similarities of alternative tools and methods is required. In this report a comparison between BAMA indoor air model and ConsExpo has been made. The assumptions and structure of both models are described. In simulations the differences in models are illustrated. The BAMA model is build on simpler assumptions than the ConsExpo spray model. The simplifications in the BAMA model are especially important in cases where the model is used to estimate exposure to low-volatile substances in sprays that are released as aerosol droplets. In these applications the BAMA model will give higher estimates than the ConsExpo model. The BAMA model predictions are expected to be unrealistically high in most of these cases. The model is only suited for screening of potential exposure for these substances. A second limitation in the BAMA model is the assumption of instantaneous release of material. This assumption limits the applicability of the model to evaluation of short term (acute) exposures. The BAMA model is expected to be only suited for estimating longer term exposures.VW

Aggregatie van de humane blootstelling aan chemische stoffen: een overzicht van computermodellen en methoden

Alleen digitaal verschenenDagelijks staat de consument bloot aan chemische stoffen die zijn verwerkt in verschillende (non-food) producten. Om de gevolgen voor de volksgezondheid te kunnen beoordelen moet in de eerste plaats de blootstelling bepaald worden. De optelsom van de totale (geaggregeerde) blootstelling aan een stof uit verschillende consumentenproducten (denk bijvoorbeeld aan geurstoffen, vlamvertragers, weekmakers) moet kunnen worden vastgesteld. Dit rapport kijkt in welke mate bestaande computermodellen geschikt zijn om geaggregeerde blootstelling aan chemische stoffen uit consumentenproducten te bepalen. Op dit moment berekenen de Europese beoordelingskaders deze geaggregeerde consumentenblootstelling (non-food) nog niet routinematig. Als eerste aanzet tot het opvullen van dit hiaat beschrijft dit rapport een methode waarmee een dergelijke geaggregeerde blootstellingsbepaling kan worden uitgevoerd.Available computer models for estimating the exposure to substances from multiple consumer products are not suited for this task. Consumers are daily exposed to chemical substances from consumer products. The level of this exposure has to be assessed to evaluate the consequences of exposure to a substance for public health. Considering that a substance may be contained in several consumer products (for instance, aromatic substances, flame retardants and softeners), the contribution of these products to the total exposure will have to be added up to determine the aggregate exposure. Aggregate consumer (non-food) exposure is not routinely evaluated in European assessment frameworks. This report examines to what extent available computer models are suited for evaluating aggregate exposure to consumer products. A method for performing aggregate exposure assessment is also described.AFSSE

ConsExpo - Consumenten blootstellings- en opnamemodellen - Programma handleiding

Dit rapport is een handleiding voor het gebruik van ConsExpo 4.0, de opvolger van ConsExpo 3.0, een computer programma dat is ontwikkeld ter ondersteuning van de blootstellingsschatting van stoffen in consumentenproducten. Er is een grote verscheidenheid aan consumentenproducten, consumenten en wijzen waarop deze consumenten producten gebruiken. Gemeten blootstellingsniveaus aan stoffen in producten zijn niet altijd voorhanden. Bij afwezigheid van deze gegevens kan ConsExpo 4.0 gebruikt worden om blootstellingen te schatten voor verschillende blootstellingsscenario's. Het programma biedt een aantal algemeen toepasbare blootstellingsmodellen en een database met gegevens over blootstellingsfactoren. Tezamen bieden modellen en database een uitgangspunt van waaruit blootstelling van een specifiek product geschat kan worden. Daarnaast kan ConsExpo 4.0 inzicht geven in de factoren die de blootstellingsniveaus van stoffen in consumentenproducten beinvloeden door gebruik te maken van de mogelijkheden van gevoeligheidsanalyse en probabilistische berekeningen. Bij de ontwikkeling van ConsExpo 4.0 is speciaal aandacht besteed aan het verbeteren van de transparantie en de gebruikersvriendelijkheid van de software. Dit rapport geeft een overzicht van ConsExpo 4.0, een uitleg van de beschikbare blootstellings- en opname modellen en belangrijke informatie met betrekking tot het interpreteren van de blootstellingsschatting.This report provides guidance to the use of ConsExpo 4.0, successor to ConsExpo 3.0, a computer program that was developed to assist in the exposure assessment of compounds in non-food consumer products. The wide range of available consumer products is associated with an even wider variation in consumers and product use. Measured data on exposure to compounds in products is not always available. In the absence of these data, ConsExpo 4.0 can be used to estimate the exposure for different exposure scenarios. The program offers a number of generally applicable exposure models and a database with data on exposure factors for a broad set of consumer products. Together, database and models provide the tools to assess exposure for a wide range of consumer products, whereby only basic additional information on product composition and the physicochemical properties of the compound of interest are needed. Moreover, ConsExpo 4.0 can be used to obtain insight in the factors affecting exposure levels to compounds in consumer product by using the tools of sensitivity analysis and probabilistic calculation. In the development of the fourth version of the program special effort has been taken to improve transparency and ease of use of the software. This report provides an overview of ConsExpo 4.0, an explanation of the available exposure and uptake models in ConsExpo 4.0 and important notes on the interpretation of the exposure assessment.VW

