A review of predicting environmental concentrations of nanomaterials for exposure assessment. Nanomaterials are widely used in various industries, leading to their release into the environment. Predicting their environmental concentrations is crucial for risk assessment. Material flow analysis (MFA) and environmental fate models (EFMs) are used to estimate nanomaterial releases and their fate in the environment. MFA models provide information on the magnitude of nanomaterial releases, while EFMs account for processes like aggregation, transformation, and dissolution. Multimedia compartment models and spatially-resolved watershed models are used to predict environmental concentrations. These models consider factors such as particle size, form, and environmental conditions. Bioaccumulation models are also used to predict internal concentrations in organisms. Challenges include the lack of field data for validation and the need for more accurate input data for MFA models. Recent advances include the development of more sophisticated EFMs and the integration of nanomaterial-specific processes. The review highlights the importance of these models in assessing the environmental risks of nanomaterials and the need for further research to improve their accuracy and applicability.A review of predicting environmental concentrations of nanomaterials for exposure assessment. Nanomaterials are widely used in various industries, leading to their release into the environment. Predicting their environmental concentrations is crucial for risk assessment. Material flow analysis (MFA) and environmental fate models (EFMs) are used to estimate nanomaterial releases and their fate in the environment. MFA models provide information on the magnitude of nanomaterial releases, while EFMs account for processes like aggregation, transformation, and dissolution. Multimedia compartment models and spatially-resolved watershed models are used to predict environmental concentrations. These models consider factors such as particle size, form, and environmental conditions. Bioaccumulation models are also used to predict internal concentrations in organisms. Challenges include the lack of field data for validation and the need for more accurate input data for MFA models. Recent advances include the development of more sophisticated EFMs and the integration of nanomaterial-specific processes. The review highlights the importance of these models in assessing the environmental risks of nanomaterials and the need for further research to improve their accuracy and applicability.