# Does pollution change the rate of evaporation?

Oct 19, 2017

Yes. Excess pollutants slows the rate of evaporation.

#### Explanation:

Raoult's law says that the vapor pressure of mixture is the sum of the partial vapor pressure of each component multiplied by its mole fraction.

Let $a , b$… the component of the mixture.
p=p_ax_a+ p_bx_b+ …
$p$ is the total vapor pressure, ${p}_{a} , {p}_{b}$... are partial vapor pressure of $a , b$… and ${x}_{a} , {x}_{b}$… are their mole fraction.

If the amount of pollutants in water increases, $\textcolor{red}{\text{the mole fraction of water will decrease.}}$ This means that vapor pressure of water also goes down and evaoration is decelerated.

https://en.wikipedia.org/wiki/Raoult%27s_law