# Condensation and evaporation

Once released in the atmosphere, ENMs are transported by atmospheric motion and ultimately deposited through surface processes and rain. In addition, ENMs can contribute to chemical reactions in the atmosphere.

In NanoFASE, spatial and time resolved maps are made of concentrations and depositions of ENMs using a Eulerian model at the European scale and, in higher resolution, at Thames catchment scale. Key input to all models are:

• Time resolved and spatially resolved emissions of ENM, as developed in the NanoFASE project
• Meteorological fields, in particular wind and rain
• Surface type information, e.g. forest, water, built-up surface.

Daily total deposition maps as modelled by the air model serve as input to the water and soil models.

## Used for

 Condensation                                       Evaporation

## Algorithms

 Vapour pressure                                     Temperature $\frac{dd_{p}}{dt}=\frac{4\cdot D_{v}\cdot M}{R\cdot \rho _{p}\cdot d_{p}}\left (\frac{p_{\infty }}{T_{\infty}} \right )\cdot \Phi$ Particle size change due to condensation and evaporation      $t= \frac{R\cdot \rho _{p}\cdot d_{p}^{2}}{8\cdot D_{v}\cdot M\cdot \left ( \frac{p_{d }}{T_{d}} -\frac{p_{\infty }}{T_{\infty }}\right )}$ Lifetime of airborne droplets undergoing evaporation

## Contact

Christof Asbach

Email: asbach@iuta.de