The mathematical models for the estimation of the exposure simulate the emission and transport of nanomaterials in a working or consumer environment, as well as in different open-air compartments (air, water, sediment, soil). Modeling, as well as direct measurements, are adequate tools to evaluate the exposure and fate of nanoparticles and a large number of specific models have already been developed. The ECHA (European CHemical Agency) encourages the use of some of them in its technical guidelines  and new ones are currently in the process of validation.
- Environmental model: how to model the fate of a nanoparticle in the environment
- Occupational model: modeling the exposure of a person working with nanoparticles
- Consumer model: a tool to estimate the nanoparticles inhaled or ingested by a consumer, and what part of it is transferred to the respiratory/gastrointestinal tract