Proclaimer DustEx

Site information The RIVM websites provide information about RIVM and its activities for both professionals and the general public. There are sections devoted to each of the main themes with which RIVM is concerned. The sites also offer access to various products, maps, graphs, calculation models, etc. RIVM produces and maintains its websites with the greatest possible care. We have tried to make all information as accessible and ‘user-friendly’ as possible. RIVM wishes to promote the appropriate use of calculation models and the correct interpretation of maps and graphs. Please ask for assistance if necessary. Errors and omissions Despite the ongoing care and attention we devote to our websites, it is possible that mistakes will occasionally be made. We ask for your understanding and hope that you will give us the opportunity to correct any errors or omissions. Please click on the ‘Contact’ button at the top of the page and let us know where you have noticed a problem. Your comments will be read by the person responsible for the page in question, who will make any necessary changes as quickly as possible. The contact page can also be used to forward any general questions or complaints. Links to other websites We try to provide complete and correct information. We have therefore included links to the websites of various other organizations. RIVM accepts no responsibility for the content of external sites, neither can we guarantee that the links will continue to work in future. The views and opinions expressed on external websites are not necessarily those of RIVM. Reuse of text, images, models and other site content All information and material on the RIVM websites may be used, downloaded, copied and/or distributed for any non-commercial purpose, provided it is correctly attributed (“Source: RIVM”).


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Working with the DustEx web application

To use the DustEx model for exposure calculations, input is required for different aspects of the exposure simulation. These aspects include : The indoor environment (residence) The product/emission Dust properties Substance properties Properties of indoor surfaces/sinks Airborne particulate matter properties Properties of the exposed population Simulation parameters for exposure (duration, frequency, and absorption) For the simulation parameters, input values need to be entered into the DustEx web application. In practice, data for many of these parameters is scarce. To assist in performing exposure assessments with the DustEx model a compilation of available information for the most critical simulation parameters is made. Based on this information, for a number of generic parameters (i.e. parameters that do not depend on the substance and product for which the assessment is conducted) defaults are suggested in the web application. The default values are chosen in such a way that they tend to lead to a conservative estimate of exposure. Information and suggested input can be accessed online using the ? buttons next to the parameter input fields in the DustEx web application. For a number of parameters, the input can be entered to the model as a distribution, using the ^ buttons next to the parameter input fields. In this way an uncertainty analysis of the exposure assessment can be performed. A brief discussion on how uncertainty analysis of the exposure assessment can be conducted is described in the section “Probabilistic uncertainty assessment”. Simulation duration The period over which emission, transfer and exposure are calculated. Starts with the introduction of the product in the indoor environment and ends when the exposure stops. Typically SVOC emission and distribution processes are slow and take months or years to reach(quasi-) steady states. Simulation durations should be chosen between 10 and 999 days Exposure frequency The DustEx model calculates concentrations in indoor air compartments air, airborne particles and dust. Exposure is evaluated by combining the simulated concentration data with the presence of a person in the environment. This presence is specified by the exposure frequency: the number of times a person enters the indoor environment starting with the ‘start of exposure’. Exposure is assumed to take place at regular times separated by a constant interval. Start of exposure The first time a person enters the indoor environment after introduction of the product. Exposure duration on day of exposure The number of hours a person spends indoors on the day of exposure. Exposure Oral absorption fraction The fraction of the substance that will be absorbed (reaches the blood) via the GI-tract. Dermal absorption fraction The fraction of the substance that will be absorbed (reaches the blood) via the skin. Monte Carlo simulation The number of iterations should be between 1,000 and 10,000.

Modelling exposure to nanomaterials in spray products

ConsExpo nano is a web based tool that can be used to estimate inhalation exposure to nanomaterials in consumer sprays. The tool adapts the ConsExpo spray tool for regular substances and combines this model with the ICRP deposition and clearance model to estimate inhaled and deposited doses. This page provides background on the models implemented in the ConsExpo nano tool. The use of nanomaterials in spray products may lead to inhalation exposure of consumers to the nanomaterial. Of special concern is the potential deposition of nanomaterial in the pulmonary (alveolar) region. Poorly soluble material is only slowly cleared from this region. Alveolar deposition may lead to protracted local exposure and accumulation of the nanomaterial in the case of frequent exposure. The duration and magnitude of alveolar load of a nanomaterial has been identified as one of the primary determinants of local adverse effects such as inflammation in the lung (Braakhuis et al., (2014)). ConsExpo nano is a tool that can be used to estimate inhalation exposure  as the inhaled dose and the alveolar load of nanomaterials for consumers using spray products.  The tool combines models for exposure, deposition and clearance to estimate alveolar load. The exposure is expressed in different dose metrics  for quantitative risk assessment. For comparison of the exposure evaluation in ConsExpo nano with a hazard study in rat, the latter can also be simulated in ConsExpo nano, to allow for a detailed comparison of exposure levels with hazard data.