Vergelijking van modellen om consumentenblootstelling te berekenen. Inventarisatie van mogelijke verbeteringen van ConsExpo

ConsExpo is een geschikt computerprogramma met rekenmodellen om de mate van blootstelling van mensen aan stoffen in consumentenproducten te schatten. Het programma kan verder verbeterd worden door bepaalde elementen uit andere bestaande rekenmodellen over te nemen. In ConsExpo wordt rekening gehouden met verschillende manieren van blootstelling: via de huid, via inhalatie en via orale opname. Bij het programma hoort een database, waarin standaardwaarden en blootstellingscenario's (wie wordt waar en hoe blootgesteld aan wat en hoe vaak) voor vele producttypen worden aangeboden (bijvoorbeeld cosmetica, verf, reinigingsmiddelen, ongediertebestrijdingsmiddelen en desinfectantia). De beschrijving van deze standaardwaarden en blootstellingscenario's wordt gerapporteerd in zogenoemde 'fact sheets'. Om ConsExpo verder te kunnen verbeteren is een vergelijking gemaakt met andere bestaande rekenmodellen. In de inventarisatie werd gekeken of deze modellen blootstellingscenario's, wiskundige methoden of andere aspecten bevatten die een nuttige aanvulling kunnen zijn voor ConsExpo. Uit de inventarisatie bleek dat ConsExpo zeer geschikt is om de blootstelling te schatten voor stoffen in consumentenproducten. In andere rekenmodellen werden namelijk geen blootstellingscenario's aangetroffen, die niet met ConsExpo berekend kunnen worden. Wel zijn er wiskundige methoden en andere elementen gevonden die voor ConsExpo van groot belang kunnen zijn. Zo kunnen sommige rekenmodellen blootstelling aan stoffen uit meerdere producten berekenen. De berekening van deze zogenaamde 'geaggregeerde blootstelling' zal mogelijk een rol gaan spelen in de risicoschatting van chemische stoffen onder de toekomstige wetgeving in de EU (REACH).ConsExpo is a suitable computer software programme with mathematical models for assessing the exposure of consumers to chemicals in consumer products. This tool can be further improved by adopting certain features from other existing consumer exposure modelling tools. In ConsExpo, different routes of exposure are taken into account, such as the route via the skin, and through inhalation and oral uptake. An important feature of ConsExpo 4.1 is that it contains a database with default values and standard exposure scenarios (who is exposed? where? how? and how often?) for a wide range of consumer product types. Examples include cosmetics, paint, cleaning products, pest control products and disinfectants. The default values and exposure scenarios are described in detail in fact sheets. ConsExpo was compared with other existing consumer modelling tools in an investigation to discover whether the tools contained any exposure scenarios, mathematical models or other features that might be useful for ConsExpo. The aim of the study was to find features that may improve this version (4.1). The investigation demonstrated that ConsExpo is very suitable for assessing exposure to chemicals in consumer products. The other tools did not contain any exposure scenarios for which assessment with ConsExpo is not possible. Nonetheless, a number of mathematical models and other software features have been found that may be of importance to ConsExpo. For example, some tools are capable of assessing exposure to a chemical in multiple products. Assessment of this so-called 'aggregate exposure' will possibly play an important role in the risk assessment of chemicals in future legislation in the EU (REACH).VW

Exposure modelling in Europe : how to pave the road for the future as part of the European Exposure Science Strategy 2020-2030

Exposure models are essential in almost all relevant contexts for exposure science. To address the numerous challenges and gaps that exist, exposure modelling is one of the priority areas of the European Exposure Science Strategy developed by the European Chapter of the International Society of Exposure Science (ISES Europe). A strategy was developed for the priority area of exposure modelling in Europe with four strategic objectives. These objectives are (1) improvement of models and tools, (2) development of new methodologies and support for understudied fields, (3) improvement of model use and (4) regulatory needs for modelling. In a bottom-up approach, exposure modellers from different European countries and institutions who are active in the fields of occupational, population and environmental exposure science pooled their expertise under the umbrella of the ISES Europe Working Group on exposure models. This working group assessed the state-of-the-art of exposure modelling in Europe by developing an inventory of exposure models used in Europe and reviewing the existing literature on pitfalls for exposure modelling, in order to identify crucial modelling-related strategy elements. Decisive actions were defined for ISES Europe stakeholders, including collecting available models and accompanying information in a living document curated and published by ISES Europe, as well as a long-term goal of developing a best-practices handbook. Alongside these actions, recommendations were developed and addressed to stakeholders outside of ISES Europe. Four strategic objectives were identified with an associated action plan and roadmap for the implementation of the European Exposure Science Strategy for exposure modelling. This strategic plan will foster a common understanding of modelling-related methodology, terminology and future research in Europe, and have a broader impact on strategic considerations globally.Peer reviewe

Risk Governance of Nanomaterials: Review of Criteria and Tools for Risk Communication, Evaluation, and Mitigation

Nanotechnologies have been increasingly used in industrial applications and consumer products across several sectors, including construction, transportation, energy, and healthcare. The widespread application of these technologies has raised concerns regarding their environmental, health, societal, and economic impacts. This has led to the investment of enormous resources in Europe and beyond into the development of tools to facilitate the risk assessment and management of nanomaterials, and to inform more robust risk governance process. In this context, several risk governance frameworks have been developed. In our study, we present and review those, and identify a set of criteria and tools for risk evaluation, mitigation, and communication, the implementation of which can inform better risk management decision-making by various stakeholders from e.g., industry, regulators, and the civil society. Based on our analysis, we recommend specific methods from decision science and information technologies that can improve the existing risk governance tools so that they can communicate, evaluate, and mitigate risks more transparently, taking stakeholder perspectives and expert opinion into account, and considering all relevant criteria in establishing the risk-benefit balance of these emerging technologies to enable more robust decisions about the governance of their risks

Assessing Human Exposure to SVOCs in Materials, Products, and Articles : A Modular Mechanistic Framework

A critical review of the current state of knowledge of chemical emissions from indoor sources, partitioning among indoor compartments, and the ensuing indoor exposure leads to a proposal for a modular mechanistic framework for predicting human exposure to semivolatile organic compounds (SVOCs). Mechanistically consistent source emission categories include solid, soft, frequent contact, applied, sprayed, and high temperature sources. Environmental compartments are the gas phase, airborne particles, settled dust, indoor surfaces, and clothing. Identified research needs are the development of dynamic emission models for several of the source emission categories and of estimation strategies for critical model parameters. The modular structure of the framework facilitates subsequent inclusion of new knowledge, other chemical classes of indoor pollutants, and additional mechanistic processes relevant to human exposure indoors. The framework may serve as the foundation for developing an open-source community model to better support collaborative research and improve access for application by stakeholders. Combining exposure estimates derived using this framework with toxicity data for different end points and toxicokinetic mechanisms will accelerate chemical risk prioritization, advance effective chemical management decisions, and protect public health.Peer reviewe

The probabilistic aggregate consumer exposure model (PACEM): Validation and comparison to a lower-tier assessment for the cyclic siloxane D5

a b s t r a c t a r t i c l e i n f o Current practice of chemical risk assessment for consumer product ingredients still rarely exercises the aggregation of multi-source exposure. However, focusing on a single dominant source/pathway combination may lead to a significant underestimation of the risk for substances present in numerous consumer products, which often are used simultaneously. Moreover, in most cases complex multi-route exposure scenarios also need to be accounted for. This paper introduces and evaluates the performance of the Probabilistic Aggregate Consumer Exposure Model (PACEM) applied in the context of a tiered approach to exposure assessment for ingredients in cosmetics and personal care products (C&PCPs) using decamethylcyclopentasiloxane (D5) as a worked example. It is demonstrated that PACEM predicts a more realistic, but still conservative aggregate exposure within the Dutch adult population when compared to a deterministic point estimate obtained in a lower tier screening assessment. An overall validation of PACEM is performed by quantitatively relating and comparing its estimates to currently available human biomonitoring and environmental sampling data. Moderate (by maximum one order of magnitude) overestimation of exposure is observed due to a justified conservatism built into the model structure, resulting in the tool being suitable for risk assessment

Quantitative Microbial Risk Assessment of Contracting COVID-19 Derived from Measured and Simulated Aerosol Particle Transmission in Aircraft Cabins

BACKGROUND: SARS-CoV-2 can be effectively transmitted between individuals located in close proximity to each other for extended durations. Aircraft provide such conditions. Although high attack rates during flights were reported, little was known about the risk levels of aerosol transmission of SARS-CoV-2 in aircraft cabins. OBJECTIVES: The major objective was to estimate the risk of contracting COVID-19 from transmission of aerosol particles in aircraft cabins. METHODS: In two single-aisle and one twin-aisle aircraft, dispersion of generated aerosol particles over a seven-row economy class cabin section was measured under cruise and taxi conditions and simulated with a computational fluid dynamic model under cruise conditions. Using the aerosol particle dispersion data, a quantitative microbial risk assessment was conducted for scenarios with an asymptomatic infectious person expelling aerosol particles by breathing and speaking. Effects of flight conditions were evaluated using generalized additive mixed models. RESULTS: Aerosol particle concentration decreased with increasing distance from the infectious person, and this decrease varied with direction. On a typical flight with an average shedder, estimated mean risk of contracting COVID-19 ranged from 1:3 × 10−3 to 9:0 × 10−2. Risk increased to 7:7 × 10−2 with a super shedder (<3% of cases) on a long flight. Risks increased with increasing flight duration: 2–23 cruise flights of typical duration and 2–10 flights of longer duration resulted in at least 1 case of COVID-19 due to onboard aerosol transmission by one average shedder, and in the case of one super shedder, at least 1 case in 1–3 flights of typical duration cruise and 1 flight of longer duration. DISCUSSION: Our findings indicate that the risk of contracting COVID-19 by aerosol transmission in an aircraft cabin is low, but it will not be zero. Testing before boarding may help reduce the chance of a (super)shedder boarding an aircraft and mask use further reduces aerosol transmission in the aircraft cabin